from .addon_functions import enable_label, rule_based_symbology, undo, redo
from .qt_compat import Qt, QtCompat, QColor
from qgis.PyQt.QtCore import QPointF, QVariant, QEvent, QSize
from qgis.gui import (
    QgsMapTool, QgsRubberBand, QgsMapToolZoom, QgsMapCanvas,
    QgsMapToolPan, QgsMapMouseEvent, QgsMessageBar, QgsMapToolIdentify
)
from qgis.PyQt.QtGui import QPainter, QIcon

from qgis.core import (
    QgsSymbol, QgsGeometry, QgsPointXY, QgsRuleBasedRenderer, QgsRectangle,
    QgsWkbTypes, QgsFeatureRequest, QgsSpatialIndex, QgsField,
    QgsSingleSymbolRenderer, QgsExpression, Qgis, QgsMapLayer, NULL,
    QgsAggregateCalculator, QgsApplication, QgsMapLayerStyle, QgsProject,
    QgsVectorLayer
)

from qgis.utils import iface
from .qt_compat import (
    QVBoxLayout, QMainWindow, QWidget, QSizePolicy, QInputDialog,
    QDialog, QAction, QGridLayout, QHBoxLayout, QLabel, QComboBox,
    QDoubleSpinBox, QCheckBox, QListWidget, QListWidgetItem, QProgressBar,
    QPushButton, QKeySequence, QShortcut, QTimer, QThread, pyqtSignal,
    QSpacerItem, QSpinBox, QDialogButtonBox, QFormLayout, QActionGroup,
    QMessageBox
)
import sys
import os
import inspect

cmd_folder = os.path.split(inspect.getfile(inspect.currentframe()))[0]
icon = QIcon(os.path.join(os.path.join(cmd_folder, 'images/crosshair.svg')))


class DeleteAttributesDialog(QDialog):
    def __init__(self, layer, parent=None):
        super().__init__(parent)
        self.setWindowTitle("Delete Fields")
        self.layer = layer
        self.setup_ui()

    def setup_ui(self):
        layout = QVBoxLayout()
        self.list_widget = QListWidget()

        # Populate with existing fields
        for field in self.layer.fields():
            item = QListWidgetItem(field.name())
            item.setFlags(item.flags() | QtCompat.ItemIsUserCheckable)
            item.setCheckState(QtCompat.unchecked())
            self.list_widget.addItem(item)

        layout.addWidget(self.list_widget)

        button_box = QDialogButtonBox(
            QtCompat.DialogOk | QtCompat.DialogCancel)
        button_box.accepted.connect(self.accept)
        button_box.rejected.connect(self.reject)
        layout.addWidget(button_box)

        self.setLayout(layout)

    def get_selected_indexes(self):
        selected_indexes = []
        for i in range(self.list_widget.count()):
            item = self.list_widget.item(i)
            if item.checkState() == QtCompat.checked():
                # Find index of field with this name
                # (Robust against field order changes if we used names, but list is built from fields)
                # However, layer.deleteAttributes takes indexes.
                idx = self.layer.fields().indexFromName(item.text())
                if idx != -1:
                    selected_indexes.append(idx)
        return selected_indexes


class AutoNumberDialog(QDialog):
    def __init__(self, layer, parent=None):
        super().__init__(parent)
        self.layer = layer
        self.setWindowTitle("Auto Number Settings")
        self.setup_ui()

    def setup_ui(self):
        layout = QVBoxLayout(self)
        form_layout = QFormLayout()

        # Field Selection
        self.field_combo = QComboBox()
        self.field_combo.setEditable(True)  # Allow typing new field name

        # Populate with existing fields
        fields = [f.name() for f in self.layer.fields()]
        self.field_combo.addItems(fields)

        # Set default to LP_NO if exists, else first item
        index = self.field_combo.findText("LP_NO")
        if index >= 0:
            self.field_combo.setCurrentIndex(index)
        else:
            self.field_combo.setEditText("LP_NO")

        form_layout.addRow("Field Name:", self.field_combo)

        # Start Number
        self.start_num_spin = QSpinBox()
        self.start_num_spin.setRange(1, 999999)
        self.start_num_spin.setValue(1)
        form_layout.addRow("Start Number:", self.start_num_spin)

        layout.addLayout(form_layout)

        # Buttons
        button_box = QDialogButtonBox(
            QtCompat.DialogOk | QtCompat.DialogCancel)
        button_box.accepted.connect(self.accept)
        button_box.rejected.connect(self.reject)
        layout.addWidget(button_box)

        # Connect signals
        self.field_combo.currentTextChanged.connect(self.update_start_number)
        self.field_combo.editTextChanged.connect(self.update_start_number)

        # Initial update
        self.update_start_number()

    def update_start_number(self):
        field_name = self.field_combo.currentText()
        idx = self.layer.fields().indexFromName(field_name)

        max_val = 0
        if idx != -1:
            try:
                # Use aggregate to find max value
                max_val = self.layer.aggregate(
                    QgsAggregateCalculator.Aggregate.Max, field_name)[0]
                if max_val is None:
                    max_val = 0
                max_val = int(max_val)
            except:
                max_val = 0

        self.start_num_spin.setValue(max_val + 1)

        if idx != -1:
            try:
                # Efficiently collect all values
                request = QgsFeatureRequest().setFlags(
                    QgsFeatureRequest.Flag.NoGeometry).setSubsetOfAttributes([idx])

                existing_values = []
                for f in self.layer.getFeatures(request):
                    val = f[idx]
                    if val is not None:
                        try:
                            # Handle string numbers
                            int_val = int(val)
                            if int_val > 0:
                                existing_values.append(int_val)
                        except (ValueError, TypeError):
                            continue

                val_count = len(existing_values)
                unique_values = set(existing_values)
            except:
                val_count = 0
                unique_values = set()

            # Enhanced validation checking (Check earlier)
            from collections import Counter
            counts = Counter(existing_values)
            duplicate_values = {k for k, v in counts.items() if v > 1}
            has_duplicates = len(duplicate_values) > 0

            # Guard Clause: Check for mismatch OR internal duplicates (e.g. 1, 3, 3)
            if max_val != val_count or has_duplicates:
                # Mismatch detected! Prepare warning.
                # Avoid showing this if user is just typing characters?
                # Ideally only on combo box selection change, not necessarily every keystroke.
                # But signals are connected. We can rely on user interaction.

                msg = QMessageBox(self)
                msg.setIcon(QtCompat.Warning)

                # Pre-calculate duplicate string for both cases
                if has_duplicates:
                    dupes = [f"{k} ({v}x)" for k, v in counts.items() if v > 1]
                    dupes.sort()
                    dupe_str = ", ".join(dupes[:5])
                    if len(dupes) > 5:
                        dupe_str += f", ... (+{len(dupes)-5} more)"
                else:
                    dupe_str = ""

                if max_val > val_count:
                    # Case 1: Gaps Detected
                    all_nums = set(range(1, max_val + 1))
                    gaps = sorted(list(all_nums - unique_values))

                    gap_str = ", ".join(map(str, gaps[:10]))
                    if len(gaps) > 10:
                        gap_str += f", ... (+{len(gaps)-10} more)"

                    first_gap = gaps[0] if gaps else val_count + 1

                    msg.setWindowTitle("Sequence Gaps Detected")

                    text = (f"Highest value is <b>{max_val}</b>, but only <b>{val_count}</b> features are labeled.<br>"
                            f"Missing numbers: <b style='color:red;'>{gap_str}</b><br>")

                    if has_duplicates:
                        text += (f"<br><b>Warning: {len(duplicate_values)} duplicates also detected.</b><br>"
                                 f"Duplicate values: <b style='color:orange;'>{dupe_str}</b><br>")

                    text += "<br>How would you like to continue?"

                    btn_max_text = f"Continue from {max_val + 1} (Append)"
                    btn_count_text = f"Fill Gap (Start from {first_gap})"

                else:
                    # Case 2: Duplicates Detected (or just mismatch logic failed to catch gap?)
                    # If max_val <= val_count but max_val != val_count implies what?
                    # actually invalid state if strictly 1..N.
                    # Standard duplicate logic:
                    dupes = [f"{k} ({v}x)" for k, v in counts.items() if v > 1]
                    dupes.sort()

                    dupe_str = ", ".join(dupes[:5])
                    if len(dupes) > 5:
                        dupe_str += f", ... (+{len(dupes)-5} more)"

                    msg.setWindowTitle("Sequence Duplicates Detected")
                    text = (f"Highest value is <b>{max_val}</b>, but <b>{val_count}</b> features are labeled.<br>"
                            f"Duplicates found: <b style='color:orange;'>{dupe_str}</b><br><br>"
                            "How would you like to continue?")

                    btn_max_text = f"Continue from {max_val + 1} (Recommended)"
                    btn_count_text = f"Continue from {val_count + 1} (Skip/Jump)"

                msg.setText(text)

                btn_max = QPushButton(btn_max_text)
                btn_count = QPushButton(btn_count_text)
                btn_clear = None

                if has_duplicates:
                    btn_clear = QPushButton("Clear Duplicates (Set NULL)")

                btn_cancel = QPushButton("Cancel")

                msg.addButton(btn_max, QtCompat.AcceptRole)
                msg.addButton(btn_count, QtCompat.AcceptRole)
                if btn_clear:
                    msg.addButton(btn_clear, QtCompat.DestructiveRole)
                msg.addButton(btn_cancel, QtCompat.RejectRole)
                msg.setDefaultButton(btn_max)

                QtCompat.exec(msg)

                if msg.clickedButton() == btn_max:
                    self.start_num_spin.setValue(max_val + 1)
                elif msg.clickedButton() == btn_count:
                    # For Gaps: Start from first gap
                    if max_val > val_count:
                        self.start_num_spin.setValue(first_gap)
                    else:
                        self.start_num_spin.setValue(val_count + 1)

                elif btn_clear and msg.clickedButton() == btn_clear:
                    # Clear duplicate values
                    if not self.layer.isEditable():
                        self.layer.startEditing()

                    idx = self.layer.fields().indexFromName(field_name)  # Ensure idx is available
                    status_idx = self.layer.fields().indexFromName('STATUS')

                    cleared_count = 0
                    for f in self.layer.getFeatures():
                        val = f[idx]
                        if val is not None:
                            try:
                                int_val = int(val)
                                if int_val in duplicate_values:
                                    self.layer.changeAttributeValue(
                                        f.id(), idx, None)
                                    cleared_count += 1
                                    if status_idx != -1:
                                        self.layer.changeAttributeValue(
                                            f.id(), status_idx, 'cleared')
                            except (ValueError, TypeError):
                                pass

                    self.start_num_spin.setValue(max_val + 1)
                    QMessageBox.information(self, "Duplicates Cleared",
                                            f"Successfully cleared {cleared_count} duplicate values.\\nFeatures marked as 'cleared' (Blue).")

    def get_values(self):
        return self.field_combo.currentText(), self.start_num_spin.value()


class SmartSelectionTool(QgsMapTool):
    def __init__(self, canvas, parent):
        super().__init__(canvas)
        self.canvas = canvas
        self.parent = parent
        self.rubberBand = None
        self.startPoint = None
        self.isEmittingPoint = False

    def canvasPressEvent(self, e):
        if e.button() != QtCompat.LeftButton:
            return

        self.startPoint = self.toMapCoordinates(e.pos())
        self.rubberBand = QgsRubberBand(
            self.canvas, QgsWkbTypes.GeometryType.PolygonGeometry)
        self.rubberBand.setColor(QColor(255, 0, 0, 65))
        self.rubberBand.setWidth(1)
        self.isEmittingPoint = True

    def canvasMoveEvent(self, e):
        if not self.isEmittingPoint:
            return

        endPoint = self.toMapCoordinates(e.pos())
        point1 = QgsPointXY(self.startPoint.x(), self.startPoint.y())
        point2 = QgsPointXY(endPoint.x(), self.startPoint.y())
        point3 = QgsPointXY(endPoint.x(), endPoint.y())
        point4 = QgsPointXY(self.startPoint.x(), endPoint.y())

        self.rubberBand.reset(QgsWkbTypes.GeometryType.PolygonGeometry)
        self.rubberBand.addPoint(point1, False)
        self.rubberBand.addPoint(point2, False)
        self.rubberBand.addPoint(point3, False)
        self.rubberBand.addPoint(point4, True)
        self.rubberBand.show()

    def canvasReleaseEvent(self, e):
        self.isEmittingPoint = False

        # Left Click - Selection Logic
        if self.rubberBand:
            rect = self.rubberBand.asGeometry().boundingBox()
            self.rubberBand.reset(QgsWkbTypes.GeometryType.PolygonGeometry)
            self.rubberBand = None

            layer = self.parent.layer
            if not layer:
                return

            # Check for modifiers
            modifiers = e.modifiers()
            is_ctrl = modifiers & QtCompat.ControlModifier

            # Check if it's a point click (or very small drag)
            # Use a small tolerance to distinguish click from drag
            tolerance = self.canvas.mapUnitsPerPixel() * 2
            is_point_click = rect.width() < tolerance and rect.height() < tolerance

            if is_point_click:
                # Point Selection - Toggle
                point = self.toMapCoordinates(e.pos())
                # Use a small buffer for point selection to make it easier to hit features
                search_rect = QgsRectangle(
                    point.x(), point.y(), point.x(), point.y())
                search_rect.grow(self.canvas.mapUnitsPerPixel() * 3)

                request = QgsFeatureRequest().setFilterRect(search_rect).setFlags(
                    QgsFeatureRequest.Flag.NoGeometry).setLimit(1)
                ids = [f.id() for f in layer.getFeatures(request)]

                if ids:
                    fid = ids[0]
                    if fid in layer.selectedFeatureIds():
                        layer.deselect(fid)
                    else:
                        layer.select(fid)
            else:
                # Drag Selection
                if is_ctrl:
                    # Ctrl + Drag -> Remove from selection
                    layer.selectByRect(
                        rect, QgsVectorLayer.SelectBehavior.RemoveFromSelection)
                else:
                    # Drag -> Add to selection (Default to allow building selection)
                    layer.selectByRect(rect, QgsVectorLayer.SelectBehavior.AddToSelection)


class LabelIncrementer(QgsMapToolIdentify):
    def __init__(self, canvas, layer):
        super().__init__(canvas)
        self.canvas = canvas
        self.layer = layer  # Just store the layer without checking
        self.label = 'LP_NO'
        self.max_label_value = 0

        # Drawing state
        self.isDrawing = False
        self.startPoint = None
        self.endPoint = None
        self.points = []

        # Initialize rubber band
        self.rubberBand = QgsRubberBand(self.canvas, QgsWkbTypes.GeometryType.LineGeometry)
        self.rubberBand.setColor(QColor("red"))
        self.rubberBand.setWidth(1)

        self.setCursor(QtCompat.pointing_hand_cursor())
        self.right_mouse_button_pressed = False
        self.left_mouse_button_pressed = False

        # Remove layer type checking from init

        # if self.layer:
        #     self.initializeFields()
        #     self.updateMaxLabelValue()

    def activate(self):
        """Called when tool is activated"""
        super().activate()
        if self.layer:
            self.initializeFields()
            self.updateMaxLabelValue()

    def initializeFields(self):
        """Initialize required fields"""
        if not self.layer or self.layer.type() != QgsMapLayer.LayerType.VectorLayer:
            return

        try:
            # Get existing field names
            existing_fields = [field.name() for field in self.layer.fields()]

            # Check and create LP_NO field if it doesn't exist
            if self.label not in existing_fields:
                if not self.layer.isEditable():
                    self.layer.startEditing()

                self.layer.addAttribute(QgsField(self.label, QVariant.Int))
                print(f"Created field: {self.label}")

            # Check and create STATUS field if it doesn't exist
            if 'STATUS' not in existing_fields:
                if not self.layer.isEditable():
                    self.layer.startEditing()

                self.layer.addAttribute(QgsField('STATUS', QVariant.String))
                print(f"Created field: STATUS")

            if self.layer.isEditable():
                self.layer.commitChanges()

            # Apply default styling
            self.apply_styling()

        except Exception as e:
            print(f"Error creating fields: {str(e)}")
            if self.layer.isEditable():
                self.layer.rollBack()

    def canvasPressEvent(self, event):
        if not self.layer:
            return

        point = self.toMapCoordinates(event.pos())
        modifiers = event.modifiers()

        if event.button() == QtCompat.LeftButton and modifiers == QtCompat.AltModifier:
            self.edit_label(point)
        elif event.button() == QtCompat.LeftButton and modifiers == QtCompat.ControlModifier:
            # Start left-click+control drag operation
            self.left_mouse_button_pressed = True
            self.isDrawing = True
            self.startPoint = point
            self.points = [point]
        elif event.button() == QtCompat.LeftButton and not modifiers:
            self.addNewLabel(point)
        elif event.button() == QtCompat.RightButton:
            # Start right-click drag operation
            self.right_mouse_button_pressed = True
            self.isDrawing = True
            self.startPoint = point
            self.points = [point]

    def createRect(self, point, radius):
        """Create search rectangle around point"""
        return QgsRectangle(
            point.x() - radius,
            point.y() - radius,
            point.x() + radius,
            point.y() + radius
        )

    def keyPressEvent(self, event):
        # Detect key press events here
        if event.key() == QtCompat.Key_Z and event.modifiers() == QtCompat.ControlModifier:
            undo(self.layer)
            # Update max label value after undo without showing validation
            self.updateMaxLabelValue(show_validation=False)
        elif event.key() == QtCompat.Key_Y and event.modifiers() == QtCompat.ControlModifier:
            redo(self.layer)
            # Update max label value after redo without showing validation
            self.updateMaxLabelValue(show_validation=False)
        else:
            super().keyPressEvent(event)

    def canvasMoveEvent(self, event):
        if self.layer is None:
            return

        current_point = self.toMapCoordinates(event.pos())

        if (self.right_mouse_button_pressed or
                (self.left_mouse_button_pressed and event.modifiers() == QtCompat.ControlModifier)) and self.isDrawing:
            # Add current point to rubber band
            self.points.append(current_point)
            self.drawRubberBand()

            # Label features under the rubber band
            if len(self.points) > 1:
                # Create geometry from rubber band points
                line = QgsGeometry.fromPolylineXY(
                    [QgsPointXY(p) for p in self.points])
                # Small buffer around the line
                buffer = line.buffer(0.00001, 5)

                # Find features intersecting with the buffer
                request = QgsFeatureRequest().setFilterRect(buffer.boundingBox())
                for feature in self.layer.getFeatures(request):
                    if feature.geometry().intersects(buffer):
                        self.addNewLabel(
                            feature.geometry().centroid().asPoint(),
                            silent=True,
                            refresh=False
                        )

                # Trigger repaint once after processing batch
                self.layer.triggerRepaint()

        elif self.left_mouse_button_pressed and not event.modifiers():
            self.addNewLabel(current_point)

    def canvasReleaseEvent(self, event):
        if event.button() == QtCompat.RightButton and self.isDrawing:
            self.right_mouse_button_pressed = False
            self.isDrawing = False
            self.startPoint = None
            self.points = []
            self.removeRubberBand()
        elif event.button() == QtCompat.LeftButton and self.isDrawing:
            self.left_mouse_button_pressed = False
            self.isDrawing = False
            self.startPoint = None
            self.points = []
            self.removeRubberBand()

        # Reset drawing state
        self.isDrawing = False
        self.startPoint = None
        self.endPoint = None
        self.points = []

        # Clear the rubber band
        self.removeRubberBand()

    def drawRubberBand(self):
        if len(self.points) > 1:
            # Clear existing points and add new ones
            self.rubberBand.reset(QgsWkbTypes.GeometryType.LineGeometry)
            line = [QgsPointXY(point) for point in self.points]
            self.rubberBand.setToGeometry(
                QgsGeometry.fromPolylineXY(line), None)
            self.rubberBand.show()

    def removeRubberBand(self):
        if self.rubberBand:
            self.rubberBand.reset(QgsWkbTypes.GeometryType.LineGeometry)
            self.rubberBand.hide()

    def deactivate(self):
        self.isDrawing = False
        self.startPoint = None
        self.endPoint = None
        self.points = []
        self.removeRubberBand()
        super().deactivate()

    def createLPNField(self):
        if self.layer:
            # Check if 'LPM_NO' field exists
            field_names = [field.name() for field in self.layer.fields()]
            if self.label not in field_names:
                self.layer.startEditing()
                self.layer.addAttribute(QgsField(self.label, QVariant.Int))

    def createStatusFields(self):
        """Create fields to track label status"""
        if self.layer:
            self.layer.startEditing()
            field_names = [field.name() for field in self.layer.fields()]

            if 'STATUS' not in field_names:
                self.layer.addAttribute(QgsField('STATUS', QVariant.String))

    def apply_styling(self):
        """Apply rule-based styling for status visualization"""
        if not self.layer or not self.layer.isValid():
            return

        try:
            # Check if STATUS field exists
            if self.layer.fields().indexFromName('STATUS') == -1:
                return

            # Helper to create rules
            def create_rule(label, expression, color_hex):
                symbol = QgsSymbol.defaultSymbol(self.layer.geometryType())
                if symbol:
                    symbol.setColor(QColor(color_hex))
                rule = QgsRuleBasedRenderer.Rule(symbol)
                rule.setLabel(label)
                rule.setFilterExpression(expression)
                return rule

            # Define rules
            root_rule = QgsRuleBasedRenderer.Rule(None)

            # Rule 1: Duplicates (Red)
            root_rule.appendChild(create_rule(
                "Duplicate", "\"STATUS\" = 'duplicate'", "#FF4444"))

            # Rule 2: Edited (Orange)
            root_rule.appendChild(create_rule(
                "Edited", "\"STATUS\" = 'edited'", "#FFAA00"))

            # Rule 3: Auto Numbered (Green)
            root_rule.appendChild(create_rule(
                "Auto Numbered", "\"STATUS\" = 'auto_numbered'", "#44AA44"))

            # Rule 4: Cleared / Null (Blue/Purple)
            # Match 'cleared' status OR null values in the label field if we want
            # user asked for 'cleared duplicates', so specific status is better.
            root_rule.appendChild(create_rule(
                "Cleared", "\"STATUS\" = 'cleared'", "#4444FF"))

            # Rule 5: Default (Else)
            default_symbol = QgsSymbol.defaultSymbol(self.layer.geometryType())
            default_rule = QgsRuleBasedRenderer.Rule(default_symbol)
            default_rule.setLabel("Other")
            default_rule.setIsElse(True)
            root_rule.appendChild(default_rule)

            # Apply renderer
            renderer = QgsRuleBasedRenderer(root_rule)
            self.layer.setRenderer(renderer)
            self.layer.triggerRepaint()
            self.canvas.refresh()

        except Exception as e:
            print(f"Error applying styling: {e}")

    def updateMaxLabelValue(self, show_validation=True):
        """Update maximum label value with enhanced validation UI (no icons)"""
        if not self.layer:
            self.max_label_value = 0
            return

        # Check if LP_NO field exists
        field_names = [field.name() for field in self.layer.fields()]
        if self.label not in field_names:
            self.max_label_value = 0
            return

        try:
            # OPTIMIZATION: Fast Path using QGIS Aggregates
            label_idx = self.layer.fields().indexFromName(self.label)
            if label_idx == -1:
                return

            # Get Max Value (Fast C++)
            max_val_agg = self.layer.aggregate(
                QgsAggregateCalculator.Aggregate.Max, self.label)
            if isinstance(max_val_agg, tuple):
                max_val = max_val_agg[0]
            else:
                max_val = max_val_agg

            if max_val is None or max_val == NULL:
                max_val = 0
            else:
                max_val = int(max_val)

            self.max_label_value = max_val

            # Get Feature Count (Fast)
            # Using aggregate Count is safer
            labeled_count_agg = self.layer.aggregate(
                QgsAggregateCalculator.Aggregate.Count, self.label)
            if isinstance(labeled_count_agg, tuple):
                labeled_count = labeled_count_agg[0]
            else:
                labeled_count = labeled_count_agg

            if labeled_count is None:
                labeled_count = 0

            # Get Unique Values Count (Fast-ish)
            unique_values_set = self.layer.uniqueValues(label_idx)
            # Filter out NULLs
            unique_values = {
                v for v in unique_values_set if v is not None and v != NULL and str(v).strip() != ""}
            unique_count = len(unique_values)

            # HAPPY PATH: Sequence is perfect [1..N]
            # No duplicates (labeled_count == unique_count) AND No gaps (max_val == unique_count)
            # Assumption: Min value is 1. If min > 1, this check implies gaps.
            # If max_val == unique_count and labeled_count == unique_count:
            # It means we have 'unique_count' distinct values, and the max value is 'unique_count'.
            # Therefore values must be 1..N.

            if max_val == unique_count and labeled_count == unique_count:
                # Data is clean. No need to scan.
                return

            # SLOW PATH: Issues detected (Duplicates or Gaps).
            # We must identify duplicates to mark them.

            values = []
            duplicates = set()

            # First pass: collect values and find duplicates
            for feat in self.layer.getFeatures():
                val = feat[self.label]
                if val is not None and str(val).strip() not in ("", "NULL"):
                    try:
                        int_val = int(val)
                        if int_val in values:
                            duplicates.add(int_val)
                        values.append(int_val)
                    except (ValueError, TypeError):
                        continue

            # Second pass: mark duplicates if found
            if duplicates:
                if not self.layer.isEditable():
                    self.layer.startEditing()

                status_idx = self.layer.fields().indexFromName('STATUS')
                label_idx = self.layer.fields().indexFromName(self.label)

                for feat in self.layer.getFeatures():
                    val = feat[self.label]
                    if val is not None and str(val).strip() not in ("", "NULL"):
                        try:
                            if int(val) in duplicates:
                                self.layer.changeAttributeValue(
                                    feat.id(), status_idx, 'duplicate')
                        except (ValueError, TypeError):
                            continue

            # Enhanced validation UI
            # Ensure has_duplicates is calculated BEFORE the check
            from collections import Counter
            counts = Counter(values)
            duplicate_values = {k for k, v in counts.items() if v > 1}
            has_duplicates = len(duplicate_values) > 0

            # Enhanced validation UI without icons
            if (max_val != labeled_count or has_duplicates) and show_validation:
                msg = QMessageBox()
                msg.setIcon(QtCompat.Warning)

                unique_values = set(values)

                # Pre-calculate duplicate string for both cases
                if has_duplicates:
                    dupes = [f"{k} ({v}x)" for k, v in counts.items() if v > 1]
                    dupes.sort()
                    dupe_str = ", ".join(dupes[:5])
                    if len(dupes) > 5:
                        dupe_str += f", ... (+{len(dupes)-5} more)"
                else:
                    dupe_str = ""

                if max_val > labeled_count:
                    # Case 1: Gaps Detected
                    all_nums = set(range(1, max_val + 1))
                    gaps = sorted(list(all_nums - unique_values))

                    gap_str = ", ".join(map(str, gaps[:10]))
                    if len(gaps) > 10:
                        gap_str += f", ... (+{len(gaps)-10} more)"

                    first_gap = gaps[0] if gaps else int(labeled_count) + 1

                    msg.setWindowTitle("Sequence Gaps Detected")

                    text = (f"Highest value is <b>{max_val}</b>, but only <b>{int(labeled_count)}</b> features are labeled.<br>"
                            f"Missing numbers: <b style='color:red;'>{gap_str}</b><br>")

                    if has_duplicates:
                        text += (f"<br><b>Warning: {len(duplicate_values)} duplicates also detected.</b><br>"
                                 f"Duplicate values: <b style='color:orange;'>{dupe_str}</b><br>")

                    text += "<br>How would you like to continue?"

                    btn_max_text = f"Continue from {max_val + 1} (Append)"
                    btn_count_text = f"Fill Gap (Start from {first_gap})"

                else:
                    # Case 2: Duplicates Detected
                    msg.setWindowTitle("Sequence Duplicates Detected")
                    text = (f"Highest value is <b>{max_val}</b>, but <b>{int(labeled_count)}</b> features are labeled.<br>"
                            f"Duplicates found: <b style='color:orange;'>{dupe_str}</b><br><br>"
                            "How would you like to continue?")

                    btn_max_text = f"Continue from {max_val + 1} (Recommended)"
                    btn_count_text = f"Continue from {int(labeled_count) + 1} (Skip)"

                msg.setText(text)

                btn_max = QPushButton(btn_max_text)
                btn_count = QPushButton(btn_count_text)
                btn_clear = None

                if has_duplicates:
                    btn_clear = QPushButton("Clear Duplicates (Set NULL)")

                btn_cancel = QPushButton("Cancel")

                msg.addButton(btn_max, QtCompat.AcceptRole)
                msg.addButton(btn_count, QtCompat.AcceptRole)
                if btn_clear:
                    msg.addButton(btn_clear, QtCompat.DestructiveRole)
                msg.addButton(btn_cancel, QtCompat.RejectRole)
                msg.setDefaultButton(btn_max)

                QtCompat.exec(msg)

                if msg.clickedButton() == btn_max:
                    self.max_label_value = max_val
                elif msg.clickedButton() == btn_count:
                    # For Gaps: Start from first gap
                    if max_val > labeled_count:
                        self.max_label_value = first_gap - 1  # Manual logic: logic adds +1
                    else:
                        self.max_label_value = labeled_count

                elif btn_clear and msg.clickedButton() == btn_clear:
                    # Clear duplicate values
                    if not self.layer.isEditable():
                        self.layer.startEditing()

                    idx = self.layer.fields().indexFromName(self.label)
                    status_idx = self.layer.fields().indexFromName('STATUS')

                    cleared_count = 0
                    for f in self.layer.getFeatures():
                        val = f[idx]
                        if val is not None:
                            try:
                                int_val = int(val)
                                if int_val in duplicate_values:
                                    self.layer.changeAttributeValue(
                                        f.id(), idx, None)
                                    cleared_count += 1
                                    if status_idx != -1:
                                        self.layer.changeAttributeValue(
                                            f.id(), status_idx, 'cleared')
                            except (ValueError, TypeError):
                                pass
                    self.max_label_value = max_val
                    QMessageBox.information(self.canvas.window(), "Duplicates Cleared",
                                            f"Successfully cleared {cleared_count} duplicate values.\nFeatures marked as 'cleared' (Blue).")
                else:  # Cancel
                    return
            else:
                self.max_label_value = max_val

            # Update symbology to reflect any duplicate markings
            self.updateSymbology()

        except KeyError:
            self.max_label_value = 0

    def addNewLabel(self, point, silent=False, refresh=True):
        """Add new label to feature"""
        if not self.layer:
            return

        # Check if LP_NO field exists, if not recreate it
        if self.label not in [field.name() for field in self.layer.fields()]:
            messagebar = MessageBar(self.canvas)
            messagebar.pushMessage(
                "Warning",
                f"'{self.label}' field was missing. Recreating field...",
                Qgis.MessageLevel.Warning,
                2
            )
            self.initializeFields()
            if not self.layer.isEditable():
                self.layer.startEditing()

        # Find feature at click point
        searchRadius = 0.00001
        rect = self.createRect(point, searchRadius)
        request = QgsFeatureRequest().setFilterRect(rect)

        try:
            for feature in self.layer.getFeatures(request):
                if feature.geometry().contains(point):
                    current_value = feature[self.label]

                    if current_value is None or str(current_value).strip() in ("", "NULL"):
                        self.max_label_value += 1
                        new_val = self.max_label_value

                        if not self.layer.isEditable():
                            self.layer.startEditing()

                        # Check for duplicates (robustness)
                        is_duplicate = False
                        duplicate_feat_id = None
                        expr = QgsExpression(f'"{self.label}" = {new_val}')
                        req = QgsFeatureRequest(expr)
                        for other_feat in self.layer.getFeatures(req):
                            if other_feat.id() != feature.id():
                                is_duplicate = True
                                duplicate_feat_id = other_feat.id()
                                break

                        self.layer.changeAttributeValue(
                            feature.id(),
                            self.layer.fields().indexFromName(self.label),
                            new_val
                        )

                        # Update status
                        status_idx = self.layer.fields().indexFromName('STATUS')
                        if status_idx != -1:
                            if is_duplicate:
                                self.layer.changeAttributeValue(
                                    feature.id(), status_idx, 'duplicate')
                                if duplicate_feat_id:
                                    self.layer.changeAttributeValue(
                                        duplicate_feat_id, status_idx, 'duplicate')
                            else:
                                # Leave status blank for new manual numbering
                                self.layer.changeAttributeValue(
                                    feature.id(), status_idx, '')

                        # self.layer.commitChanges()
                        print(
                            f"Feature {feature.id()} labeled with: {new_val}")

                        if not silent:
                            messagebar = MessageBar(self.canvas)
                            if is_duplicate:
                                messagebar.pushMessage(
                                    "Duplicate", f"Labeled with {new_val} (Duplicate!)", Qgis.MessageLevel.Warning, 2)
                            else:
                                messagebar.pushMessage(
                                    "Success", f"Feature labeled with {new_val}", Qgis.MessageLevel.Success, 2)
                    else:
                        if not silent:
                            messagebar = MessageBar(self.canvas)
                            messagebar.pushMessage(
                                "Already Labeled",
                                "Feature already has a label. Hold Alt and click to edit!",
                                Qgis.MessageLevel.Warning,
                                2
                            )

                    if refresh:
                        self.layer.triggerRepaint()
                    return

        except KeyError:
            messagebar = MessageBar(self.canvas)
            messagebar.pushMessage(
                "Error",
                f"Failed to access '{self.label}' field. Please check layer fields.",
                Qgis.MessageLevel.Critical,
                3
            )
            return

        print("No feature found at click location")

    def edit_label(self, point):
        """Edit existing label"""
        if not self.layer:
            return

        # Check if LP_NO field exists, if not recreate it
        if self.label not in [field.name() for field in self.layer.fields()]:
            messagebar = MessageBar(self.canvas)
            messagebar.pushMessage(
                "Warning",
                f"'{self.label}' field was missing. Recreating field...",
                Qgis.MessageLevel.Warning,
                2
            )
            self.initializeFields()
            if not self.layer.isEditable():
                self.layer.startEditing()

        try:
            # Find feature at click point
            searchRadius = 0.00001
            rect = self.createRect(point, searchRadius)
            request = QgsFeatureRequest().setFilterRect(rect)

            for feature in self.layer.getFeatures(request):
                if feature.geometry().contains(point):
                    current_value = feature[self.label]

                    if current_value is not None and str(current_value).strip() not in ("", "NULL"):
                        new_value, ok = QInputDialog.getInt(
                            None,
                            "Edit Label",
                            f"Current value: {current_value}\nEnter new value:",
                            value=current_value,
                            min=1
                        )

                        if ok:
                            old_value = current_value

                            if not self.layer.isEditable():
                                self.layer.startEditing()

                            # Check for duplicates using efficient request
                            is_duplicate = False
                            duplicate_feat_id = None

                            # Search for ANY feature with this new value
                            expr = QgsExpression(
                                f'"{self.label}" = {new_value}')
                            req = QgsFeatureRequest(expr)
                            # We only need to know if ONE exists, and which one
                            for other_feat in self.layer.getFeatures(req):
                                if other_feat.id() != feature.id():
                                    is_duplicate = True
                                    duplicate_feat_id = other_feat.id()
                                    break

                            # Update label
                            self.layer.changeAttributeValue(
                                feature.id(),
                                self.layer.fields().indexFromName(self.label),
                                new_value
                            )

                            # Update status
                            status_idx = self.layer.fields().indexFromName('STATUS')
                            if is_duplicate:
                                self.layer.changeAttributeValue(
                                    feature.id(), status_idx, 'duplicate')
                                if duplicate_feat_id:
                                    self.layer.changeAttributeValue(
                                        duplicate_feat_id, status_idx, 'duplicate')
                            else:
                                self.layer.changeAttributeValue(
                                    feature.id(), status_idx, 'edited')

                            if new_value > self.max_label_value:
                                self.max_label_value = new_value

                            # Trigger repaint to show red status immediately
                            self.layer.triggerRepaint()
                            # self.updateSymbology()

                            # --- Fix for updating previous duplicates ---
                            if old_value is not None:
                                try:
                                    # Find remaining features with the old value
                                    expr_old = QgsExpression(
                                        f'"{self.label}" = {old_value}')
                                    req_old = QgsFeatureRequest(expr_old)
                                    old_peers = [
                                        f for f in self.layer.getFeatures(req_old)]

                                    # If exactly one remains, it is now unique
                                    if len(old_peers) == 1:
                                        peer = old_peers[0]
                                        # Only update if it was marked as duplicate
                                        if peer['STATUS'] == 'duplicate':
                                            if status_idx != -1:
                                                self.layer.changeAttributeValue(
                                                    peer.id(), status_idx, 'cleared')
                                except Exception as e:
                                    print(
                                        f"Error updating old peer status: {e}")
                            # --------------------------------------------

                            messagebar = MessageBar(self.canvas)
                            if is_duplicate:
                                messagebar.pushMessage(
                                    "Duplicate Value",
                                    f"Value {new_value} marked as duplicate",
                                    Qgis.MessageLevel.Warning,
                                    2
                                )
                            else:
                                messagebar.pushMessage(
                                    "Success",
                                    f"Label updated from {current_value} to {new_value}",
                                    Qgis.MessageLevel.Success,
                                    2
                                )
                    return

        except KeyError:
            messagebar = MessageBar(self.canvas)
            messagebar.pushMessage(
                "Error",
                f"Failed to access '{self.label}' field. Please check layer fields.",
                Qgis.MessageLevel.Critical,
                3
            )
            return

        print("No feature found at click location")

    def updateSymbology(self):
        """Update layer symbology"""
        if not self.layer:
            return

        rules = (
            ('Has_Value', f'"{self.label}" >= 1', '#97ee3a', None),
            ('Blank', 'ELSE', '#93b8c3', None),
            ('Edited', '"STATUS" = \'edited\'', '#ffff00', None),
            ('Duplicate', '"STATUS" = \'duplicate\'', '#ff0000', None),
            ('Cleared', '"STATUS" = \'cleared\'', '#0000ff', None),
        )

        rule_based_symbology(self.layer, rules, False)
        # Removed triggerRepaint() - QGIS will auto-refresh

    def updateStatusValues(self):
        """Update status values for all features based on their labels"""
        if not self.layer or not self.layer.isEditable():
            return

        try:
            status_idx = self.layer.fields().indexFromName('STATUS')
            label_idx = self.layer.fields().indexFromName(self.label)

            # Dictionary to track label values
            label_counts = {}

            # First pass: count occurrences of each label value
            for feature in self.layer.getFeatures():
                label_value = feature[self.label]
                if label_value is not None and str(label_value).strip() not in ("", "NULL"):
                    if label_value in label_counts:
                        label_counts[label_value] += 1
                    else:
                        label_counts[label_value] = 1

            # Second pass: update status for each feature
            for feature in self.layer.getFeatures():
                label_value = feature[self.label]

                if label_value is None or str(label_value).strip() in ("", "NULL"):
                    self.layer.changeAttributeValue(
                        feature.id(), status_idx, '')
                elif label_counts[label_value] > 1:
                    self.layer.changeAttributeValue(
                        feature.id(), status_idx, 'duplicate')
                else:
                    current_status = feature['STATUS']
                    # If it was duplicate, mark as cleared.
                    # If it was cleared or edited, preserve it.
                    if current_status == 'duplicate':
                        self.layer.changeAttributeValue(
                            feature.id(), status_idx, 'cleared')
                    elif current_status in ('edited', 'cleared'):
                        # Preserve existing special status
                        pass
                    else:
                        # Otherwise reset to normal (empty status)
                        self.layer.changeAttributeValue(
                            feature.id(), status_idx, '')

            # Removed triggerRepaint() - QGIS will auto-refresh

        except Exception as e:
            print(f"Error updating status values: {str(e)}")


class MessageBar(QgsMessageBar):
    def __init__(self, parent=None):
        super(MessageBar, self).__init__(parent)
        self.parent().installEventFilter(self)

    def showEvent(self, event):
        self.resize(
            QSize(self.parent().geometry().size().width(), self.height()))
        self.move(0, self.parent().geometry().size().height() - self.height())
        self.raise_()

    # def showEvent(self, event):
    #     """
    #     Ensure the active layer is updated when the widget is shown.
    #     """
    #     super().showEvent(event)
    #     self.layer = iface.activeLayer()
    #     if self.layer:
    #         print(f"Active layer updated: {self.layer.name()}")
    #         self.canvas.setLayers([self.layer])

    def eventFilter(self, object, event):
        if event.type() == QtCompat.Resize:
            self.showEvent(None)

        return super(MessageBar, self).eventFilter(object, event)


class LpmCanvas(QMainWindow):
    def __init__(self, iface):
        self.iface = iface
        QMainWindow.__init__(self, iface.mainWindow())
        self.setWindowTitle('Land Parcel Numbering')
        self.setWindowIcon(QIcon(icon))
        self.label = 'LP_NO'

        # Setup canvas
        self.canvas = QgsMapCanvas()
        self.canvas.setCanvasColor(QColor("white"))

        # Enable caching to prevent white screen flash during zoom/pan
        self.canvas.setCachingEnabled(True)
        self.canvas.setParallelRenderingEnabled(True)

        self.setMinimumSize(1000, 500)

        # Setup layout
        self.main_layout = QVBoxLayout()
        self.main_layout.addWidget(self.canvas)
        self.central_widget = QWidget()
        self.central_widget.setLayout(self.main_layout)
        self.setCentralWidget(self.central_widget)

        # Initialize layer
        self.layer = None
        self.label_incrementer = None

        # Remove connection from init
        # self.iface.currentLayerChanged.connect(self.activelyrchanged)

        # Create canvas actions
        self.createCanvasActions()

        # Initial layer setup - get the current active layer
        # Initial layer setup
        self.activelyrchanged()

    def showEvent(self, event):
        """Ensure the active layer is loaded when the window is shown"""
        super().showEvent(event)
        # Connect to layer changes when window opens
        try:
            self.iface.currentLayerChanged.disconnect(self.activelyrchanged)
        except:  # nosec B110
            pass
        self.iface.currentLayerChanged.connect(self.activelyrchanged)

        # Trigger update if needed
        self.activelyrchanged()

    def activelyrchanged(self):
        """Handle active layer changes"""
        new_layer = self.iface.activeLayer()

        # Only proceed if layer is vector
        if new_layer and new_layer.type() == QgsMapLayer.LayerType.VectorLayer:
            # Check if layer actually changed
            if self.layer and self.layer.id() == new_layer.id():
                # Only return if canvas actually has THIS layer loaded
                current_layers = self.canvas.layers()
                if current_layers and current_layers[0].id() == new_layer.id():
                    return

            self.layer = new_layer

            # Set the layer in canvas
            self.canvas.setLayers([self.layer])

            # Set the extent to the layer's extent
            self.canvas.setExtent(self.layer.extent())
            self.canvas.refresh()
        elif self.layer:
            # If new_layer is None but we have a layer, DO NOT clear it.
            pass

    def closeEvent(self, event):
        """Handle window close event"""
        # Safely disconnect from layer changes when window closes
        try:
            self.iface.currentLayerChanged.disconnect(self.activelyrchanged)
        except TypeError:
            pass  # Connection didn't exist, ignore error

        if not self.layer:
            event.accept()
            return

        label_field = self.label
        total = self.layer.featureCount()
        expression = QgsExpression(f"\"{label_field}\" IS NOT NULL")
        request = QgsFeatureRequest(expression)
        fvalues = sum(1 for _ in self.layer.getFeatures(request))
        leftover_labels = total - fvalues

        if leftover_labels > 0:
            msg = (f"Are you sure you want to exit?<br><br>"
                   f"Unlock the Mystery: <b>{leftover_labels}</b> Features are still waiting for their identity! 🌟")

            confirm = QtCompat.message_box_question(self, "Confirmation", msg,
                                                    QtCompat.Yes | QtCompat.No,
                                                    QtCompat.No)
            if confirm != QtCompat.Yes:
                event.ignore()
                return

        # Proceed with exit
        if self.layer.isEditable():
            self.layer.commitChanges()
        self.canvas.setMapTool(self.toolPan)

        # Reset layer symbology
        symbol = QgsSymbol.defaultSymbol(self.layer.geometryType())
        renderer = QgsSingleSymbolRenderer(symbol)
        self.layer.setRenderer(renderer)
        self.layer.triggerRepaint()

        event.accept()

    def createCanvasActions(self):
        """Create canvas toolbar actions"""
        self.toolbar = self.addToolBar("Canvas Actions")

        # Zoom In
        actionZoomIn = QAction(QIcon(os.path.join(os.path.join(
            cmd_folder, 'images/canvas_one/zoomin.svg'))), 'Zoom In', self)
        actionZoomIn.setCheckable(True)
        actionZoomIn.triggered.connect(self.zoomIn)
        self.toolbar.addAction(actionZoomIn)

        # Zoom Out
        actionZoomOut = QAction(QIcon(os.path.join(os.path.join(
            cmd_folder, 'images/canvas_one/zoomout.svg'))), 'Zoom Out', self)
        actionZoomOut.setCheckable(True)
        actionZoomOut.triggered.connect(self.zoomOut)
        self.toolbar.addAction(actionZoomOut)

        # Pan
        actionPan = QAction(QIcon(os.path.join(os.path.join(
            cmd_folder, 'images/canvas_one/pan.svg'))), 'Pan', self)
        actionPan.setCheckable(True)
        actionPan.triggered.connect(self.pan)
        self.toolbar.addAction(actionPan)

        # Smart Select Tool
        actionSmartSelect = QAction(QIcon(os.path.join(os.path.join(
            cmd_folder, 'images/canvas_one/select.svg'))), 'Smart Select', self)
        actionSmartSelect.setCheckable(True)
        actionSmartSelect.triggered.connect(self.activate_select_tool)
        self.toolbar.addAction(actionSmartSelect)

        # Native Deselect Action
        actionDeselect = QAction(QIcon(os.path.join(os.path.join(
            cmd_folder, 'images/canvas_one/deselect.svg'))), 'Deselect Features', self)
        actionDeselect.triggered.connect(self.deselect_features)
        self.toolbar.addAction(actionDeselect)

        actionAutoNumber = QAction(QIcon(os.path.join(os.path.join(
            cmd_folder, 'images/canvas_one/snake_smart.svg'))), 'Auto Number (Serpentine - Smart)', self)
        actionAutoNumber.triggered.connect(self.auto_number_serpentine)
        self.toolbar.addAction(actionAutoNumber)

        # Auto Number (Original)
        actionAutoNumberOrig = QAction(QIcon(os.path.join(os.path.join(
            cmd_folder, 'images/canvas_one/snake_original.svg'))), 'Auto Number (Original)', self)
        actionAutoNumberOrig.triggered.connect(self.auto_number_original)
        self.toolbar.addAction(actionAutoNumberOrig)

        # Manual Numbering Tool
        actionPoint = QAction(QIcon(os.path.join(os.path.join(
            cmd_folder, 'images/crosshair.svg'))), 'Manual Numbering', self)
        actionPoint.setCheckable(True)
        actionPoint.triggered.connect(self.point)
        self.toolbar.addAction(actionPoint)

        # Add Spacer to push next buttons to the right
        spacer = QWidget()
        spacer.setSizePolicy(QtCompat.size_policy_expanding(),
                             QtCompat.size_policy_preferred())
        self.toolbar.addWidget(spacer)

        # Open Attribute Table
        actionOpenTable = QAction(QgsApplication.getThemeIcon(
            '/mActionOpenTable.svg'), 'Open Attribute Table', self)
        actionOpenTable.triggered.connect(
            lambda: iface.showAttributeTable(self.layer))
        self.toolbar.addAction(actionOpenTable)

        # Delete Label Field
        actionDeleteField = QAction(QgsApplication.getThemeIcon(
            '/mActionDeleteAttribute.svg'), 'Delete Label Field', self)
        actionDeleteField.triggered.connect(self.delete_label_field)
        self.toolbar.addAction(actionDeleteField)

        # Group checkable actions
        self.action_group = QActionGroup(self)
        self.action_group.addAction(actionZoomIn)
        self.action_group.addAction(actionZoomOut)
        self.action_group.addAction(actionPan)
        self.action_group.addAction(actionSmartSelect)
        self.action_group.addAction(actionPoint)

        # Initialize label incrementer
        self.label_incrementer = LabelIncrementer(self.canvas, self.layer)
        self.label_incrementer.setAction(actionPoint)

        # Initialize map tools
        self.toolPan = QgsMapToolPan(self.canvas)
        self.toolPan.setAction(actionPan)

        self.toolZoomIn = QgsMapToolZoom(self.canvas, False)
        self.toolZoomIn.setAction(actionZoomIn)

        self.toolZoomOut = QgsMapToolZoom(self.canvas, True)
        self.toolZoomOut.setAction(actionZoomOut)

        # Set default tool
        self.canvas.setMapTool(self.toolPan)

    def drawLine(self):
        self.canvas.setMapTool(self.toolLineDrawing)

    def zoomIn(self):
        self.canvas.setMapTool(self.toolZoomIn)

    def zoomOut(self):
        self.canvas.setMapTool(self.toolZoomOut)

    def pan(self):
        self.canvas.setMapTool(self.toolPan)

    def deselect_features(self):
        if self.layer:
            self.layer.removeSelection()
            # self.canvas.refresh()

    def activate_select_tool(self):
        if self.layer:
            self.select_tool = SmartSelectionTool(self.canvas, self)
            self.canvas.setMapTool(self.select_tool)

    def point(self):
        current_layer = self.iface.activeLayer()

        # Check if there's a layer selected
        if not current_layer:
            QMessageBox.warning(
                self, "Warning", "Please select a layer first!")
            return

        # Check if it's a vector layer
        if current_layer.type() != QgsMapLayer.LayerType.VectorLayer:
            QMessageBox.warning(
                self, "Warning", "Please select a vector layer!")
            return

        # Ask user to select field for numbering
        fields = [f.name() for f in current_layer.fields() if f.type() in [
            QVariant.Int, QVariant.LongLong, QVariant.String]]

        # Create a simple dialog with editable combo box
        dialog = QDialog(self)
        dialog.setWindowTitle("Select Field for Manual Numbering")
        layout = QVBoxLayout(dialog)

        label = QLabel("Choose existing field or type new field name:")
        layout.addWidget(label)

        field_combo = QComboBox()
        field_combo.setEditable(True)  # Allow typing new field names
        field_combo.addItems(fields)

        # Set default to LP_NO if exists
        if 'LP_NO' in fields:
            field_combo.setCurrentText('LP_NO')
        else:
            field_combo.setEditText('LP_NO')

        layout.addWidget(field_combo)

        button_box = QDialogButtonBox(
            QtCompat.DialogOk | QtCompat.DialogCancel)
        button_box.accepted.connect(dialog.accept)
        button_box.rejected.connect(dialog.reject)
        layout.addWidget(button_box)

        if QtCompat.exec(dialog) != QtCompat.DialogAccepted:
            return

        field_name = field_combo.currentText().strip()
        if not field_name:
            QMessageBox.warning(self, "Warning", "Please enter a field name!")
            return

        # Update the label field
        self.label = field_name

        # Update the layer reference
        self.layer = current_layer
        if self.label_incrementer:
            self.label_incrementer.layer = current_layer
            # Ensure incrementer uses the selected label field
            self.label_incrementer.label = self.label
            self.label_incrementer.initializeFields()
            # Update max label value with validation when starting numbering

            # Start editing if not already in edit mode
            if not self.layer.isEditable():
                reply = QtCompat.message_box_question(self.canvas.window(), "Edit Mode",
                                                      "Layer is not in edit mode. Start editing for manual numbering?",
                                                      QtCompat.Yes | QtCompat.No, QtCompat.Yes)
                if reply == QtCompat.Yes:
                    self.layer.startEditing()
                else:
                    return

            # Update status values when tool is activated
            self.label_incrementer.updateStatusValues()

        # Set the tool and update display
        self.canvas.setMapTool(self.label_incrementer)
        self.canvas.setLayers([self.layer])
        # self.canvas.refresh()

        # Enable labeling
        enable_label(self.layer.id(), 'Verdana', 8, self.label, 50, False,
                     placement_index=1, font_color='#000')

        # Set symbology rules
        rules = (
            ('Has_Value', f'"{self.label}" >= 1', '#97ee3a', None),
            ('Blank', 'ELSE', '#93b8c3', None),
            ('Auto_Numbered', '"STATUS" = \'auto_numbered\'', '#00ff00', None),
            ('Edited', '"STATUS" = \'edited\'', '#ffff00', None),
            ('Duplicate', '"STATUS" = \'duplicate\'', '#ff0000', None),
        )
        rule_based_symbology(self.layer, rules, False)

    def sort_features_spatially(self, features, pattern='z', algorithm='smart'):
        """
        Sort features using Adjacency-Guided Spatial Sort (Topological Sort).
        1. Rank features spatially (Hybrid Snake Pattern).
        2. Traverse graph greedily: from current feature, pick unvisited neighbor with lowest rank.
        """
        if not features:
            return []

        # --- Step 1: Spatial Ranking ---
        # Use the existing Hybrid Sorting logic to assign a "Rank" to each feature.

        # Calculate centroids and average height
        feature_infos = []
        total_height = 0
        valid_height_count = 0

        for feat in features:
            geom = feat.geometry()
            if not geom:
                continue
            bbox = geom.boundingBox()
            # Use Pole of Inaccessibility for better visual center (handles U-shapes)
            try:
                # Tolerance can be small, e.g., 10% of bbox width (Optimized for performance)
                tolerance = bbox.width() * 0.10
                visual_center_geom = geom.poleOfInaccessibility(tolerance)
                if visual_center_geom:
                    visual_center = visual_center_geom.asPoint()
                else:
                    visual_center = geom.pointOnSurface().asPoint()
            except:
                # Fallback to pointOnSurface or centroid
                visual_center = geom.pointOnSurface().asPoint()

            height = bbox.height()

            # Robustly handle visual_center type (QgsPointXY, QgsPoint, or tuple)
            if hasattr(visual_center, 'x'):
                vx = visual_center.x()
                vy = visual_center.y()
            elif isinstance(visual_center, (tuple, list)) and len(visual_center) >= 2:
                vx = visual_center[0]
                vy = visual_center[1]
            else:
                # Absolute fallback
                center = bbox.center()
                vx = center.x()
                vy = center.y()

            feature_infos.append({
                'feature': feat,
                'id': feat.id(),
                'x': vx,
                'y': vy,
                'bbox_top': bbox.yMaximum(),
                'height': height,
                'geometry': geom
            })

            if height > 0:
                total_height += height
                valid_height_count += 1

        if not feature_infos:
            return []

        # Calculate average height
        if valid_height_count > 0:
            avg_height = total_height / valid_height_count
        else:
            # Handle points or zero-height features
            total_bounds = QgsRectangle(
                feature_infos[0]['x'], feature_infos[0]['y'], feature_infos[0]['x'], feature_infos[0]['y'])
            for info in feature_infos:
                total_bounds.combineExtentWith(QgsGeometry(
                    info['x'], info['y'], info['x'], info['y']).boundingBox())

            import math
            avg_height = total_bounds.height() / math.sqrt(len(features)
                                                           ) if len(features) > 0 else 0
            if avg_height == 0:
                avg_height = 1.0

        # Hybrid Logic for Ranking
        large_feature_threshold = avg_height * 1.5
        for info in feature_infos:
            if info['height'] > large_feature_threshold:
                info['y'] = info['bbox_top'] - (avg_height * 0.5)

        row_tolerance = avg_height * 0.75

        # Sort by bbox_top descending (highest feature first), then by X ascending (left to right)
        # This ensures the topmost feature is ALWAYS first, regardless of hybrid logic adjustments
        feature_infos.sort(key=lambda k: (-k['bbox_top'], k['x']))

        # Overlap-Based Row Grouping
        # Use bbox_top for grouping to maintain correct top-to-bottom order
        # The adjusted 'y' values are only used for graph traversal, not initial ranking

        rows = []
        current_row = []

        if feature_infos:
            current_row_top = feature_infos[0]['bbox_top']
            current_row_height = feature_infos[0]['height']

            # Tolerance: 0.75 * avg_height.
            # 0.5 was too strict (split wavy rows). 1.0 was too loose (merged rows).
            row_tolerance = avg_height * 0.75

            for info in feature_infos:
                # Check vertical distance from the row's top edge
                # Use bbox_top to maintain correct ordering
                if abs(info['bbox_top'] - current_row_top) <= row_tolerance:
                    current_row.append(info)
                    # Update running average top to follow the row's drift
                    sum_top = sum(item['bbox_top'] for item in current_row)
                    current_row_top = sum_top / len(current_row)
                else:
                    rows.append(current_row)
                    current_row = [info]
                    current_row_top = info['bbox_top']
            if current_row:
                rows.append(current_row)

        # Create Ranked List
        ranked_features = []
        for i, row in enumerate(rows):
            row.sort(key=lambda k: k['x'])
            if pattern == 'snake' and i % 2 == 1:
                row.reverse()
            for info in row:
                ranked_features.append(info)

        # Assign Rank
        for rank, info in enumerate(ranked_features):
            info['rank'] = rank

        # --- Step 2: Graph Traversal ---

        # Build spatial index for fast neighbor lookup
        spatial_index = QgsSpatialIndex()
        id_to_info = {info['id']: info for info in feature_infos}
        for info in feature_infos:
            spatial_index.addFeature(info['feature'])

        sorted_features = []
        visited_ids = set()

        # Start with the feature that has Rank 0 (Top-Left-most)
        current_info = ranked_features[0]

        while len(sorted_features) < len(features):
            sorted_features.append(current_info['feature'])
            visited_ids.add(current_info['id'])

            if len(sorted_features) == len(features):
                break

            # Find unvisited neighbors
            # Use intersection with a small buffer to handle touching boundaries
            geom = current_info['geometry']
            # Buffer slightly to ensure intersection with touching neighbors
            # Use a relative buffer size based on avg_height
            buffer_dist = avg_height * 0.05
            search_geom = geom.buffer(buffer_dist, 5)

            neighbor_ids = spatial_index.intersects(search_geom.boundingBox())

            candidates = []
            for nid in neighbor_ids:
                if nid == current_info['id'] or nid in visited_ids:
                    continue

                neighbor_info = id_to_info[nid]
                # Verify actual intersection
                intersection = geom.intersection(neighbor_info['geometry'])
                if not intersection.isEmpty():
                    # Calculate shared length to distinguish Edge vs Vertex sharing
                    shared_length = intersection.length()
                    candidates.append({
                        'info': neighbor_info,
                        'shared_length': shared_length,
                        'rank': neighbor_info['rank']
                    })

            if candidates:
                edge_tolerance = avg_height * 0.01

                if algorithm == 'smart':
                    # --- SMART ALGORITHM ---
                    # 1. Sort by Rank ONLY to find the "Snake" direction baseline
                    candidates.sort(key=lambda k: k['rank'])
                    best_rank = candidates[0]['rank']

                    # 2. Define a "Local Window" (e.g., 5 ranks)
                    rank_tolerance = 5
                    local_candidates = [
                        c for c in candidates if c['rank'] <= best_rank + rank_tolerance]

                    # 3. Pick the best connected feature from the local group
                    local_candidates.sort(
                        key=lambda k: k['shared_length'], reverse=True)
                    next_info = local_candidates[0]['info']

                else:
                    # --- ORIGINAL ALGORITHM (STRICT SNAKE) ---
                    # Priority: Strict Snake Pattern (Rank) > Shared Length
                    candidates.sort(key=lambda k: k['rank'])
                    next_info = candidates[0]['info']

            else:
                # Dead End: Jump to the unvisited feature with the lowest Rank
                next_info = None
                for info in ranked_features:
                    if info['id'] not in visited_ids:
                        next_info = info
                        break

            if next_info:
                current_info = next_info
            else:
                break  # Should not happen if loop condition is correct
        return sorted_features

    def auto_number_serpentine(self):
        """
        Trigger auto-numbering on the current selection (Smart Algorithm).
        """
        if not self.layer:
            return

        selected_features = self.layer.selectedFeatures()
        if selected_features:
            self.perform_auto_numbering(
                selected_features, pattern='snake', algorithm='smart')
        else:
            reply = QtCompat.message_box_question(self.canvas.window(), "Auto Number",
                                                  "No features selected. Number all features in the layer?",
                                                  QtCompat.Yes | QtCompat.No, QtCompat.No)
            if reply == QtCompat.Yes:
                self.perform_auto_numbering(
                    list(self.layer.getFeatures()), pattern='snake', algorithm='smart')

    def auto_number_original(self):
        """
        Trigger auto-numbering on the current selection (Original Algorithm).
        """
        if not self.layer:
            return

        selected_features = self.layer.selectedFeatures()
        if selected_features:
            self.perform_auto_numbering(
                selected_features, pattern='snake', algorithm='original')
        else:
            reply = QtCompat.message_box_question(self.canvas.window(), "Auto Number",
                                                  "No features selected. Number all features in the layer?",
                                                  QtCompat.Yes | QtCompat.No, QtCompat.No)
            if reply == QtCompat.Yes:
                self.perform_auto_numbering(
                    list(self.layer.getFeatures()), pattern='snake', algorithm='original')

    def perform_auto_numbering(self, features, pattern='snake', algorithm='smart'):
        """
        Execute auto numbering logic on provided features.
        """
        if not self.layer.isEditable():
            reply = QtCompat.message_box_question(self.canvas.window(), "Edit Mode",
                                                  "Layer is not in edit mode. Start editing?",
                                                  QtCompat.Yes | QtCompat.No, QtCompat.Yes)
            if reply == QtCompat.Yes:
                self.layer.startEditing()
            else:
                return

        if not features:
            return

        # Custom Dialog for Field Name and Start Number
        dialog = AutoNumberDialog(self.layer, self.canvas.window())
        if QtCompat.exec(dialog) != QtCompat.DialogAccepted:
            return

        field_name, start_num = dialog.get_values()

        # Update class-level label so manual tool uses it too
        self.label = field_name
        idx = self.layer.fields().indexFromName(field_name)
        if idx == -1:
            # Ensure layer is in edit mode before creating field
            if not self.layer.isEditable():
                self.layer.startEditing()

            # Create field immediately
            self.layer.addAttribute(QgsField(field_name, QVariant.Int))
            # Verify creation
            idx = self.layer.fields().indexFromName(field_name)
            if idx == -1:
                QMessageBox.critical(self.canvas.window(
                ), "Error", f"Failed to create field '{field_name}'.")
                return

        # Ensure STATUS field exists for tracking
        status_idx = self.layer.fields().indexFromName('STATUS')
        if status_idx == -1:
            # Ensure layer is in edit mode before creating field
            if not self.layer.isEditable():
                self.layer.startEditing()

            self.layer.addAttribute(QgsField('STATUS', QVariant.String))
            print("Created STATUS field for auto-numbering")

        # Check for existing values in the selected features
        existing_values_count = 0
        for feat in features:
            attrs = feat.attributes()
            if idx < len(attrs):
                val = attrs[idx]
                if val != None and val != NULL:  # Check for NULL/None
                    try:
                        if int(val) > 0:
                            existing_values_count += 1
                    except:  # nosec B110
                        pass
            else:
                pass

        skip_existing = False
        if existing_values_count > 0:
            msg = f"{existing_values_count} features already have values in '{field_name}'.\nDo you want to overwrite them?"
            reply = QtCompat.message_box_question(self.canvas.window(), "Existing Values", msg,
                                                  QtCompat.Yes | QtCompat.No | QtCompat.Cancel, QtCompat.No)

            if reply == QtCompat.Cancel:
                return
            elif reply == QtCompat.No:
                skip_existing = True
                # Filter features to only those without values (or 0/NULL)
                features_to_number = []
                for feat in features:
                    val = feat.attributes()[idx]
                    is_valid = False
                    try:
                        if val != None and val != NULL and int(val) > 0:
                            is_valid = True
                    except:  # nosec B110
                        pass

                    if not is_valid:
                        features_to_number.append(feat)

                features = features_to_number
                if not features:
                    QMessageBox.information(self.canvas.window(
                    ), "Info", "No features to number after skipping existing values.")
                    return

        # Sort features
        sorted_features = self.sort_features_spatially(
            features, pattern, algorithm)

        # Apply numbering
        self.layer.beginEditCommand(f"Auto Number ({pattern})")
        try:
            current_num = start_num

            # Ensure we have the latest field index
            idx = self.layer.fields().indexFromName(field_name)
            status_idx = self.layer.fields().indexFromName('STATUS')

            # 1. Pre-scan existing values (O(N))
            # Map value -> list of feature IDs
            existing_values = {}

            # Get IDs of features we are about to re-number to exclude their OLD values
            ids_to_renumber = set(f.id() for f in sorted_features)

            # Scan ALL features in layer
            all_feats = self.layer.getFeatures(
                QgsFeatureRequest().setSubsetOfAttributes([idx, status_idx]))
            for f in all_feats:
                if f.id() in ids_to_renumber:
                    continue  # Skip features we are about to change

                val = f.attributes()[idx]  # index of label field
                if val != None and val != NULL:
                    try:
                        v_int = int(val)
                        if v_int not in existing_values:
                            existing_values[v_int] = []
                        existing_values[v_int].append(f.id())
                    except:  # nosec B110
                        pass

            # 2. Assign and Validate
            for feat in sorted_features:
                # Set the new number
                self.layer.changeAttributeValue(feat.id(), idx, current_num)

                # Check for duplicates
                status = 'auto_numbered'
                if current_num in existing_values:
                    status = 'duplicate'
                    # Mark the conflicting existing features as duplicate too!
                    if status_idx != -1:
                        for conflict_id in existing_values[current_num]:
                            self.layer.changeAttributeValue(
                                conflict_id, status_idx, 'duplicate')

                # Update current feature status
                if status_idx != -1:
                    self.layer.changeAttributeValue(
                        feat.id(), status_idx, status)

                # Add this assignment to our map for future collisions in this same loop
                if current_num not in existing_values:
                    existing_values[current_num] = []
                existing_values[current_num].append(feat.id())

                current_num += 1

            self.layer.triggerRepaint()

            # Enable labeling for the newly numbered features
            enable_label(self.layer.id(), 'Verdana', 8, self.label, 50, False,
                         placement_index=1, font_color='#000')

            self.layer.endEditCommand()
            # self.canvas.refresh()
            QMessageBox.information(
                self.canvas.window(), "Success", "Auto-numbering completed.")

        except Exception as e:
            self.layer.destroyEditCommand()
            QMessageBox.critical(self.canvas.window(),
                                 "Error", f"An error occurred: {str(e)}")

    def delete_label_field(self):
        if not self.layer:
            return

        # Check if editable
        if not self.layer.isEditable():
            reply = QtCompat.message_box_question(self.canvas.window(), "Edit Mode",
                                                  "Layer is not in edit mode. Start editing to delete fields?",
                                                  QtCompat.Yes | QtCompat.No, QtCompat.Yes)
            if reply == QtCompat.Yes:
                self.layer.startEditing()
            else:
                return

        dialog = DeleteAttributesDialog(self.layer, self.canvas.window())
        if QtCompat.exec(dialog) == QtCompat.DialogAccepted:
            indexes = dialog.get_selected_indexes()
            if indexes:
                reply = QtCompat.message_box_question(self.canvas.window(), "Delete Fields",
                                                      f"Are you sure you want to delete {len(indexes)} field(s)?",
                                                      QtCompat.Yes | QtCompat.No, QtCompat.No)
                if reply == QtCompat.Yes:
                    self.layer.deleteAttributes(indexes)
                    self.layer.updateFields()
            else:
                QMessageBox.information(
                    self.canvas.window(), "Info", "No fields selected.")


lpno = LpmCanvas(iface)
