import yaml
from qgis.PyQt.QtCore import Qt, QUrl, pyqtSignal
from qgis.PyQt.QtGui import QDesktopServices
from qgis.PyQt.QtWidgets import QApplication, QFileDialog, QWidget

from ..core.module import Module
from ..core.module_package import ModulePackage
from ..core.modules_config import ModulesConfig
from ..core.package_prepare_task import PackagePrepareTask, PackagePrepareTaskCanceled
from ..core.settings import Settings
from ..libs.pgserviceparser.gui.message_bar import MessageBar
from ..utils.plugin_utils import PluginUtils, logger
from ..utils.qt_utils import OverrideCursor, QtUtils

DIALOG_UI = PluginUtils.get_ui_class("module_selection_widget.ui")


class ModuleSelectionWidget(QWidget, DIALOG_UI):

    module_package_SPECIAL_LOAD_DEVELOPMENT = "Load pre-releases and development branches"

    signal_loadingStarted = pyqtSignal()
    signal_loadingFinished = pyqtSignal()

    def __init__(self, modules_config_path, parent=None):
        QWidget.__init__(self, parent)
        self.setupUi(self)

        self.__current_module = None
        self.__current_module_package = None
        self.__modules_config = None
        self.__installed_version: str | None = None

        try:
            with modules_config_path.open() as f:
                data = yaml.safe_load(f)
                self.__modules_config = ModulesConfig(**data)
        except Exception as e:
            logger.error(f"Error loading modules config from {modules_config_path}: {e}")
            MessageBar.pushErrorToBar(
                self,
                self.tr(f"Can't load modules configuration from '{modules_config_path}': {e}"),
            )
            self.__modules_config = None

        self.module_progressBar.setVisible(False)

        self.__populate_module_combobox()

        self.module_latestVersion_label.setText("")
        QtUtils.setForegroundColor(self.module_latestVersion_label, PluginUtils.COLOR_GREEN)

        self.__reset_package_selection()
        self.module_seeChangeLog_pushButton.setEnabled(False)

        self.module_zipPackage_groupBox.setVisible(False)
        self.module_directoryPackage_groupBox.setVisible(False)

        self.module_module_comboBox.currentIndexChanged.connect(self.__moduleChanged)
        self.module_package_comboBox.currentIndexChanged.connect(self.__moduleVersionChanged)
        self.module_seeChangeLog_pushButton.clicked.connect(self.__seeChangeLogClicked)
        self.module_browseZip_toolButton.clicked.connect(self.__moduleBrowseZipClicked)
        self.module_browseDirectory_toolButton.clicked.connect(self.__moduleBrowseDirectoryClicked)

        self.__packagePrepareTask = PackagePrepareTask(self)
        self.__packagePrepareTask.finished.connect(self.__packagePrepareTaskFinished)
        self.__packagePrepareTask.signalPackagingProgress.connect(
            self.__packagePrepareTaskProgress
        )

    def reloadModules(self):
        """Reload the module combobox, e.g. after settings change."""
        self.__populate_module_combobox()

    def __populate_module_combobox(self):
        """Populate the module combobox based on config and current settings."""
        self.module_module_comboBox.blockSignals(True)
        self.module_module_comboBox.clear()
        self.module_module_comboBox.addItem(self.tr("Please select a module"), None)
        show_experimental = Settings().show_experimental_modules.value()
        if self.__modules_config is not None:
            for config_module in self.__modules_config.modules:
                if config_module.experimental and not show_experimental:
                    continue
                module = Module(
                    name=config_module.name,
                    id=config_module.id,
                    organisation=config_module.organisation,
                    repository=config_module.repository,
                    exclude_releases=config_module.exclude_releases,
                    parent=self,
                )
                display_name = (
                    f"{module.name} (experimental)" if config_module.experimental else module.name
                )
                self.module_module_comboBox.addItem(display_name, module)
                module.signal_versionsLoaded.connect(self.__loadVersionsFinished)
                module.signal_developmentVersionsLoaded.connect(
                    self.__loadDevelopmentVersionsFinished
                )
        self.module_module_comboBox.blockSignals(False)
        self.module_module_comboBox.setCurrentIndex(0)

    def close(self):
        if self.__packagePrepareTask.isRunning():
            # Disconnect signals first to prevent crashes when emitting to destroyed widgets
            try:
                self.__packagePrepareTask.signalPackagingProgress.disconnect()
                self.__packagePrepareTask.finished.disconnect()
            except TypeError:
                # Already disconnected
                pass

            self.__packagePrepareTask.cancel()
            self.__packagePrepareTask.wait()

    def selectModuleById(self, module_id: str) -> bool:
        """Select a module in the combobox by its ID.

        Args:
            module_id: The module ID to select.

        Returns:
            True if a matching module was found and selected.
        """
        for i in range(self.module_module_comboBox.count()):
            module = self.module_module_comboBox.itemData(i)
            if module is not None and module.id == module_id:
                self.module_module_comboBox.setCurrentIndex(i)
                return True
        return False

    def setInstalledVersion(self, version: str | None):
        """Store the installed version so it can be auto-selected when versions finish loading."""
        self.__installed_version = version

    def getSelectedModulePackage(self):
        return self.__current_module_package

    def lastError(self):
        """
        Returns the last error occurred during the loading process.
        If no error occurred, returns None.
        """
        return self.__packagePrepareTask.lastError

    def __reset_package_selection(self):
        """Reset package selection combo box to initial state."""
        self.module_package_comboBox.clear()
        self.module_package_comboBox.addItem(self.tr("Please select a version"), None)
        self.module_package_comboBox.setEnabled(False)
        # Disable this placeholder item so it can't be selected once a version is chosen
        model = self.module_package_comboBox.model()
        item = model.item(0)
        if item:
            item.setEnabled(False)

    def __enable_package_selection(self):
        """Enable package selection combo box."""
        self.module_package_comboBox.setEnabled(True)

    def __moduleChanged(self, index):
        logger.debug(f"__moduleChanged START, index={index}")
        if self.module_module_comboBox.currentData() == self.__current_module:
            logger.debug("Same module selected, returning")
            return

        logger.debug(f"Module changed to: {self.module_module_comboBox.currentText()}")
        self.__current_module = self.module_module_comboBox.currentData()

        logger.debug("Resetting labels and UI")
        self.module_latestVersion_label.setText("")
        self.__reset_package_selection()
        self.module_seeChangeLog_pushButton.setEnabled(False)

        if self.__current_module is None:
            logger.debug("No module selected")
            return

        logger.debug(f"Module versions list length: {len(self.__current_module.versions)}")
        if self.__current_module.versions == list():
            logger.debug("Versions empty, starting load")
            # Emit signal first to allow UI to update before showing wait cursor
            self.signal_loadingStarted.emit()
            QApplication.setOverrideCursor(Qt.CursorShape.WaitCursor)
            self.__current_module.start_load_versions()
        else:
            logger.debug("Versions already loaded, populating UI")
            # Versions already loaded (from cache or previous selection) - populate UI
            self.__loadVersionsFinished("")
        logger.debug("__moduleChanged END")

    def __moduleVersionChanged(self, index):

        if (
            self.module_package_comboBox.currentData()
            == self.module_package_SPECIAL_LOAD_DEVELOPMENT
        ):
            self.__loadDevelopmentVersions()
            return

        if self.__packagePrepareTask.isRunning():
            logger.info("Package prepare task is running, canceling it.")
            self.__packagePrepareTask.cancel()
            self.__packagePrepareTask.wait()

        self.__current_module_package = self.module_package_comboBox.currentData()
        if self.__current_module_package is None:
            self.module_seeChangeLog_pushButton.setEnabled(False)
            # Clear module information when placeholder is selected
            self.module_information_label.setText(self.tr("Please select a version"))
            QtUtils.resetForegroundColor(self.module_information_label)
            self.module_informationProject_label.setText("-")
            self.module_informationPlugin_label.setText("-")
            # Emit signal to clear module widgets
            self.signal_loadingFinished.emit()
            return

        # Enable changelog button for valid selections
        self.module_seeChangeLog_pushButton.setEnabled(True)

        if self.__current_module_package.type == self.__current_module_package.Type.FROM_ZIP:
            self.module_zipPackage_groupBox.setVisible(True)
            self.module_directoryPackage_groupBox.setVisible(False)
            return
        elif (
            self.__current_module_package.type == self.__current_module_package.Type.FROM_DIRECTORY
        ):
            self.module_zipPackage_groupBox.setVisible(False)
            self.module_directoryPackage_groupBox.setVisible(True)
            return
        else:
            self.module_zipPackage_groupBox.setVisible(False)
            self.module_directoryPackage_groupBox.setVisible(False)

        loading_text = self.tr("Loading package...")
        self.module_information_label.setText(loading_text)
        self.module_information_label.setToolTip(
            f"{self.module_module_comboBox.currentText()} - {self.__current_module_package.display_name()}"
        )
        QtUtils.resetForegroundColor(self.module_information_label)
        logger.info(
            f"Loading packages for module '{self.module_module_comboBox.currentText()}' "
            f"version '{self.__current_module_package.display_name()}'..."
        )

        self.module_informationProject_label.setText("-")
        self.module_informationPlugin_label.setText("-")

        self.__packagePrepareTask.startFromModulePackage(self.__current_module_package)

        self.signal_loadingStarted.emit()
        self.module_progressBar.setMaximum(100)
        self.module_progressBar.setValue(0)
        self.module_progressBar.setVisible(True)

    def __loadDevelopmentVersions(self):
        if self.__current_module is None:
            return

        if self.__current_module.development_versions == list():
            # Emit signal first to allow UI to update before showing wait cursor
            self.signal_loadingStarted.emit()
            QApplication.setOverrideCursor(Qt.CursorShape.WaitCursor)
            self.__current_module.start_load_development_versions()

    def __moduleBrowseZipClicked(self):
        filename, format = QFileDialog.getOpenFileName(
            self, self.tr("Open from zip"), None, self.tr("Zip package (*.zip)")
        )

        if filename == "":
            return

        self.module_fromZip_lineEdit.setText(filename)

        try:
            with OverrideCursor(Qt.CursorShape.WaitCursor):
                self.__loadModuleFromZip(filename)
        except Exception as exception:
            MessageBar.pushErrorToBar(self, self.tr("Can't load module from zip file:"), exception)
            return

    def __loadModuleFromZip(self, filename):

        if self.__packagePrepareTask.isRunning():
            self.__packagePrepareTask.cancel()
            self.__packagePrepareTask.wait()

        self.__packagePrepareTask.startFromZip(self.__current_module_package, filename)

        self.signal_loadingStarted.emit()
        self.module_progressBar.setMaximum(100)
        self.module_progressBar.setValue(0)

    def __moduleBrowseDirectoryClicked(self):
        directory = QFileDialog.getExistingDirectory(self, self.tr("Open from directory"), None)

        if directory == "":
            return

        self.module_fromDirectory_lineEdit.setText(directory)

        try:
            with OverrideCursor(Qt.CursorShape.WaitCursor):
                self.__loadModuleFromDirectory(directory)
        except Exception as exception:
            MessageBar.pushErrorToBar(
                self, self.tr("Can't load module from directory:"), exception
            )
            return

    def __loadModuleFromDirectory(self, directory):

        if self.__packagePrepareTask.isRunning():
            self.__packagePrepareTask.cancel()
            self.__packagePrepareTask.wait()

        self.__packagePrepareTask.startFromDirectory(self.__current_module_package, directory)

        self.signal_loadingStarted.emit()
        self.module_progressBar.setMaximum(0)
        self.module_progressBar.setValue(0)
        self.module_progressBar.setVisible(True)

    def __packagePrepareTaskFinished(self):
        logger.info("Load package task finished")

        if isinstance(self.__packagePrepareTask.lastError, PackagePrepareTaskCanceled):
            logger.info("Load package task was canceled by user.")
            # A new task may already be running (user switched versions).
            # Only update UI if no new task has started.
            if not self.__packagePrepareTask.isRunning():
                self.module_progressBar.setVisible(False)
                self.module_information_label.setText(self.tr("Package loading canceled."))
                QtUtils.setForegroundColor(
                    self.module_information_label, PluginUtils.COLOR_WARNING
                )
            # Don't emit signal_loadingFinished when cancelled - a new load may be starting
            return

        self.module_progressBar.setVisible(False)

        if self.__packagePrepareTask.lastError is not None:
            error_text = self.tr("Can't load module package:")
            MessageBar.pushErrorToBar(self, error_text, self.__packagePrepareTask.lastError)
            self.module_information_label.setText(error_text)
            QtUtils.setForegroundColor(self.module_information_label, PluginUtils.COLOR_WARNING)
            self.signal_loadingFinished.emit()
            return

        self.signal_loadingFinished.emit()

        package_dir = self.module_package_comboBox.currentData().source_package_dir
        logger.info(f"Package loaded into '{package_dir}'")
        QtUtils.resetForegroundColor(self.module_information_label)
        QtUtils.setPathLinkWithEllipsis(self.module_information_label, package_dir)

        asset_project = self.module_package_comboBox.currentData().asset_project
        if asset_project:
            QtUtils.setPathLinkWithEllipsis(
                self.module_informationProject_label, asset_project.package_dir
            )
        else:
            self.module_informationProject_label.setText("No asset available")
            self.module_informationProject_label.setToolTip("")

        asset_plugin = self.module_package_comboBox.currentData().asset_plugin
        if asset_plugin:
            QtUtils.setPathLinkWithEllipsis(
                self.module_informationPlugin_label, asset_plugin.package_dir
            )
        else:
            self.module_informationPlugin_label.setText("No asset available")
            self.module_informationPlugin_label.setToolTip("")

    def __packagePrepareTaskProgress(self, progress, bytes_downloaded):
        if progress < 0:
            # Indeterminate progress (size unknown)
            self.module_progressBar.setMaximum(0)
            self.module_progressBar.setValue(0)
            if bytes_downloaded > 0:
                mb_downloaded = bytes_downloaded / (1024 * 1024)
                loading_text = self.tr(f"Downloading package... {mb_downloaded:.1f} MB")
            else:
                loading_text = self.tr("Downloading package...")
        else:
            # Determinate progress (0-100%)
            self.module_progressBar.setMaximum(100)
            self.module_progressBar.setValue(int(progress))
            mb_downloaded = bytes_downloaded / (1024 * 1024)
            loading_text = self.tr(f"Downloading... {mb_downloaded:.1f} MB ({progress:.0f}%)")

        self.module_information_label.setText(loading_text)

    def __seeChangeLogClicked(self):
        if self.__current_module_package is None:
            MessageBar.pushWarningToBar(self, self.tr("Please select a module and version first."))
            return

        if self.__current_module_package.type in (
            ModulePackage.Type.FROM_ZIP,
            ModulePackage.Type.FROM_DIRECTORY,
        ):
            MessageBar.pushWarningToBar(
                self, self.tr("Changelog is not available for local packages.")
            )
            return

        if self.__current_module_package.html_url is None:
            MessageBar.pushWarningToBar(
                self,
                self.tr(
                    f"Changelog not available for version '{self.__current_module_package.display_name()}'."
                ),
            )
            return

        changelog_url = self.__current_module_package.html_url
        logger.info(f"Opening changelog URL: {changelog_url}")
        QDesktopServices.openUrl(QUrl(changelog_url))

    def __loadVersionsFinished(self, error):
        logger.info("Loading versions finished")

        QApplication.restoreOverrideCursor()
        self.signal_loadingFinished.emit()
        self.module_progressBar.setVisible(False)

        if error:
            if "rate limit exceeded for url" in error.lower():
                MessageBar.pushErrorToBar(
                    self,
                    self.tr(
                        "GitHub API Rate Limit Exceeded. "
                        "Please create a free GitHub personal access token and enter it in the Settings dialog "
                        "to increase your request limit."
                    ),
                )
                return

            error_text = self.tr(f"Can't load module versions: {error}")
            MessageBar.pushErrorToBar(self, error_text)
            self.module_information_label.setText(error_text)
            QtUtils.setForegroundColor(self.module_information_label, PluginUtils.COLOR_WARNING)
            return

        for module_package in self.__current_module.versions:
            # Skip pre-releases in the main list (they'll be shown in development versions)
            if module_package.prerelease is True:
                continue
            self.module_package_comboBox.addItem(module_package.display_name(), module_package)

        if self.__current_module.latest_version is not None:
            self.module_latestVersion_label.setText(
                f"Latest: {self.__current_module.latest_version.name}"
            )

        self.module_package_comboBox.insertSeparator(self.module_package_comboBox.count())
        self.module_package_comboBox.addItem(
            self.tr("Load from ZIP file"),
            ModulePackage(
                module=self.__current_module,
                organisation=self.__current_module.organisation,
                repository=self.__current_module.repository,
                json_payload=None,
                type=ModulePackage.Type.FROM_ZIP,
                name="from_zip",
            ),
        )
        self.module_package_comboBox.addItem(
            self.tr("Load from directory"),
            ModulePackage(
                module=self.__current_module,
                organisation=self.__current_module.organisation,
                repository=self.__current_module.repository,
                json_payload=None,
                type=ModulePackage.Type.FROM_DIRECTORY,
                name="from_directory",
            ),
        )

        self.module_package_comboBox.insertSeparator(self.module_package_comboBox.count())

        # If development versions were already loaded, add them directly
        # Otherwise show the option to load them (or auto-load if setting enabled)
        if self.__current_module.development_versions:
            for module_package in self.__current_module.development_versions:
                self.module_package_comboBox.addItem(module_package.display_name(), module_package)
        elif Settings().auto_load_development_versions.value():
            self.__enable_package_selection()
            self.__loadDevelopmentVersions()
            return
        else:
            self.module_package_comboBox.addItem(
                self.tr("Load pre-releases and development branches"),
                self.module_package_SPECIAL_LOAD_DEVELOPMENT,
            )

        self.__enable_package_selection()
        self.module_progressBar.setVisible(False)
        logger.info(f"Versions loaded for module '{self.__current_module.name}'.")

        # Auto-select the version matching the installed one (if the latest matches)
        if self.__installed_version and self.__current_module.latest_version:
            if self.__current_module.latest_version.name == self.__installed_version:
                for i in range(self.module_package_comboBox.count()):
                    pkg = self.module_package_comboBox.itemData(i)
                    if isinstance(pkg, ModulePackage) and pkg.name == self.__installed_version:
                        self.module_package_comboBox.setCurrentIndex(i)
                        break

    def __loadDevelopmentVersionsFinished(self, error):
        logger.info("Loading development versions finished")

        QApplication.restoreOverrideCursor()
        self.module_progressBar.setVisible(False)

        # Hide zip/directory widgets when loading development versions
        self.module_zipPackage_groupBox.setVisible(False)
        self.module_directoryPackage_groupBox.setVisible(False)

        # Clear current module package - user needs to select a specific version
        self.__current_module_package = None

        if error:
            if "rate limit exceeded for url" in error.lower():
                MessageBar.pushErrorToBar(
                    self,
                    self.tr(
                        "GitHub API Rate Limit Exceeded. "
                        "Please create a free GitHub personal access token and enter it in the Settings dialog "
                        "to increase your request limit."
                    ),
                )
                return

            error_text = self.tr(f"Can't load module versions: {error}")
            MessageBar.pushErrorToBar(self, error_text)
            self.module_information_label.setText(error_text)
            QtUtils.setForegroundColor(self.module_information_label, PluginUtils.COLOR_WARNING)
            return

        if self.__current_module.development_versions == list():
            MessageBar.pushWarningToBar(
                self, self.tr("No development versions found for this module.")
            )
            return

        self.module_package_comboBox.removeItem(self.module_package_comboBox.count() - 1)
        self.module_package_comboBox.setCurrentIndex(0)

        for module_package in self.__current_module.development_versions:
            self.module_package_comboBox.addItem(module_package.display_name(), module_package)

        self.__enable_package_selection()
