"""
/***************************************************************************
Name                 : DB Manager
Description          : Database manager plugin for QGIS
Date                 : May 23, 2011
copyright            : (C) 2011 by Giuseppe Sucameli
email                : brush.tyler@gmail.com

The content of this file is based on
- PG_Manager by Martin Dobias (GPLv2 license)
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
"""

import functools

from qgis.PyQt.QtCore import Qt, QByteArray, QSize
from qgis.PyQt.QtWidgets import (
    QAction,
    QMainWindow,
    QApplication,
    QMenu,
    QTabWidget,
    QGridLayout,
    QSpacerItem,
    QSizePolicy,
    QDockWidget,
    QStatusBar,
    QMenuBar,
    QToolBar,
    QTabBar,
)
from qgis.PyQt.QtGui import QIcon, QKeySequence

from qgis.gui import QgsMessageBar
from qgis.core import Qgis, QgsApplication, QgsSettings, QgsMapLayerType
from qgis.utils import OverrideCursor

from .info_viewer import InfoViewer
from .table_viewer import TableViewer
from .layer_preview import LayerPreview

from .db_tree import DBTree

from .db_plugins.plugin import BaseError
from .dlg_db_error import DlgDbError
from .gui_utils import GuiUtils


class DBManager(QMainWindow):

    def __init__(self, iface, parent=None):
        QMainWindow.__init__(self, parent)
        self.setAttribute(Qt.WidgetAttribute.WA_DeleteOnClose)
        self.setupUi()
        self.iface = iface

        # restore the window state
        settings = QgsSettings()
        self.restoreGeometry(
            settings.value(
                "/DB_Manager/mainWindow/geometry", QByteArray(), type=QByteArray
            )
        )
        self.restoreState(
            settings.value(
                "/DB_Manager/mainWindow/windowState", QByteArray(), type=QByteArray
            )
        )

        self.toolBar.setIconSize(self.iface.iconSize())
        self.toolBarOrientation()
        self.toolBar.orientationChanged.connect(self.toolBarOrientation)
        self.tabs.currentChanged.connect(self.tabChanged)
        self.tree.selectedItemChanged.connect(self.itemChanged)
        self.tree.model().dataChanged.connect(self.iface.reloadConnections)
        self.itemChanged(None)

    def closeEvent(self, e):
        self.unregisterAllActions()
        # clear preview, this will delete the layer in preview tab
        self.preview.loadPreview(None)

        # save the window state
        settings = QgsSettings()
        settings.setValue("/DB_Manager/mainWindow/windowState", self.saveState())
        settings.setValue("/DB_Manager/mainWindow/geometry", self.saveGeometry())

        QMainWindow.closeEvent(self, e)

    def refreshItem(self, item=None):
        with OverrideCursor(Qt.CursorShape.WaitCursor):
            try:
                if item is None:
                    item = self.tree.currentItem()
                self.tree.refreshItem(item)  # refresh item children in the db tree
            except BaseError as e:
                DlgDbError.showError(e, self)

    def itemChanged(self, item):
        with OverrideCursor(Qt.CursorShape.WaitCursor):
            try:
                self.reloadButtons()
                # Force-reload information on the layer
                self.info.setDirty()
                # clear preview, this will delete the layer in preview tab
                self.preview.loadPreview(None)
                self.refreshTabs()
            except BaseError as e:
                DlgDbError.showError(e, self)

    def reloadButtons(self):
        db = self.tree.currentDatabase()
        if not hasattr(self, "_lastDb"):
            self._lastDb = db

        elif db == self._lastDb:
            return

        # remove old actions
        if self._lastDb is not None:
            self.unregisterAllActions()

        # add actions of the selected database
        self._lastDb = db
        if self._lastDb is not None:
            self._lastDb.registerAllActions(self)

    def tabChanged(self, index):
        with OverrideCursor(Qt.CursorShape.WaitCursor):
            try:
                self.refreshTabs()
            except BaseError as e:
                DlgDbError.showError(e, self)

    def refreshTabs(self):
        index = self.tabs.currentIndex()
        item = self.tree.currentItem()
        table = self.tree.currentTable()

        # enable/disable tabs
        self.tabs.setTabEnabled(self.tabs.indexOf(self.table), table is not None)
        self.tabs.setTabEnabled(
            self.tabs.indexOf(self.preview),
            table is not None
            and table.type in [table.VectorType, table.RasterType]
            and table.geomColumn is not None,
        )
        # show the info tab if the current tab is disabled
        if not self.tabs.isTabEnabled(index):
            self.tabs.setCurrentWidget(self.info)

        current_tab = self.tabs.currentWidget()
        if current_tab == self.info:
            self.info.showInfo(item)
        elif current_tab == self.table:
            self.table.loadData(item)
        elif current_tab == self.preview:
            self.preview.loadPreview(item)

    def refreshActionSlot(self):
        self.info.setDirty()
        self.table.setDirty()
        self.preview.setDirty()
        self.refreshItem()

    def importActionSlot(self):
        db = self.tree.currentDatabase()
        if db is None:
            self.infoBar.pushMessage(
                self.tr("No database selected or you are not connected to it."),
                Qgis.MessageLevel.Info,
                self.iface.messageTimeout(),
            )
            return

        outUri = db.uri()
        schema = self.tree.currentSchema()
        if schema:
            outUri.setDataSource(schema.name, "", "", "")

        from .dlg_import_vector import DlgImportVector

        dlg = DlgImportVector(None, db, outUri, self)
        dlg.exec()

    def exportActionSlot(self):
        table = self.tree.currentTable()
        if table is None:
            self.infoBar.pushMessage(
                self.tr("Select the table you want export to file."),
                Qgis.MessageLevel.Info,
                self.iface.messageTimeout(),
            )
            return

        inLayer = table.toMapLayer()
        if inLayer.type() != QgsMapLayerType.VectorLayer:
            self.infoBar.pushMessage(
                self.tr("Select a vector or a tabular layer you want export."),
                Qgis.MessageLevel.Warning,
                self.iface.messageTimeout(),
            )
            return

        from .dlg_export_vector import DlgExportVector

        dlg = DlgExportVector(inLayer, table.database(), self)
        dlg.exec()

        inLayer.deleteLater()

    def runSqlWindow(self):
        db = self.tree.currentDatabase()
        if db is None:
            self.infoBar.pushMessage(
                self.tr("No database selected or you are not connected to it."),
                Qgis.MessageLevel.Info,
                self.iface.messageTimeout(),
            )
            # force displaying of the message, it appears on the first tab (i.e. Info)
            self.tabs.setCurrentIndex(0)
            return

        from .dlg_sql_window import DlgSqlWindow

        query = DlgSqlWindow(self.iface, db, self)
        dbname = db.connection().connectionName()
        tabname = self.tr("Query ({0})").format(dbname)
        index = self.tabs.addTab(query, tabname)
        self.tabs.setTabIcon(index, db.connection().icon())
        self.tabs.setCurrentIndex(index)
        query.nameChanged.connect(
            functools.partial(self.update_query_tab_name, index, dbname)
        )

    def update_query_tab_name(self, index, dbname, queryname):
        if not queryname:
            queryname = self.tr("Query")
        tabname = f"{queryname} ({dbname})"
        self.tabs.setTabText(index, tabname)

    def showSystemTables(self):
        self.tree.showSystemTables(self.actionShowSystemTables.isChecked())

    def registerAction(self, action, menuName, callback=None):
        """register an action to the manager's main menu"""
        if not hasattr(self, "_registeredDbActions"):
            self._registeredDbActions = {}

        if callback is not None:

            def invoke_callback(x):
                return self.invokeCallback(callback)

        if menuName is None or menuName == "":
            self.addAction(action)

            if menuName not in self._registeredDbActions:
                self._registeredDbActions[menuName] = list()
            self._registeredDbActions[menuName].append(action)

            if callback is not None:
                action.triggered.connect(invoke_callback)
            return True

        # search for the menu
        actionMenu = None
        helpMenuAction = None
        for a in self.menuBar.actions():
            if not a.menu() or a.menu().title() != menuName:
                continue
            if a.menu() != self.menuHelp:
                helpMenuAction = a

            actionMenu = a
            break

        # not found, add a new menu before the help menu
        if actionMenu is None:
            menu = QMenu(menuName, self)
            if helpMenuAction is not None:
                actionMenu = self.menuBar.insertMenu(helpMenuAction, menu)
            else:
                actionMenu = self.menuBar.addMenu(menu)

        menu = actionMenu.menu()
        menuActions = menu.actions()

        # get the placeholder's position to insert before it
        pos = 0
        for pos in range(len(menuActions)):
            if menuActions[pos].isSeparator() and menuActions[
                pos
            ].objectName().endswith("_placeholder"):
                menuActions[pos].setVisible(True)
                break

        if pos < len(menuActions):
            before = menuActions[pos]
            menu.insertAction(before, action)
        else:
            menu.addAction(action)

        actionMenu.setVisible(True)  # show the menu

        if menuName not in self._registeredDbActions:
            self._registeredDbActions[menuName] = list()
        self._registeredDbActions[menuName].append(action)

        if callback is not None:
            action.triggered.connect(invoke_callback)

        return True

    def invokeCallback(self, callback, *params):
        """Call a method passing the selected item in the database tree,
        the sender (usually a QAction), the plugin mainWindow and
        optionally additional parameters.

        This method takes care to override and restore the cursor,
        but also catches exceptions and displays the error dialog.
        """
        with OverrideCursor(Qt.CursorShape.WaitCursor):
            try:
                callback(self.tree.currentItem(), self.sender(), self, *params)
            except BaseError as e:
                # catch database errors and display the error dialog
                DlgDbError.showError(e, self)

    def unregisterAction(self, action, menuName):
        if not hasattr(self, "_registeredDbActions"):
            return

        if menuName is None or menuName == "":
            self.removeAction(action)

            if menuName in self._registeredDbActions:
                if self._registeredDbActions[menuName].count(action) > 0:
                    self._registeredDbActions[menuName].remove(action)

            action.deleteLater()
            return True

        for a in self.menuBar.actions():
            if not a.menu() or a.menu().title() != menuName:
                continue

            menu = a.menu()
            menuActions = menu.actions()

            menu.removeAction(action)
            if menu.isEmpty():  # hide the menu
                a.setVisible(False)

            if menuName in self._registeredDbActions:
                if self._registeredDbActions[menuName].count(action) > 0:
                    self._registeredDbActions[menuName].remove(action)

                # hide the placeholder if there're no other registered actions
                if len(self._registeredDbActions[menuName]) <= 0:
                    for i in range(len(menuActions)):
                        if menuActions[i].isSeparator() and menuActions[
                            i
                        ].objectName().endswith("_placeholder"):
                            menuActions[i].setVisible(False)
                            break

            action.deleteLater()
            return True

        return False

    def unregisterAllActions(self):
        if not hasattr(self, "_registeredDbActions"):
            return

        for menuName in self._registeredDbActions:
            for action in list(self._registeredDbActions[menuName]):
                self.unregisterAction(action, menuName)
        del self._registeredDbActions

    def close_tab(self, index):
        widget = self.tabs.widget(index)
        if widget not in [self.info, self.table, self.preview]:
            if hasattr(widget, "close"):
                if widget.close():
                    self.tabs.removeTab(index)
                    widget.deleteLater()
            else:
                self.tabs.removeTab(index)
                widget.deleteLater()

    def toolBarOrientation(self):
        button_style = Qt.ToolButtonStyle.ToolButtonIconOnly
        if self.toolBar.orientation() == Qt.Orientation.Horizontal:
            button_style = Qt.ToolButtonStyle.ToolButtonTextBesideIcon

        widget = self.toolBar.widgetForAction(self.actionImport)
        widget.setToolButtonStyle(button_style)
        widget = self.toolBar.widgetForAction(self.actionExport)
        widget.setToolButtonStyle(button_style)

    def setupUi(self):
        self.setWindowTitle(self.tr("DB Manager"))
        self.setWindowIcon(GuiUtils.get_icon("dbmanager"))
        self.resize(QSize(700, 500).expandedTo(self.minimumSizeHint()))

        # create central tab widget and add the first 3 tabs: info, table and preview
        self.tabs = QTabWidget()
        self.info = InfoViewer(self)
        self.tabs.addTab(self.info, self.tr("Info"))
        self.table = TableViewer(self)
        self.tabs.addTab(self.table, self.tr("Table"))
        self.preview = LayerPreview(self)
        self.tabs.addTab(self.preview, self.tr("Preview"))
        self.setCentralWidget(self.tabs)

        # display close button for all tabs but the first 3 ones, i.e.
        # HACK: just hide the close button where not needed (GS)
        self.tabs.setTabsClosable(True)
        self.tabs.tabCloseRequested.connect(self.close_tab)
        tabbar = self.tabs.tabBar()
        for i in range(3):
            btn = (
                tabbar.tabButton(i, QTabBar.ButtonPosition.RightSide)
                if tabbar.tabButton(i, QTabBar.ButtonPosition.RightSide)
                else tabbar.tabButton(i, QTabBar.ButtonPosition.LeftSide)
            )
            btn.resize(0, 0)
            btn.hide()

        # Creates layout for message bar
        self.layout = QGridLayout(self.info)
        self.layout.setContentsMargins(0, 0, 0, 0)
        spacerItem = QSpacerItem(
            20, 40, QSizePolicy.Policy.Minimum, QSizePolicy.Policy.Expanding
        )
        self.layout.addItem(spacerItem, 1, 0, 1, 1)
        # init messageBar instance
        self.infoBar = QgsMessageBar(self.info)
        sizePolicy = QSizePolicy(QSizePolicy.Policy.Minimum, QSizePolicy.Policy.Fixed)
        self.infoBar.setSizePolicy(sizePolicy)
        self.layout.addWidget(self.infoBar, 0, 0, 1, 1)

        # create database tree
        self.dock = QDockWidget(self.tr("Providers"), self)
        self.dock.setObjectName("DB_Manager_DBView")
        self.dock.setFeatures(QDockWidget.DockWidgetFeature.DockWidgetMovable)
        self.tree = DBTree(self)
        self.dock.setWidget(self.tree)
        self.addDockWidget(Qt.DockWidgetArea.LeftDockWidgetArea, self.dock)

        # create status bar
        self.statusBar = QStatusBar(self)
        self.setStatusBar(self.statusBar)

        # create menus
        self.menuBar = QMenuBar(self)
        self.menuDb = QMenu(self.tr("&Database"), self)
        self.menuBar.addMenu(self.menuDb)
        self.menuSchema = QMenu(self.tr("&Schema"), self)
        actionMenuSchema = self.menuBar.addMenu(self.menuSchema)
        self.menuTable = QMenu(self.tr("&Table"), self)
        actionMenuTable = self.menuBar.addMenu(self.menuTable)
        self.menuHelp = None  # QMenu(self.tr("&Help"), self)
        # actionMenuHelp = self.menuBar.addMenu(self.menuHelp)

        self.setMenuBar(self.menuBar)

        # create toolbar
        self.toolBar = QToolBar(self.tr("Default"), self)
        self.toolBar.setObjectName("DB_Manager_ToolBar")
        self.addToolBar(self.toolBar)

        # create menus' actions

        # menu DATABASE
        sep = self.menuDb.addSeparator()
        sep.setObjectName("DB_Manager_DbMenu_placeholder")
        sep.setVisible(False)

        self.actionRefresh = QAction(
            QgsApplication.getThemeIcon("/mActionRefresh.svg"),
            self.tr("&Refresh"),
            self.menuDb,
        )
        self.actionRefresh.triggered.connect(self.refreshActionSlot)
        self.actionRefresh.setShortcut(QKeySequence("F5"))
        self.menuDb.addAction(self.actionRefresh)

        self.actionSqlWindow = QAction(
            GuiUtils.get_icon("mActionSQLWindow"), self.tr("&SQL Window"), self.menuDb
        )
        self.actionSqlWindow.triggered.connect(self.runSqlWindow)
        self.actionSqlWindow.setShortcut(QKeySequence("F2"))
        self.menuDb.addAction(self.actionSqlWindow)

        self.menuDb.addSeparator()

        self.actionClose = QAction(QIcon(), self.tr("&Exit"), self.menuDb)
        self.actionClose.triggered.connect(self.close)
        self.actionClose.setShortcut(QKeySequence("CTRL+Q"))
        self.menuDb.addAction(self.actionClose)

        # menu SCHEMA
        sep = self.menuSchema.addSeparator()
        sep.setObjectName("DB_Manager_SchemaMenu_placeholder")
        sep.setVisible(False)

        actionMenuSchema.setVisible(False)

        # menu TABLE
        sep = self.menuTable.addSeparator()
        sep.setObjectName("DB_Manager_TableMenu_placeholder")
        sep.setVisible(False)

        self.actionImport = self.menuTable.addAction(
            GuiUtils.get_icon("mActionDBImport"),
            QApplication.translate("DBManager", "&Import Layer/File…"),
            self.importActionSlot,
        )
        self.actionExport = self.menuTable.addAction(
            GuiUtils.get_icon("mActionDBExport"),
            QApplication.translate("DBManager", "&Export to File…"),
            self.exportActionSlot,
        )
        self.menuTable.addSeparator()
        # self.actionShowSystemTables = self.menuTable.addAction(self.tr("Show system tables/views"), self.showSystemTables)
        # self.actionShowSystemTables.setCheckable(True)
        # self.actionShowSystemTables.setChecked(True)
        actionMenuTable.setVisible(False)

        # add actions to the toolbar
        self.toolBar.addAction(self.actionRefresh)
        self.toolBar.addAction(self.actionSqlWindow)
        self.toolBar.addSeparator()
        self.toolBar.addAction(self.actionImport)
        self.toolBar.addAction(self.actionExport)
