# -*- coding: utf-8 -*-
# Copyright: Ankitects Pty Ltd and contributors
# License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html

from __future__ import annotations

from concurrent.futures import Future
from enum import Enum
from typing import Iterable, List, Optional

import aqt
from anki.collection import (  # pylint: disable=unused-import
    FilterToSearchIn,
    NamedFilter,
)
from anki.errors import DeckRenameError
from anki.rsbackend import DeckTreeNode, TagTreeNode
from aqt import gui_hooks
from aqt.main import ResetReason
from aqt.models import Models
from aqt.qt import *
from aqt.theme import theme_manager
from aqt.utils import TR, getOnlyText, showInfo, showWarning, tr


class SidebarItemType(Enum):
    ROOT = 0
    COLLECTION = 1
    CURRENT_DECK = 2
    FILTER = 3
    DECK = 4
    NOTETYPE = 5
    TAG = 6
    CUSTOM = 7
    TEMPLATE = 8


#  used by an add-on hook
class SidebarStage(Enum):
    ROOT = 0
    STANDARD = 1
    FAVORITES = 2
    DECKS = 3
    MODELS = 4
    TAGS = 5


class SidebarItem:
    def __init__(
        self,
        name: str,
        icon: str,
        onClick: Callable[[], None] = None,
        onExpanded: Callable[[bool], None] = None,
        expanded: bool = False,
        item_type: SidebarItemType = SidebarItemType.CUSTOM,
        id: int = 0,
        full_name: str = None,
    ) -> None:
        self.name = name
        if not full_name:
            full_name = name
        self.full_name = full_name
        self.icon = icon
        self.item_type = item_type
        self.id = id
        self.onClick = onClick
        self.onExpanded = onExpanded
        self.expanded = expanded
        self.children: List["SidebarItem"] = []
        self.parentItem: Optional["SidebarItem"] = None
        self.tooltip: Optional[str] = None

    def addChild(self, cb: "SidebarItem") -> None:
        self.children.append(cb)
        cb.parentItem = self

    def rowForChild(self, child: "SidebarItem") -> Optional[int]:
        try:
            return self.children.index(child)
        except ValueError:
            return None


class SidebarModel(QAbstractItemModel):
    def __init__(self, root: SidebarItem) -> None:
        super().__init__()
        self.root = root

    # Qt API
    ######################################################################

    def rowCount(self, parent: QModelIndex = QModelIndex()) -> int:
        if not parent.isValid():
            return len(self.root.children)
        else:
            item: SidebarItem = parent.internalPointer()
            return len(item.children)

    def columnCount(self, parent: QModelIndex = QModelIndex()) -> int:
        return 1

    def index(
        self, row: int, column: int, parent: QModelIndex = QModelIndex()
    ) -> QModelIndex:
        if not self.hasIndex(row, column, parent):
            return QModelIndex()

        parentItem: SidebarItem
        if not parent.isValid():
            parentItem = self.root
        else:
            parentItem = parent.internalPointer()

        item = parentItem.children[row]
        return self.createIndex(row, column, item)

    def parent(self, child: QModelIndex) -> QModelIndex:  # type: ignore
        if not child.isValid():
            return QModelIndex()

        childItem: SidebarItem = child.internalPointer()
        parentItem = childItem.parentItem

        if parentItem is None or parentItem == self.root:
            return QModelIndex()

        row = parentItem.rowForChild(childItem)
        if row is None:
            return QModelIndex()

        return self.createIndex(row, 0, parentItem)

    def data(self, index: QModelIndex, role: int = Qt.DisplayRole) -> QVariant:
        if not index.isValid():
            return QVariant()

        if role not in (Qt.DisplayRole, Qt.DecorationRole, Qt.ToolTipRole):
            return QVariant()

        item: SidebarItem = index.internalPointer()

        if role == Qt.DisplayRole:
            return QVariant(item.name)
        elif role == Qt.ToolTipRole:
            return QVariant(item.tooltip)
        else:
            return QVariant(theme_manager.icon_from_resources(item.icon))

    # Helpers
    ######################################################################

    def iconFromRef(self, iconRef: str) -> QIcon:
        print("iconFromRef() deprecated")
        return theme_manager.icon_from_resources(iconRef)

    def expandWhereNeccessary(self, tree: QTreeView) -> None:
        for row, child in enumerate(self.root.children):
            if child.expanded:
                idx = self.index(row, 0, QModelIndex())
                self._expandWhereNeccessary(idx, tree)

    def _expandWhereNeccessary(self, parent: QModelIndex, tree: QTreeView) -> None:
        parentItem: SidebarItem
        if not parent.isValid():
            parentItem = self.root
        else:
            parentItem = parent.internalPointer()

        # nothing to do?
        if not parentItem.expanded:
            return

        # expand children
        for row, child in enumerate(parentItem.children):
            if not child.expanded:
                continue
            childIdx = self.index(row, 0, parent)
            self._expandWhereNeccessary(childIdx, tree)

        # then ourselves
        tree.setExpanded(parent, True)


class SidebarTreeView(QTreeView):
    def __init__(self, browser: aqt.browser.Browser) -> None:
        super().__init__()
        self.browser = browser
        self.mw = browser.mw
        self.col = self.mw.col

        self.setContextMenuPolicy(Qt.CustomContextMenu)
        self.customContextMenuRequested.connect(self.onContextMenu)  # type: ignore
        self.context_menus = {
            SidebarItemType.DECK: (
                (tr(TR.ACTIONS_RENAME), self.rename_deck),
                (tr(TR.ACTIONS_DELETE), self.delete_deck),
            ),
            SidebarItemType.TAG: (
                (tr(TR.ACTIONS_RENAME), self.rename_tag),
                (tr(TR.ACTIONS_DELETE), self.remove_tag),
            ),
            SidebarItemType.FILTER: (
                (tr(TR.ACTIONS_RENAME), self.rename_filter),
                (tr(TR.ACTIONS_DELETE), self.remove_filter),
            ),
            SidebarItemType.NOTETYPE: ((tr(TR.ACTIONS_MANAGE), self.manage_notetype),),
        }

        self.setUniformRowHeights(True)
        self.setHeaderHidden(True)
        self.setIndentation(15)

        qconnect(self.expanded, self.onExpansion)
        qconnect(self.collapsed, self.onCollapse)

        # match window background color
        bgcolor = QPalette().window().color().name()
        self.setStyleSheet("QTreeView { background: '%s'; }" % bgcolor)

    def refresh(self) -> None:
        "Refresh list. No-op if sidebar is not visible."
        if not self.isVisible():
            return

        def on_done(fut: Future):
            root = fut.result()
            model = SidebarModel(root)
            self.setModel(model)
            model.expandWhereNeccessary(self)

        self.mw.taskman.run_in_background(self._root_tree, on_done)

    def onClickCurrent(self) -> None:
        idx = self.currentIndex()
        if idx.isValid():
            item: "aqt.browser.SidebarItem" = idx.internalPointer()
            if item.onClick:
                item.onClick()

    def mouseReleaseEvent(self, event: QMouseEvent) -> None:
        super().mouseReleaseEvent(event)
        if event.button() == Qt.LeftButton:
            self.onClickCurrent()

    def keyPressEvent(self, event: QKeyEvent) -> None:
        if event.key() in (Qt.Key_Return, Qt.Key_Enter):
            self.onClickCurrent()
        else:
            super().keyPressEvent(event)

    def onExpansion(self, idx: QModelIndex) -> None:
        self._onExpansionChange(idx, True)

    def onCollapse(self, idx: QModelIndex) -> None:
        self._onExpansionChange(idx, False)

    def _onExpansionChange(self, idx: QModelIndex, expanded: bool) -> None:
        item: "aqt.browser.SidebarItem" = idx.internalPointer()
        if item.expanded != expanded:
            item.expanded = expanded
            if item.onExpanded:
                item.onExpanded(expanded)

    # Tree building
    ###########################

    def _root_tree(self) -> SidebarItem:
        root = SidebarItem("", "", item_type=SidebarItemType.ROOT)

        handled = gui_hooks.browser_will_build_tree(
            False, root, SidebarStage.ROOT, self
        )
        if handled:
            return root

        for stage, builder in zip(
            list(SidebarStage)[1:],
            (
                self._commonly_used_tree,
                self._favorites_tree,
                self._deck_tree,
                self._notetype_tree,
                self._tag_tree,
            ),
        ):
            handled = gui_hooks.browser_will_build_tree(False, root, stage, self)
            if not handled and builder:
                builder(root)

        return root

    def _commonly_used_tree(self, root: SidebarItem) -> None:
        item = SidebarItem(
            tr(TR.BROWSING_WHOLE_COLLECTION),
            ":/icons/collection.svg",
            self._named_filter(NamedFilter.WHOLE_COLLECTION),
            item_type=SidebarItemType.COLLECTION,
        )
        root.addChild(item)
        item = SidebarItem(
            tr(TR.BROWSING_CURRENT_DECK),
            ":/icons/deck.svg",
            self._named_filter(NamedFilter.CURRENT_DECK),
            item_type=SidebarItemType.CURRENT_DECK,
        )
        root.addChild(item)

    def _favorites_tree(self, root: SidebarItem) -> None:
        assert self.col
        saved = self.col.get_config("savedFilters", {})
        for name, filt in sorted(saved.items()):
            item = SidebarItem(
                name,
                ":/icons/heart.svg",
                self._saved_filter(filt),
                item_type=SidebarItemType.FILTER,
            )
            root.addChild(item)

    def _tag_tree(self, root: SidebarItem) -> None:
        tree = self.col.backend.tag_tree()

        def render(root: SidebarItem, nodes: Iterable[TagTreeNode], head="") -> None:
            for node in nodes:

                def toggle_expand():
                    full_name = head + node.name  # pylint: disable=cell-var-from-loop
                    return lambda expanded: self.mw.col.tags.set_collapsed(
                        full_name, not expanded
                    )

                item = SidebarItem(
                    node.name,
                    ":/icons/tag.svg",
                    self._tag_filter(head + node.name),
                    toggle_expand(),
                    not node.collapsed,
                    item_type=SidebarItemType.TAG,
                    full_name=head + node.name,
                )
                root.addChild(item)
                newhead = head + node.name + "::"
                render(item, node.children, newhead)

        render(root, tree.children)

    def _deck_tree(self, root: SidebarItem) -> None:
        tree = self.col.decks.deck_tree()

        def render(root, nodes: Iterable[DeckTreeNode], head="") -> None:
            for node in nodes:

                def toggle_expand():
                    did = node.deck_id  # pylint: disable=cell-var-from-loop
                    return lambda _: self.mw.col.decks.collapseBrowser(did)

                item = SidebarItem(
                    node.name,
                    ":/icons/deck.svg",
                    self._deck_filter(head + node.name),
                    toggle_expand(),
                    not node.collapsed,
                    item_type=SidebarItemType.DECK,
                    id=node.deck_id,
                )
                root.addChild(item)
                newhead = head + node.name + "::"
                render(item, node.children, newhead)

        render(root, tree.children)

    def _notetype_tree(self, root: SidebarItem) -> None:
        assert self.col

        for nt in sorted(self.col.models.all(), key=lambda nt: nt["name"].lower()):
            item = SidebarItem(
                nt["name"],
                ":/icons/notetype.svg",
                self._note_filter(nt["name"]),
                item_type=SidebarItemType.NOTETYPE,
                id=nt["id"],
            )

            for c, tmpl in enumerate(nt["tmpls"]):
                child = SidebarItem(
                    tmpl["name"],
                    ":/icons/notetype.svg",
                    self._template_filter(nt["name"], c),
                    item_type=SidebarItemType.TEMPLATE,
                )
                item.addChild(child)

            root.addChild(item)

    def _named_filter(self, name: "FilterToSearchIn.NamedFilterValue") -> Callable:
        return lambda: self.browser.update_search(self.col.search_string(name=name))

    def _tag_filter(self, tag: str) -> Callable:
        return lambda: self.browser.update_search(self.col.search_string(tag=tag))

    def _deck_filter(self, deck: str) -> Callable:
        return lambda: self.browser.update_search(self.col.search_string(deck=deck))

    def _note_filter(self, note: str) -> Callable:
        return lambda: self.browser.update_search(self.col.search_string(note=note))

    def _template_filter(self, note: str, template: int) -> Callable:
        return lambda: self.browser.update_search(
            self.col.search_string(note=note), self.col.search_string(template=template)
        )

    def _saved_filter(self, saved: str) -> Callable:
        return lambda: self.browser.update_search(saved)

    # Context menu actions
    ###########################

    def onContextMenu(self, point: QPoint) -> None:
        idx: QModelIndex = self.indexAt(point)
        item: "aqt.browser.SidebarItem" = idx.internalPointer()
        if not item:
            return
        item_type: SidebarItemType = item.item_type
        if item_type not in self.context_menus:
            return

        m = QMenu()
        for action in self.context_menus[item_type]:
            act_name = action[0]
            act_func = action[1]
            a = m.addAction(act_name)
            a.triggered.connect(lambda _, func=act_func: func(item))  # type: ignore
        m.exec_(QCursor.pos())

    def rename_deck(self, item: "aqt.browser.SidebarItem") -> None:
        deck = self.mw.col.decks.get(item.id)
        old_name = deck["name"]
        new_name = getOnlyText(tr(TR.DECKS_NEW_DECK_NAME), default=old_name)
        new_name = new_name.replace('"', "")
        if not new_name or new_name == old_name:
            return
        self.mw.checkpoint(tr(TR.ACTIONS_RENAME_DECK))
        try:
            self.mw.col.decks.rename(deck, new_name)
        except DeckRenameError as e:
            return showWarning(e.description)
        self.browser.maybeRefreshSidebar()
        self.mw.deckBrowser.refresh()

    def remove_tag(self, item: "aqt.browser.SidebarItem") -> None:
        self.browser.editor.saveNow(lambda: self._remove_tag(item))

    def _remove_tag(self, item: "aqt.browser.SidebarItem") -> None:
        old_name = item.full_name

        def do_remove():
            self.mw.col.backend.clear_tag(old_name)
            self.col.tags.rename_tag(old_name, "")

        def on_done(fut: Future):
            self.mw.requireReset(reason=ResetReason.BrowserRemoveTags, context=self)
            self.browser.model.endReset()
            fut.result()
            self.browser.maybeRefreshSidebar()

        self.mw.checkpoint(tr(TR.ACTIONS_REMOVE_TAG))
        self.browser.model.beginReset()
        self.mw.taskman.run_in_background(do_remove, on_done)

    def rename_tag(self, item: "aqt.browser.SidebarItem") -> None:
        self.browser.editor.saveNow(lambda: self._rename_tag(item))

    def _rename_tag(self, item: "aqt.browser.SidebarItem") -> None:
        old_name = item.full_name
        new_name = getOnlyText(tr(TR.ACTIONS_NEW_NAME), default=old_name)
        if new_name == old_name or not new_name:
            return

        def do_rename():
            self.mw.col.backend.clear_tag(old_name)
            return self.col.tags.rename_tag(old_name, new_name)

        def on_done(fut: Future):
            self.mw.requireReset(reason=ResetReason.BrowserAddTags, context=self)
            self.browser.model.endReset()

            count = fut.result()
            if not count:
                showInfo(tr(TR.BROWSING_TAG_RENAME_WARNING_EMPTY))
                return

            self.browser.maybeRefreshSidebar()

        self.mw.checkpoint(tr(TR.ACTIONS_RENAME_TAG))
        self.browser.model.beginReset()
        self.mw.taskman.run_in_background(do_rename, on_done)

    def delete_deck(self, item: "aqt.browser.SidebarItem") -> None:
        self.browser.editor.saveNow(lambda: self._delete_deck(item))

    def _delete_deck(self, item: "aqt.browser.SidebarItem") -> None:
        did = item.id
        if self.mw.deckBrowser.ask_delete_deck(did):

            def do_delete():
                return self.mw.col.decks.rem(did, True)

            def on_done(fut: Future):
                self.mw.requireReset(reason=ResetReason.BrowserDeleteDeck, context=self)
                self.browser.search()
                self.browser.model.endReset()
                self.browser.maybeRefreshSidebar()
                res = fut.result()  # Required to check for errors

            self.mw.checkpoint(tr(TR.DECKS_DELETE_DECK))
            self.browser.model.beginReset()
            self.mw.taskman.run_in_background(do_delete, on_done)

    def remove_filter(self, item: "aqt.browser.SidebarItem") -> None:
        self.browser.removeFilter(item.name)

    def rename_filter(self, item: "aqt.browser.SidebarItem") -> None:
        self.browser.renameFilter(item.name)

    def manage_notetype(self, item: "aqt.browser.SidebarItem") -> None:
        Models(
            self.mw, parent=self.browser, fromMain=True, selected_notetype_id=item.id
        )