#!/usr/bin/python3

# @begin:license
#
# Copyright (c) 2015-2019, Benjamin Niemann <pink@odahoda.de>
#
# 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.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
# @end:license

import logging
import os
import os.path
import shutil
import time
import urllib.parse
from typing import cast, Any, List, Iterable, Iterator

from PyQt5.QtCore import Qt
from PyQt5 import QtCore

from noisicaa.core.typing_extra import down_cast
from noisicaa import music
from . import ui_base

logger = logging.getLogger(__name__)


class Item(QtCore.QObject):
    contentsChanged = QtCore.pyqtSignal()

    PathRole = 0x0100

    def __init__(self, *, path: str) -> None:
        super().__init__()

        self.path = path
        self.index = 0
        self.childItems = []  # type: List[Item]

    def isOpened(self) -> bool:
        return False

    def projects(self) -> Iterator['Project']:
        for child in self.childItems:
            yield from child.projects()

    def data(self, role: int) -> Any:
        if role == Item.PathRole:
            return self.path

        return None

    def flags(self) -> Qt.ItemFlags:
        return cast(Qt.ItemFlags, Qt.NoItemFlags)


class Root(Item):
    def __init__(self) -> None:
        super().__init__(path='<root>')


class Project(ui_base.CommonMixin, Item):
    NameRole = 0x0101
    MTimeRole = 0x0102

    def __init__(self, **kwargs: Any) -> None:
        super().__init__(**kwargs)

        self.__debuggerRunning = False

        self.client = None  # type: music.ProjectClient
        if os.path.isfile(os.path.join(self.path, 'project.noise')):
            self.__mtime = os.path.getmtime(os.path.join(self.path, 'project.noise'))
        else:
            self.__mtime = time.time()

    def projects(self) -> Iterator['Project']:
        yield self
        yield from super().projects()

    def flags(self) -> Qt.ItemFlags:
        return cast(Qt.ItemFlags, Qt.ItemIsSelectable | Qt.ItemIsEnabled)

    def data(self, role: int) -> Any:
        if role == Project.NameRole:
            return self.name

        if role == Project.MTimeRole:
            return self.mtime

        return super().data(role)

    def isOpened(self) -> bool:
        return self.client is not None or self.__debuggerRunning

    @property
    def name(self) -> str:
        return urllib.parse.unquote(os.path.splitext(os.path.basename(self.path))[0])

    @property
    def mtime(self) -> float:
        return self.__mtime

    def startDebugger(self) -> None:
        self.__debuggerRunning = True
        self.contentsChanged.emit()

    def endDebugger(self) -> None:
        self.__debuggerRunning = False
        self.contentsChanged.emit()

    async def __create_process(self) -> music.ProjectClient:
        client = music.ProjectClient(
            event_loop=self.event_loop,
            server=self.app.process.server,
            node_db=self.app.node_db,
            urid_mapper=self.app.urid_mapper,
            manager=self.app.process.manager,
            tmp_dir=self.app.process.tmp_dir,
        )
        await client.setup()
        return client

    async def open(self) -> None:
        assert not self.isOpened()
        client = await self.__create_process()
        try:
            await client.open(self.path)
        except:  # pylint: disable=bare-except
            await client.cleanup()
            raise
        self.client = client
        self.app.project_registry.updateOpenedProjects()
        self.__mtime = time.time()
        self.contentsChanged.emit()

    async def create(self) -> None:
        assert not self.isOpened()
        client = await self.__create_process()
        try:
            await client.create(self.path)
        except:  # pylint: disable=bare-except
            await client.cleanup()
            raise
        self.client = client
        self.app.project_registry.addProject(self)
        self.app.project_registry.updateOpenedProjects()
        self.__mtime = time.time()
        self.contentsChanged.emit()

    async def close(self) -> None:
        if self.client is not None:
            await self.client.close()
            await self.client.cleanup()
            self.client = None
            self.app.project_registry.updateOpenedProjects()
            self.__mtime = time.time()
            self.contentsChanged.emit()

    async def delete(self) -> None:
        assert not self.isOpened()
        shutil.rmtree(self.path)


class ProjectRegistry(ui_base.CommonMixin, QtCore.QAbstractItemModel):
    contentsChanged = QtCore.pyqtSignal()

    def __init__(self, **kwargs: Any) -> None:
        super().__init__(**kwargs)

        self.__root = Root()
        self.__in_cleanup = False

    async def setup(self) -> None:
        await self.refresh()

    async def cleanup(self) -> None:
        self.__in_cleanup = True
        for project in self.__root.projects():
            await project.close()
        self.__root = None

    def __scan_projects(self, directories: Iterable[str]) -> List[str]:
        paths = []  # type: List[str]
        for directory in directories:
            directory = os.path.expanduser(directory)
            directory = os.path.abspath(directory)
            logger.info("Scanning project directory %s...", directory)
            for dirpath, dirnames, _ in os.walk(directory):
                for dirname in list(dirnames):
                    if os.path.isfile(os.path.join(dirpath, dirname, 'project.noise')):
                        dirnames.remove(dirname)
                        paths.append(os.path.join(dirpath, dirname))

        return paths

    def projects(self) -> List[Project]:
        return list(self.__root.projects())

    async def refresh(self) -> None:
        directories = self.app.settings.value('project_folders', ['~/Music/Noisicaä'])

        paths = await self.event_loop.run_in_executor(None, self.__scan_projects, directories)

        old_paths = {project.path for project in self.__root.projects()}
        new_paths = set(paths)

        for path in old_paths - new_paths:
            logger.info("Removing project at %s...", path)

            for idx, project in enumerate(self.__root.childItems):
                if project.path == path:
                    self.beginRemoveRows(QtCore.QModelIndex(), idx, idx)
                    del self.__root.childItems[idx]
                    for i, item in enumerate(self.__root.childItems[idx:], idx):
                        item.index = i
                    self.endRemoveRows()
                    await project.close()
                    self.contentsChanged.emit()
                    break

        for path in new_paths - old_paths:
            logger.info("Adding project at %s...", path)
            project = Project(path=path, context=self.context)
            self.addProject(project)

    def getProject(self, path: str) -> Project:
        path = os.path.expanduser(path)
        path = os.path.abspath(path)
        for project in self.projects():
            if project.path == path:
                return project
        raise KeyError("No known project at '%s'" % path)

    def addProject(self, project: Project) -> None:
        idx = 0
        while idx < len(self.__root.childItems) and project.path > self.__root.childItems[idx].path:
            idx += 1

        project.setParent(self.__root)

        self.beginInsertRows(QtCore.QModelIndex(), idx, idx)
        self.__root.childItems.insert(idx, project)
        for idx, item in enumerate(self.__root.childItems[idx:], idx):
            item.index = idx
        self.endInsertRows()

        project.contentsChanged.connect(lambda: self.__projectChanged(project))
        project.contentsChanged.connect(self.contentsChanged.emit)
        self.contentsChanged.emit()

    def updateOpenedProjects(self) -> None:
        if self.__in_cleanup:
            return
        opened_project_paths = sorted(
            project.path for project in self.projects() if project.isOpened())
        logger.info("Currently opened projects:\n%s", '\n'.join(opened_project_paths))
        self.app.settings.setValue('opened_projects', opened_project_paths)

    def __projectChanged(self, project: Project) -> None:
        index = self.index(project.index)
        self.dataChanged.emit(index, index)

    def item(self, index: QtCore.QModelIndex = QtCore.QModelIndex()) -> Item:
        if not index.isValid():
            return self.__root
        else:
            return down_cast(Item, index.internalPointer())

    def index(
            self, row: int, column: int = 0, parent: QtCore.QModelIndex = QtCore.QModelIndex()
    ) -> QtCore.QModelIndex:
        if not self.hasIndex(row, column, parent):  # pragma: no coverage
            return QtCore.QModelIndex()

        parent_item = self.item(parent)
        return self.createIndex(row, column, parent_item.childItems[row])

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

        item = down_cast(Item, index.internalPointer())
        if item is self.__root:
            return QtCore.QModelIndex()

        return self.createIndex(item.parent().index, 0, item.parent())

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

    def rowCount(self, parent: QtCore.QModelIndex = QtCore.QModelIndex()) -> int:
        parent_item = self.item(parent)
        if parent_item is None:
            return 0
        return len(parent_item.childItems)

    def flags(self, index: QtCore.QModelIndex) -> Qt.ItemFlags:
        return self.item(index).flags()

    def data(self, index: QtCore.QModelIndex, role: int = Qt.DisplayRole) -> Any:
        return self.item(index).data(role)

    def headerData(
            self, section: int, orientation: Qt.Orientation, role: int = Qt.DisplayRole
    ) -> Any:  # pragma: no coverage
        return None