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

from __future__ import annotations

import time
from typing import Optional

import aqt.forms
from anki.lang import _
from aqt.qt import *

# Progress info
##########################################################################


class ProgressManager:
    def __init__(self, mw):
        self.mw = mw
        self.app = QApplication.instance()
        self.inDB = False
        self.blockUpdates = False
        self._show_timer: Optional[QTimer] = None
        self._win = None
        self._levels = 0

    # Safer timers
    ##########################################################################
    # A custom timer which avoids firing while a progress dialog is active
    # (likely due to some long-running DB operation)

    def timer(self, ms, func, repeat, requiresCollection=True):
        def handler():
            if self._levels:
                # retry in 100ms
                self.timer(100, func, False, requiresCollection)
            elif not self.mw.col and requiresCollection:
                # ignore timer events that fire after collection has been
                # unloaded
                print("Ignored progress func as collection unloaded: %s" % repr(func))
            else:
                func()

        t = QTimer(self.mw)
        if not repeat:
            t.setSingleShot(True)
        qconnect(t.timeout, handler)
        t.start(ms)
        return t

    # Creating progress dialogs
    ##########################################################################

    def start(
        self, max=0, min=0, label=None, parent=None, immediate=False
    ) -> Optional[ProgressDialog]:
        self._levels += 1
        if self._levels > 1:
            return None
        # setup window
        parent = parent or self.app.activeWindow()
        if not parent and self.mw.isVisible():
            parent = self.mw

        label = label or _("Processing...")
        self._win = ProgressDialog(parent)
        self._win.form.progressBar.setMinimum(min)
        self._win.form.progressBar.setMaximum(max)
        self._win.form.progressBar.setTextVisible(False)
        self._win.form.label.setText(label)
        self._win.setWindowTitle("Anki")
        self._win.setWindowModality(Qt.ApplicationModal)
        self._win.setMinimumWidth(300)
        self._setBusy()
        self._shown: float = 0
        self._counter = min
        self._min = min
        self._max = max
        self._firstTime = time.time()
        self._lastUpdate = time.time()
        self._updating = False
        self._show_timer = QTimer(self.mw)
        self._show_timer.setSingleShot(True)
        self._show_timer.start(immediate and 100 or 600)
        qconnect(self._show_timer.timeout, self._on_show_timer)
        return self._win

    def update(
        self,
        label=None,
        value=None,
        process=True,
        maybeShow=True,
        max: Optional[int] = None,
    ) -> None:
        # print self._min, self._counter, self._max, label, time.time() - self._lastTime
        if not self.mw.inMainThread():
            print("progress.update() called on wrong thread")
            return
        if self._updating:
            return
        if maybeShow:
            self._maybeShow()
        if not self._shown:
            return
        elapsed = time.time() - self._lastUpdate
        if label:
            self._win.form.label.setText(label)

        self._max = max or 0
        self._win.form.progressBar.setMaximum(self._max)
        if self._max:
            self._counter = value or (self._counter + 1)
            self._win.form.progressBar.setValue(self._counter)

        if process and elapsed >= 0.2:
            self._updating = True
            self.app.processEvents()  # type: ignore #possibly related to https://github.com/python/mypy/issues/6910
            self._updating = False
            self._lastUpdate = time.time()

    def finish(self):
        self._levels -= 1
        self._levels = max(0, self._levels)
        if self._levels == 0:
            if self._win:
                self._closeWin()
            self._unsetBusy()
            if self._show_timer:
                self._show_timer.stop()
                self._show_timer = None

    def clear(self):
        "Restore the interface after an error."
        if self._levels:
            self._levels = 1
            self.finish()

    def _maybeShow(self):
        if not self._levels:
            return
        if self._shown:
            return
        delta = time.time() - self._firstTime
        if delta > 0.5:
            self._showWin()

    def _showWin(self) -> None:
        self._shown = time.time()
        self._win.show()

    def _closeWin(self) -> None:
        if self._shown:
            while True:
                # give the window system a second to present
                # window before we close it again - fixes
                # progress window getting stuck, especially
                # on ubuntu 16.10+
                elap = time.time() - self._shown
                if elap >= 0.5:
                    break
                self.app.processEvents(QEventLoop.ExcludeUserInputEvents)  # type: ignore #possibly related to https://github.com/python/mypy/issues/6910
        self._win.cancel()
        self._win = None
        self._shown = 0

    def _setBusy(self):
        self.mw.app.setOverrideCursor(QCursor(Qt.WaitCursor))

    def _unsetBusy(self):
        self.app.restoreOverrideCursor()

    def busy(self):
        "True if processing."
        return self._levels

    def _on_show_timer(self):
        self._show_timer = None
        self._showWin()

    def want_cancel(self) -> bool:
        win = self._win
        if win:
            return win.wantCancel
        else:
            return False

    def set_title(self, title: str) -> None:
        win = self._win
        if win:
            win.setWindowTitle(title)


class ProgressDialog(QDialog):
    def __init__(self, parent):
        QDialog.__init__(self, parent)
        self.form = aqt.forms.progress.Ui_Dialog()
        self.form.setupUi(self)
        self._closingDown = False
        self.wantCancel = False
        # required for smooth progress bars
        self.form.progressBar.setStyleSheet("QProgressBar::chunk { width: 1px; }")

    def cancel(self):
        self._closingDown = True
        self.hide()

    def closeEvent(self, evt):
        if self._closingDown:
            evt.accept()
        else:
            self.wantCancel = True
            evt.ignore()

    def keyPressEvent(self, evt):
        if evt.key() == Qt.Key_Escape:
            evt.ignore()
            self.wantCancel = True