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

import difflib
import html
import html.parser
import json
import re
import unicodedata as ucd
from typing import List

import aqt
from anki.cards import Card
from anki.hooks import addHook, runFilter, runHook
from anki.lang import _, ngettext
from anki.sound import clearAudioQueue, play, playFromText
from anki.utils import bodyClass, stripHTML
from aqt import AnkiQt
from aqt.qt import *
from aqt.sound import getAudio
from aqt.utils import (askUserDialog, downArrow, mungeQA,
                       qtMenuShortcutWorkaround, tooltip)


class Reviewer:
    "Manage reviews.  Maintains a separate state."

    def __init__(self, mw: AnkiQt):
        self.mw = mw
        self.web = mw.web
        self.card = None
        self.cardQueue: List[Card] = []
        self.hadCardQueue = False
        self._answeredIds: List[int] = []
        self._recordedAudio = None
        self.typeCorrect = None # web init happens before this is set
        self.state = None
        self.bottom = aqt.toolbar.BottomBar(mw, mw.bottomWeb)
        addHook("leech", self.onLeech)

    def show(self):
        self.mw.col.reset()
        self.web.resetHandlers()
        self.mw.setStateShortcuts(self._shortcutKeys())
        self.web.onBridgeCmd = self._linkHandler
        self.bottom.web.onBridgeCmd = self._linkHandler
        self._reps = None
        self.nextCard()

    def lastCard(self):
        if self._answeredIds:
            if not self.card or self._answeredIds[-1] != self.card.id:
                try:
                    return self.mw.col.getCard(self._answeredIds[-1])
                except TypeError:
                    # id was deleted
                    return

    def cleanup(self):
        runHook("reviewCleanup")

    # Fetching a card
    ##########################################################################

    def nextCard(self):
        elapsed = self.mw.col.timeboxReached()
        if elapsed:
            part1 = ngettext("%d card studied in", "%d cards studied in", elapsed[1]) % elapsed[1]
            mins = int(round(elapsed[0]/60))
            part2 = ngettext("%s minute.", "%s minutes.", mins) % mins
            fin = _("Finish")
            diag = askUserDialog("%s %s" % (part1, part2),
                             [_("Continue"), fin])
            diag.setIcon(QMessageBox.Information)
            if diag.run() == fin:
                return self.mw.moveToState("deckBrowser")
            self.mw.col.startTimebox()
        if self.cardQueue:
            # undone/edited cards to show
            c = self.cardQueue.pop()
            c.startTimer()
            self.hadCardQueue = True
        else:
            if self.hadCardQueue:
                # the undone/edited cards may be sitting in the regular queue;
                # need to reset
                self.mw.col.reset()
                self.hadCardQueue = False
            c = self.mw.col.sched.getCard()
        self.card = c
        clearAudioQueue()
        if not c:
            self.mw.moveToState("overview")
            return
        if self._reps is None or self._reps % 100 == 0:
            # we recycle the webview periodically so webkit can free memory
            self._initWeb()
        self._showQuestion()

    # Audio
    ##########################################################################

    def replayAudio(self, previewer=None):
        if previewer:
            state = previewer._previewState
            c = previewer.card
        else:
            state = self.state
            c = self.card
        clearAudioQueue()
        if state == "question":
            playFromText(c.q())
        elif state == "answer":
            txt = ""
            if self._replayq(c, previewer):
                txt = c.q()
            txt += c.a()
            playFromText(txt)

    # Initializing the webview
    ##########################################################################

    def revHtml(self):
        extra = self.mw.col.conf.get("reviewExtra", "")
        fade=""
        if self.mw.pm.glMode() == "software":
            fade="<script>qFade=0;</script>"
        return """
<div id=_mark>&#x2605;</div>
<div id=_flag>&#x2691;</div>
{}
<div id=qa></div>
{}
""".format(fade, extra)

    def _initWeb(self):
        self._reps = 0
        # main window
        self.web.stdHtml(self.revHtml(),
                         css=["reviewer.css"],
                         js=["jquery.js",
                             "browsersel.js",
                             "mathjax/conf.js",
                             "mathjax/MathJax.js",
                             "reviewer.js"])
        # show answer / ease buttons
        self.bottom.web.show()
        self.bottom.web.stdHtml(
            self._bottomHTML(),
            css=["toolbar-bottom.css", "reviewer-bottom.css"],
            js=["jquery.js", "reviewer-bottom.js"]
        )

    # Showing the question
    ##########################################################################

    def _mungeQA(self, buf):
        return self.typeAnsFilter(mungeQA(self.mw.col, buf))

    def _showQuestion(self):
        self._reps += 1
        self.state = "question"
        self.typedAnswer = None
        c = self.card
        # grab the question and play audio
        if c.isEmpty():
            q = _("""\
The front of this card is empty. Please run Tools>Empty Cards.""")
        else:
            q = c.q()
        if self.autoplay(c):
            playFromText(q)
        # render & update bottom
        q = self._mungeQA(q)
        q = runFilter("prepareQA", q, c, "reviewQuestion")

        bodyclass = bodyClass(self.mw.col, c)

        self.web.eval("_showQuestion(%s,'%s');" % (json.dumps(q), bodyclass))
        self._drawFlag()
        self._drawMark()
        self._showAnswerButton()
        # if we have a type answer field, focus main web
        if self.typeCorrect:
            self.mw.web.setFocus()
        # user hook
        runHook('showQuestion')

    def autoplay(self, card):
        return self.mw.col.decks.confForDid(
            card.odid or card.did)['autoplay']

    def _replayq(self, card, previewer=None):
        s = previewer if previewer else self
        return s.mw.col.decks.confForDid(
            s.card.odid or s.card.did).get('replayq', True)

    def _drawFlag(self):
        self.web.eval("_drawFlag(%s);" % self.card.userFlag())

    def _drawMark(self):
        self.web.eval("_drawMark(%s);" % json.dumps(
                        self.card.note().hasTag("marked")))

    # Showing the answer
    ##########################################################################

    def _showAnswer(self):
        if self.mw.state != "review":
            # showing resetRequired screen; ignore space
            return
        self.state = "answer"
        c = self.card
        a = c.a()
        # play audio?
        clearAudioQueue()
        if self.autoplay(c):
            playFromText(a)
        a = self._mungeQA(a)
        a = runFilter("prepareQA", a, c, "reviewAnswer")
        # render and update bottom
        self.web.eval("_showAnswer(%s);" % json.dumps(a))
        self._showEaseButtons()
        # user hook
        runHook('showAnswer')

    # Answering a card
    ############################################################

    def _answerCard(self, ease):
        "Reschedule card and show next."
        if self.mw.state != "review":
            # showing resetRequired screen; ignore key
            return
        if self.state != "answer":
            return
        if self.mw.col.sched.answerButtons(self.card) < ease:
            return
        self.mw.col.sched.answerCard(self.card, ease)
        self._answeredIds.append(self.card.id)
        self.mw.autosave()
        self.nextCard()

    # Handlers
    ############################################################

    def _shortcutKeys(self):
        return [
            ("e", self.mw.onEditCurrent),
            (" ", self.onEnterKey),
            (Qt.Key_Return, self.onEnterKey),
            (Qt.Key_Enter, self.onEnterKey),
            ("r", self.replayAudio),
            (Qt.Key_F5, self.replayAudio),
            ("Ctrl+1", lambda: self.setFlag(1)),
            ("Ctrl+2", lambda: self.setFlag(2)),
            ("Ctrl+3", lambda: self.setFlag(3)),
            ("Ctrl+4", lambda: self.setFlag(4)),
            ("*", self.onMark),
            ("=", self.onBuryNote),
            ("-", self.onBuryCard),
            ("!", self.onSuspend),
            ("@", self.onSuspendCard),
            ("Ctrl+Delete", self.onDelete),
            ("v", self.onReplayRecorded),
            ("Shift+v", self.onRecordVoice),
            ("o", self.onOptions),
            ("1", lambda: self._answerCard(1)),
            ("2", lambda: self._answerCard(2)),
            ("3", lambda: self._answerCard(3)),
            ("4", lambda: self._answerCard(4)),
        ]

    def onEnterKey(self):
        if self.state == "question":
            self._getTypedAnswer()
        elif self.state == "answer":
            self.bottom.web.evalWithCallback("selectedAnswerButton()", self._onAnswerButton)

    def _onAnswerButton(self, val):
        # button selected?
        if val and val in "1234":
            self._answerCard(int(val))
        else:
            self._answerCard(self._defaultEase())

    def _linkHandler(self, url):
        if url == "ans":
            self._getTypedAnswer()
        elif url.startswith("ease"):
            self._answerCard(int(url[4:]))
        elif url == "edit":
            self.mw.onEditCurrent()
        elif url == "more":
            self.showContextMenu()
        else:
            print("unrecognized anki link:", url)

    # Type in the answer
    ##########################################################################

    typeAnsPat = r"\[\[type:(.+?)\]\]"

    def typeAnsFilter(self, buf):
        if self.state == "question":
            return self.typeAnsQuestionFilter(buf)
        else:
            return self.typeAnsAnswerFilter(buf)

    def typeAnsQuestionFilter(self, buf):
        self.typeCorrect = None
        clozeIdx = None
        m = re.search(self.typeAnsPat, buf)
        if not m:
            return buf
        fld = m.group(1)
        # if it's a cloze, extract data
        if fld.startswith("cloze:"):
            # get field and cloze position
            clozeIdx = self.card.ord + 1
            fld = fld.split(":")[1]
        # loop through fields for a match
        for f in self.card.model()['flds']:
            if f['name'] == fld:
                self.typeCorrect = self.card.note()[f['name']]
                if clozeIdx:
                    # narrow to cloze
                    self.typeCorrect = self._contentForCloze(
                        self.typeCorrect, clozeIdx)
                self.typeFont = f['font']
                self.typeSize = f['size']
                break
        if not self.typeCorrect:
            if self.typeCorrect is None:
                if clozeIdx:
                    warn = _("""\
Please run Tools>Empty Cards""")
                else:
                    warn = _("Type answer: unknown field %s") % fld
                return re.sub(self.typeAnsPat, warn, buf)
            else:
                # empty field, remove type answer pattern
                return re.sub(self.typeAnsPat, "", buf)
        return re.sub(self.typeAnsPat, """
<center>
<input type=text id=typeans onkeypress="_typeAnsPress();"
   style="font-family: '%s'; font-size: %spx;">
</center>
""" % (self.typeFont, self.typeSize), buf)

    def typeAnsAnswerFilter(self, buf):
        if not self.typeCorrect:
            return re.sub(self.typeAnsPat, "", buf)
        origSize = len(buf)
        buf = buf.replace("<hr id=answer>", "")
        hadHR = len(buf) != origSize
        # munge correct value
        parser = html.parser.HTMLParser()
        cor = self.mw.col.media.strip(self.typeCorrect)
        cor = re.sub("(\n|<br ?/?>|</?div>)+", " ", cor)
        cor = stripHTML(cor)
        # ensure we don't chomp multiple whitespace
        cor = cor.replace(" ", "&nbsp;")
        cor = parser.unescape(cor)
        cor = cor.replace("\xa0", " ")
        cor = cor.strip()
        given = self.typedAnswer
        # compare with typed answer
        res = self.correct(given, cor, showBad=False)
        # and update the type answer area
        def repl(match):
            # can't pass a string in directly, and can't use re.escape as it
            # escapes too much
            s = """
<span style="font-family: '%s'; font-size: %spx">%s</span>""" % (
                self.typeFont, self.typeSize, res)
            if hadHR:
                # a hack to ensure the q/a separator falls before the answer
                # comparison when user is using {{FrontSide}}
                s = "<hr id=answer>" + s
            return s
        return re.sub(self.typeAnsPat, repl, buf)

    def _contentForCloze(self, txt, idx):
        matches = re.findall(r"\{\{c%s::(.+?)\}\}"%idx, txt, re.DOTALL)
        if not matches:
            return None
        def noHint(txt):
            if "::" in txt:
                return txt.split("::")[0]
            return txt
        matches = [noHint(txt) for txt in matches]
        uniqMatches = set(matches)
        if len(uniqMatches) == 1:
            txt = matches[0]
        else:
            txt = ", ".join(matches)
        return txt

    def tokenizeComparison(self, given, correct):
        # compare in NFC form so accents appear correct
        given = ucd.normalize("NFC", given)
        correct = ucd.normalize("NFC", correct)
        s = difflib.SequenceMatcher(None, given, correct, autojunk=False)
        givenElems = []
        correctElems = []
        givenPoint = 0
        correctPoint = 0
        offby = 0
        def logBad(old, new, str, array):
            if old != new:
                array.append((False, str[old:new]))
        def logGood(start, cnt, str, array):
            if cnt:
                array.append((True, str[start:start+cnt]))
        for x, y, cnt in s.get_matching_blocks():
            # if anything was missed in correct, pad given
            if cnt and y-offby > x:
                givenElems.append((False, "-"*(y-x-offby)))
                offby = y-x
            # log any proceeding bad elems
            logBad(givenPoint, x, given, givenElems)
            logBad(correctPoint, y, correct, correctElems)
            givenPoint = x+cnt
            correctPoint = y+cnt
            # log the match
            logGood(x, cnt, given, givenElems)
            logGood(y, cnt, correct, correctElems)
        return givenElems, correctElems

    def correct(self, given, correct, showBad=True):
        "Diff-corrects the typed-in answer."
        givenElems, correctElems = self.tokenizeComparison(given, correct)
        def good(s):
            return "<span class=typeGood>"+html.escape(s)+"</span>"
        def bad(s):
            return "<span class=typeBad>"+html.escape(s)+"</span>"
        def missed(s):
            return "<span class=typeMissed>"+html.escape(s)+"</span>"
        if given == correct:
            res = good(given)
        else:
            res = ""
            for ok, txt in givenElems:
                txt = self._noLoneMarks(txt)
                if ok:
                    res += good(txt)
                else:
                    res += bad(txt)
            res += "<br>&darr;<br>"
            for ok, txt in correctElems:
                txt = self._noLoneMarks(txt)
                if ok:
                    res += good(txt)
                else:
                    res += missed(txt)
        res = "<div><code id=typeans>" + res + "</code></div>"
        return res

    def _noLoneMarks(self, s):
        # ensure a combining character at the start does not join to
        # previous text
        if s and ucd.category(s[0]).startswith("M"):
            return "\xa0" + s
        return s

    def _getTypedAnswer(self):
        self.web.evalWithCallback("typeans ? typeans.value : null", self._onTypedAnswer)

    def _onTypedAnswer(self, val):
        self.typedAnswer = val or ""
        self._showAnswer()

    # Bottom bar
    ##########################################################################

    def _bottomHTML(self):
        return """
<center id=outer>
<table id=innertable width=100%% cellspacing=0 cellpadding=0>
<tr>
<td align=left width=50 valign=top class=stat>
<br>
<button title="%(editkey)s" onclick="pycmd('edit');">%(edit)s</button></td>
<td align=center valign=top id=middle>
</td>
<td width=50 align=right valign=top class=stat><span id=time class=stattxt>
</span><br>
<button onclick="pycmd('more');">%(more)s %(downArrow)s</button>
</td>
</tr>
</table>
</center>
<script>
time = %(time)d;
</script>
""" % dict(rem=self._remaining(), edit=_("Edit"),
           editkey=_("Shortcut key: %s") % "E",
           more=_("More"),
           downArrow=downArrow(),
           time=self.card.timeTaken() // 1000)

    def _showAnswerButton(self):
        if not self.typeCorrect:
            self.bottom.web.setFocus()
        middle = '''
<span class=stattxt>%s</span><br>
<button title="%s" id=ansbut onclick='pycmd("ans");'>%s</button>''' % (
        self._remaining(), _("Shortcut key: %s") % _("Space"), _("Show Answer"))
        # wrap it in a table so it has the same top margin as the ease buttons
        middle = "<table cellpadding=0><tr><td class=stat2 align=center>%s</td></tr></table>" % middle
        if self.card.shouldShowTimer():
            maxTime = self.card.timeLimit() / 1000
        else:
            maxTime = 0
        self.bottom.web.eval("showQuestion(%s,%d);" % (
            json.dumps(middle), maxTime))
        self.bottom.web.adjustHeightToFit()

    def _showEaseButtons(self):
        self.bottom.web.setFocus()
        middle = self._answerButtons()
        self.bottom.web.eval("showAnswer(%s);" % json.dumps(middle))

    def _remaining(self):
        if not self.mw.col.conf['dueCounts']:
            return ""
        if self.hadCardQueue:
            # if it's come from the undo queue, don't count it separately
            counts = list(self.mw.col.sched.counts())
        else:
            counts = list(self.mw.col.sched.counts(self.card))
        idx = self.mw.col.sched.countIdx(self.card)
        counts[idx] = "<u>%s</u>" % (counts[idx])
        space = " + "
        ctxt = '<font color="#000099">%s</font>' % counts[0]
        ctxt += space + '<font color="#C35617">%s</font>' % counts[1]
        ctxt += space + '<font color="#007700">%s</font>' % counts[2]
        return ctxt

    def _defaultEase(self):
        if self.mw.col.sched.answerButtons(self.card) == 4:
            return 3
        else:
            return 2

    def _answerButtonList(self):
        l = ((1, _("Again")),)
        cnt = self.mw.col.sched.answerButtons(self.card)
        if cnt == 2:
            return l + ((2, _("Good")),)
        elif cnt == 3:
            return l + ((2, _("Good")), (3, _("Easy")))
        else:
            return l + ((2, _("Hard")), (3, _("Good")), (4, _("Easy")))

    def _answerButtons(self):
        default = self._defaultEase()
        def but(i, label):
            if i == default:
                extra = "id=defease"
            else:
                extra = ""
            due = self._buttonTime(i)
            return '''
<td align=center>%s<button %s title="%s" data-ease="%s" onclick='pycmd("ease%d");'>\
%s</button></td>''' % (due, extra, _("Shortcut key: %s") % i, i, i, label)
        buf = "<center><table cellpading=0 cellspacing=0><tr>"
        for ease, label in self._answerButtonList():
            buf += but(ease, label)
        buf += "</tr></table>"
        script = """
<script>$(function () { $("#defease").focus(); });</script>"""
        return buf + script

    def _buttonTime(self, i):
        if not self.mw.col.conf['estTimes']:
            return "<div class=spacer></div>"
        txt = self.mw.col.sched.nextIvlStr(self.card, i, True) or "&nbsp;"
        return '<span class=nobold>%s</span><br>' % txt

    # Leeches
    ##########################################################################

    def onLeech(self, card):
        # for now
        s = _("Card was a leech.")
        if card.queue < 0:
            s += " " + _("It has been suspended.")
        tooltip(s)

    # Context menu
    ##########################################################################

    # note the shortcuts listed here also need to be defined above
    def _contextMenu(self):
        currentFlag = self.card and self.card.userFlag()
        opts = [
            [_("Flag Card"), [
                [_("Red Flag"), "Ctrl+1", lambda: self.setFlag(1),
                 dict(checked=currentFlag == 1)],
                [_("Orange Flag"), "Ctrl+2", lambda: self.setFlag(2),
                 dict(checked=currentFlag == 2)],
                [_("Green Flag"), "Ctrl+3", lambda: self.setFlag(3),
                 dict(checked=currentFlag == 3)],
                [_("Blue Flag"), "Ctrl+4", lambda: self.setFlag(4),
                 dict(checked=currentFlag == 4)],
            ]],
            [_("Mark Note"), "*", self.onMark],
            [_("Bury Card"), "-", self.onBuryCard],
            [_("Bury Note"), "=", self.onBuryNote],
            [_("Suspend Card"), "@", self.onSuspendCard],
            [_("Suspend Note"), "!", self.onSuspend],
            [_("Delete Note"), "Ctrl+Delete", self.onDelete],
            [_("Options"), "O", self.onOptions],
            None,
            [_("Replay Audio"), "R", self.replayAudio],
            [_("Record Own Voice"), "Shift+V", self.onRecordVoice],
            [_("Replay Own Voice"), "V", self.onReplayRecorded],
        ]
        return opts
    
    def showContextMenu(self):
        opts = self._contextMenu()
        m = QMenu(self.mw)
        self._addMenuItems(m, opts)

        runHook("Reviewer.contextMenuEvent", self, m)
        qtMenuShortcutWorkaround(m)
        m.exec_(QCursor.pos())

    def _addMenuItems(self, m, rows):
        for row in rows:
            if not row:
                m.addSeparator()
                continue
            if len(row) == 2:
                subm = m.addMenu(row[0])
                self._addMenuItems(subm, row[1])
                qtMenuShortcutWorkaround(subm)
                continue
            if len(row) == 4:
                label, scut, func, opts = row
            else:
                label, scut, func = row
                opts = {}
            a = m.addAction(label)
            if scut:
                a.setShortcut(QKeySequence(scut))
            if opts.get("checked"):
                a.setCheckable(True)
                a.setChecked(True)
            a.triggered.connect(func)

    def onOptions(self):
        self.mw.onDeckConf(self.mw.col.decks.get(
            self.card.odid or self.card.did))

    def setFlag(self, flag):
        # need to toggle off?
        if self.card.userFlag() == flag:
            flag = 0
        self.card.setUserFlag(flag)
        self.card.flush()
        self._drawFlag()

    def onMark(self):
        f = self.card.note()
        if f.hasTag("marked"):
            f.delTag("marked")
        else:
            f.addTag("marked")
        f.flush()
        self._drawMark()

    def onSuspend(self):
        self.mw.checkpoint(_("Suspend"))
        self.mw.col.sched.suspendCards(
            [c.id for c in self.card.note().cards()])
        tooltip(_("Note suspended."))
        self.mw.reset()

    def onSuspendCard(self):
        self.mw.checkpoint(_("Suspend"))
        self.mw.col.sched.suspendCards([self.card.id])
        tooltip(_("Card suspended."))
        self.mw.reset()

    def onDelete(self):
        # need to check state because the shortcut is global to the main
        # window
        if self.mw.state != "review" or not self.card:
            return
        self.mw.checkpoint(_("Delete"))
        cnt = len(self.card.note().cards())
        self.mw.col.remNotes([self.card.note().id])
        self.mw.reset()
        tooltip(ngettext(
            "Note and its %d card deleted.",
            "Note and its %d cards deleted.",
            cnt) % cnt)

    def onBuryCard(self):
        self.mw.checkpoint(_("Bury"))
        self.mw.col.sched.buryCards([self.card.id])
        self.mw.reset()
        tooltip(_("Card buried."))

    def onBuryNote(self):
        self.mw.checkpoint(_("Bury"))
        self.mw.col.sched.buryNote(self.card.nid)
        self.mw.reset()
        tooltip(_("Note buried."))

    def onRecordVoice(self):
        self._recordedAudio = getAudio(self.mw, encode=False)
        self.onReplayRecorded()

    def onReplayRecorded(self):
        if not self._recordedAudio:
            return tooltip(_("You haven't recorded your voice yet."))
        clearAudioQueue()
        play(self._recordedAudio)