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

from __future__ import annotations

import copy
import os
import pprint
import random
import re
import time
import traceback
import weakref
from typing import Any, Iterable, List, Optional, Sequence, Tuple, Union

import anki.find
import anki.latex  # sets up hook
import anki.template
from anki import hooks
from anki.cards import Card
from anki.config import ConfigManager
from anki.consts import *
from anki.dbproxy import DBProxy
from anki.decks import DeckManager
from anki.errors import AnkiError
from anki.lang import _
from anki.media import MediaManager
from anki.models import ModelManager, NoteType, Template
from anki.notes import Note
from anki.rsbackend import TR, DBError, RustBackend
from anki.sched import Scheduler as V1Scheduler
from anki.schedv2 import Scheduler as V2Scheduler
from anki.tags import TagManager
from anki.utils import devMode, ids2str, intTime, joinFields


# this is initialized by storage.Collection
class _Collection:
    db: Optional[DBProxy]
    sched: Union[V1Scheduler, V2Scheduler]
    mod: int
    scm: int
    _usn: int
    ls: int
    _undo: List[Any]

    def __init__(
        self,
        db: DBProxy,
        backend: RustBackend,
        server: bool = False,
        log: bool = False,
    ) -> None:
        self.backend = backend
        self._debugLog = log
        self.db = db
        self.path = db._path
        self._openLog()
        self.log(self.path, anki.version)
        self.server = server
        self._lastSave = time.time()
        self.clearUndo()
        self.media = MediaManager(self, server)
        self.models = ModelManager(self)
        self.decks = DeckManager(self)
        self.tags = TagManager(self)
        self.conf = ConfigManager(self)
        self.load()
        self._loadScheduler()

    def name(self) -> Any:
        n = os.path.splitext(os.path.basename(self.path))[0]
        return n

    def tr(self, key: TR, **kwargs: Union[str, int, float]) -> str:
        return self.backend.translate(key, **kwargs)

    def weakref(self) -> anki.storage._Collection:
        "Shortcut to create a weak reference that doesn't break code completion."
        return weakref.proxy(self)

    # Scheduler
    ##########################################################################

    supportedSchedulerVersions = (1, 2)

    def schedVer(self) -> Any:
        ver = self.conf.get("schedVer", 1)
        if ver in self.supportedSchedulerVersions:
            return ver
        else:
            raise Exception("Unsupported scheduler version")

    def _loadScheduler(self) -> None:
        ver = self.schedVer()
        if ver == 1:
            self.sched = V1Scheduler(self)
        elif ver == 2:
            self.sched = V2Scheduler(self)

    def changeSchedulerVer(self, ver: int) -> None:
        if ver == self.schedVer():
            return
        if ver not in self.supportedSchedulerVersions:
            raise Exception("Unsupported scheduler version")

        self.modSchema(check=True)
        self.clearUndo()

        v2Sched = V2Scheduler(self)

        if ver == 1:
            v2Sched.moveToV1()
        else:
            v2Sched.moveToV2()

        self.conf["schedVer"] = ver
        self.setMod()

        self._loadScheduler()

    # the sync code uses this to send the local timezone to AnkiWeb
    def localOffset(self) -> Optional[int]:
        "Minutes west of UTC. Only applies to V2 scheduler."
        if isinstance(self.sched, V1Scheduler):
            return None
        else:
            return self.backend.local_minutes_west(intTime())

    # DB-related
    ##########################################################################

    def load(self) -> None:
        (self.mod, self.scm, self._usn, self.ls,) = self.db.first(
            """
select mod, scm, usn, ls from col"""
        )

    def _get_crt(self) -> int:
        return self.db.scalar("select crt from col")

    def _set_crt(self, val: int) -> None:
        self.db.execute("update col set crt=?", val)

    crt = property(_get_crt, _set_crt)

    def setMod(self) -> None:
        """Mark DB modified.

DB operations and the deck/model managers do this automatically, so this
is only necessary if you modify properties of this object."""
        self.db.mod = True

    def flush(self, mod: Optional[int] = None) -> None:
        "Flush state to DB, updating mod time."
        self.mod = intTime(1000) if mod is None else mod
        self.db.execute(
            """update col set
mod=?, scm=?, usn=?, ls=?""",
            self.mod,
            self.scm,
            self._usn,
            self.ls,
        )

    def flush_all_changes(self, mod: Optional[int] = None):
        self.models.flush()
        self.decks.flush()
        # set mod flag if mtime changed by backend
        if self.db.scalar("select mod from col") != self.mod:
            self.db.mod = True
        if self.db.mod:
            self.flush(mod)

    def save(
        self, name: Optional[str] = None, mod: Optional[int] = None, trx: bool = True
    ) -> None:
        "Flush, commit DB, and take out another write lock if trx=True."
        self.flush_all_changes(mod)
        # and flush deck + bump mod if db has been changed
        if self.db.mod:
            self.db.commit()
            self.db.mod = False
            if trx:
                self.db.begin()
        elif not trx:
            # if no changes were pending but calling code expects to be
            # outside of a transaction, we need to roll back
            self.db.rollback()

        self._markOp(name)
        self._lastSave = time.time()

    def autosave(self) -> Optional[bool]:
        "Save if 5 minutes has passed since last save. True if saved."
        if time.time() - self._lastSave > 300:
            self.save()
            return True
        return None

    def close(self, save: bool = True, downgrade: bool = False) -> None:
        "Disconnect from DB."
        if self.db:
            if save:
                self.save(trx=False)
            else:
                self.db.rollback()
            self.models._clear_cache()
            self.backend.close_collection(downgrade=downgrade)
            self.db = None
            self.media.close()
            self._closeLog()

    def rollback(self) -> None:
        self.db.rollback()
        self.db.begin()
        self.load()

    def modSchema(self, check: bool) -> None:
        "Mark schema modified. Call this first so user can abort if necessary."
        if not self.schemaChanged():
            if check and not hooks.schema_will_change(proceed=True):
                raise AnkiError("abortSchemaMod")
        self.scm = intTime(1000)
        self.setMod()
        self.save()

    def schemaChanged(self) -> Any:
        "True if schema changed since last sync."
        return self.scm > self.ls

    def usn(self) -> Any:
        return self._usn if self.server else -1

    def beforeUpload(self) -> None:
        "Called before a full upload."
        tbls = "notes", "cards", "revlog"
        for t in tbls:
            self.db.execute("update %s set usn=0 where usn=-1" % t)
        # we can save space by removing the log of deletions
        self.db.execute("delete from graves")
        self._usn += 1
        self.models.beforeUpload()
        self.decks.beforeUpload()
        self.backend.before_upload()
        self.modSchema(check=False)
        self.ls = self.scm
        # ensure db is compacted before upload
        self.save(trx=False)
        self.db.execute("vacuum")
        self.db.execute("analyze")
        self.close(save=False, downgrade=True)

    # Object creation helpers
    ##########################################################################

    def getCard(self, id: int) -> Card:
        return Card(self, id)

    def getNote(self, id: int) -> Note:
        return Note(self, id=id)

    # Utils
    ##########################################################################

    def nextID(self, type: str, inc: bool = True) -> Any:
        type = "next" + type.capitalize()
        id = self.conf.get(type, 1)
        if inc:
            self.conf[type] = id + 1
        return id

    def reset(self) -> None:
        "Rebuild the queue and reload data after DB modified."
        self.sched.reset()

    # Deletion logging
    ##########################################################################

    def _logRem(self, ids: List[int], type: int) -> None:
        self.db.executemany(
            "insert into graves values (%d, ?, %d)" % (self.usn(), type),
            ([x] for x in ids),
        )

    # Notes
    ##########################################################################

    def noteCount(self) -> Any:
        return self.db.scalar("select count() from notes")

    def newNote(self, forDeck: bool = True) -> Note:
        "Return a new note with the current model."
        return Note(self, self.models.current(forDeck))

    def add_note(self, note: Note, deck_id: int) -> None:
        note.id = self.backend.add_note(note.to_backend_note(), deck_id)

    def addNote(self, note: Note) -> int:
        self.add_note(note, note.model()["did"])
        return len(note.cards())

    def remNotes(self, ids: Iterable[int]) -> None:
        """Deletes notes with the given IDs."""
        self.remCards(self.db.list("select id from cards where nid in " + ids2str(ids)))

    def _remNotes(self, ids: List[int]) -> None:
        """Bulk delete notes by ID. Don't call this directly."""
        if not ids:
            return
        strids = ids2str(ids)
        # we need to log these independently of cards, as one side may have
        # more card templates
        hooks.notes_will_be_deleted(self, ids)
        self._logRem(ids, REM_NOTE)
        self.db.execute("delete from notes where id in %s" % strids)

    # Card creation
    ##########################################################################

    def findTemplates(self, note: Note) -> List:
        "Return (active), non-empty templates."
        model = note.model()
        avail = self.models.availOrds(model, joinFields(note.fields))
        return self._tmplsFromOrds(model, avail)

    def _tmplsFromOrds(self, model: NoteType, avail: List[int]) -> List:
        ok = []
        if model["type"] == MODEL_STD:
            for t in model["tmpls"]:
                if t["ord"] in avail:
                    ok.append(t)
        else:
            # cloze - generate temporary templates from first
            for ord in avail:
                t = copy.copy(model["tmpls"][0])
                t["ord"] = ord
                ok.append(t)
        return ok

    # type is no longer used
    def previewCards(
        self, note: Note, type: int = 0, did: Optional[int] = None
    ) -> List:
        existing_cards = {}
        for card in note.cards():
            existing_cards[card.ord] = card

        all_cards = []
        for idx, template in enumerate(note.model()["tmpls"]):
            if idx in existing_cards:
                all_cards.append(existing_cards[idx])
            else:
                # card not currently in database, generate an ephemeral one
                all_cards.append(self._newCard(note, template, 1, flush=False, did=did))

        return all_cards

    def _newCard(
        self,
        note: Note,
        template: Template,
        due: int,
        flush: bool = True,
        did: Optional[int] = None,
    ) -> Card:
        "Create a new card."
        card = Card(self)
        card.nid = note.id
        card.ord = template["ord"]  # type: ignore
        card.did = self.db.scalar(
            "select did from cards where nid = ? and ord = ?", card.nid, card.ord
        )
        # Use template did (deck override) if valid, otherwise did in argument, otherwise model did
        if not card.did:
            if template["did"] and str(template["did"]) in self.decks.decks:
                card.did = int(template["did"])
            elif did:
                card.did = did
            else:
                card.did = note.model()["did"]
        # if invalid did, use default instead
        deck = self.decks.get(card.did)
        assert deck
        if deck["dyn"]:
            # must not be a filtered deck
            card.did = 1
        else:
            card.did = deck["id"]
        card.due = self._dueForDid(card.did, due)
        if flush:
            card.flush()
        return card

    def _dueForDid(self, did: int, due: int) -> int:
        conf = self.decks.confForDid(did)
        # in order due?
        if conf["new"]["order"] == NEW_CARDS_DUE:
            return due
        else:
            # random mode; seed with note ts so all cards of this note get the
            # same random number
            r = random.Random()
            r.seed(due)
            return r.randrange(1, max(due, 1000))

    # Cards
    ##########################################################################

    def isEmpty(self) -> bool:
        return not self.db.scalar("select 1 from cards limit 1")

    def cardCount(self) -> Any:
        return self.db.scalar("select count() from cards")

    def remCards(self, ids: List[int], notes: bool = True) -> None:
        "Bulk delete cards by ID."
        if not ids:
            return
        sids = ids2str(ids)
        nids = self.db.list("select nid from cards where id in " + sids)
        # remove cards
        self._logRem(ids, REM_CARD)
        self.db.execute("delete from cards where id in " + sids)
        # then notes
        if not notes:
            return
        nids = self.db.list(
            """
select id from notes where id in %s and id not in (select nid from cards)"""
            % ids2str(nids)
        )
        self._remNotes(nids)

    def emptyCids(self) -> List[int]:
        print("emptyCids() will go away")
        return []

    # Card generation & field checksums/sort fields
    ##########################################################################

    def after_note_updates(
        self, nids: List[int], mark_modified: bool, generate_cards: bool = True
    ) -> None:
        self.backend.after_note_updates(
            nids=nids, generate_cards=generate_cards, mark_notes_modified=mark_modified
        )

    # legacy

    def updateFieldCache(self, nids: List[int]) -> None:
        self.after_note_updates(nids, mark_modified=False, generate_cards=False)

    # this also updates field cache
    def genCards(self, nids: List[int]) -> List[int]:
        self.after_note_updates(nids, mark_modified=False, generate_cards=True)
        # previously returned empty cards, no longer does
        return []

    # Finding cards
    ##########################################################################

    # if order=True, use the sort order stored in the collection config
    # if order=False, do no ordering
    #
    # if order is a string, that text is added after 'order by' in the sql statement.
    # you must add ' asc' or ' desc' to the order, as Anki will replace asc with
    # desc and vice versa when reverse is set in the collection config, eg
    # order="c.ivl asc, c.due desc"
    #
    # if order is an int enum, sort using that builtin sort, eg
    # col.find_cards("", order=BuiltinSortKind.CARD_DUE)
    # the reverse argument only applies when a BuiltinSortKind is provided;
    # otherwise the collection config defines whether reverse is set or not
    def find_cards(
        self, query: str, order: Union[bool, str, int] = False, reverse: bool = False,
    ) -> Sequence[int]:
        self.flush_all_changes()
        return self.backend.search_cards(query, order, reverse)

    def find_notes(self, query: str) -> Sequence[int]:
        self.flush_all_changes()
        return self.backend.search_notes(query)

    def find_and_replace(
        self,
        nids: List[int],
        src: str,
        dst: str,
        regex: Optional[bool] = None,
        field: Optional[str] = None,
        fold: bool = True,
    ) -> int:
        return anki.find.findReplace(self, nids, src, dst, regex, field, fold)

    def findDupes(self, fieldName: str, search: str = "") -> List[Tuple[Any, list]]:
        return anki.find.findDupes(self, fieldName, search)

    findCards = find_cards
    findNotes = find_notes
    findReplace = find_and_replace

    # Config
    ##########################################################################

    def get_config(self, key: str, default: Any = None) -> Any:
        try:
            return self.conf.get_immutable(key)
        except KeyError:
            return default

    def set_config(self, key: str, val: Any):
        self.setMod()
        self.conf.set(key, val)

    def remove_config(self, key):
        self.setMod()
        self.conf.remove(key)

    # Stats
    ##########################################################################

    def cardStats(self, card: Card) -> str:
        from anki.stats import CardStats

        return CardStats(self, card).report()

    def stats(self) -> "anki.stats.CollectionStats":
        from anki.stats import CollectionStats

        return CollectionStats(self)

    # Timeboxing
    ##########################################################################

    def startTimebox(self) -> None:
        self._startTime = time.time()
        self._startReps = self.sched.reps

    # FIXME: Use Literal[False] when on Python 3.8
    def timeboxReached(self) -> Union[bool, Tuple[Any, int]]:
        "Return (elapsedTime, reps) if timebox reached, or False."
        if not self.conf["timeLim"]:
            # timeboxing disabled
            return False
        elapsed = time.time() - self._startTime
        if elapsed > self.conf["timeLim"]:
            return (self.conf["timeLim"], self.sched.reps - self._startReps)
        return False

    # Undo
    ##########################################################################

    def clearUndo(self) -> None:
        # [type, undoName, data]
        # type 1 = review; type 2 = checkpoint
        self._undo = None

    def undoName(self) -> Any:
        "Undo menu item name, or None if undo unavailable."
        if not self._undo:
            return None
        return self._undo[1]

    def undo(self) -> Any:
        if self._undo[0] == 1:
            return self._undoReview()
        else:
            self._undoOp()

    def markReview(self, card: Card) -> None:
        old: List[Any] = []
        if self._undo:
            if self._undo[0] == 1:
                old = self._undo[2]
            self.clearUndo()
        wasLeech = card.note().hasTag("leech") or False
        self._undo = [1, _("Review"), old + [copy.copy(card)], wasLeech]

    def _undoReview(self) -> Any:
        data = self._undo[2]
        wasLeech = self._undo[3]
        c = data.pop()  # pytype: disable=attribute-error
        if not data:
            self.clearUndo()
        # remove leech tag if it didn't have it before
        if not wasLeech and c.note().hasTag("leech"):
            c.note().delTag("leech")
            c.note().flush()
        # write old data
        c.flush()
        # and delete revlog entry
        last = self.db.scalar(
            "select id from revlog where cid = ? " "order by id desc limit 1", c.id
        )
        self.db.execute("delete from revlog where id = ?", last)
        # restore any siblings
        self.db.execute(
            "update cards set queue=type,mod=?,usn=? where queue=-2 and nid=?",
            intTime(),
            self.usn(),
            c.nid,
        )
        # and finally, update daily counts
        n = 1 if c.queue in (3, 4) else c.queue
        type = ("new", "lrn", "rev")[n]
        self.sched._updateStats(c, type, -1)
        self.sched.reps -= 1
        return c.id

    def _markOp(self, name: Optional[str]) -> None:
        "Call via .save()"
        if name:
            self._undo = [2, name]
        else:
            # saving disables old checkpoint, but not review undo
            if self._undo and self._undo[0] == 2:
                self.clearUndo()

    def _undoOp(self) -> None:
        self.rollback()
        self.clearUndo()

    # DB maintenance
    ##########################################################################

    def basicCheck(self) -> bool:
        "Basic integrity check for syncing. True if ok."
        # cards without notes
        if self.db.scalar(
            """
select 1 from cards where nid not in (select id from notes) limit 1"""
        ):
            return False
        # notes without cards or models
        if self.db.scalar(
            """
select 1 from notes where id not in (select distinct nid from cards)
or mid not in %s limit 1"""
            % ids2str(self.models.ids())
        ):
            return False
        # invalid ords
        for m in self.models.all():
            # ignore clozes
            if m["type"] != MODEL_STD:
                continue
            if self.db.scalar(
                """
select 1 from cards where ord not in %s and nid in (
select id from notes where mid = ?) limit 1"""
                % ids2str([t["ord"] for t in m["tmpls"]]),
                m["id"],
            ):
                return False
        return True

    def fixIntegrity(self) -> Tuple[str, bool]:
        """Fix possible problems and rebuild caches.

        Returns tuple of (error: str, ok: bool). 'ok' will be true if no
        problems were found.
        """
        self.save(trx=False)
        try:
            problems = self.backend.check_database()
            ok = not problems
            problems.append(self.tr(TR.DATABASE_CHECK_REBUILT))
        except DBError as e:
            problems = [str(e.args[0])]
            ok = False
        finally:
            try:
                self.db.begin()
            except:
                # may fail if the DB is very corrupt
                pass
        return ("\n".join(problems), ok)

    def optimize(self) -> None:
        self.save(trx=False)
        self.db.execute("vacuum")
        self.db.execute("analyze")
        self.db.begin()

    # Logging
    ##########################################################################

    def log(self, *args, **kwargs) -> None:
        if not self._debugLog:
            return

        def customRepr(x):
            if isinstance(x, str):
                return x
            return pprint.pformat(x)

        path, num, fn, y = traceback.extract_stack(limit=2 + kwargs.get("stack", 0))[0]
        buf = "[%s] %s:%s(): %s" % (
            intTime(),
            os.path.basename(path),
            fn,
            ", ".join([customRepr(x) for x in args]),
        )
        self._logHnd.write(buf + "\n")
        if devMode:
            print(buf)

    def _openLog(self) -> None:
        if not self._debugLog:
            return
        lpath = re.sub(r"\.anki2$", ".log", self.path)
        if os.path.exists(lpath) and os.path.getsize(lpath) > 10 * 1024 * 1024:
            lpath2 = lpath + ".old"
            if os.path.exists(lpath2):
                os.unlink(lpath2)
            os.rename(lpath, lpath2)
        self._logHnd = open(lpath, "a", encoding="utf8")

    def _closeLog(self) -> None:
        if not self._debugLog:
            return
        self._logHnd.close()
        self._logHnd = None

    # Card Flags
    ##########################################################################

    def setUserFlag(self, flag: int, cids: List[int]) -> None:
        assert 0 <= flag <= 7
        self.db.execute(
            "update cards set flags = (flags & ~?) | ?, usn=?, mod=? where id in %s"
            % ids2str(cids),
            0b111,
            flag,
            self.usn(),
            intTime(),
        )