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

# Taken from https://github.com/ankitects/anki/blob/cca3fcb2418880d0430a5c5c2e6b81ba260065b7/anki/sync.py

import io
import gzip
import random
import requests
import json
import os
from typing import List,Tuple

from anki.db import DB, DBError
from anki.utils import ids2str, intTime, platDesc, checksum, devMode
from anki.consts import *
from anki.config import ConfigManager
from anki.utils import versionWithBuild
import anki
from anki.lang import ngettext


# https://github.com/ankitects/anki/blob/04b1ca75599f18eb783a8bf0bdeeeb32362f4da0/rslib/src/sync/http_client.rs#L11
SYNC_VER = 10
# https://github.com/ankitects/anki/blob/cca3fcb2418880d0430a5c5c2e6b81ba260065b7/anki/consts.py#L50
SYNC_ZIP_SIZE = int(2.5*1024*1024)
# https://github.com/ankitects/anki/blob/cca3fcb2418880d0430a5c5c2e6b81ba260065b7/anki/consts.py#L51
SYNC_ZIP_COUNT = 25

# syncing vars
HTTP_TIMEOUT = 90
HTTP_PROXY = None
HTTP_BUF_SIZE = 64*1024

# Incremental syncing
##########################################################################

class Syncer(object):
    def __init__(self, col, server=None):
        self.col = col
        self.server = server

    def meta(self):
        return dict(
            mod=self.col.mod,
            scm=self.col.scm,
            usn=self.col._usn,
            ts=intTime(),
            musn=0,
            msg="",
            cont=True
        )

    def changes(self):
        "Bundle up small objects."
        d = dict(models=self.getModels(),
                 decks=self.getDecks(),
                 tags=self.getTags())
        if self.lnewer:
            d['conf'] = json.loads(self.col.backend.get_all_config())
            d['crt'] = self.col.crt
        return d

    def mergeChanges(self, lchg, rchg):
        # then the other objects
        self.mergeModels(rchg['models'])
        self.mergeDecks(rchg['decks'])
        self.mergeTags(rchg['tags'])
        if 'conf' in rchg:
            self.mergeConf(rchg['conf'])
        # this was left out of earlier betas
        if 'crt' in rchg:
            self.col.crt = rchg['crt']
        self.prepareToChunk()

    def sanityCheck(self, full):
        if not self.col.basicCheck():
            return "failed basic check"
        for t in "cards", "notes", "revlog", "graves":
            if self.col.db.scalar(
                "select count() from %s where usn = -1" % t):
                return "%s had usn = -1" % t
        for g in self.col.decks.all():
            if g['usn'] == -1:
                return "deck had usn = -1"
        for t, usn in self.allItems():
            if usn == -1:
                return "tag had usn = -1"
        found = False
        for m in self.col.models.all():
            if m['usn'] == -1:
                return "model had usn = -1"
        if found:
            self.col.models.save()
        self.col.sched.reset()
        # check for missing parent decks
        #self.col.sched.deckDueList()
        # return summary of deck
        return [
            list(self.col.sched.counts()),
            self.col.db.scalar("select count() from cards"),
            self.col.db.scalar("select count() from notes"),
            self.col.db.scalar("select count() from revlog"),
            self.col.db.scalar("select count() from graves"),
            len(self.col.models.all()),
            len(self.col.decks.all()),
            len(self.col.decks.allConf()),
        ]

    def usnLim(self):
        return "usn = -1"

    def finish(self, mod=None):
        self.col.ls = mod
        self.col._usn = self.maxUsn + 1
        # ensure we save the mod time even if no changes made
        self.col.db.mod = True
        self.col.save(mod=mod)
        return mod

    # Chunked syncing
    ##########################################################################

    def prepareToChunk(self):
        self.tablesLeft = ["revlog", "cards", "notes"]
        self.cursor = None

    def queryTable(self, table):
        lim = self.usnLim()
        if table == "revlog":
            return self.col.db.execute("""
select id, cid, ?, ease, ivl, lastIvl, factor, time, type
from revlog where %s""" % lim, self.maxUsn)
        elif table == "cards":
            return self.col.db.execute("""
select id, nid, did, ord, mod, ?, type, queue, due, ivl, factor, reps,
lapses, left, odue, odid, flags, data from cards where %s""" % lim, self.maxUsn)
        else:
            return self.col.db.execute("""
select id, guid, mid, mod, ?, tags, flds, '', '', flags, data
from notes where %s""" % lim, self.maxUsn)

    def chunk(self):
        buf = dict(done=False)
        while self.tablesLeft:
            curTable = self.tablesLeft.pop()
            buf[curTable] = self.queryTable(curTable)
            self.col.db.execute(
                f"update {curTable} set usn=? where usn=-1", self.maxUsn
            )
        if not self.tablesLeft:
            buf['done'] = True
        return buf

    def applyChunk(self, chunk):
        if "revlog" in chunk:
            self.mergeRevlog(chunk['revlog'])
        if "cards" in chunk:
            self.mergeCards(chunk['cards'])
        if "notes" in chunk:
            self.mergeNotes(chunk['notes'])

    # Deletions
    ##########################################################################

    def removed(self):
        cards = []
        notes = []
        decks = []

        curs = self.col.db.execute(
            "select oid, type from graves where usn = -1")

        for oid, type in curs:
            if type == REM_CARD:
                cards.append(oid)
            elif type == REM_NOTE:
                notes.append(oid)
            else:
                decks.append(oid)

        self.col.db.execute("update graves set usn=? where usn=-1",
                             self.maxUsn)

        return dict(cards=cards, notes=notes, decks=decks)

    def remove(self, graves):
        # remove card and the card's orphaned notes
        self.col.remove_cards_and_orphaned_notes(graves['cards'])

        # only notes
        self.col.remove_notes(graves['notes'])

        # since level 0 deck ,we only remove deck ,but backend will delete child,it is ok, the delete
        # will have once effect
        for oid in graves['decks']:
            self.col.decks.rem(oid)


      # we can place non-exist grave after above delete.
        localgcards = []
        localgnotes = []
        localgdecks = []
        curs = self.col.db.execute(
            "select oid, type from graves where usn = %d" % self.col.usn())

        for oid, type in curs:
            if type == REM_CARD:
                localgcards.append(oid)
            elif type == REM_NOTE:
                localgnotes.append(oid)
            else:
                localgdecks.append(oid)

        # n meaning non-exsiting grave in the server compared to client
        ncards =  [ oid for oid in graves['cards'] if oid not in localgcards]
        for oid in ncards:
             self.col._logRem([oid], REM_CARD)

        nnotes =  [ oid for oid in graves['notes'] if oid not in localgnotes]
        for oid in nnotes:
             self.col._logRem([oid], REM_NOTE)

        ndecks =  [ oid for oid in graves['decks'] if oid not in localgdecks]
        for oid in ndecks:
             self.col._logRem([oid], REM_DECK)

    # Models
    ##########################################################################

    def getModels(self):
        mods = [m for m in self.col.models.all() if m['usn'] == -1]
        for m in mods:
            m['usn'] = self.maxUsn
        self.col.models.save()
        return mods

    def mergeModels(self, rchg):
        for r in rchg:
            l = self.col.models.get(r['id'])
            # if missing locally or server is newer, update
            if not l or r['mod'] > l['mod']:
                self.col.models.update(r)

    # Decks
    ##########################################################################

    def getDecks(self):
        decks = [g for g in self.col.decks.all() if g['usn'] == -1]
        for g in decks:
            g['usn'] = self.maxUsn
        dconf = [g for g in self.col.decks.allConf() if g['usn'] == -1]
        for g in dconf:
            g['usn'] = self.maxUsn
        self.col.decks.save()
        return [decks, dconf]

    def mergeDecks(self, rchg):
        for r in rchg[0]:
            l = self.col.decks.get(r['id'], False)
            # work around mod time being stored as string
            if l and not isinstance(l['mod'], int):
                l['mod'] = int(l['mod'])

            # if missing locally or server is newer, update
            if not l or r['mod'] > l['mod']:
                self.col.decks.update(r)
        for r in rchg[1]:
            try:
                l = self.col.decks.getConf(r['id'])
            except KeyError:
                l = None
            # if missing locally or server is newer, update
            if not l or r['mod'] > l['mod']:
                self.col.decks.updateConf(r)

    # Tags
    ##########################################################################
    def allItems(self) -> List[Tuple[str, int]]:
        tags=self.col.db.execute("select tag, usn from tags")
        return [(tag, int(usn)) for tag,usn in tags]
    def getTags(self):
        tags = []
        for t, usn in self.allItems():
            if usn == -1:
                self.col.tags.tags[t] = self.maxUsn
                tags.append(t)
        self.col.tags.save()
        return tags

    def mergeTags(self, tags):
        self.col.tags.register(tags, usn=self.maxUsn)

    # Cards/notes/revlog
    ##########################################################################

    def mergeRevlog(self, logs):
        self.col.db.executemany(
            "insert or ignore into revlog values (?,?,?,?,?,?,?,?,?)",
            logs)

    def newerRows(self, data, table, modIdx):
        ids = (r[0] for r in data)
        lmods = {}
        for id, mod in self.col.db.execute(
            "select id, mod from %s where id in %s and %s" % (
                table, ids2str(ids), self.usnLim())):
            lmods[id] = mod
        update = []
        for r in data:
            if r[0] not in lmods or lmods[r[0]] < r[modIdx]:
                update.append(r)
        self.col.log(table, data)
        return update

    def mergeCards(self, cards):
        self.col.db.executemany(
            "insert or replace into cards values "
            "(?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)",
            self.newerRows(cards, "cards", 4))

    def mergeNotes(self, notes):
        rows = self.newerRows(notes, "notes", 3)
        self.col.db.executemany(
            "insert or replace into notes values (?,?,?,?,?,?,?,?,?,?,?)",
            rows)
        self.col.updateFieldCache([f[0] for f in rows])

    # Col config
    ##########################################################################

    def getConf(self):
        return self.col.conf

    def mergeConf(self, conf):
        for key, value in conf.items():
            self.col.set_config(key, value)
#         self.col.backend.set_all_config(json.dumps(conf).encode())

# Wrapper for requests that tracks upload/download progress
##########################################################################

class AnkiRequestsClient(object):
    verify = True
    timeout = 60

    def __init__(self):
        self.session = requests.Session()

    def post(self, url, data, headers):
        data = _MonitoringFile(data)
        headers['User-Agent'] = self._agentName()
        return self.session.post(
            url, data=data, headers=headers, stream=True, timeout=self.timeout, verify=self.verify)

    def get(self, url, headers=None):
        if headers is None:
            headers = {}
        headers['User-Agent'] = self._agentName()
        return self.session.get(url, stream=True, headers=headers, timeout=self.timeout, verify=self.verify)

    def streamContent(self, resp):
        resp.raise_for_status()

        buf = io.BytesIO()
        for chunk in resp.iter_content(chunk_size=HTTP_BUF_SIZE):
            buf.write(chunk)
        return buf.getvalue()

    def _agentName(self):
        from anki import version
        return "Anki {}".format(version)

# allow user to accept invalid certs in work/school settings
if os.environ.get("ANKI_NOVERIFYSSL"):
    AnkiRequestsClient.verify = False

    import warnings
    warnings.filterwarnings("ignore")

class _MonitoringFile(io.BufferedReader):
    def read(self, size=-1):
        data = io.BufferedReader.read(self, HTTP_BUF_SIZE)

        return data

# HTTP syncing tools
##########################################################################

class HttpSyncer(object):
    def __init__(self, hkey=None, client=None, hostNum=None):
        self.hkey = hkey
        self.skey = checksum(str(random.random()))[:8]
        self.client = client or AnkiRequestsClient()
        self.postVars = {}
        self.hostNum = hostNum
        self.prefix = "sync/"

    def syncURL(self):
        if devMode:
            url = "https://l1sync.ankiweb.net/"
        else:
            url = SYNC_BASE % (self.hostNum or "")
        return url + self.prefix

    def assertOk(self, resp):
        # not using raise_for_status() as aqt expects this error msg
        if resp.status_code != 200:
            raise Exception("Unknown response code: %s" % resp.status_code)

    # Posting data as a file
    ######################################################################
    # We don't want to post the payload as a form var, as the percent-encoding is
    # costly. We could send it as a raw post, but more HTTP clients seem to
    # support file uploading, so this is the more compatible choice.

    def _buildPostData(self, fobj, comp):
        BOUNDARY=b"Anki-sync-boundary"
        bdry = b"--"+BOUNDARY
        buf = io.BytesIO()
        # post vars
        self.postVars['c'] = 1 if comp else 0
        for (key, value) in list(self.postVars.items()):
            buf.write(bdry + b"\r\n")
            buf.write(
                ('Content-Disposition: form-data; name="%s"\r\n\r\n%s\r\n' %
                (key, value)).encode("utf8"))
        # payload as raw data or json
        rawSize = 0
        if fobj:
            # header
            buf.write(bdry + b"\r\n")
            buf.write(b"""\
Content-Disposition: form-data; name="data"; filename="data"\r\n\
Content-Type: application/octet-stream\r\n\r\n""")
            # write file into buffer, optionally compressing
            if comp:
                tgt = gzip.GzipFile(mode="wb", fileobj=buf, compresslevel=comp)
            else:
                tgt = buf
            while 1:
                data = fobj.read(65536)
                if not data:
                    if comp:
                        tgt.close()
                    break
                rawSize += len(data)
                tgt.write(data)
            buf.write(b"\r\n")
        buf.write(bdry + b'--\r\n')
        size = buf.tell()
        # connection headers
        headers = {
            'Content-Type': 'multipart/form-data; boundary=%s' % BOUNDARY.decode("utf8"),
            'Content-Length': str(size),
        }
        buf.seek(0)

        if size >= 100*1024*1024 or rawSize >= 250*1024*1024:
            raise Exception("Collection too large to upload to AnkiWeb.")

        return headers, buf

    def req(self, method, fobj=None, comp=6, badAuthRaises=True):
        headers, body = self._buildPostData(fobj, comp)

        r = self.client.post(self.syncURL()+method, data=body, headers=headers)
        if not badAuthRaises and r.status_code == 403:
            return False
        self.assertOk(r)

        buf = self.client.streamContent(r)
        return buf

# Incremental sync over HTTP
######################################################################

class RemoteServer(HttpSyncer):
    def __init__(self, hkey, hostNum):
        super().__init__(self, hkey, hostNum=hostNum)

    def hostKey(self, user, pw):
        "Returns hkey or none if user/pw incorrect."
        self.postVars = dict()
        ret = self.req(
            "hostKey", io.BytesIO(json.dumps(dict(u=user, p=pw)).encode("utf8")),
            badAuthRaises=False)
        if not ret:
            # invalid auth
            return
        self.hkey = json.loads(ret.decode("utf8"))['key']
        return self.hkey

    def meta(self):
        self.postVars = dict(
            k=self.hkey,
            s=self.skey,
        )
        ret = self.req(
            "meta", io.BytesIO(json.dumps(dict(
                v=SYNC_VER, cv="ankidesktop,%s,%s"%(versionWithBuild(), platDesc()))).encode("utf8")),
            badAuthRaises=False)
        if not ret:
            # invalid auth
            return
        return json.loads(ret.decode("utf8"))

    def applyGraves(self, **kw):
        return self._run("applyGraves", kw)

    def applyChanges(self, **kw):
        return self._run("applyChanges", kw)

    def start(self, **kw):
        return self._run("start", kw)

    def chunk(self, **kw):
        return self._run("chunk", kw)

    def applyChunk(self, **kw):
        return self._run("applyChunk", kw)

    def sanityCheck2(self, **kw):
        return self._run("sanityCheck2", kw)

    def finish(self, **kw):
        return self._run("finish", kw)

    def abort(self, **kw):
        return self._run("abort", kw)

    def _run(self, cmd, data):
        return json.loads(
            self.req(cmd, io.BytesIO(json.dumps(data).encode("utf8"))).decode("utf8"))

# Full syncing
##########################################################################

class FullSyncer(HttpSyncer):
    def __init__(self, col, hkey, client, hostNum):
        super().__init__(self, hkey, client, hostNum=hostNum)
        self.postVars = dict(
            k=self.hkey,
            v="ankidesktop,%s,%s"%(anki.version, platDesc()),
        )
        self.col = col

    def download(self):
        localNotEmpty = self.col.db.scalar("select 1 from cards")
        self.col.close()
        cont = self.req("download")
        tpath = self.col.path + ".tmp"
        if cont == "upgradeRequired":
            return
        open(tpath, "wb").write(cont)
        # check the received file is ok
        d = DB(tpath)
        assert d.scalar("pragma integrity_check") == "ok"
        remoteEmpty = not d.scalar("select 1 from cards")
        d.close()
        # accidental clobber?
        if localNotEmpty and remoteEmpty:
            os.unlink(tpath)
            return "downloadClobber"
        # overwrite existing collection
        os.unlink(self.col.path)
        os.rename(tpath, self.col.path)
        self.col = None

    def upload(self):
        "True if upload successful."
        # make sure it's ok before we try to upload
        if self.col.db.scalar("pragma integrity_check") != "ok":
            return False
        if not self.col.basicCheck():
            return False
        # apply some adjustments, then upload
        self.col.beforeUpload()
        if self.req("upload", open(self.col.path, "rb")) != b"OK":
            return False
        return True

# Remote media syncing
##########################################################################

class RemoteMediaServer(HttpSyncer):
    def __init__(self, col, hkey, client, hostNum):
        self.col = col
        super().__init__(self, hkey, client, hostNum=hostNum)
        self.prefix = "msync/"

    def begin(self):
        self.postVars = dict(
            k=self.hkey,
            v="ankidesktop,%s,%s"%(anki.version, platDesc())
        )
        ret = self._dataOnly(self.req(
            "begin", io.BytesIO(json.dumps(dict()).encode("utf8"))))
        self.skey = ret['sk']
        return ret

    # args: lastUsn
    def mediaChanges(self, **kw):
        self.postVars = dict(
            sk=self.skey,
        )
        return self._dataOnly(
            self.req("mediaChanges", io.BytesIO(json.dumps(kw).encode("utf8"))))

    # args: files
    def downloadFiles(self, **kw):
        return self.req("downloadFiles", io.BytesIO(json.dumps(kw).encode("utf8")))

    def uploadChanges(self, zip):
        # no compression, as we compress the zip file instead
        return self._dataOnly(
            self.req("uploadChanges", io.BytesIO(zip), comp=0))

    # args: local
    def mediaSanity(self, **kw):
        return self._dataOnly(
            self.req("mediaSanity", io.BytesIO(json.dumps(kw).encode("utf8"))))

    def _dataOnly(self, resp):
        resp = json.loads(resp.decode("utf8"))
        if resp['err']:
            self.col.log("error returned:%s"%resp['err'])
            raise Exception("SyncError:%s"%resp['err'])
        return resp['data']

    # only for unit tests
    def mediatest(self, cmd):
        self.postVars = dict(
            k=self.hkey,
        )
        return self._dataOnly(
            self.req("newMediaTest", io.BytesIO(
                json.dumps(dict(cmd=cmd)).encode("utf8"))))