# -*- coding: utf-8 -*-
# Copyright: Damien Elmes <anki@ichi2.net>
# License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html

import re
import urllib
import unicodedata
import sys
import zipfile
from cStringIO import StringIO

from anki.utils import checksum, isWin, isMac, json
from anki.db import DB
from anki.consts import *
from anki.latex import mungeQA

class MediaManager(object):

    soundRegexps = ["(?i)(\[sound:(?P<fname>[^]]+)\])"]
    imgRegexps = [
        # src element quoted case
        "(?i)(<img[^>]* src=(?P<str>[\"'])(?P<fname>[^>]+?)(?P=str)[^>]*>)",
        # unquoted case
        "(?i)(<img[^>]* src=(?!['\"])(?P<fname>[^ >]+)[^>]*?>)",
    ]
    regexps = soundRegexps + imgRegexps

    def __init__(self, col, server):
        self.col = col
        if server:
            self._dir = None
            return
        # media directory
        self._dir = re.sub("(?i)\.(anki2)$", ".media", self.col.path)
        # convert dir to unicode if it's not already
        if isinstance(self._dir, str):
            self._dir = unicode(self._dir, sys.getfilesystemencoding())
        if not os.path.exists(self._dir):
            os.makedirs(self._dir)
        try:
            self._oldcwd = os.getcwd()
        except OSError:
            # cwd doesn't exist
            self._oldcwd = None
        try:
            os.chdir(self._dir)
        except OSError:
            raise Exception("invalidTempFolder")
        # change database
        self.connect()

    def connect(self):
        if self.col.server:
            return
        path = self.dir()+".db2"
        create = not os.path.exists(path)
        os.chdir(self._dir)
        self.db = DB(path)
        if create:
            self._initDB()
        self.maybeUpgrade()

    def _initDB(self):
        self.db.executescript("""
create table media (
 fname text not null primary key,
 csum text,           -- null indicates deleted file
 mtime int not null,  -- zero if deleted
 dirty int not null
);

create index idx_media_dirty on media (dirty);

create table meta (dirMod int, lastUsn int); insert into meta values (0, 0);
""")

    def maybeUpgrade(self):
        oldpath = self.dir()+".db"
        if os.path.exists(oldpath):
            self.db.execute('attach "../collection.media.db" as old')
            self.db.execute("""
insert into media
 select m.fname, csum, mod, ifnull((select 1 from log l2 where l2.fname=m.fname), 0) as dirty
 from old.media m
 left outer join old.log l using (fname)
 union
 select fname, null, 0, 1 from old.log where type=1;""")
            self.db.execute("delete from meta")
            self.db.execute("""
insert into meta select dirMod, usn from old.meta
""")
            self.db.execute("detach old")
            self.db.commit()
            self.db.execute("vacuum analyze")
            os.rename("../collection.media.db", "../collection.media.db.old")

    def close(self):
        if self.col.server:
            return
        self.db.close()
        self.db = None
        # change cwd back to old location
        if self._oldcwd:
            try:
                os.chdir(self._oldcwd)
            except:
                # may have been deleted
                pass

    def dir(self):
        return self._dir

    def _isFAT32(self):
        if not isWin:
            return
        import win32api, win32file
        try:
            name = win32file.GetVolumeNameForVolumeMountPoint(self._dir[:3])
        except:
            # mapped & unmapped network drive; pray that it's not vfat
            return
        if win32api.GetVolumeInformation(name)[4].lower().startswith("fat"):
            return True

    # Adding media
    ##########################################################################
    # opath must be in unicode

    def addFile(self, opath):
        return self.writeData(opath, open(opath, "rb").read())

    def writeData(self, opath, data):
        # if fname is a full path, use only the basename
        fname = os.path.basename(opath)
        # make sure we write it in NFC form (on mac will autoconvert to NFD),
        # and return an NFC-encoded reference
        fname = unicodedata.normalize("NFC", fname)
        # remove any dangerous characters
        base = self.stripIllegal(fname)
        (root, ext) = os.path.splitext(base)
        def repl(match):
            n = int(match.group(1))
            return " (%d)" % (n+1)
        # find the first available name
        csum = checksum(data)
        while True:
            fname = root + ext
            path = os.path.join(self.dir(), fname)
            # if it doesn't exist, copy it directly
            if not os.path.exists(path):
                open(path, "wb").write(data)
                return fname
            # if it's identical, reuse
            if checksum(open(path, "rb").read()) == csum:
                return fname
            # otherwise, increment the index in the filename
            reg = " \((\d+)\)$"
            if not re.search(reg, root):
                root = root + " (1)"
            else:
                root = re.sub(reg, repl, root)

    # String manipulation
    ##########################################################################

    def filesInStr(self, mid, string, includeRemote=False):
        l = []
        model = self.col.models.get(mid)
        strings = []
        if model['type'] == MODEL_CLOZE and "{{c" in string:
            # if the field has clozes in it, we'll need to expand the
            # possibilities so we can render latex
            strings = self._expandClozes(string)
        else:
            strings = [string]
        for string in strings:
            # handle latex
            string = mungeQA(string, None, None, model, None, self.col)
            # extract filenames
            for reg in self.regexps:
                for match in re.finditer(reg, string):
                    fname = match.group("fname")
                    isLocal = not re.match("(https?|ftp)://", fname.lower())
                    if isLocal or includeRemote:
                        l.append(fname)
        return l

    def _expandClozes(self, string):
        ords = set(re.findall("{{c(\d+)::.+?}}", string))
        strings = []
        from anki.template.template import clozeReg
        def qrepl(m):
            if m.group(3):
                return "[%s]" % m.group(3)
            else:
                return "[...]"
        def arepl(m):
            return m.group(1)
        for ord in ords:
            s = re.sub(clozeReg%ord, qrepl, string)
            s = re.sub(clozeReg%".+?", "\\1", s)
            strings.append(s)
        strings.append(re.sub(clozeReg%".+?", arepl, string))
        return strings

    def transformNames(self, txt, func):
        for reg in self.regexps:
            txt = re.sub(reg, func, txt)
        return txt

    def strip(self, txt):
        for reg in self.regexps:
            txt = re.sub(reg, "", txt)
        return txt

    def escapeImages(self, string):
        def repl(match):
            tag = match.group(0)
            fname = match.group("fname")
            if re.match("(https?|ftp)://", fname):
                return tag
            return tag.replace(
                fname, urllib.quote(fname.encode("utf-8")))
        for reg in self.imgRegexps:
            string = re.sub(reg, repl, string)
        return string

    # Rebuilding DB
    ##########################################################################

    def check(self, local=None):
        "Return (missingFiles, unusedFiles)."
        mdir = self.dir()
        # gather all media references in NFC form
        allRefs = set()
        for nid, mid, flds in self.col.db.execute("select id, mid, flds from notes"):
            noteRefs = self.filesInStr(mid, flds)
            # check the refs are in NFC
            for f in noteRefs:
                # if they're not, we'll need to fix them first
                if f != unicodedata.normalize("NFC", f):
                    self._normalizeNoteRefs(nid)
                    noteRefs = self.filesInStr(mid, flds)
                    break
            allRefs.update(noteRefs)
        # loop through media folder
        unused = []
        invalid = []
        if local is None:
            files = os.listdir(mdir)
        else:
            files = local
        renamedFiles = False
        for file in files:
            if not local:
                if not os.path.isfile(file):
                    # ignore directories
                    continue
            if file.startswith("_"):
                # leading _ says to ignore file
                continue
            if not isinstance(file, unicode):
                invalid.append(unicode(file, sys.getfilesystemencoding(), "replace"))
                continue
            nfcFile = unicodedata.normalize("NFC", file)
            # we enforce NFC fs encoding on non-macs; on macs we'll have gotten
            # NFD so we use the above variable for comparing references
            if not isMac and not local:
                if file != nfcFile:
                    # delete if we already have the NFC form, otherwise rename
                    if os.path.exists(nfcFile):
                        os.unlink(file)
                        renamedFiles = True
                    else:
                        os.rename(file, nfcFile)
                        renamedFiles = True
                    file = nfcFile
            # compare
            if nfcFile not in allRefs:
                unused.append(file)
            else:
                allRefs.discard(nfcFile)
        # if we renamed any files to nfc format, we must rerun the check
        # to make sure the renamed files are not marked as unused
        if renamedFiles:
            return self.check(local=local)
        nohave = [x for x in allRefs if not x.startswith("_")]
        return (nohave, unused, invalid)

    def _normalizeNoteRefs(self, nid):
        note = self.col.getNote(nid)
        for c, fld in enumerate(note.fields):
            nfc = unicodedata.normalize("NFC", fld)
            if nfc != fld:
                note.fields[c] = nfc
        note.flush()

    # Copying on import
    ##########################################################################

    def have(self, fname):
        return os.path.exists(os.path.join(self.dir(), fname))

    # Illegal characters
    ##########################################################################

    _illegalCharReg = re.compile(r'[][><:"/?*^\\|\0\r\n]')

    def stripIllegal(self, str):
        return re.sub(self._illegalCharReg, "", str)

    def hasIllegal(self, str):
        # a file that couldn't be decoded to unicode is considered invalid
        if not isinstance(str, unicode):
            return True
        return not not re.search(self._illegalCharReg, str)

    # Tracking changes
    ##########################################################################

    def findChanges(self):
        "Scan the media folder if it's changed, and note any changes."
        if self._changed():
            self._logChanges()

    def haveDirty(self):
        return self.db.scalar("select 1 from media where dirty=1 limit 1")

    def _mtime(self, path):
        return int(os.stat(path).st_mtime)

    def _checksum(self, path):
        return checksum(open(path, "rb").read())

    def _changed(self):
        "Return dir mtime if it has changed since the last findChanges()"
        # doesn't track edits, but user can add or remove a file to update
        mod = self.db.scalar("select dirMod from meta")
        mtime = self._mtime(self.dir())
        if not self._isFAT32() and mod and mod == mtime:
            return False
        return mtime

    def _logChanges(self):
        (added, removed) = self._changes()
        media = []
        for f in added:
            mt = self._mtime(f)
            media.append((f, self._checksum(f), mt, 1))
        for f in removed:
            media.append((f, None, 0, 1))
        # update media db
        self.db.executemany("insert or replace into media values (?,?,?,?)",
                            media)
        self.db.execute("update meta set dirMod = ?", self._mtime(self.dir()))
        self.db.commit()

    def _changes(self):
        self.cache = {}
        for (name, csum, mod) in self.db.execute(
            "select fname, csum, mtime from media"):
            self.cache[name] = [csum, mod, False]
        added = []
        removed = []
        # loop through on-disk files
        for f in os.listdir(self.dir()):
            # ignore folders and thumbs.db
            if os.path.isdir(f):
                continue
            if f.lower() == "thumbs.db":
                continue
            # and files with invalid chars
            if self.hasIllegal(f):
                continue
            # empty files are invalid; clean them up and continue
            if not os.path.getsize(f):
                os.unlink(f)
                continue
            # newly added?
            if f not in self.cache:
                added.append(f)
            else:
                # modified since last time?
                if self._mtime(f) != self.cache[f][1]:
                    # and has different checksum?
                    if self._checksum(f) != self.cache[f][0]:
                        added.append(f)
                # mark as used
                self.cache[f][2] = True
        # look for any entries in the cache that no longer exist on disk
        for (k, v) in self.cache.items():
            if not v[2]:
                removed.append(k)
        return added, removed

    # Syncing-related
    ##########################################################################

    def lastUsn(self):
        return self.db.scalar("select lastUsn from meta")

    def setLastUsn(self, usn):
        self.db.execute("update meta set lastUsn = ?", usn)
        self.db.commit()

    def syncInfo(self, fname):
        ret = self.db.first(
            "select csum, dirty from media where fname=?", fname)
        return ret or (None, 0)

    def markClean(self, fnames):
        for fname in fnames:
            self.db.execute(
                "update media set dirty=0 where fname=?", fname)

    def syncDelete(self, fname):
        if os.path.exists(fname):
            os.unlink(fname)
        self.db.execute("delete from media where fname=?", fname)

    def mediaCount(self):
        return self.db.scalar(
            "select count() from media where csum is not null")

    def forceResync(self):
        self.db.execute("delete from media")
        self.db.execute("vacuum analyze")
        self.db.commit()

    # Media syncing: zips
    ##########################################################################

    def mediaChangesZip(self):
        f = StringIO()
        z = zipfile.ZipFile(f, "w", compression=zipfile.ZIP_DEFLATED)

        fnames = []
        # meta is list of (fname, zipname), where zipname of None
        # is a deleted file
        meta = []
        sz = 0

        for c, (fname, csum) in enumerate(self.db.execute(
                        "select fname, csum from media where dirty=1"
                        " limit %d"%SYNC_ZIP_COUNT)):

            fnames.append(fname)
            normname = unicodedata.normalize("NFC", fname)

            if csum:
                z.write(fname, str(c))
                meta.append((normname, str(c)))
                sz += os.path.getsize(fname)
            else:
                meta.append((normname, ""))

            if sz >= SYNC_ZIP_SIZE:
                break

        z.writestr("_meta", json.dumps(meta))
        z.close()
        return f.getvalue(), fnames

    def addFilesFromZip(self, zipData):
        "Extract zip data; true if finished."
        f = StringIO(zipData)
        z = zipfile.ZipFile(f, "r")
        media = []
        # get meta info first
        meta = json.loads(z.read("_meta"))
        # then loop through all files
        cnt = 0
        for i in z.infolist():
            if i.filename == "_meta":
                # ignore previously-retrieved meta
                continue
            else:
                data = z.read(i)
                csum = checksum(data)
                name = meta[i.filename]
                if not isinstance(name, unicode):
                    name = unicode(name, "utf8")
                # normalize name for platform
                if isMac:
                    name = unicodedata.normalize("NFD", name)
                else:
                    name = unicodedata.normalize("NFC", name)
                # save file
                open(name, "wb").write(data)
                # update db
                media.append((name, csum, self._mtime(name), 0))
                cnt += 1
        if media:
            self.db.executemany(
                "insert or replace into media values (?,?,?,?)", media)
        return cnt