#!/usr/bin/env python
#
# Copyright (C) 2006 Søren Roug, European Environment Agency
#
# This is free software.  You may redistribute it under the terms
# of the Apache license and the GNU General Public License Version
# 2 or at your option any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public
# License along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
#
# Contributor(s):
#


import io
import json
import os
import re

from lxml.etree import fromstring, tostring
from odf.draw import Frame as odFrame
from odf.draw import Image as odImage
from odf.namespaces import DCNS, METANS, OFFICENS
from odf.opendocument import load as odLoad

from calibre.ebooks.metadata import MetaInformation, authors_to_string, check_isbn, string_to_authors
from calibre.utils.date import isoformat, parse_date
from calibre.utils.imghdr import identify
from calibre.utils.localization import canonicalize_lang, lang_as_iso639_1
from calibre.utils.zipfile import ZipFile, safe_replace
from polyglot.builtins import as_unicode

fields = {
    'title':            (DCNS, 'title'),
    'description':      (DCNS, 'description'),
    'subject':          (DCNS, 'subject'),
    'creator':          (DCNS, 'creator'),
    'date':             (DCNS, 'date'),
    'language':         (DCNS, 'language'),
    'generator':        (METANS, 'generator'),
    'initial-creator':  (METANS, 'initial-creator'),
    'keyword':          (METANS, 'keyword'),
    'keywords':         (METANS, 'keywords'),
    'editing-duration': (METANS, 'editing-duration'),
    'editing-cycles':   (METANS, 'editing-cycles'),
    'printed-by':       (METANS, 'printed-by'),
    'print-date':       (METANS, 'print-date'),
    'creation-date':    (METANS, 'creation-date'),
    'user-defined':     (METANS, 'user-defined'),
    # 'template':         (METANS, 'template'),
}


def uniq(vals):
    ''' Remove all duplicates from vals, while preserving order.  '''
    vals = vals or ()
    seen = set()
    seen_add = seen.add
    return [x for x in vals if x not in seen and not seen_add(x)]


def get_metadata(stream, extract_cover=True):
    whitespace = re.compile(r'\s+')

    def normalize(s):
        return whitespace.sub(' ', s).strip()

    with ZipFile(stream) as zf:
        meta = zf.read('meta.xml')
        root = fromstring(meta)

        def find(field):
            ns, tag = fields[field]
            ans = root.xpath(f'//ns0:{tag}', namespaces={'ns0': ns})
            if ans:
                return normalize(tostring(ans[0], method='text', encoding='unicode', with_tail=False)).strip()

        def find_all(field):
            ns, tag = fields[field]
            for x in root.xpath(f'//ns0:{tag}', namespaces={'ns0': ns}):
                yield normalize(tostring(x, method='text', encoding='unicode', with_tail=False)).strip()

        mi = MetaInformation(None, [])
        title = find('title')
        if title:
            mi.title = title
        creator = find('initial-creator') or find('creator')
        if creator:
            mi.authors = string_to_authors(creator)
        desc = find('description')
        if desc:
            mi.comments = desc
        lang = find('language')
        if lang and canonicalize_lang(lang):
            mi.languages = [canonicalize_lang(lang)]
        keywords = []
        for q in ('keyword', 'keywords'):
            for kw in find_all(q):
                keywords += [x.strip() for x in kw.split(',') if x.strip()]
        mi.tags = uniq(keywords)
        data = {}
        for tag in root.xpath('//ns0:user-defined', namespaces={'ns0': fields['user-defined'][0]}):
            name = (tag.get(f'{{{METANS}}}name') or '').lower()
            vtype = tag.get(f'{{{METANS}}}value-type') or 'string'
            val = tag.text
            if name and val:
                if vtype == 'boolean':
                    val = val == 'true'
                data[name] = val
        opfmeta = False  # we need this later for the cover
        opfnocover = False
        if data.get('opf.metadata'):
            # custom metadata contains OPF information
            opfmeta = True
            if data.get('opf.titlesort'):
                mi.title_sort = data['opf.titlesort']
            if data.get('opf.authors'):
                mi.authors = string_to_authors(data['opf.authors'])
            if data.get('opf.authorsort'):
                mi.author_sort = data['opf.authorsort']
            if data.get('opf.isbn'):
                isbn = check_isbn(data['opf.isbn'])
                if isbn is not None:
                    mi.isbn = isbn
            if data.get('opf.publisher'):
                mi.publisher = data['opf.publisher']
            if data.get('opf.pubdate'):
                mi.pubdate = parse_date(data['opf.pubdate'], assume_utc=True)
            if data.get('opf.identifiers'):
                try:
                    mi.identifiers = json.loads(data['opf.identifiers'])
                except Exception:
                    pass
            if data.get('opf.rating'):
                try:
                    mi.rating = max(0, min(float(data['opf.rating']), 10))
                except Exception:
                    pass
            if data.get('opf.series'):
                mi.series = data['opf.series']
                if data.get('opf.seriesindex'):
                    try:
                        mi.series_index = float(data['opf.seriesindex'])
                    except Exception:
                        mi.series_index = 1.0
            if data.get('opf.language'):
                cl = canonicalize_lang(data['opf.language'])
                if cl:
                    mi.languages = [cl]
            opfnocover = data.get('opf.nocover', False)
        if not opfnocover:
            try:
                read_cover(stream, zf, mi, opfmeta, extract_cover)
            except Exception:
                pass  # Do not let an error reading the cover prevent reading other data

    return mi


def set_metadata(stream, mi):

    with ZipFile(stream) as zf:
        raw = _set_metadata(zf.open('meta.xml').read(), mi)
        # print(raw.decode('utf-8'))

    stream.seek(os.SEEK_SET)
    safe_replace(stream, 'meta.xml', io.BytesIO(raw))


def _set_metadata(raw, mi):
    root = fromstring(raw)
    namespaces = {'office': OFFICENS, 'meta': METANS, 'dc': DCNS}
    nsrmap = {v: k for k, v in namespaces.items()}

    def xpath(expr, parent=root):
        return parent.xpath(expr, namespaces=namespaces)

    def remove(*tag_names):
        for tag_name in tag_names:
            ns = fields[tag_name][0]
            tag_name = f'{nsrmap[ns]}:{tag_name}'
            for x in xpath('descendant::' + tag_name, meta):
                x.getparent().remove(x)

    def add(tag, val=None):
        ans = meta.makeelement('{{{}}}{}'.format(*fields[tag]))
        ans.text = val
        meta.append(ans)
        return ans

    def remove_user_metadata(*names):
        for x in xpath('//meta:user-defined'):
            q = (x.get(f'{{{METANS}}}name') or '').lower()
            if q in names:
                x.getparent().remove(x)

    def add_um(name, val, vtype='string'):
        ans = add('user-defined', val)
        ans.set(f'{{{METANS}}}value-type', vtype)
        ans.set(f'{{{METANS}}}name', name)

    def add_user_metadata(name, val):
        if not hasattr(add_user_metadata, 'sentinel_added'):
            add_user_metadata.sentinel_added = True
            remove_user_metadata('opf.metadata')
            add_um('opf.metadata', 'true', 'boolean')
        val_type = 'string'
        if hasattr(val, 'strftime'):
            val = isoformat(val, as_utc=True).split('T')[0]
            val_type = 'date'
        add_um(name, val, val_type)

    meta = xpath('//office:meta')[0]

    if not mi.is_null('title'):
        remove('title')
        add('title', mi.title)
        if not mi.is_null('title_sort'):
            remove_user_metadata('opf.titlesort')
            add_user_metadata('opf.titlesort', mi.title_sort)
    if not mi.is_null('authors'):
        remove('initial-creator', 'creator')
        val = authors_to_string(mi.authors)
        add('initial-creator', val), add('creator', val)
        remove_user_metadata('opf.authors')
        add_user_metadata('opf.authors', val)
        if not mi.is_null('author_sort'):
            remove_user_metadata('opf.authorsort')
            add_user_metadata('opf.authorsort', mi.author_sort)
    if not mi.is_null('comments'):
        remove('description')
        add('description', mi.comments)
    if not mi.is_null('tags'):
        remove('keyword')
        add('keyword', ', '.join(mi.tags))
    if not mi.is_null('languages'):
        lang = lang_as_iso639_1(mi.languages[0])
        if lang:
            remove('language')
            add('language', lang)
    if not mi.is_null('pubdate'):
        remove_user_metadata('opf.pubdate')
        add_user_metadata('opf.pubdate', mi.pubdate)
    if not mi.is_null('publisher'):
        remove_user_metadata('opf.publisher')
        add_user_metadata('opf.publisher', mi.publisher)
    if not mi.is_null('series'):
        remove_user_metadata('opf.series', 'opf.seriesindex')
        add_user_metadata('opf.series', mi.series)
        add_user_metadata('opf.seriesindex', f'{mi.series_index}')
    if not mi.is_null('identifiers'):
        remove_user_metadata('opf.identifiers')
        add_user_metadata('opf.identifiers', as_unicode(json.dumps(mi.identifiers)))
    if not mi.is_null('rating'):
        remove_user_metadata('opf.rating')
        add_user_metadata('opf.rating', f'{mi.rating:.2g}')

    return tostring(root, encoding='utf-8', pretty_print=True)


def read_cover(stream, zin, mi, opfmeta, extract_cover):
    # search for an draw:image in a draw:frame with the name 'opf.cover'
    # if opf.metadata prop is false, just use the first image that
    # has a proper size (borrowed from docx)
    otext = odLoad(stream)
    cover_href = None
    cover_data = None
    cover_frame = None
    imgnum = 0
    for frm in otext.topnode.getElementsByType(odFrame):
        img = frm.getElementsByType(odImage)
        if len(img) == 0:
            continue
        i_href = img[0].getAttribute('href')
        try:
            raw = zin.read(i_href)
        except KeyError:
            continue
        try:
            fmt, width, height = identify(raw)
        except Exception:
            continue
        imgnum += 1
        if opfmeta and frm.getAttribute('name').lower() == 'opf.cover':
            cover_href = i_href
            cover_data = (fmt, raw)
            cover_frame = frm.getAttribute('name')  # could have upper case
            break
        if cover_href is None and imgnum == 1 and 0.8 <= height/width <= 1.8 and height*width >= 12000:
            # Pick the first image as the cover if it is of a suitable size
            cover_href = i_href
            cover_data = (fmt, raw)
            if not opfmeta:
                break

    if cover_href is not None:
        mi.cover = cover_href
        mi.odf_cover_frame = cover_frame
        if extract_cover:
            if not cover_data:
                raw = zin.read(cover_href)
                try:
                    fmt = identify(raw)[0]
                except Exception:
                    pass
                else:
                    cover_data = (fmt, raw)
            mi.cover_data = cover_data
