#!/usr/bin/env python2
# vim:fileencoding=utf-8
from __future__ import (unicode_literals, division, absolute_import,
                        print_function)

__license__ = 'GPL v3'
__copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'

import sys
from collections import defaultdict

from calibre import replace_entities
from calibre.spell.break_iterator import split_into_words, index_of
from calibre.spell.dictionary import parse_lang_code
from calibre.ebooks.oeb.base import barename
from calibre.ebooks.oeb.polish.container import OPF_NAMESPACES, get_container
from calibre.ebooks.oeb.polish.parsing import parse
from calibre.ebooks.oeb.polish.toc import find_existing_ncx_toc, find_existing_nav_toc

_patterns = None


class Patterns(object):

    __slots__ = ('sanitize_invisible_pat', 'split_pat', 'digit_pat', 'fr_elision_pat')

    def __init__(self):
        import regex
        # Remove soft hyphens/zero width spaces/control codes
        self.sanitize_invisible_pat = regex.compile(
            r'[\u00ad\u200b\u200c\u200d\ufeff\0-\x08\x0b\x0c\x0e-\x1f\x7f]', regex.VERSION1 | regex.UNICODE)
        self.split_pat = regex.compile(
            r'\W+', flags=regex.VERSION1 | regex.WORD | regex.FULLCASE | regex.UNICODE)
        self.digit_pat = regex.compile(
            r'^\d+$', flags=regex.VERSION1 | regex.WORD | regex.UNICODE)
        # French words with prefixes are reduced to the stem word, so that the
        # words appear only once in the word list
        self.fr_elision_pat = regex.compile(
            u"^(?:l|d|m|t|s|j|c|ç|lorsqu|puisqu|quoiqu|qu)['’]", flags=regex.UNICODE | regex.VERSION1 | regex.IGNORECASE)


def patterns():
    global _patterns
    if _patterns is None:
        _patterns = Patterns()
    return _patterns


class Location(object):

    __slots__ = ('file_name', 'sourceline', 'original_word', 'location_node', 'node_item', 'elided_prefix')

    def __init__(self, file_name=None, elided_prefix='', original_word=None, location_node=None, node_item=(None, None)):
        self.file_name, self.elided_prefix, self.original_word = file_name, elided_prefix, original_word
        self.location_node, self.node_item, self.sourceline = location_node, node_item, location_node.sourceline

    def __repr__(self):
        return '%s @ %s:%s' % (self.original_word, self.file_name, self.sourceline)
    __str__ = __repr__

    def replace(self, new_word):
        self.original_word = self.elided_prefix + new_word


def filter_words(word):
    if not word:
        return False
    p = patterns()
    if p.digit_pat.match(word) is not None:
        return False
    return True


def get_words(text, lang):
    try:
        ans = split_into_words(unicode(text), lang)
    except (TypeError, ValueError):
        return ()
    return filter(filter_words, ans)


def add_words(text, node, words, file_name, locale, node_item):
    candidates = get_words(text, locale.langcode)
    if candidates:
        p = patterns()
        is_fr = locale.langcode == 'fra'
        for word in candidates:
            sword = p.sanitize_invisible_pat.sub('', word)
            elided_prefix = ''
            if is_fr:
                m = p.fr_elision_pat.match(sword)
                if m is not None and len(sword) > len(elided_prefix):
                    elided_prefix = m.group()
                    sword = sword[len(elided_prefix):]
            loc = Location(file_name, elided_prefix, word, node, node_item)
            words[(sword, locale)].append(loc)
            words[None] += 1


def add_words_from_attr(node, attr, words, file_name, locale):
    text = node.get(attr, None)
    if text:
        add_words(text, node, words, file_name, locale, (True, attr))


def add_words_from_text(node, attr, words, file_name, locale):
    add_words(getattr(node, attr), node, words, file_name, locale, (False, attr))


def add_words_from_escaped_html(text, words, file_name, node, attr, locale):
    text = replace_entities(text)
    root = parse('<html><body><div>%s</div></body></html>' % text, decoder=lambda x:x.decode('utf-8'))
    ewords = defaultdict(list)
    ewords[None] = 0
    read_words_from_html(root, ewords, file_name, locale)
    words[None] += ewords.pop(None)
    for k, locs in ewords.iteritems():
        for loc in locs:
            loc.location_node, loc.node_item = node, (False, attr)
        words[k].extend(locs)

_opf_file_as = '{%s}file-as' % OPF_NAMESPACES['opf']

opf_spell_tags = {'title', 'creator', 'subject', 'description', 'publisher'}

# We can only use barename() for tag names and simple attribute checks so that
# this code matches up with the syntax highlighter base spell checking


def read_words_from_opf(root, words, file_name, book_locale):
    for tag in root.iterdescendants('*'):
        if tag.text is not None and barename(tag.tag) in opf_spell_tags:
            if barename(tag.tag) == 'description':
                add_words_from_escaped_html(tag.text, words, file_name, tag, 'text', book_locale)
            else:
                add_words_from_text(tag, 'text', words, file_name, book_locale)
        add_words_from_attr(tag, _opf_file_as, words, file_name, book_locale)

ncx_spell_tags = {'text'}
xml_spell_tags = opf_spell_tags | ncx_spell_tags


def read_words_from_ncx(root, words, file_name, book_locale):
    for tag in root.xpath('//*[local-name()="text"]'):
        if tag.text is not None:
            add_words_from_text(tag, 'text', words, file_name, book_locale)

html_spell_tags = {'script', 'style', 'link'}


def read_words_from_html_tag(tag, words, file_name, parent_locale, locale):
    if tag.text is not None and barename(tag.tag) not in html_spell_tags:
        add_words_from_text(tag, 'text', words, file_name, locale)
    for attr in {'alt', 'title'}:
        add_words_from_attr(tag, attr, words, file_name, locale)
    if tag.tail is not None and tag.getparent() is not None and barename(tag.getparent().tag) not in html_spell_tags:
        add_words_from_text(tag, 'tail', words, file_name, parent_locale)


def locale_from_tag(tag):
    if 'lang' in tag.attrib:
        try:
            loc = parse_lang_code(tag.get('lang'))
        except ValueError:
            loc = None
        if loc is not None:
            return loc
    if '{http://www.w3.org/XML/1998/namespace}lang' in tag.attrib:
        try:
            loc = parse_lang_code(tag.get('{http://www.w3.org/XML/1998/namespace}lang'))
        except ValueError:
            loc = None
        if loc is not None:
            return loc


def read_words_from_html(root, words, file_name, book_locale):
    stack = [(root, book_locale)]
    while stack:
        parent, parent_locale = stack.pop()
        locale = locale_from_tag(parent) or parent_locale
        read_words_from_html_tag(parent, words, file_name, parent_locale, locale)
        stack.extend((tag, locale) for tag in parent.iterchildren('*'))


def group_sort(locations):
    order = {}
    for loc in locations:
        if loc.file_name not in order:
            order[loc.file_name] = len(order)
    return sorted(locations, key=lambda l:(order[l.file_name], l.sourceline))


def get_checkable_file_names(container):
    file_names = [name for name, linear in container.spine_names] + [container.opf_name]
    for f in (find_existing_ncx_toc, find_existing_nav_toc):
        toc = f(container)
        if toc is not None and container.exists(toc) and toc not in file_names:
            file_names.append(toc)
    return file_names, toc


def get_all_words(container, book_locale, get_word_count=False):
    words = defaultdict(list)
    words[None] = 0
    file_names, toc = get_checkable_file_names(container)
    for file_name in file_names:
        if not container.exists(file_name):
            continue
        root = container.parsed(file_name)
        if file_name == container.opf_name:
            read_words_from_opf(root, words, file_name, book_locale)
        elif file_name == toc:
            read_words_from_ncx(root, words, file_name, book_locale)
        else:
            read_words_from_html(root, words, file_name, book_locale)
    count = words.pop(None)
    ans = {k:group_sort(v) for k, v in words.iteritems()}
    if get_word_count:
        return count, ans
    return ans


def merge_locations(locs1, locs2):
    return group_sort(locs1 + locs2)


def replace(text, original_word, new_word, lang):
    indices = []
    original_word, new_word, text = unicode(original_word), unicode(new_word), unicode(text)
    q = text
    offset = 0
    while True:
        idx = index_of(original_word, q, lang=lang)
        if idx == -1:
            break
        indices.append(offset + idx)
        offset += idx + len(original_word)
        q = text[offset:]
    for idx in reversed(indices):
        text = text[:idx] + new_word + text[idx+len(original_word):]
    return text, bool(indices)


def replace_word(container, new_word, locations, locale, undo_cache=None):
    changed = set()
    for loc in locations:
        node = loc.location_node
        is_attr, attr = loc.node_item
        if is_attr:
            text = node.get(attr)
        else:
            text = getattr(node, attr)
        replacement = loc.elided_prefix + new_word
        rtext, replaced = replace(text, loc.original_word, replacement, locale.langcode)
        if replaced:
            if undo_cache is not None:
                undo_cache[(loc.file_name, node, is_attr, attr)] = text
            if is_attr:
                node.set(attr, rtext)
            else:
                setattr(node, attr, rtext)
            container.replace(loc.file_name, node.getroottree().getroot())
            changed.add(loc.file_name)
    return changed


def undo_replace_word(container, undo_cache):
    changed = set()
    for (file_name, node, is_attr, attr), text in undo_cache.iteritems():
        node.set(attr, text) if is_attr else setattr(node, attr, text)
        container.replace(file_name, node.getroottree().getroot())
        changed.add(file_name)
    return changed

if __name__ == '__main__':
    import pprint
    from calibre.gui2.tweak_book import set_book_locale, dictionaries
    container = get_container(sys.argv[-1], tweak_mode=True)
    set_book_locale(container.mi.language)
    pprint.pprint(get_all_words(container, dictionaries.default_locale))
