"""Grow translation importers."""

import io
import collections
import copy
import csv
import errno
import logging
import os
import shutil
import tempfile
import zipfile
from babel.messages import catalog
from babel.messages import pofile


default_external_to_babel_locales = collections.defaultdict(list)
builtin_locales = {
    'en-GB': 'en_GB',
    'es-419': 'es_419',
    'fr-CA': 'fr_CA',
    'iw': 'he_IL',
    'no': 'nb_NO',
    'pt-BR': 'pt_BR',
    'pt-PT': 'pt_PT',
    'zh-CN': 'zh_Hans_CN',
    'zh-HK': 'zh_Hant_HK',
    'zh-TW': 'zh_Hant_TW',
}
for key, value in builtin_locales.items():
    default_external_to_babel_locales[key].append(value)


def _mkdir(path):
    try:
        os.makedirs(path)
    except OSError as exc:
        if exc.errno == errno.EEXIST and os.path.isdir(path):
            return
        raise


class Error(Exception):

    def __init__(self, message):
        super(Error, self).__init__(message)
        self.message = message


class Importer:

    def __init__(self, pod, include_obsolete=True, untranslated=False):
        self.pod = pod
        self.include_obsolete = include_obsolete
        self.untranslated = untranslated

    def _validate_path(self, path):
        if not os.path.isfile(path):
            raise Error('Not found: {}'.format(path))

    def import_path(self, path, locale=None):
        if path.endswith('.zip'):
            self._validate_path(path)
            return self.import_zip_file(path)
        elif path.endswith('.po'):
            self._validate_path(path)
            return self.import_file(locale, path)
        elif os.path.isdir(path):
            return self.import_dir(path)
        elif path.endswith('.csv'):
            return self.import_csv_file(path)
        else:
            raise Error('Must import a .zip, .csv, .po file, or directory.')

    def import_csv_file(self, path):
        """Imports a CSV file formatted with locales in the header row and
        translations in the body rows."""
        default_locale = self.pod.podspec.localization.get('default_locale', 'en')
        locales_to_catalogs = {}
        with open(path) as fp:
            reader = csv.DictReader(fp)
            for row in reader:
                if default_locale not in row:
                    text = 'Locale {} not found in {}'.format(default_locale, path)
                    raise Error(text)
                msgid = row[default_locale]
                msgid = msgid
                for locale, translation in row.items():
                    if locale == default_locale:
                        continue
                    translation = translation
                    message = catalog.Message(msgid, translation)
                    if locale not in locales_to_catalogs:
                        locales_to_catalogs[locale] = catalog.Catalog()
                    locales_to_catalogs[locale][msgid] = message
        for locale, catalog_obj in locales_to_catalogs.items():
            fp = io.BytesIO()
            pofile.write_po(fp, catalog_obj)
            fp.seek(0)
            content = fp.read()
            self.import_content(locale, content)
            fp.close()

    def import_zip_file(self, zip_path):
        try:
            temp_dir_path = tempfile.mkdtemp()
            with zipfile.ZipFile(zip_path, 'r') as zip_file:
                zip_file.extractall(temp_dir_path)
            return self.import_dir(temp_dir_path)
        finally:
            shutil.rmtree(temp_dir_path)

    def import_dir(self, dir_path):
        # Track if the imported content is actually changing the translations.
        has_changed_content = False

        # Detect whether importing from another pod.
        podspec_path = os.path.join(dir_path, 'podspec.yaml')
        if os.path.exists(podspec_path):
            text = 'Importing from pod -> {}'.format(podspec_path)
            self.pod.logger.info(text)
            translations_dir = os.path.join(dir_path, 'translations')
            for locale in os.listdir(translations_dir):
                po_path = os.path.join(
                        translations_dir, locale, 'LC_MESSAGES', 'messages.po')
                if os.path.exists(po_path):
                    if self.import_file(locale, po_path):
                        has_changed_content = True
            return has_changed_content

        # TODO(jeremydw): Allow a custom syntax for translation importers.
        # Currently, assume one directory per locale.
        for locale in os.listdir(dir_path):
            locale_dir = os.path.join(dir_path, locale)
            if locale.startswith('.') or os.path.isfile(locale_dir):
                continue
            for basename in os.listdir(locale_dir):
                po_path = os.path.join(locale_dir, basename)
                if basename.endswith('.po'):
                    if self.import_file(locale, po_path):
                        has_changed_content = True
                else:
                    self.pod.logger.warning('Skipping: {}'.format(po_path))

        return has_changed_content

    def import_file(self, locale, po_path):
        if not os.path.exists(po_path):
            raise Error('Couldn\'t find PO file: {}'.format(po_path))
        content = open(po_path).read()
        return self.import_content(locale, content)

    def import_content(self, locale, content):
        if locale is None:
            raise Error('Must specify locale.')

        # Track if the imported content is actually changing the translations.
        has_changed_content = False
        imported_translations = 0
        total_translations = 0

        # Leverage user-defined locale identifiers when importing translations.
        external_to_babel_locales = copy.deepcopy(
            default_external_to_babel_locales)
        if self.pod.podspec.localization:
            if 'import_as' in self.pod.podspec.localization:
                import_as = self.pod.podspec.localization['import_as']
                for external_locale, babel_locales in import_as.items():
                    for babel_locale in babel_locales:
                        external_to_babel_locales[external_locale].append(
                            babel_locale)

        babel_locales = external_to_babel_locales.get(locale, [locale])
        for babel_locale in babel_locales:
            pod_translations_dir = os.path.join(
                'translations', babel_locale, 'LC_MESSAGES')
            pod_po_path = os.path.join(pod_translations_dir, 'messages.po')
            if self.pod.file_exists(pod_po_path):
                try:
                    existing_po_file = self.pod.open_file(pod_po_path)
                    existing_catalog = pofile.read_po(
                        existing_po_file, babel_locale)
                    po_file_to_merge = io.StringIO()
                    try:
                        po_file_to_merge.write(content)
                    except TypeError:
                        po_file_to_merge.write(content.decode())
                    po_file_to_merge.seek(0)
                    catalog_to_merge = pofile.read_po(
                        po_file_to_merge, babel_locale)
                except Exception as e:
                    text = 'Error merging catalogs for locale -> {}'
                    logging.error(text.format(locale))
                    raise
                for message in catalog_to_merge:
                    if message.id not in existing_catalog:
                        # Skip messages that don't exist if we are not
                        # including obsolete messages.
                        if not self.include_obsolete:
                            continue
                        existing_catalog[message.id] = message
                        if message.id:  # Only count the non-header messages.
                            imported_translations += 1
                    elif (message.string
                          and existing_catalog[message.id].string != message.string):
                        # Skip messages that have translations in the catalog
                        # if we are only importing untranslated strings.
                        if self.untranslated and existing_catalog[message.id].string:
                            continue
                        # Avoid overwriting with empty/identical strings.
                        existing_catalog[message.id].string = message.string
                        imported_translations += 1

                if imported_translations > 0:
                    has_changed_content = True
                    existing_po_file = self.pod.open_file(pod_po_path, mode='wb')
                    pofile.write_po(existing_po_file, existing_catalog, width=80,
                                    sort_output=True, sort_by_file=True)
                    total_translations = len(catalog_to_merge)
            else:
                # Skip new catalogs if not including obsolete messages.
                if not self.include_obsolete:
                    continue
                has_changed_content = True
                self.pod.write_file(pod_po_path, content)
                existing_po_file = self.pod.open_file(pod_po_path)
                existing_catalog = pofile.read_po(
                    existing_po_file, babel_locale)
                imported_translations = len(existing_catalog)
                total_translations = imported_translations

        return has_changed_content, imported_translations, total_translations
