#!/usr/bin/python3
#
# Migrate data from the rss2email 2.x format to the 3.x format.
#
# Copyright (c) 2013, Etienne Millon <me@emillon.org>
# Redistributable under the GPL version 2 or later
#
# Please report bugs and suggestion on the Debian bugtracker using the
# "reportbug rss2email" command.
#
# Changelog:
#
#   v6 (2017-12-28)
#      - ported to Python 3 using 2to3
#
#   v5 (2015-07-04)
#      - support per-feed addresses
#
#   v4 (2014-06-10)
#      - support XDG directories
#
#   v3 (2014-02-04)
#      - Write status file (already-seen DB)
#      - Fix path in error message
#
#   v2 (2013-09-17)
#      - Preserve paused status (Denis Laxalde)
#
#   v1 (2013-08-12)
#      - Migrate feed names only.
#

import json
import os.path
import pickle
import string
import subprocess
import sys
import xdg.BaseDirectory


class Feed:
    def __init__(self, url, to):
        self.url, self.etag, self.modified, self.seen = url, None, None, {}
        self.active = True
        self.to = to

    def __repr__(self):
        fmt = '\n'.join(['Feed(url={url},',
                         '     etag={etag},',
                         '     modified={modified},',
                         '     seen={seen},',
                         '     active={active},',
                         '     to={to},',
                         ')',
                         ])
        return fmt.format(**self.__dict__)


def not_empty(g):
    try:
        next(g)
        return True
    except StopIteration:
        return False


def new_db_exists():
    config = xdg.BaseDirectory.load_config_paths('rss2email.cfg')
    data = xdg.BaseDirectory.load_data_paths('rss2email.json')
    return not_empty(config) or not_empty(data)


def set_email(s):
    return subprocess.call(['r2e', 'email', s])


def slugify_char(c):
    allowed = string.ascii_letters + string.digits + '._-'
    if c in allowed:
        return c
    else:
        return '_'


def slugify(s):
    return ''.join([slugify_char(c) for c in s])


def add(url, name, to):
    extra_args = []
    if to is not None:
        extra_args = [to]
    return subprocess.call(['r2e', 'add', name, url] + extra_args)


def pause(name):
    return subprocess.call(['r2e', 'pause', name])


def main():
    if new_db_exists():
        print("""
        It seems that a rss2email 3.x database already exists, exiting.
        If you want to import your old (rss2email 2.x) database, please remove
        ~/.config/rss2email.cfg and ~/.local/share/rss2email.json (or XDG
        equivalents) and re-run r2e-migrate.
        """)
        sys.exit(1)

    old_feed_data_file = os.path.expanduser('~/.rss2email/feeds.dat')
    with open(old_feed_data_file) as f:
        data = pickle.load(f)

    email = data[0]
    feeds = data[1:]

    status = {'version': 2,
              'feeds': [],
              }

    print('Default email address: {}'.format(email))
    set_email(email)

    print('Adding feeds:')
    for feed in feeds:
        url = feed.url
        print(url)
        name = slugify(url)
        add(url, name, feed.to)
        if not feed.active:
            pause(name)
        modified = None
        if feed.modified:
            modified = str(feed.modified)
        feed_status = {'seen': {},
                       'etag': feed.etag,
                       'name': str(name),
                       'modified': modified,
                       }
        for k, v in list(feed.seen.items()):
            feed_status['seen'][k] = {'id': v}
        status['feeds'].append(feed_status)

    # save_data_path would work but rss2email uses a bare file
    data_dir = xdg.BaseDirectory.xdg_data_home
    new_status_file = os.path.join(data_dir, 'rss2email.json')
    with open(new_status_file, 'w') as statf:
        json.dump(status, statf)


if __name__ == '__main__':
    main()