#!/usr/bin/env python3

import os
import sys

import json
import re
import tempfile
from urllib.parse import urlparse

import requests
from mastodon import Mastodon

MAX_SIZE = 39000000

def load_config():
    with open(os.getenv('MR_CONFIG', 'config.json'), 'r') as f:
        return json.loads(f.read())

def load_recents():
    try:
        with open(os.getenv('MR_RECENTS', 'recents.json'), 'r') as f:
            return json.loads(f.read())
    except NotFound:
        return []

def save_recents(recents):
    with open(os.getenv('MR_RECENTS', 'recents.json'), 'w') as f:
        f.write(json.dumps(recents))

def make_masto(config):
    baseurl = 'https://%s' % config['hostname']
    return Mastodon(access_token=config['token'], api_base_url=baseurl)

def download_file(url, destdir):
    resp = requests.get(url)
    resp.raise_for_status()

    fname = None
    if 'content-disposition' in resp.headers:
        # Taken from: https://stackoverflow.com/questions/31804799/
        d = resp.headers['content-disposition']
        fname = re.findall("filename=(.+)", d)[0]
    else:
        u = urlparse(url)
        fname = u.path.rsplit('/', 1)[-1]

    destpath = os.path.join(destdir, fname)

    with open(destpath, 'wb') as f:
        f.write(resp.content)

    return destpath

def make_post(masto, data):
    with tempfile.TemporaryDirectory(prefix='mastoreddit.', dir='/tmp') as td:
        os.makedirs(td, exist_ok=True)

        if len(data['media']) > 4:
            data['media'] = data['media'][:4]

        image_resps = None
        if data['media'] is not None and len(data['media']) > 0:
            image_resps = []
            for a in data['media']:
                dlpath = download_file(a, td)
                fsize = os.path.getsize(dlpath)
                if fsize > MAX_SIZE:
                    print('ignoring file (too big):', dlpath, fsize, 'bytes')
                    continue
                res = masto.media_post(dlpath)
                image_resps.append(res)

        body = '%s\n\nby /u/%s at https://old.reddit.com/%s' % (data['title'], data['username'], data['rid'])
        masto.status_post(body, media_ids=image_resps)

def extract_media_urls(data):

    if 'selftext' in data:
        st = data['selftext']
        if st is not None and len(st) > 0:
            return []

    if 'post_hint' not in data:
        if 'gallery_data' in data:
            gd = data['gallery_data']['items']
            mmd = data['media_metadata']

            ents = []
            for ent in gd:
                mid = ent['media_id']
                mime = mmd[mid]['m']
                _, ext = mime.split('/')
                url = 'https://i.redd.it/%s.%s' % (mid, ext)
                ents.append(url)

            return ents
        else:
            raise ValueError('no hint type and missing gallery')

    hint = data['post_hint']

    if hint == 'link':
        if 'crosspost_parent_list' in data:
            return extract_media_urls(data['crosspost_parent_list'][0])
        else:
            # Not a reddit crosspost.
            return []

    if hint == 'hosted:video':
        return [data['secure_media']['reddit_video']['fallback_url']]

    if hint == 'image':
        return [data['url']]

    if hint == 'rich:video':
        # TODO maybe use thumbnail?
        print('got a video at', data['url'], 'but ignoring')

    raise ValueError('unknown hint type ' + hint)

def process_post(post):
    d = post['data']

    media = []
    try:
        media = extract_media_urls(d)
    except Exception as e:
        print('error processing ' + d['id'] + ': ' + str(e))

    return {
        'rid': d['id'],
        'title': d['title'],
        'username': d['author'],
        'score': d['ups'],
        'media': media
    }

def query_tops(config):
    url = 'https://www.reddit.com/r/%s/hot.json' % config['subreddit']
    resp = requests.get(url, headers = {'User-agent': 'mastoreddit'})
    resp.raise_for_status()
    j = resp.json()

    posts = []

    for post in j['data']['children']:
        if post['kind'] != 't3':
            print('found post of kind', post['kind'])

        p = process_post(post)

        lt = p['title'].lower()
        if any(f in lt for f in config['skip_titles']):
            continue

        posts.append(p)

    return posts

def filter_posts(config, posts, filt):
    tp = config['top_posts']
    ok = []
    filt = set(filt)
    newfilt = set()

    for i, p in enumerate(posts):
        if i < tp and p['score'] >= config['min_score']:
            if p['rid'] not in filt:
                ok.append(p)
            else:
                print('filtered out:', p['rid'], p['title'])
            newfilt.add(p['rid'])
            continue

        if p['rid'] in filt:
            newfilt.add(p['rid'])
            continue

        print('ignoring for now:', p['rid'], p['title'])

    return ok, list(newfilt)

def just_toot(config, msg):
    masto = make_masto(config)
    masto.toot(msg)

def main():
    config = load_config()
    masto = make_masto(config)

    recents = load_recents()

    res = query_tops(config)
    okps, newrecents = filter_posts(config, res, recents)

    for p in okps:
        print('posting', p['rid'], '-', p['title'])
        try:
            make_post(masto, p)
        except Exception as e:
            print('error posting:', p['rid'], str(e))

    save_recents(newrecents)

if __name__ == '__main__':
    main()