#!/usr/bin/env python3

import json
import logging
from typing import Optional

import requests
from praw.models import Submission

from bulkredditdownloader.authenticator import Authenticator
from bulkredditdownloader.errors import NotADownloadableLinkError, ResourceNotFound
from bulkredditdownloader.resource import Resource
from bulkredditdownloader.site_downloaders.base_downloader import BaseDownloader

logger = logging.getLogger(__name__)


class Gallery(BaseDownloader):
    def __init__(self, post: Submission):
        super().__init__(post)
        link = self.post.url
        self.raw_data = self._get_data(link)

    def find_resources(self, authenticator: Optional[Authenticator] = None) -> list[Resource]:
        images = {}
        count = 0
        for model in self.raw_data['posts']['models']:
            try:
                for item in self.raw_data['posts']['models'][model]['media']['gallery']['items']:
                    try:
                        images[count] = {'id': item['mediaId'], 'url': self.raw_data['posts']
                                         ['models'][model]['media']['mediaMetadata'][item['mediaId']]['s']['u']}
                        count += 1
                    except KeyError:
                        continue
            except KeyError:
                continue

        return self._download_album(images)

    @staticmethod
    def _get_data(link: str) -> dict:
        headers = {
            "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko)"
            " Chrome/67.0.3396.87 Safari/537.36 OPR/54.0.2952.64",
            "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8",
        }
        res = requests.get(link, headers=headers)
        if res.status_code != 200:
            raise ResourceNotFound(f"Server responded with {res.status_code} to {link}")
        page_source = res.text

        starting_string = "_r = {"
        ending_string = "</script>"

        starting_string_lenght = len(starting_string)
        try:
            start_index = page_source.index(starting_string) + starting_string_lenght
            end_index = page_source.index(ending_string, start_index)
        except ValueError:
            raise NotADownloadableLinkError(f"Could not read the page source on {link}")

        data = json.loads(page_source[start_index - 1:end_index + 1].strip()[:-1])
        return data

    def _download_album(self, images: dict):
        out = [Resource(self.post, images[image_key]['url']) for image_key in images.keys()]
        return out