#!/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, SiteDownloaderError
from bulkredditdownloader.resource import Resource
from bulkredditdownloader.site_downloaders.base_downloader import BaseDownloader
from bulkredditdownloader.site_downloaders.direct import Direct

logger = logging.getLogger(__name__)


class Imgur(BaseDownloader):
    imgur_image_domain = "https://i.imgur.com/"

    def __init__(self, post: Submission):
        super().__init__(post)
        self.raw_data = {}

    def find_resources(self, authenticator: Optional[Authenticator] = None) -> list[Resource]:
        link = self.post.url

        if link.endswith(".gifv"):
            direct_thing = Direct(self.post)
            return direct_thing.find_resources(authenticator)

        self.raw_data = self._get_data(link)

        if self._is_album:
            if self.raw_data["album_images"]["count"] != 1:
                out = self._download_album(self.raw_data["album_images"])
            else:
                out = self._download_image(self.raw_data["album_images"]["images"][0])
        else:
            out = self._download_image(self.raw_data)
        return out

    def _download_album(self, images: dict):
        images_length = images["count"]

        out = []

        for i in range(images_length):
            extension = self._validate_extension(images["images"][i]["ext"])
            image_url = self.imgur_image_domain + images["images"][i]["hash"] + extension
            out.append(Resource(self.post, image_url))
        return out

    def _download_image(self, image: dict):
        extension = self._validate_extension(image["ext"])
        image_url = self.imgur_image_domain + image["hash"] + extension
        return [Resource(self.post, image_url)]

    def _is_album(self) -> bool:
        return "album_images" in self.raw_data

    @staticmethod
    def _get_data(link: str) -> dict:
        cookies = {"over18": "1", "postpagebeta": "0"}
        res = requests.get(link, cookies=cookies)
        if res.status_code != 200:
            raise ResourceNotFound(f"Server responded with {res.status_code} to {link}")
        page_source = requests.get(link, cookies=cookies).text

        starting_string = "image               : "
        ending_string = "group               :"

        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}")

        while page_source[end_index] != "}":
            end_index -= 1
        try:
            data = page_source[start_index:end_index + 2].strip()[:-1]
        except IndexError:
            page_source[end_index + 1] = '}'
            data = page_source[start_index:end_index + 3].strip()[:-1]

        return json.loads(data)

    @staticmethod
    def _validate_extension(extension_suffix: str) -> str:
        possible_extensions = [".jpg", ".png", ".mp4", ".gif"]
        for extension in possible_extensions:
            if extension in extension_suffix:
                return extension
        else:
            raise SiteDownloaderError(f'"{extension_suffix}" is not recognized as a valid extension for Imgur')