#include "../../plugins/Youtube.hpp"
#include <json/reader.h>
#include <string.h>

namespace QuickMedia {
    static size_t find_end_of_json(const std::string &website_data, size_t data_start) {
        int brace_count = 0;
        char string_char = '\0';
        bool escape = false;
        for(size_t i = data_start; i < website_data.size(); ++i) {
            char c = website_data[i];
            if(c == '{' && string_char == '\0') {
                escape = false;
                ++brace_count;
            } else if(c == '}' && string_char == '\0') {
                escape = false;
                --brace_count;
                if(brace_count == 0) {
                    return i + 1;
                }
            } else if(c == '"' || c == '\'') {
                if(string_char == '\0') {
                    string_char = c;
                } else if(c == string_char && !escape) {
                    string_char = '\0';
                }
                escape = false;
            } else if(c == '\\' && string_char) {
                escape = !escape;
            } else if(string_char) {
                escape = false;
            }
        }
        return std::string::npos;
    }

    // Returns empty string if continuation token can't be found
    static std::string item_section_renderer_get_continuation_token(const Json::Value &item_section_renderer_json) {
        const Json::Value &continuations_json = item_section_renderer_json["continuations"];
        if(!continuations_json.isArray() || continuations_json.empty())
            return "";
        
        const Json::Value &first_continuation_json = continuations_json[0];
        if(!first_continuation_json.isObject())
            return "";
        
        const Json::Value &next_continuation_data_json = first_continuation_json["nextContinuationData"];
        if(!next_continuation_data_json.isObject())
            return "";
        
        const Json::Value &continuation_json = next_continuation_data_json["continuation"];
        if(!continuation_json.isString())
            return "";
        
        return continuation_json.asString();
    }

    static void parse_item_section_renderer(const Json::Value &item_section_renderer_json, std::string &continuation_token, BodyItems &result_items) {
        if(continuation_token.empty())
            continuation_token = item_section_renderer_get_continuation_token(item_section_renderer_json);
        
        const Json::Value &item_contents_json = item_section_renderer_json["contents"];
        if(!item_contents_json.isArray())
            return;
        
        for(const Json::Value &content_item_json : item_contents_json) {
            if(!content_item_json.isObject())
                continue;
            
            const Json::Value &video_renderer_json = content_item_json["videoRenderer"];
            if(!video_renderer_json.isObject())
                continue;
            
            const Json::Value &video_id_json = video_renderer_json["videoId"];
            if(!video_id_json.isString())
                continue;

            std::string video_id_str = video_id_json.asString();
            std::string thumbnail_url = "https://img.youtube.com/vi/" + video_id_str + "/hqdefault.jpg";

            const char *title = nullptr;
            const Json::Value &title_json = video_renderer_json["title"];
            if(title_json.isObject()) {
                const Json::Value &runs_json = title_json["runs"];
                if(runs_json.isArray() && !runs_json.empty()) {
                    const Json::Value &first_runs_json = runs_json[0];
                    if(first_runs_json.isObject()) {
                        const Json::Value &text_json = first_runs_json["text"];
                        if(text_json.isString())
                            title = text_json.asCString();
                    }
                }
            }

            if(!title)
                continue;
            
            auto body_item = std::make_unique<BodyItem>(title);
            body_item->url = "https://www.youtube.com/watch?v=" + video_id_str;
            body_item->thumbnail_url = std::move(thumbnail_url);
            result_items.push_back(std::move(body_item));
        }
    }

    SuggestionResult Youtube::update_search_suggestions(const std::string &text, BodyItems &result_items) {
        std::string url = "https://youtube.com/results?search_query=";
        url += url_param_encode(text);

        std::vector<CommandArg> additional_args = {
            { "-H", "x-spf-referer: " + url },
            { "-H", "x-youtube-client-name: 1" },
            { "-H", "x-youtube-client-version: 2.20200626.03.00" },
            { "-H", "referer: " + url }
        };

        std::string website_data;
        if(download_to_string(url + "&pbj=1", website_data, additional_args, use_tor, true) != DownloadResult::OK)
            return SuggestionResult::NET_ERR;

        Json::Value json_root;
        Json::CharReaderBuilder json_builder;
        std::unique_ptr<Json::CharReader> json_reader(json_builder.newCharReader());
        std::string json_errors;
        if(!json_reader->parse(&website_data[0], &website_data[website_data.size()], &json_root, &json_errors)) {
            fprintf(stderr, "Youtube search json error: %s\n", json_errors.c_str());
            return SuggestionResult::ERR;
        }

        if(!json_root.isArray())
            return SuggestionResult::ERR;

        std::string continuation_token;

        for(const Json::Value &json_item : json_root) {
            if(!json_item.isObject())
                continue;

            const Json::Value &response_json = json_item["response"];
            if(!response_json.isObject())
                continue;

            const Json::Value &contents_json = response_json["contents"];
            if(!contents_json.isObject())
                return SuggestionResult::ERR;

            const Json::Value &tcsrr_json = contents_json["twoColumnSearchResultsRenderer"];
            if(!tcsrr_json.isObject())
                return SuggestionResult::ERR;

            const Json::Value &primary_contents_json = tcsrr_json["primaryContents"];
            if(!primary_contents_json.isObject())
                return SuggestionResult::ERR;

            const Json::Value &section_list_renderer_json = primary_contents_json["sectionListRenderer"];
            if(!section_list_renderer_json.isObject())
                return SuggestionResult::ERR;
            
            const Json::Value &contents2_json = section_list_renderer_json["contents"];
            if(!contents2_json.isArray())
                return SuggestionResult::ERR;
            
            for(const Json::Value &item_json : contents2_json) {
                if(!item_json.isObject())
                    continue;
                
                const Json::Value &item_section_renderer_json = item_json["itemSectionRenderer"];
                if(!item_section_renderer_json.isObject())
                    continue;

                parse_item_section_renderer(item_section_renderer_json, continuation_token, result_items);
            }
        }

        // The continuation data can also contain continuation, but we ignore that for now. Only get the first continuation data
        if(!continuation_token.empty())
            search_suggestions_get_continuation(url, continuation_token, result_items);

        return SuggestionResult::OK;
    }

    void Youtube::search_suggestions_get_continuation(const std::string &url, const std::string &continuation_token, BodyItems &result_items) {
        std::string next_url = url + "&pbj=1&ctoken=" + continuation_token;

        std::vector<CommandArg> additional_args = {
            { "-H", "x-spf-referer: " + url },
            { "-H", "x-youtube-client-name: 1" },
            { "-H", "x-spf-previous: " + url },
            { "-H", "x-youtube-client-version: 2.20200626.03.00" },
            { "-H", "referer: " + url }
        };

        std::string website_data;
        if(download_to_string(next_url, website_data, additional_args, use_tor, true) != DownloadResult::OK)
            return;

        Json::Value json_root;
        Json::CharReaderBuilder json_builder;
        std::unique_ptr<Json::CharReader> json_reader(json_builder.newCharReader());
        std::string json_errors;
        if(!json_reader->parse(&website_data[0], &website_data[website_data.size()], &json_root, &json_errors)) {
            fprintf(stderr, "Youtube search continuation json error: %s\n", json_errors.c_str());
            return;
        }

        if(!json_root.isArray())
            return;

        std::string next_continuation_token;

        for(const Json::Value &json_item : json_root) {
            if(!json_item.isObject())
                continue;

            const Json::Value &response_json = json_item["response"];
            if(!response_json.isObject())
                continue;

            const Json::Value &continuation_contents_json = response_json["continuationContents"];
            if(!continuation_contents_json.isObject())
                continue;

            const Json::Value &item_section_continuation_json = continuation_contents_json["itemSectionContinuation"];
            if(!item_section_continuation_json.isObject())
                continue;

            // Note: item_section_continuation json object is compatible with item_section_renderer json object
            parse_item_section_renderer(item_section_continuation_json, next_continuation_token, result_items);
        }
    }

    static std::string get_playlist_id_from_url(const std::string &url) {
        std::string playlist_id = url;
        size_t list_index = playlist_id.find("&list=");
        if(list_index == std::string::npos)
            return playlist_id;
        return playlist_id.substr(list_index);
    }

    static std::string remove_index_from_playlist_url(const std::string &url) {
        std::string result = url;
        size_t index = result.rfind("&index=");
        if(index == std::string::npos)
            return result;
        return result.substr(0, index);
    }

    static std::unique_ptr<BodyItem> parse_compact_video_renderer_json(const Json::Value &item_json) {
        const Json::Value &compact_video_renderer_json = item_json["compactVideoRenderer"];
        if(!compact_video_renderer_json.isObject())
            return nullptr;
        
        const Json::Value &video_id_json = compact_video_renderer_json["videoId"];
        if(!video_id_json.isString())
            return nullptr;

        std::string video_id_str = video_id_json.asString();
        std::string thumbnail_url = "https://img.youtube.com/vi/" + video_id_str + "/hqdefault.jpg";

        const char *title = nullptr;
        const Json::Value &title_json = compact_video_renderer_json["title"];
        if(title_json.isObject()) {
            const Json::Value &simple_text_json = title_json["simpleText"];
            if(simple_text_json.isString()) {
                title = simple_text_json.asCString();
            }
        }

        if(!title)
            return nullptr;
        
        auto body_item = std::make_unique<BodyItem>(title);
        body_item->url = "https://www.youtube.com/watch?v=" + video_id_str;
        body_item->thumbnail_url = std::move(thumbnail_url);
        return body_item;
    }

    // TODO: Make this faster by using string search instead of parsing html.
    // TODO: If the result is a play
    BodyItems Youtube::get_related_media(const std::string &url) {
        BodyItems result_items;

        std::string modified_url = remove_index_from_playlist_url(url);
        std::string playlist_id = get_playlist_id_from_url(modified_url);
        if(playlist_id == last_related_media_playlist_id) {
            result_items.reserve(last_playlist_data.size());
            for(auto &data : last_playlist_data) {
                result_items.push_back(std::make_unique<BodyItem>(*data));
            }
            return result_items;
        }

        std::string website_data;
        if(download_to_string(modified_url, website_data, {}, use_tor, true) != DownloadResult::OK)
            return result_items;

        size_t data_start = website_data.find("window[\"ytInitialData\"] = {");
        if(data_start == std::string::npos)
            return result_items;
        
        data_start = data_start + 26;
        size_t data_end = find_end_of_json(website_data, data_start);

        if(data_end == std::string::npos)
            return result_items;

        Json::Value json_root;
        Json::CharReaderBuilder json_builder;
        std::unique_ptr<Json::CharReader> json_reader(json_builder.newCharReader());
        std::string json_errors;
        if(!json_reader->parse(&website_data[data_start], &website_data[data_end], &json_root, &json_errors)) {
            fprintf(stderr, "Youtube search json error: %s\n", json_errors.c_str());
            return result_items;
        }

        const Json::Value &contents_json = json_root["contents"];
        if(!contents_json.isObject())
            return result_items;

        const Json::Value &tcwnr_json = contents_json["twoColumnWatchNextResults"];
        if(!tcwnr_json.isObject())
            return result_items;

        const Json::Value &secondary_results_json = tcwnr_json["secondaryResults"];
        if(!secondary_results_json.isObject())
            return result_items;

        const Json::Value &secondary_results2_json = secondary_results_json["secondaryResults"];
        if(!secondary_results2_json.isObject())
            return result_items;
        
        const Json::Value &results_json = secondary_results2_json["results"];
        if(!results_json.isArray())
            return result_items;

        for(const Json::Value &item_json : results_json) {
            if(!item_json.isObject())
                continue;

            auto body_item = parse_compact_video_renderer_json(item_json);
            if(body_item)
                result_items.push_back(std::move(body_item));
            
            const Json::Value &compact_autoplay_renderer_json = item_json["compactAutoplayRenderer"];
            if(!compact_autoplay_renderer_json.isObject())
                continue;
            
            const Json::Value &item_contents_json = compact_autoplay_renderer_json["contents"];
            if(!item_contents_json.isArray())
                continue;
            
            for(const Json::Value &content_item_json : item_contents_json) {
                if(!content_item_json.isObject())
                    continue;
                
                const Json::Value &compact_video_renderer_json = content_item_json["compactVideoRenderer"];
                if(!compact_video_renderer_json.isObject())
                    continue;
                
                auto body_item = parse_compact_video_renderer_json(content_item_json);
                result_items.push_back(std::move(body_item));
            }
        }

        return result_items;
    }
}