#include "../../plugins/Mangadex.hpp"
#include "../../include/Storage.hpp"
#include <quickmedia/HtmlSearch.h>
#include <json/reader.h>

static const std::string mangadex_url = "https://mangadex.org";
// TODO: Allow selecting other languages than english
static const char *language_code = "1"; // english
static const std::string useragent_str = "user-agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.138 Safari/537.36";

namespace QuickMedia {
    static std::string title_url_extract_manga_id(const std::string &url) {
        size_t find_index = url.find("/title/");
        if(find_index == std::string::npos)
            return "";
        
        size_t id_start_index = find_index + 7;
        size_t end_index = url.find("/", id_start_index);
        if(end_index == std::string::npos)
            return url.substr(id_start_index);
        
        return url.substr(id_start_index, end_index - id_start_index);
    }

    static std::string chapter_url_extract_manga_id(const std::string &url) {
        size_t find_index = url.find("/chapter/");
        if(find_index == std::string::npos)
            return "";
        return url.substr(find_index + 9);
    }

    struct BodyItemChapterContext {
        BodyItems *body_items;
        int prev_chapter_number;
        bool *is_last_page;
    };

    SearchResult Mangadex::search_page(const std::string &url, BodyItems &result_items, int page, bool *is_last_page) {
        *is_last_page = true;
        CommandArg user_agent_arg = { "-H", useragent_str };

        std::string chapter_url = url;
        if(chapter_url[0] != '/')
            chapter_url += "/";
        chapter_url += "chapters/" + std::to_string(page) + "/";
        std::string website_data;
        if(download_to_string(chapter_url, website_data, {std::move(user_agent_arg)}, use_tor) != DownloadResult::OK)
            return SearchResult::NET_ERR;

        std::string manga_id = title_url_extract_manga_id(chapter_url);
        std::string query = "//div[data-manga-id='" + manga_id + "']";

        BodyItemChapterContext body_item_chapter_context;
        body_item_chapter_context.body_items = &result_items;
        body_item_chapter_context.prev_chapter_number = -1;
        body_item_chapter_context.is_last_page = is_last_page;

        QuickMediaHtmlSearch html_search;
        int result = quickmedia_html_search_init(&html_search, website_data.c_str());
        if(result != 0)
            goto cleanup;
        
        result = quickmedia_html_find_nodes_xpath(&html_search, query.c_str(),
            [](QuickMediaHtmlNode *node, void *userdata) {
                auto *item_data = (BodyItemChapterContext*)userdata;
                const char *data_lang = quickmedia_html_node_get_attribute_value(node, "data-lang");
                if(strcmp(data_lang, language_code) != 0)
                    return;

                const char *chapter_id = quickmedia_html_node_get_attribute_value(node, "data-id");
                if(!chapter_id)
                    return;

                const char *chapter_number_str = quickmedia_html_node_get_attribute_value(node, "data-chapter");
                if(!chapter_number_str)
                    return;

                int chapter_number = atoi(chapter_number_str);
                if(chapter_number == 0 || chapter_number == item_data->prev_chapter_number)
                    return;
                
                item_data->prev_chapter_number = chapter_number;

                const char *chapter_title = quickmedia_html_node_get_attribute_value(node, "data-title");
                std::string chapter_url = mangadex_url + "/chapter/" + chapter_id;
                std::string chapter_name = std::string("Ch. ") + chapter_number_str;
                if(chapter_title)
                    chapter_name += std::string(" - ") + chapter_title;

                auto item = std::make_unique<BodyItem>(std::move(chapter_name));
                item->url = std::move(chapter_url);
                item_data->body_items->push_back(std::move(item));
                *item_data->is_last_page = false;
            }, &body_item_chapter_context);

        cleanup:
        quickmedia_html_search_deinit(&html_search);
        return result == 0 ? SearchResult::OK : SearchResult::ERR;
    }

    // TODO: Make pagination asynchronous and make it go to the next page when navigating to the bottom in the list of chapters
    // in the GUI. Currently all pages are fetched at once, synchronously. This can be very slow for certain manga like Naruto
    // which has 21 pages of chapters...
    SearchResult Mangadex::search(const std::string &url, BodyItems &result_items) {
#if 0
        int page = 1;
        while(true) {
            bool is_last_page;
            SearchResult search_result = search_page(url, result_items, page, &is_last_page);
            if(search_result != SearchResult::OK)
                return search_result;

            ++page;
            if(is_last_page)
                break;
        }
        return SearchResult::OK;
#else
        CommandArg user_agent_arg = { "-H", useragent_str };

        std::string manga_id = title_url_extract_manga_id(url);
        std::string request_url = "https://mangadex.org/api/?id=" + manga_id + "&type=manga";
        std::string server_response;
        if(download_to_string(request_url, server_response, {std::move(user_agent_arg)}, use_tor) != DownloadResult::OK)
            return SearchResult::NET_ERR;

        if(server_response.empty())
            return SearchResult::OK;
        
        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(&server_response[0], &server_response[server_response.size()], &json_root, &json_errors)) {
            fprintf(stderr, "Mangadex search json error: %s\n", json_errors.c_str());
            return SearchResult::ERR;
        }

        Json::Value &status_json = json_root["status"];
        if(!status_json.isString() || status_json.asString() != "OK")
            return SearchResult::ERR;

        Json::Value &chapter_json = json_root["chapter"];
        if(!chapter_json.isObject())
            return SearchResult::ERR;

        std::vector<std::pair<std::string, Json::Value>> chapters(chapter_json.size());
        for(auto &member_name : chapter_json.getMemberNames()) {
            Json::Value chapter = chapter_json[member_name];
            if(chapter.isObject())
                chapters.push_back(std::make_pair(member_name, std::move(chapter)));
        }

        std::sort(chapters.begin(), chapters.end(), [](std::pair<std::string, Json::Value> &a, std::pair<std::string, Json::Value> &b) {
            Json::Value &a_timestamp_json = a.second["timestamp"];
            Json::Value &b_timestamp_json = b.second["timestamp"];
            int64_t a_timestamp = 0;
            int64_t b_timestamp = 0;
            if(a_timestamp_json.isInt64())
                a_timestamp = a_timestamp_json.asInt64();
            if(b_timestamp_json.isInt64())
                b_timestamp = b_timestamp_json.asInt64();
            return a_timestamp > b_timestamp;
        });

        int prev_chapter_number = -1;
        for(auto it = chapters.begin(); it != chapters.end(); ++it) {
            const std::string &chapter_id = it->first;
            Json::Value &chapter = it->second;

            Json::Value &lang_code = chapter["lang_code"];
            // TODO: Allow selecting other languages than english
            if(!lang_code.isString() || lang_code.asString() != "gb")
                continue;

            Json::Value &chapter_number_json = chapter["chapter"];
            if(!chapter_number_json.isString())
                continue;

            int chapter_number = atoi(chapter_number_json.asCString());
            if(chapter_number == 0 || chapter_number == prev_chapter_number)
                continue;
            prev_chapter_number = chapter_number;

            Json::Value &chapter_title_json = chapter["title"];
            std::string chapter_url = mangadex_url + "/chapter/" + chapter_id;
            std::string chapter_name = std::string("Ch. ") + chapter_number_json.asCString();
            if(chapter_title_json.isString())
                chapter_name += std::string(" - ") + chapter_title_json.asCString();

            auto item = std::make_unique<BodyItem>(std::move(chapter_name));
            item->url = std::move(chapter_url);
            result_items.push_back(std::move(item));
        }
        return SearchResult::OK;
#endif
    }

    static bool get_rememberme_token(std::string &rememberme_token) {
        Path mangadex_credentials_path = get_storage_dir().join("credentials").join("mangadex.json");
        std::string mangadex_credentials;
        if(file_get_content(mangadex_credentials_path, mangadex_credentials) != 0) {
            fprintf(stderr, "Failed to get content of file: %s\n", mangadex_credentials_path.data.c_str());
            return false;
        }

        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(&mangadex_credentials[0], &mangadex_credentials[mangadex_credentials.size()], &json_root, &json_errors)) {
            fprintf(stderr, "Mangadex credentials json error: %s\n", json_errors.c_str());
            return false;
        }

        if(json_root.isObject()) {
            Json::Value &rememberme_token_json = json_root["rememberme_token"];
            if(rememberme_token_json.isString()) {
                rememberme_token = rememberme_token_json.asString();
                return true;
            }
        }
        return true;
    }

    struct BodyItemImageContext {
        BodyItems *body_items;
        size_t index;
    };

    // TODO: Implement pagination (go to next page and get all results as well)
    SuggestionResult Mangadex::update_search_suggestions(const std::string &text, BodyItems &result_items) {
        std::string rememberme_token;
        if(!get_rememberme_token(rememberme_token))
            return SuggestionResult::ERR;

        std::string url = "https://mangadex.org/search?title=";
        url += url_param_encode(text);
        CommandArg cookie_arg = { "-H", "cookie: mangadex_rememberme_token=" + rememberme_token };
        CommandArg user_agent_arg = { "-H", useragent_str };

        std::string website_data;
        if(download_to_string(url, website_data, {std::move(cookie_arg), std::move(user_agent_arg)}, use_tor) != DownloadResult::OK)
            return SuggestionResult::NET_ERR;

        QuickMediaHtmlSearch html_search;
        int result = quickmedia_html_search_init(&html_search, website_data.c_str());
        if(result != 0)
            goto cleanup;

        result = quickmedia_html_find_nodes_xpath(&html_search, "//a",
            [](QuickMediaHtmlNode *node, void *userdata) {
                auto *item_data = (BodyItems*)userdata;
                const char *href = quickmedia_html_node_get_attribute_value(node, "href");
                const char *title = quickmedia_html_node_get_attribute_value(node, "title");
                if(title && href && strncmp(href, "/title/", 7) == 0) {
                    auto item = std::make_unique<BodyItem>(strip(title));
                    item->url = mangadex_url + href;
                    item_data->push_back(std::move(item));
                }
            }, &result_items);

        BodyItemImageContext body_item_image_context;
        body_item_image_context.body_items = &result_items;
        body_item_image_context.index = 0;

        result = quickmedia_html_find_nodes_xpath(&html_search, "//img",
            [](QuickMediaHtmlNode *node, void *userdata) {
                auto *item_data = (BodyItemImageContext*)userdata;
                const char *src = quickmedia_html_node_get_attribute_value(node, "src");
                if(src && strncmp(src, "/images/manga/", 14) == 0) {
                    if(item_data->index < item_data->body_items->size()) {
                        (*item_data->body_items)[item_data->index]->thumbnail_url = mangadex_url + src;
                        item_data->index++;
                    }
                }
            }, &body_item_image_context);

        cleanup:
        quickmedia_html_search_deinit(&html_search);
        return result == 0 ? SuggestionResult::OK : SuggestionResult::ERR;
    }

    ImageResult Mangadex::get_number_of_images(const std::string &url, int &num_images) {
        std::lock_guard<std::mutex> lock(image_urls_mutex);
        num_images = 0;
        ImageResult image_result = get_image_urls_for_chapter(url);
        if(image_result != ImageResult::OK)
            return image_result;

        num_images = last_chapter_image_urls.size();
        return ImageResult::OK;
    }

    ImageResult Mangadex::get_image_urls_for_chapter(const std::string &url) {
        if(url == last_chapter_url)
            return ImageResult::OK;

        last_chapter_image_urls.clear();

        CommandArg user_agent_arg = { "-H", useragent_str };
        std::string manga_id = chapter_url_extract_manga_id(url);
        std::string request_url = mangadex_url + "/api/?id=" + manga_id + "&server=null&type=chapter";
        std::string server_response;
        if(download_to_string(request_url, server_response, {std::move(user_agent_arg)}, use_tor) != DownloadResult::OK)
            return ImageResult::NET_ERR;

        if(server_response.empty())
            return ImageResult::OK;

        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(&server_response[0], &server_response[server_response.size()], &json_root, &json_errors)) {
            fprintf(stderr, "Mangadex image urls json error: %s\n", json_errors.c_str());
            return ImageResult::ERR;
        }

        Json::Value &status_json = json_root["status"];
        if(!status_json.isString() || status_json.asString() != "OK")
            return ImageResult::ERR;

        Json::Value &chapter_hash = json_root["hash"];
        if(!chapter_hash.isString())
            return ImageResult::ERR;
        const char *chapter_hash_str = chapter_hash.asCString();

        Json::Value &server_json = json_root["server"];
        std::string server;
        if(server_json.isString())
            server = server_json.asString();
        else
            server = mangadex_url + "/data/";

        Json::Value &page_array = json_root["page_array"];
        if(page_array.isArray()) {
            for(const Json::Value &image_name : page_array) {
                if(!image_name.isString())
                    continue;

                std::string image_url = server + chapter_hash_str + "/" + image_name.asCString();
                last_chapter_image_urls.push_back(std::move(image_url));
            }
        }

        last_chapter_url = url;
        if(last_chapter_image_urls.empty()) {
            last_chapter_url.clear();
            return ImageResult::ERR;
        }
        return ImageResult::OK;
    }

    ImageResult Mangadex::for_each_page_in_chapter(const std::string &chapter_url, PageCallback callback) {
        std::vector<std::string> image_urls;
        {
            std::lock_guard<std::mutex> lock(image_urls_mutex);
            ImageResult image_result = get_image_urls_for_chapter(chapter_url);
            if(image_result != ImageResult::OK)
                return image_result;

            image_urls = last_chapter_image_urls;
        }

        for(const std::string &url : image_urls) {
            if(!callback(url))
                break;
        }
        return ImageResult::OK;
    }

    bool Mangadex::extract_id_from_url(const std::string &url, std::string &manga_id) {
        manga_id = title_url_extract_manga_id(url);
        return true;
    }
}