#include "../include/ImageViewer.hpp"
#include "../include/Notification.hpp"
#include "../include/Storage.hpp"
#include "../plugins/Manga.hpp"
#include <cmath>
#include <SFML/Window/Event.hpp>
#include <SFML/Graphics/RectangleShape.hpp>

namespace QuickMedia {
    ImageViewer::ImageViewer(Manga *manga, const std::string &images_url, const std::string &chapter_title, int current_page, const Path &chapter_cache_dir, sf::Font *font) :
        current_page(current_page),
        num_pages(0),
        chapter_title(chapter_title),
        chapter_cache_dir(chapter_cache_dir),
        focused_page(current_page),
        font(font),
        page_text("", *font, 14)
    {
        if(manga->get_number_of_images(images_url, num_pages) != ImageResult::OK) {
            show_notification("Plugin", "Failed to get number of images", Urgency::CRITICAL);
            return;
        }
        current_page = std::min(current_page, num_pages);
        image_data.resize(num_pages);
        page_size.resize(num_pages);
        for(int i = 0; i < num_pages; ++i) {
            image_data[i] = nullptr;
            page_size[i].loaded = false;
        }
        page_text.setFillColor(sf::Color::White);
    }

    bool ImageViewer::render_page(sf::RenderWindow &window, int page, double offset_y) {
        if(page < 0 || page >= (int)image_data.size())
            return false;

        const sf::Vector2<double> image_size = get_page_size(page);
        std::unique_ptr<ImageData> &page_image_data = image_data[page];
        sf::Vector2<double> render_pos(window_size.x * 0.5 - image_size.x * 0.5, - image_size.y * 0.5 + scroll + offset_y);
        if(render_pos.y + image_size.y <= 0.0 || render_pos.y >= window_size.y) {
            if(page_image_data)
                page_image_data->visible_on_screen = false;
            return true;
        }

        double center_dist = std::abs(window_size.y * 0.5 - (render_pos.y + image_size.y * 0.5));
        if(center_dist < min_page_center_dist) {
            min_page_center_dist = center_dist;
            page_closest_to_center = page;
        }

        if(page_image_data) {
            if(page_image_data->failed_to_load_image) {
                sf::Text error_message("Failed to load image for page " + std::to_string(1 + page), *font, 30);
                auto text_bounds = error_message.getLocalBounds();
                error_message.setFillColor(sf::Color::Black);
                sf::Vector2<double> render_pos_text(window_size.x * 0.5 - text_bounds.width * 0.5, - text_bounds.height * 0.5 + scroll + offset_y);

                sf::RectangleShape background(sf::Vector2f(image_size.x, image_size.y));
                background.setFillColor(sf::Color::White);
                background.setPosition(render_pos.x, render_pos.y);
                window.draw(background);

                error_message.setPosition(render_pos_text.x, render_pos_text.y);
                window.draw(error_message);
            } else {
                page_image_data->sprite.setPosition(render_pos.x, render_pos.y);
                window.draw(page_image_data->sprite);
            }
        } else {
            std::string page_str = std::to_string(1 + page);

            sf::Text error_message("Downloading page " + page_str, *font, 30);
            auto text_bounds = error_message.getLocalBounds();
            error_message.setFillColor(sf::Color::Black);
            sf::Vector2<double> render_pos_text(window_size.x * 0.5 - text_bounds.width * 0.5, - text_bounds.height * 0.5 + scroll + offset_y);

            sf::RectangleShape background(sf::Vector2f(image_size.x, image_size.y));
            background.setFillColor(sf::Color::White);
            background.setPosition(render_pos.x, render_pos.y);
            window.draw(background);

            error_message.setPosition(render_pos_text.x, render_pos_text.y);
            window.draw(error_message);

            Path image_path = chapter_cache_dir;
            image_path.join(page_str);

            // TODO: Make image loading asynchronous
            if(get_file_type(image_path) == FileType::REGULAR) {
                fprintf(stderr, "ImageViewer: Load page %d\n", 1 + page);
                page_image_data = std::make_unique<ImageData>();
                page_image_data->visible_on_screen = true;
                std::string image_data;
                if(file_get_content(image_path, image_data) == 0) {
                    if(page_image_data->texture.loadFromMemory(image_data.data(), image_data.size())) {
                        page_image_data->texture.setSmooth(true);
                        page_image_data->sprite.setTexture(page_image_data->texture, true);
                        //image_texture.generateMipmap();
                        page_image_data->failed_to_load_image = false;
                        page_size[page].size = get_page_size(page);
                        page_size[page].loaded = true;
                    } else {
                        page_image_data->failed_to_load_image = true;
                    }
                } else {
                    show_notification("Manga", "Failed to load image for page " + page_str + ". Image filepath: " + image_path.data, Urgency::CRITICAL);
                    page_image_data->failed_to_load_image = true;
                }
            }

        }

        return true;
    }

    ImageViewerAction ImageViewer::draw(sf::RenderWindow &window) {
        const double frame_delta = frame_timer.restart().asSeconds();
        const double scroll_speed_key_input = 450.0;
        const double scroll_speed_mouse_wheel = 600.0;
        const double scroll_deaccel = 0.96;

        if(!window_size_set) {
            auto window_size_i = window.getSize();
            window_size.x = window_size_i.x;
            window_size.y = window_size_i.y;
            window_size_set = true;
        }

        // TODO: Only redraw when scrolling and when image has finished downloading
        sf::Event event;
        while(window.pollEvent(event)) {
            if (event.type == sf::Event::Closed) {
                //current_page = Page::EXIT;
                window.close();
                return ImageViewerAction::RETURN;
            } else if(event.type == sf::Event::Resized) {
                window_size.x = event.size.width;
                window_size.y = event.size.height;
                sf::FloatRect visible_area(0, 0, window_size.x, window_size.y);
                window.setView(sf::View(visible_area));
                //redraw = true;
            } else if(event.type == sf::Event::GainedFocus) {
                //redraw = true;
            } else if(event.type == sf::Event::KeyPressed) {
                if(event.key.code == sf::Keyboard::Up) {
                    scroll_speed += scroll_speed_key_input * frame_delta;
                } else if(event.key.code == sf::Keyboard::Down) {
                    scroll_speed -= scroll_speed_key_input * frame_delta;
                } else if(event.key.code == sf::Keyboard::Escape) {
                    return ImageViewerAction::RETURN;
                } else if(event.key.code == sf::Keyboard::I) {
                    return ImageViewerAction::SWITCH_TO_SINGLE_IMAGE_MODE;
                }
            } else if(event.type == sf::Event::MouseWheelScrolled && event.mouseWheelScroll.wheel == sf::Mouse::VerticalWheel) {
                scroll_speed += scroll_speed_mouse_wheel * event.mouseWheelScroll.delta * frame_delta;
            }
        }

        scroll += scroll_speed;
        scroll *= scroll_deaccel;
        if(std::abs(scroll) < 0.1)
            scroll = 0.0;

        min_page_center_dist = 9999999.0;
        page_closest_to_center = -1;

        const sf::Vector2<double> selected_page_size = get_page_size(current_page);
        render_page(window, current_page, window_size.y*0.5);
        //if(!focused_page_rendered)
        //    return;

        // Render previous pages
        double page_offset = window_size.y*0.5 - selected_page_size.y*0.5;
        int page = current_page - 1;
        while(true) {
            const sf::Vector2<double> image_size = get_page_size(page);
            page_offset -= image_size.y*0.5;
            if(!render_page(window, page, page_offset))
                break;
            --page;
            page_offset -= image_size.y*0.5;
        }

        // Render next pages
        page_offset = window_size.y*0.5 + selected_page_size.y*0.5;
        page = current_page + 1;
        while(true) {
            const sf::Vector2<double> image_size = get_page_size(page);
            page_offset += image_size.y*0.5;
            if(!render_page(window, page, page_offset))
                break;
            ++page;
            page_offset += image_size.y*0.5;
        }

        if(page_closest_to_center != -1) {
            focused_page = page_closest_to_center;
        }

        if(focused_page != prev_focused_page) {
            prev_focused_page = focused_page;
            page_text.setString(chapter_title + " | Page " + std::to_string(1 + focused_page) + "/" + std::to_string(num_pages));
        }

        const float font_height = page_text.getCharacterSize() + 8.0f;
        const float background_height = font_height + 6.0f;

        sf::RectangleShape page_text_background(sf::Vector2f(window_size.x, background_height));
        page_text_background.setFillColor(sf::Color(0, 0, 0, 150));
        page_text_background.setPosition(0.0f, window_size.y - background_height);
        window.draw(page_text_background);

        auto page_text_bounds = page_text.getLocalBounds();
        page_text.setPosition(std::floor(window_size.x * 0.5f - page_text_bounds.width * 0.5f), std::floor(window_size.y - background_height * 0.5f - font_height * 0.5f));
        window.draw(page_text);

        // Free pages that are not visible on the screen
        int i = 0;
        for(auto &page_data : image_data) {
            if(page_data && !page_data->visible_on_screen) {
                fprintf(stderr, "ImageViewer: Unload page %d\n", 1 + i);
                page_data.reset();
            }
            ++i;
        }

        return ImageViewerAction::NONE;
    }

    int ImageViewer::get_focused_page() const {
        return 1 + focused_page;
    }

    sf::Vector2<double> ImageViewer::get_page_size(int page) {
        const sf::Vector2<double> no_image_page_size(720.0, 1280.0);

        if(page < 0 || page >= (int)image_data.size())
            return no_image_page_size;

        if(page_size[page].loaded)
            return page_size[page].size;

        if(!image_data[page])
            return no_image_page_size;

        sf::Vector2u texture_size = image_data[page]->texture.getSize();
        return sf::Vector2<double>(texture_size.x, texture_size.y);
    }
}