#include "core/rendering/menu.hpp"

#include <cstdio>
#include <functional>
#include <memory>
#include <string>
#include <vector>

#include "core/input/key_config.hpp"
#include "core/locale/locale.hpp"
#include "core/rendering/overlay.hpp"
#include "core/rendering/screen.hpp"
#include "core/rendering/text.hpp"
#include "game/options.hpp"
#include "utils/easing.hpp"

namespace Menu {

    // --- Constants visuals ---
    static constexpr int SCREEN_W = 320;
    static constexpr int SCREEN_H = 200;

    static constexpr int BOX_W = 220;

    static constexpr Uint32 BG_COLOR = 0xFF1A0E0E;      // fons marró fosc (ABGR)
    static constexpr Uint8 BG_ALPHA = 220;              // semi-transparent
    static constexpr Uint32 BORDER_COLOR = 0xFFFFFF00;  // cyan
    static constexpr Uint32 TITLE_COLOR = 0xFFFFFFFF;   // blanc
    static constexpr Uint32 LABEL_COLOR = 0xFFCCCCCC;   // gris clar
    static constexpr Uint32 VALUE_COLOR = 0xFFFFFF00;   // cyan
    static constexpr Uint32 CURSOR_COLOR = 0xFF00FFFF;  // groc
    static constexpr Uint32 EMPTY_COLOR = 0xFF888888;   // gris

    static constexpr int TITLE_PAD_Y = 4;
    static constexpr int ITEM_PAD_X = 10;
    static constexpr int ITEM_SPACING = 11;
    static constexpr int BOTTOM_PAD = 6;
    static constexpr int HEADER_H = TITLE_PAD_Y + 8 /*charH*/ + 2 + 4;  // títol + línia + gap

    // --- Animació ---
    static constexpr float OPEN_SPEED = 8.0F;  // 1.0 / 0.125s

    // --- Items ---
    enum class ItemKind { Toggle,
        Cycle,
        IntRange,
        Submenu,
        KeyBind };

    struct Item {
        const char* label;
        ItemKind kind;
        std::function<std::string()> getValue;  // opcional
        std::function<void(int dir)> change;    // per Toggle/Cycle/IntRange
        std::function<void()> enter;            // per Submenu
        SDL_Scancode* scancode{nullptr};        // per KeyBind
    };

    struct Page {
        const char* title;
        std::vector<Item> items;
        int cursor{0};
    };

    // --- Estat ---
    static std::vector<Page> stack_;
    static std::unique_ptr<Text> font_;
    static float open_anim_{0.0F};  // 0 = tancat, 1 = obert
    static Uint32 last_ticks_{0};
    static SDL_Scancode* capturing_{nullptr};  // != null → esperant tecla per assignar

    // --- Transició entre pàgines ---
    static constexpr float TRANSITION_SPEED = 5.5F;  // ~180 ms
    static Page transition_outgoing_{"", {}, 0};
    static bool transition_active_{false};
    static float transition_progress_{1.0F};
    static int transition_dir_{+1};  // +1 endavant, -1 enrere

    // Helpers per triggerar transicions
    static void pushPage(Page newPage) {
        transition_outgoing_ = stack_.back();
        stack_.push_back(std::move(newPage));
        transition_active_ = true;
        transition_progress_ = 0.0F;
        transition_dir_ = +1;
    }
    static void popPage() {
        transition_outgoing_ = stack_.back();
        stack_.pop_back();
        transition_active_ = true;
        transition_progress_ = 0.0F;
        transition_dir_ = -1;
    }

    // --- Helpers ---

    static std::string yesNo(bool b) { return b ? Locale::get("menu.values.yes") : Locale::get("menu.values.no"); }
    static std::string onOff(bool b) { return b ? Locale::get("menu.values.on") : Locale::get("menu.values.off"); }

    // --- Builders de pàgines ---

    static Page buildVideo();
    static Page buildAudio();
    static Page buildControls();
    static Page buildGame();

    static Page buildRoot() {
        Page p{Locale::get("menu.titles.root"), {}, 0};
        p.items.push_back({Locale::get("menu.items.video"), ItemKind::Submenu, nullptr, nullptr, [] { pushPage(buildVideo()); }, nullptr});
        p.items.push_back({Locale::get("menu.items.audio"), ItemKind::Submenu, nullptr, nullptr, [] { pushPage(buildAudio()); }, nullptr});
        p.items.push_back({Locale::get("menu.items.controls"), ItemKind::Submenu, nullptr, nullptr, [] { pushPage(buildControls()); }, nullptr});
        p.items.push_back({Locale::get("menu.items.game"), ItemKind::Submenu, nullptr, nullptr, [] { pushPage(buildGame()); }, nullptr});
        return p;
    }

    static Page buildVideo() {
        Page p{Locale::get("menu.titles.video"), {}, 0};

        p.items.push_back({Locale::get("menu.items.zoom"), ItemKind::IntRange, [] {
                char buf[16];
                std::snprintf(buf, sizeof(buf), "%dX", Screen::get()->getZoom());
                return std::string(buf); }, [](int dir) {
                if (dir < 0) Screen::get()->decZoom();
                else if (dir > 0) Screen::get()->incZoom(); }, nullptr});

        p.items.push_back({Locale::get("menu.items.screen"), ItemKind::Toggle, [] { return std::string(Screen::get()->isFullscreen() ? Locale::get("menu.values.fullscreen") : Locale::get("menu.values.windowed")); }, [](int) { Screen::get()->toggleFullscreen(); }, nullptr});

        p.items.push_back({Locale::get("menu.items.shader"), ItemKind::Toggle, [] { return onOff(Options::video.shader_enabled); }, [](int) { Screen::get()->toggleShaders(); }, nullptr});

        p.items.push_back({Locale::get("menu.items.aspect_4_3"), ItemKind::Toggle, [] { return yesNo(Options::video.aspect_ratio_4_3); }, [](int) { Screen::get()->toggleAspectRatio(); }, nullptr});

        p.items.push_back({Locale::get("menu.items.supersampling"), ItemKind::Toggle, [] { return onOff(Options::video.supersampling); }, [](int) { Screen::get()->toggleSupersampling(); }, nullptr});

        p.items.push_back({Locale::get("menu.items.vsync"), ItemKind::Toggle, [] { return onOff(Options::video.vsync); }, [](int) { Screen::get()->toggleVSync(); }, nullptr});

        p.items.push_back({Locale::get("menu.items.integer_scale"), ItemKind::Toggle, [] { return onOff(Options::video.integer_scale); }, [](int) { Screen::get()->toggleIntegerScale(); }, nullptr});

        p.items.push_back({Locale::get("menu.items.shader_type"), ItemKind::Cycle, [] { return std::string(Screen::get()->getActiveShaderName()); }, [](int dir) {
                if (dir < 0) Screen::get()->prevShaderType();
                else Screen::get()->nextShaderType(); }, nullptr});

        p.items.push_back({Locale::get("menu.items.preset"), ItemKind::Cycle, [] { return std::string(Screen::get()->getCurrentPresetName()); }, [](int dir) {
                if (dir < 0) Screen::get()->prevPreset();
                else Screen::get()->nextPreset(); }, nullptr});

        p.items.push_back({Locale::get("menu.items.stretch_filter"), ItemKind::Toggle, [] { return std::string(Options::video.stretch_filter_linear ? Locale::get("menu.values.linear") : Locale::get("menu.values.nearest")); }, [](int) { Screen::get()->toggleStretchFilter(); }, nullptr});

        p.items.push_back({Locale::get("menu.items.render_info"), ItemKind::Cycle, [] {
                switch (Options::render_info.position) {
                    case Options::RenderInfoPosition::OFF: return std::string(Locale::get("menu.values.off"));
                    case Options::RenderInfoPosition::TOP: return std::string(Locale::get("menu.values.top"));
                    case Options::RenderInfoPosition::BOTTOM: return std::string(Locale::get("menu.values.bottom"));
                }
                return std::string(Locale::get("menu.values.off")); }, [](int dir) { Overlay::cycleRenderInfo(dir); }, nullptr});

        p.items.push_back({Locale::get("menu.items.uptime"), ItemKind::Toggle, [] { return onOff(Options::render_info.show_time); }, [](int) { Options::render_info.show_time = !Options::render_info.show_time; }, nullptr});

        return p;
    }

    // Converteix volum 0..1 a percentatge i ho formata com "50%"
    static std::string volPct(float v) {
        int pct = static_cast<int>(v * 100.0F + 0.5F);
        if (pct < 0) pct = 0;
        if (pct > 100) pct = 100;
        char buf[8];
        std::snprintf(buf, sizeof(buf), "%d%%", pct);
        return std::string(buf);
    }

    // Canvi +/- d'un volum en steps de 0.05 (5%) amb clamping
    static void stepVolume(float& v, int dir) {
        v += (dir >= 0 ? 0.05F : -0.05F);
        if (v < 0.0F) v = 0.0F;
        if (v > 1.0F) v = 1.0F;
        Options::applyAudio();
    }

    static Page buildControls() {
        Page p{Locale::get("menu.titles.controls"), {}, 0};
        p.items.push_back({Locale::get("menu.items.move_up"), ItemKind::KeyBind, nullptr, nullptr, nullptr, &Options::keys_game.up});
        p.items.push_back({Locale::get("menu.items.move_down"), ItemKind::KeyBind, nullptr, nullptr, nullptr, &Options::keys_game.down});
        p.items.push_back({Locale::get("menu.items.move_left"), ItemKind::KeyBind, nullptr, nullptr, nullptr, &Options::keys_game.left});
        p.items.push_back({Locale::get("menu.items.move_right"), ItemKind::KeyBind, nullptr, nullptr, nullptr, &Options::keys_game.right});
        p.items.push_back({Locale::get("menu.items.menu_key"), ItemKind::KeyBind, nullptr, nullptr, nullptr, KeyConfig::scancodePtr("menu_toggle")});
        return p;
    }

    static Page buildAudio() {
        Page p{Locale::get("menu.titles.audio"), {}, 0};

        p.items.push_back({Locale::get("menu.items.master_enable"), ItemKind::Toggle, [] { return onOff(Options::audio.enabled); }, [](int) {
                Options::audio.enabled = !Options::audio.enabled;
                Options::applyAudio(); }, nullptr});

        p.items.push_back({Locale::get("menu.items.master_volume"), ItemKind::IntRange, [] { return volPct(Options::audio.volume); }, [](int dir) { stepVolume(Options::audio.volume, dir); }, nullptr});

        p.items.push_back({Locale::get("menu.items.music"), ItemKind::Toggle, [] { return onOff(Options::audio.music_enabled); }, [](int) {
                Options::audio.music_enabled = !Options::audio.music_enabled;
                Options::applyAudio(); }, nullptr});

        p.items.push_back({Locale::get("menu.items.music_volume"), ItemKind::IntRange, [] { return volPct(Options::audio.music_volume); }, [](int dir) { stepVolume(Options::audio.music_volume, dir); }, nullptr});

        p.items.push_back({Locale::get("menu.items.sounds"), ItemKind::Toggle, [] { return onOff(Options::audio.sound_enabled); }, [](int) {
                Options::audio.sound_enabled = !Options::audio.sound_enabled;
                Options::applyAudio(); }, nullptr});

        p.items.push_back({Locale::get("menu.items.sounds_volume"), ItemKind::IntRange, [] { return volPct(Options::audio.sound_volume); }, [](int dir) { stepVolume(Options::audio.sound_volume, dir); }, nullptr});

        return p;
    }

    static Page buildGame() {
        Page p{Locale::get("menu.titles.game"), {}, 0};

        p.items.push_back({Locale::get("menu.items.use_new_logo"), ItemKind::Toggle, [] { return yesNo(Options::game.use_new_logo); }, [](int) { Options::game.use_new_logo = !Options::game.use_new_logo; }, nullptr});

        p.items.push_back({Locale::get("menu.items.show_title_credits"), ItemKind::Toggle, [] { return yesNo(Options::game.show_title_credits); }, [](int) { Options::game.show_title_credits = !Options::game.show_title_credits; }, nullptr});

        return p;
    }

    // --- Dibuix ---

    // Alpha blending per pixel sobre el buffer ARGB (ABGR en memòria)
    static void blendRect(Uint32* buf, int x, int y, int w, int h, Uint32 src_argb, Uint8 src_alpha) {
        const Uint8 sa = src_alpha;
        const Uint8 sr = src_argb & 0xFF;
        const Uint8 sg = (src_argb >> 8) & 0xFF;
        const Uint8 sb = (src_argb >> 16) & 0xFF;
        const Uint8 inv = 255 - sa;
        for (int row = y; row < y + h; row++) {
            if (row < 0 || row >= SCREEN_H) continue;
            for (int col = x; col < x + w; col++) {
                if (col < 0 || col >= SCREEN_W) continue;
                Uint32* p = &buf[col + row * SCREEN_W];
                Uint32 dst = *p;
                Uint8 dr = dst & 0xFF;
                Uint8 dg = (dst >> 8) & 0xFF;
                Uint8 db = (dst >> 16) & 0xFF;
                Uint8 r = (sr * sa + dr * inv) / 255;
                Uint8 g = (sg * sa + dg * inv) / 255;
                Uint8 b = (sb * sa + db * inv) / 255;
                *p = 0xFF000000u | (static_cast<Uint32>(b) << 16) | (static_cast<Uint32>(g) << 8) | r;
            }
        }
    }

    static void fillRect(Uint32* buf, int x, int y, int w, int h, Uint32 color) {
        for (int row = y; row < y + h; row++) {
            if (row < 0 || row >= SCREEN_H) continue;
            for (int col = x; col < x + w; col++) {
                if (col < 0 || col >= SCREEN_W) continue;
                buf[col + row * SCREEN_W] = color;
            }
        }
    }

    static void drawBorder(Uint32* buf, int x, int y, int w, int h, Uint32 color) {
        fillRect(buf, x, y, w, 1, color);
        fillRect(buf, x, y + h - 1, w, 1, color);
        fillRect(buf, x, y, 1, h, color);
        fillRect(buf, x + w - 1, y, 1, h, color);
    }

    // Mida final de la caixa segons el nombre d'items
    static int boxHeight(const Page& page) {
        int n = static_cast<int>(page.items.size());
        int body = (n == 0) ? ITEM_SPACING : n * ITEM_SPACING;
        return HEADER_H + body + BOTTOM_PAD;
    }

    // --- API pública ---

    void init() {
        font_ = std::make_unique<Text>("fonts/8bithud.fnt", "fonts/8bithud.gif");
        stack_.clear();
        open_anim_ = 0.0F;
        last_ticks_ = SDL_GetTicks();
    }

    void destroy() {
        font_.reset();
        stack_.clear();
    }

    auto isOpen() -> bool {
        return !stack_.empty();
    }

    void toggle() {
        if (isOpen()) {
            close();
        } else {
            stack_.push_back(buildRoot());
            open_anim_ = 0.0F;
            last_ticks_ = SDL_GetTicks();
        }
    }

    void close() {
        stack_.clear();
        open_anim_ = 0.0F;
        capturing_ = nullptr;
        transition_active_ = false;
        transition_progress_ = 1.0F;
    }

    auto isCapturing() -> bool {
        return capturing_ != nullptr;
    }

    void captureKey(SDL_Scancode sc) {
        if (!capturing_) return;
        if (sc == SDL_SCANCODE_ESCAPE) {
            // Cancel·la
            capturing_ = nullptr;
            return;
        }
        *capturing_ = sc;
        capturing_ = nullptr;
    }

    void handleKey(SDL_Scancode sc) {
        if (!isOpen()) return;
        Page& page = stack_.back();
        if (page.items.empty()) {
            // Pàgina buida — només backspace surt
            if (sc == SDL_SCANCODE_BACKSPACE) {
                if (stack_.size() > 1)
                    popPage();
                else
                    close();
            }
            return;
        }
        const int n = static_cast<int>(page.items.size());
        switch (sc) {
            case SDL_SCANCODE_UP:
                page.cursor = (page.cursor - 1 + n) % n;
                break;
            case SDL_SCANCODE_DOWN:
                page.cursor = (page.cursor + 1) % n;
                break;
            case SDL_SCANCODE_LEFT:
                if (page.items[page.cursor].kind != ItemKind::Submenu &&
                    page.items[page.cursor].change) {
                    page.items[page.cursor].change(-1);
                }
                break;
            case SDL_SCANCODE_RIGHT:
                if (page.items[page.cursor].kind != ItemKind::Submenu &&
                    page.items[page.cursor].change) {
                    page.items[page.cursor].change(+1);
                }
                break;
            case SDL_SCANCODE_RETURN:
            case SDL_SCANCODE_KP_ENTER:
                if (page.items[page.cursor].kind == ItemKind::Submenu) {
                    if (page.items[page.cursor].enter) page.items[page.cursor].enter();
                } else if (page.items[page.cursor].kind == ItemKind::KeyBind) {
                    capturing_ = page.items[page.cursor].scancode;
                } else if (page.items[page.cursor].change) {
                    page.items[page.cursor].change(+1);
                }
                break;
            case SDL_SCANCODE_BACKSPACE:
                if (stack_.size() > 1)
                    popPage();
                else
                    close();
                break;
            default:
                break;
        }
    }

    // Dibuixa el contingut d'una pàgina amb un offset horitzontal i un rang de clip.
    // box_x/box_y són les coordenades de la caixa (per calcular posicions relatives);
    // clip_x_min/clip_x_max limiten on es dibuixa text i la línia separadora.
    static void renderPageContent(Uint32* pixel_data, const Page& page, int box_x, int box_y, int x_offset, int clip_x_min, int clip_x_max, int clip_y_min, int clip_y_max) {
        // Títol
        int title_w = font_->width(page.title);
        int title_x = box_x + (BOX_W - title_w) / 2 + x_offset;
        font_->drawClipped(pixel_data, title_x, box_y + TITLE_PAD_Y, page.title, TITLE_COLOR, clip_x_min, clip_x_max, clip_y_min, clip_y_max);

        // Línia sota el títol (també lliscada) — clippada manualment
        int title_line_y = box_y + TITLE_PAD_Y + font_->charHeight() + 2;
        if (title_line_y >= clip_y_min && title_line_y < clip_y_max) {
            int line_x = box_x + 4 + x_offset;
            int line_w = BOX_W - 8;
            int line_start = line_x < clip_x_min ? clip_x_min : line_x;
            int line_end = (line_x + line_w) > clip_x_max ? clip_x_max : (line_x + line_w);
            if (line_end > line_start) {
                fillRect(pixel_data, line_start, title_line_y, line_end - line_start, 1, BORDER_COLOR);
            }
        }

        // Items o placeholder buit
        int items_y = title_line_y + 4;
        if (page.items.empty()) {
            const char* empty_text = Locale::get("menu.values.empty");
            int ew = font_->width(empty_text);
            font_->drawClipped(pixel_data, box_x + (BOX_W - ew) / 2 + x_offset, items_y + 2, empty_text, EMPTY_COLOR, clip_x_min, clip_x_max, clip_y_min, clip_y_max);
            return;
        }

        for (size_t i = 0; i < page.items.size(); i++) {
            int y = items_y + static_cast<int>(i) * ITEM_SPACING;
            bool selected = (static_cast<int>(i) == page.cursor);
            const Item& item = page.items[i];

            if (selected) {
                font_->drawClipped(pixel_data, box_x + 4 + x_offset, y, ">", CURSOR_COLOR, clip_x_min, clip_x_max, clip_y_min, clip_y_max);
            }

            Uint32 label_color = selected ? CURSOR_COLOR : LABEL_COLOR;
            font_->drawClipped(pixel_data, box_x + ITEM_PAD_X + x_offset, y, item.label, label_color, clip_x_min, clip_x_max, clip_y_min, clip_y_max);

            if (item.kind == ItemKind::Submenu) {
                const char* arrow = ">>";
                int aw = font_->width(arrow);
                Uint32 ac = selected ? CURSOR_COLOR : VALUE_COLOR;
                font_->drawClipped(pixel_data, box_x + BOX_W - ITEM_PAD_X - aw + x_offset, y, arrow, ac, clip_x_min, clip_x_max, clip_y_min, clip_y_max);
            } else if (item.kind == ItemKind::KeyBind) {
                bool this_capturing = (capturing_ == item.scancode);
                const char* text = this_capturing ? Locale::get("menu.values.press_key") : (item.scancode ? SDL_GetScancodeName(*item.scancode) : "");
                if (!text || !*text) text = Locale::get("menu.values.unknown");
                int tw = font_->width(text);
                Uint32 tc = this_capturing ? 0xFF00FFFF : (selected ? CURSOR_COLOR : VALUE_COLOR);
                font_->drawClipped(pixel_data, box_x + BOX_W - ITEM_PAD_X - tw + x_offset, y, text, tc, clip_x_min, clip_x_max, clip_y_min, clip_y_max);
            } else if (item.getValue) {
                std::string value = item.getValue();
                int value_w = font_->width(value.c_str());
                Uint32 value_color = selected ? CURSOR_COLOR : VALUE_COLOR;
                font_->drawClipped(pixel_data, box_x + BOX_W - ITEM_PAD_X - value_w + x_offset, y, value.c_str(), value_color, clip_x_min, clip_x_max, clip_y_min, clip_y_max);
            }
        }
    }

    void render(Uint32* pixel_data) {
        if (!isOpen() || !font_ || !pixel_data) return;

        // Delta time
        Uint32 now = SDL_GetTicks();
        float dt = static_cast<float>(now - last_ticks_) / 1000.0F;
        last_ticks_ = now;
        if (open_anim_ < 1.0F) {
            open_anim_ += OPEN_SPEED * dt;
            if (open_anim_ > 1.0F) open_anim_ = 1.0F;
        }

        // Avança transició
        if (transition_active_) {
            transition_progress_ += TRANSITION_SPEED * dt;
            if (transition_progress_ >= 1.0F) {
                transition_progress_ = 1.0F;
                transition_active_ = false;
            }
        }

        const Page& page = stack_.back();
        const int current_h = boxHeight(page);

        float eased = Easing::outQuad(open_anim_);

        // Calcula alçada (amb transició si escau)
        int target_h = current_h;
        if (transition_active_) {
            int outgoing_h = boxHeight(transition_outgoing_);
            float tp = Easing::outQuad(transition_progress_);
            target_h = Easing::lerpInt(outgoing_h, current_h, tp);
        }

        // Caixa creix verticalment durant l'obertura
        int box_h = static_cast<int>(target_h * eased);
        if (box_h < 2) box_h = 2;
        int box_x = (SCREEN_W - BOX_W) / 2;
        int box_y = (SCREEN_H - box_h) / 2;

        // Fons semi-transparent (alpha escalat per l'animació d'obertura)
        Uint8 alpha = static_cast<Uint8>(BG_ALPHA * eased);
        blendRect(pixel_data, box_x, box_y, BOX_W, box_h, BG_COLOR, alpha);

        // El contingut només apareix quan la caixa és prou gran
        if (open_anim_ >= 0.9F) {
            int clip_x_min = box_x + 1;
            int clip_x_max = box_x + BOX_W - 1;
            int clip_y_min = box_y + 1;
            int clip_y_max = box_y + box_h - 1;

            if (transition_active_) {
                float tp = Easing::outQuad(transition_progress_);
                int out_offset = static_cast<int>(-transition_dir_ * BOX_W * tp);
                int new_offset = static_cast<int>(transition_dir_ * BOX_W * (1.0F - tp));
                renderPageContent(pixel_data, transition_outgoing_, box_x, box_y, out_offset, clip_x_min, clip_x_max, clip_y_min, clip_y_max);
                renderPageContent(pixel_data, page, box_x, box_y, new_offset, clip_x_min, clip_x_max, clip_y_min, clip_y_max);
            } else {
                renderPageContent(pixel_data, page, box_x, box_y, 0, clip_x_min, clip_x_max, clip_y_min, clip_y_max);
            }
        }

        // Vora per damunt de tot
        drawBorder(pixel_data, box_x, box_y, BOX_W, box_h, BORDER_COLOR);
    }

}  // namespace Menu