#include "game/options.hpp"

#include <algorithm>
#include <fstream>
#include <iostream>
#include <sstream>
#include <string>

#include "external/fkyaml_node.hpp"
#include "utils/defines.hpp"

namespace {

    auto scalingModeToString(Defaults::ScalingMode mode) -> const char* {
        switch (mode) {
            case Defaults::ScalingMode::DISABLED:
                return "disabled";
            case Defaults::ScalingMode::STRETCH:
                return "stretch";
            case Defaults::ScalingMode::LETTERBOX:
                return "letterbox";
            case Defaults::ScalingMode::OVERSCAN:
                return "overscan";
            case Defaults::ScalingMode::INTEGER:
                return "integer";
        }
        return "letterbox";
    }

    auto scalingModeFromString(const std::string& text) -> Defaults::ScalingMode {
        if (text == "disabled") { return Defaults::ScalingMode::DISABLED; }
        if (text == "stretch") { return Defaults::ScalingMode::STRETCH; }
        if (text == "overscan") { return Defaults::ScalingMode::OVERSCAN; }
        if (text == "integer") { return Defaults::ScalingMode::INTEGER; }
        return Defaults::ScalingMode::LETTERBOX;
    }

    auto filterToString(Defaults::TextureFilter filter) -> const char* {
        return filter == Defaults::TextureFilter::LINEAR ? "linear" : "nearest";
    }

    auto filterFromString(const std::string& text) -> Defaults::TextureFilter {
        return text == "linear" ? Defaults::TextureFilter::LINEAR : Defaults::TextureFilter::NEAREST;
    }

    auto readFileOrEmpty(const std::string& path) -> std::string {
        std::ifstream file(path);
        if (!file) { return {}; }
        std::stringstream buffer;
        buffer << file.rdbuf();
        return buffer.str();
    }

    auto writeFile(const std::string& path, const std::string& content) -> bool {
        std::ofstream file(path, std::ios::binary);
        if (!file) { return false; }
        file.write(content.data(), static_cast<std::streamsize>(content.size()));
        return file.good();
    }

    void parseWindow(const fkyaml::node& yaml) {
        if (!yaml.contains("window")) { return; }
        const auto& node = yaml["window"];
        if (node.contains("zoom")) { Options::window.zoom = node["zoom"].get_value<int>(); }
        if (node.contains("fullscreen")) { Options::window.fullscreen = node["fullscreen"].get_value<bool>(); }
    }

    void parseGpu(const fkyaml::node& video_node) {
        if (!video_node.contains("gpu")) { return; }
        const auto& node = video_node["gpu"];
        if (node.contains("acceleration")) { Options::video.gpu.acceleration = node["acceleration"].get_value<bool>(); }
        if (node.contains("preferred_driver")) { Options::video.gpu.preferred_driver = node["preferred_driver"].get_value<std::string>(); }
    }

    void parseShader(const fkyaml::node& video_node) {
        if (!video_node.contains("shader")) { return; }
        const auto& node = video_node["shader"];
        if (node.contains("enabled")) { Options::video.shader.enabled = node["enabled"].get_value<bool>(); }
        if (node.contains("current_shader")) {
            Options::video.shader.current_shader = node["current_shader"].get_value<std::string>();
        }
        if (node.contains("current_postfx_preset")) {
            Options::video.shader.current_postfx_preset = node["current_postfx_preset"].get_value<std::string>();
        }
        if (node.contains("current_crtpi_preset")) {
            Options::video.shader.current_crtpi_preset = node["current_crtpi_preset"].get_value<std::string>();
        }
    }

    void parseVideo(const fkyaml::node& yaml) {
        if (!yaml.contains("video")) { return; }
        const auto& node = yaml["video"];
        if (node.contains("vsync")) { Options::video.vsync = node["vsync"].get_value<bool>(); }
        if (node.contains("scaling_mode")) {
            Options::video.scaling_mode = scalingModeFromString(node["scaling_mode"].get_value<std::string>());
        }
        if (node.contains("texture_filter")) {
            Options::video.texture_filter = filterFromString(node["texture_filter"].get_value<std::string>());
        }
        parseGpu(node);
        parseShader(node);
    }

    void parseMusic(const fkyaml::node& audio_node) {
        if (!audio_node.contains("music")) { return; }
        const auto& node = audio_node["music"];
        if (node.contains("enabled")) { Options::audio.music.enabled = node["enabled"].get_value<bool>(); }
        if (node.contains("volume")) { Options::audio.music.volume = node["volume"].get_value<float>(); }
    }

    void parseSound(const fkyaml::node& audio_node) {
        if (!audio_node.contains("sound")) { return; }
        const auto& node = audio_node["sound"];
        if (node.contains("enabled")) { Options::audio.sound.enabled = node["enabled"].get_value<bool>(); }
        if (node.contains("volume")) { Options::audio.sound.volume = node["volume"].get_value<float>(); }
    }

    void parseAudio(const fkyaml::node& yaml) {
        if (!yaml.contains("audio")) { return; }
        const auto& node = yaml["audio"];
        if (node.contains("enabled")) { Options::audio.enabled = node["enabled"].get_value<bool>(); }
        if (node.contains("volume")) { Options::audio.volume = node["volume"].get_value<float>(); }
        parseMusic(node);
        parseSound(node);
    }

    // Presets per defecte de PostFX, usats quan el fitxer postfx.yaml no existeix.
    auto defaultPostFXPresets() -> std::vector<Options::PostFXPreset> {
        return {
            {.name = "off"},  // passthrough (tot a 0)
            {.name = "crt",
                .vignette = 0.6F,
                .scanlines = 0.7F,
                .chroma = 0.15F,
                .mask = 0.6F,
                .gamma = 0.8F,
                .curvature = 0.0F,
                .bleeding = 0.0F,
                .flicker = 0.0F},
            {.name = "ntsc",
                .vignette = 0.4F,
                .scanlines = 0.5F,
                .chroma = 0.25F,
                .mask = 0.3F,
                .gamma = 0.6F,
                .curvature = 0.0F,
                .bleeding = 0.4F,
                .flicker = 0.1F},
        };
    }

    void parsePostFXPreset(const fkyaml::node& node, Options::PostFXPreset& preset) {
        if (node.contains("name")) { preset.name = node["name"].get_value<std::string>(); }
        if (node.contains("vignette")) { preset.vignette = node["vignette"].get_value<float>(); }
        if (node.contains("scanlines")) { preset.scanlines = node["scanlines"].get_value<float>(); }
        if (node.contains("chroma")) { preset.chroma = node["chroma"].get_value<float>(); }
        if (node.contains("mask")) { preset.mask = node["mask"].get_value<float>(); }
        if (node.contains("gamma")) { preset.gamma = node["gamma"].get_value<float>(); }
        if (node.contains("curvature")) { preset.curvature = node["curvature"].get_value<float>(); }
        if (node.contains("bleeding")) { preset.bleeding = node["bleeding"].get_value<float>(); }
        if (node.contains("flicker")) { preset.flicker = node["flicker"].get_value<float>(); }
    }

    void writePostFXPreset(std::ostringstream& out, const Options::PostFXPreset& preset) {
        out << "  - name: \"" << preset.name << "\"\n";
        out << "    vignette: " << preset.vignette << "\n";
        out << "    scanlines: " << preset.scanlines << "\n";
        out << "    chroma: " << preset.chroma << "\n";
        out << "    mask: " << preset.mask << "\n";
        out << "    gamma: " << preset.gamma << "\n";
        out << "    curvature: " << preset.curvature << "\n";
        out << "    bleeding: " << preset.bleeding << "\n";
        out << "    flicker: " << preset.flicker << "\n";
    }

    // Presets per defecte de CrtPi (tuning bàsic del shader original CRT-Pi).
    auto defaultCrtPiPresets() -> std::vector<Options::CrtPiPreset> {
        return {
            {.name = "default"},
            {.name = "sharper",
                .scanline_weight = 8.0F,
                .scanline_gap_brightness = 0.10F,
                .bloom_factor = 3.0F,
                .enable_sharper = true},
            {.name = "curved",
                .scanline_weight = 6.0F,
                .scanline_gap_brightness = 0.12F,
                .bloom_factor = 3.5F,
                .curvature_x = 0.05F,
                .curvature_y = 0.10F,
                .enable_curvature = true},
        };
    }

    void parseCrtPiPreset(const fkyaml::node& node, Options::CrtPiPreset& preset) {
        if (node.contains("name")) { preset.name = node["name"].get_value<std::string>(); }
        if (node.contains("scanline_weight")) { preset.scanline_weight = node["scanline_weight"].get_value<float>(); }
        if (node.contains("scanline_gap_brightness")) { preset.scanline_gap_brightness = node["scanline_gap_brightness"].get_value<float>(); }
        if (node.contains("bloom_factor")) { preset.bloom_factor = node["bloom_factor"].get_value<float>(); }
        if (node.contains("input_gamma")) { preset.input_gamma = node["input_gamma"].get_value<float>(); }
        if (node.contains("output_gamma")) { preset.output_gamma = node["output_gamma"].get_value<float>(); }
        if (node.contains("mask_brightness")) { preset.mask_brightness = node["mask_brightness"].get_value<float>(); }
        if (node.contains("curvature_x")) { preset.curvature_x = node["curvature_x"].get_value<float>(); }
        if (node.contains("curvature_y")) { preset.curvature_y = node["curvature_y"].get_value<float>(); }
        if (node.contains("mask_type")) { preset.mask_type = node["mask_type"].get_value<int>(); }
        if (node.contains("enable_scanlines")) { preset.enable_scanlines = node["enable_scanlines"].get_value<bool>(); }
        if (node.contains("enable_multisample")) { preset.enable_multisample = node["enable_multisample"].get_value<bool>(); }
        if (node.contains("enable_gamma")) { preset.enable_gamma = node["enable_gamma"].get_value<bool>(); }
        if (node.contains("enable_curvature")) { preset.enable_curvature = node["enable_curvature"].get_value<bool>(); }
        if (node.contains("enable_sharper")) { preset.enable_sharper = node["enable_sharper"].get_value<bool>(); }
    }

    void writeCrtPiPreset(std::ostringstream& out, const Options::CrtPiPreset& preset) {
        out << "  - name: \"" << preset.name << "\"\n";
        out << "    scanline_weight: " << preset.scanline_weight << "\n";
        out << "    scanline_gap_brightness: " << preset.scanline_gap_brightness << "\n";
        out << "    bloom_factor: " << preset.bloom_factor << "\n";
        out << "    input_gamma: " << preset.input_gamma << "\n";
        out << "    output_gamma: " << preset.output_gamma << "\n";
        out << "    mask_brightness: " << preset.mask_brightness << "\n";
        out << "    curvature_x: " << preset.curvature_x << "\n";
        out << "    curvature_y: " << preset.curvature_y << "\n";
        out << "    mask_type: " << preset.mask_type << "\n";
        out << "    enable_scanlines: " << (preset.enable_scanlines ? "true" : "false") << "\n";
        out << "    enable_multisample: " << (preset.enable_multisample ? "true" : "false") << "\n";
        out << "    enable_gamma: " << (preset.enable_gamma ? "true" : "false") << "\n";
        out << "    enable_curvature: " << (preset.enable_curvature ? "true" : "false") << "\n";
        out << "    enable_sharper: " << (preset.enable_sharper ? "true" : "false") << "\n";
    }

}  // namespace

namespace Options {

    void setConfigFile(const std::string& path) {
        config_file_path = path;
    }

    auto loadFromFile() -> bool {
        if (config_file_path.empty()) { return false; }

        const std::string CONTENT = readFileOrEmpty(config_file_path);
        if (CONTENT.empty()) {
            // Primera execució: creem el fitxer amb els valors per defecte.
            return saveToFile();
        }

        try {
            auto yaml = fkyaml::node::deserialize(CONTENT);

            std::string file_version;
            if (yaml.contains("version")) {
                file_version = yaml["version"].get_value<std::string>();
            }
            // Sense migració per ara: si la versió no coincideix, reescrivim
            // amb els defaults de la versió nova.
            if (file_version != Texts::VERSION) { return saveToFile(); }
            config_version = file_version;

            parseWindow(yaml);
            parseVideo(yaml);
            parseAudio(yaml);
            return true;
        } catch (const std::exception& e) {
            std::cerr << "Options: error parsejant config.yaml: " << e.what() << '\n';
            std::cerr << "Options: reescrivint el fitxer amb defaults.\n";
            return saveToFile();
        }
    }

    auto saveToFile() -> bool {
        if (config_file_path.empty()) { return false; }

        config_version = Texts::VERSION;

        std::ostringstream out;
        out << "# Configuració d'AEE 2026. Generat automàticament; editable a mà.\n";
        out << "version: \"" << config_version << "\"\n\n";

        out << "window:\n";
        out << "  zoom: " << window.zoom << "\n";
        out << "  fullscreen: " << (window.fullscreen ? "true" : "false") << "\n\n";

        out << "video:\n";
        out << "  vsync: " << (video.vsync ? "true" : "false") << "\n";
        out << "  scaling_mode: \"" << scalingModeToString(video.scaling_mode) << "\"\n";
        out << "  texture_filter: \"" << filterToString(video.texture_filter) << "\"\n";
        out << "  gpu:\n";
        out << "    acceleration: " << (video.gpu.acceleration ? "true" : "false") << "\n";
        out << "    preferred_driver: \"" << video.gpu.preferred_driver << "\"\n";
        out << "  shader:\n";
        out << "    enabled: " << (video.shader.enabled ? "true" : "false") << "\n";
        out << "    current_shader: \"" << video.shader.current_shader << "\"\n";
        out << "    current_postfx_preset: \"" << video.shader.current_postfx_preset << "\"\n";
        out << "    current_crtpi_preset: \"" << video.shader.current_crtpi_preset << "\"\n\n";

        out << "audio:\n";
        out << "  enabled: " << (audio.enabled ? "true" : "false") << "\n";
        out << "  volume: " << audio.volume << "\n";
        out << "  music:\n";
        out << "    enabled: " << (audio.music.enabled ? "true" : "false") << "\n";
        out << "    volume: " << audio.music.volume << "\n";
        out << "  sound:\n";
        out << "    enabled: " << (audio.sound.enabled ? "true" : "false") << "\n";
        out << "    volume: " << audio.sound.volume << "\n";

        return writeFile(config_file_path, out.str());
    }

    auto buildScreenConfig() -> Screen::Config {
        Screen::Config config;
        config.zoom = window.zoom;
        config.fullscreen = window.fullscreen;
        config.vsync = video.vsync;
        config.scaling_mode = video.scaling_mode;
        config.texture_filter = video.texture_filter;
        config.gpu_acceleration = video.gpu.acceleration;
        config.preferred_driver = video.gpu.preferred_driver;
        return config;
    }

    void setPostFXFile(const std::string& path) {
        postfx_file_path = path;
    }

    auto loadPostFXFromFile() -> bool {
        if (postfx_file_path.empty()) { return false; }

        const std::string CONTENT = readFileOrEmpty(postfx_file_path);
        if (CONTENT.empty()) {
            postfx_presets = defaultPostFXPresets();
            return savePostFXToFile();
        }

        try {
            auto yaml = fkyaml::node::deserialize(CONTENT);
            if (!yaml.contains("presets") || !yaml["presets"].is_sequence()) {
                postfx_presets = defaultPostFXPresets();
                return savePostFXToFile();
            }

            postfx_presets.clear();
            for (const auto& preset_node : yaml["presets"]) {
                PostFXPreset preset;
                parsePostFXPreset(preset_node, preset);
                postfx_presets.push_back(preset);
            }

            if (postfx_presets.empty()) {
                postfx_presets = defaultPostFXPresets();
                return savePostFXToFile();
            }
            return true;
        } catch (const std::exception& e) {
            std::cerr << "Options: error parsejant postfx.yaml: " << e.what() << '\n';
            std::cerr << "Options: reescrivint el fitxer amb presets per defecte.\n";
            postfx_presets = defaultPostFXPresets();
            return savePostFXToFile();
        }
    }

    auto savePostFXToFile() -> bool {
        if (postfx_file_path.empty()) { return false; }

        std::ostringstream out;
        out << "# Presets PostFX per a AEE 2026. Editable a mà.\n";
        out << "# Els noms han de coincidir amb config.yaml > video.shader.current_postfx_preset.\n";
        out << "presets:\n";
        for (const auto& preset : postfx_presets) {
            writePostFXPreset(out, preset);
        }
        return writeFile(postfx_file_path, out.str());
    }

    void setCrtPiFile(const std::string& path) {
        crtpi_file_path = path;
    }

    auto loadCrtPiFromFile() -> bool {
        if (crtpi_file_path.empty()) { return false; }

        const std::string CONTENT = readFileOrEmpty(crtpi_file_path);
        if (CONTENT.empty()) {
            crtpi_presets = defaultCrtPiPresets();
            return saveCrtPiToFile();
        }

        try {
            auto yaml = fkyaml::node::deserialize(CONTENT);
            if (!yaml.contains("presets") || !yaml["presets"].is_sequence()) {
                crtpi_presets = defaultCrtPiPresets();
                return saveCrtPiToFile();
            }

            crtpi_presets.clear();
            for (const auto& preset_node : yaml["presets"]) {
                CrtPiPreset preset;
                parseCrtPiPreset(preset_node, preset);
                crtpi_presets.push_back(preset);
            }

            if (crtpi_presets.empty()) {
                crtpi_presets = defaultCrtPiPresets();
                return saveCrtPiToFile();
            }
            return true;
        } catch (const std::exception& e) {
            std::cerr << "Options: error parsejant crtpi.yaml: " << e.what() << '\n';
            std::cerr << "Options: reescrivint el fitxer amb presets per defecte.\n";
            crtpi_presets = defaultCrtPiPresets();
            return saveCrtPiToFile();
        }
    }

    auto saveCrtPiToFile() -> bool {
        if (crtpi_file_path.empty()) { return false; }

        std::ostringstream out;
        out << "# Presets CRT-Pi per a AEE 2026. Editable a mà.\n";
        out << "# Els noms han de coincidir amb config.yaml > video.shader.current_crtpi_preset.\n";
        out << "presets:\n";
        for (const auto& preset : crtpi_presets) {
            writeCrtPiPreset(out, preset);
        }
        return writeFile(crtpi_file_path, out.str());
    }

    auto buildActiveShader() -> Rendering::ShaderType {
        if (video.shader.current_shader == "crtpi") {
            return Rendering::ShaderType::CRTPI;
        }
        return Rendering::ShaderType::POSTFX;
    }

    auto buildCrtPiParams() -> Rendering::CrtPiParams {
        // Si el shader està deshabilitat, retornem defaults (el dispatch anirà per
        // PostFX passthrough, però sent nets per si algú consulta aquests params).
        if (!video.shader.enabled) { return {}; }

        const auto IT = std::ranges::find_if(crtpi_presets,
            [](const CrtPiPreset& preset) { return preset.name == video.shader.current_crtpi_preset; });
        if (IT == crtpi_presets.end()) {
            std::cerr << "Options: preset CrtPi \"" << video.shader.current_crtpi_preset << "\" no trobat; aplicant defaults.\n";
            return {};
        }
        return {
            .scanline_weight = IT->scanline_weight,
            .scanline_gap_brightness = IT->scanline_gap_brightness,
            .bloom_factor = IT->bloom_factor,
            .input_gamma = IT->input_gamma,
            .output_gamma = IT->output_gamma,
            .mask_brightness = IT->mask_brightness,
            .curvature_x = IT->curvature_x,
            .curvature_y = IT->curvature_y,
            .mask_type = IT->mask_type,
            .enable_scanlines = IT->enable_scanlines,
            .enable_multisample = IT->enable_multisample,
            .enable_gamma = IT->enable_gamma,
            .enable_curvature = IT->enable_curvature,
            .enable_sharper = IT->enable_sharper,
        };
    }

    auto buildPostFXParams() -> Rendering::PostFXParams {
        // Si el shader està deshabilitat, retornem params a zero → passthrough.
        if (!video.shader.enabled) { return {}; }

        const auto IT = std::ranges::find_if(postfx_presets,
            [](const PostFXPreset& preset) { return preset.name == video.shader.current_postfx_preset; });
        if (IT == postfx_presets.end()) {
            std::cerr << "Options: preset PostFX \"" << video.shader.current_postfx_preset << "\" no trobat; aplicant passthrough.\n";
            return {};
        }
        return {
            .vignette = IT->vignette,
            .scanlines = IT->scanlines,
            .chroma = IT->chroma,
            .mask = IT->mask,
            .gamma = IT->gamma,
            .curvature = IT->curvature,
            .bleeding = IT->bleeding,
            .flicker = IT->flicker,
        };
    }

}  // namespace Options