#include <SDL2/SDL.h>
#include <csignal>
#include <iostream>
#include <chrono>
#ifdef MIYOO_BUILD
#include <cstdlib>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <linux/fb.h>
#endif
#include "Game.hpp"
#include "Synth.hpp"
#include "Renderer.hpp"

// Crash signal handler to print diagnostic trace to cybermatris.log
void crashHandler(int signum) {
    std::cerr << "\n\n==================================================" << std::endl;
    std::cerr << "[CRASH DETECTED] CyberMatris caught fatal signal " << signum;
    switch (signum) {
        case SIGSEGV: std::cerr << " (SIGSEGV: Segmentation Fault)"; break;
        case SIGABRT: std::cerr << " (SIGABRT: Abort / Assertion failed)"; break;
        case SIGFPE:  std::cerr << " (SIGFPE: Floating Point Exception)"; break;
        case SIGILL:  std::cerr << " (SIGILL: Illegal Instruction)"; break;
        case SIGBUS:  std::cerr << " (SIGBUS: Bus Error)"; break;
        default:      std::cerr << " (Unknown Signal)"; break;
    }
    std::cerr << "\n==================================================" << std::endl;
    std::cerr.flush();
    
    // Restore default handler and re-raise to complete execution termination
    std::signal(signum, SIG_DFL);
    std::raise(signum);
}

int main([[maybe_unused]] int argc, [[maybe_unused]] char* argv[]) {
    // Register crash signal handlers
    std::signal(SIGSEGV, crashHandler);
    std::signal(SIGABRT, crashHandler);
    std::signal(SIGFPE, crashHandler);
    std::signal(SIGILL, crashHandler);
    std::signal(SIGBUS, crashHandler);

    // 1. Initialize SDL2 subsystems
    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO) < 0) {
        std::cerr << "SDL could not initialize! SDL_Error: " << SDL_GetError() << std::endl;
        return -1;
    }

    // 2. Create display window
    int win_w = 800;
    int win_h = 600;
    Uint32 win_flags = SDL_WINDOW_SHOWN;

#ifdef MIYOO_BUILD
    win_flags |= SDL_WINDOW_FULLSCREEN;
    
    // Default fallback
    win_w = 640;
    win_h = 480;

    // 1. Try environment variables first
    const char* env_w = std::getenv("MIYOO_SCREEN_WIDTH");
    const char* env_h = std::getenv("MIYOO_SCREEN_HEIGHT");
    if (env_w && env_h) {
        int parsed_w = std::atoi(env_w);
        int parsed_h = std::atoi(env_h);
        if (parsed_w > 0 && parsed_h > 0) {
            win_w = parsed_w;
            win_h = parsed_h;
            std::cout << "[INFO] Detected screen resolution from environment: " << win_w << "x" << win_h << std::endl;
        }
    } else {
        // 2. Fallback to /dev/fb0 ioctl
        int fd = open("/dev/fb0", O_RDONLY);
        if (fd >= 0) {
            struct fb_var_screeninfo vinfo;
            if (ioctl(fd, FBIOGET_VSCREENINFO, &vinfo) >= 0) {
                if (vinfo.xres > 0 && vinfo.yres > 0) {
                    win_w = vinfo.xres;
                    win_h = vinfo.yres;
                    std::cout << "[INFO] Detected screen resolution from /dev/fb0: " << win_w << "x" << win_h << std::endl;
                }
            }
            close(fd);
        } else {
            std::cerr << "[WARNING] Failed to open /dev/fb0 for resolution query, using default 640x480" << std::endl;
        }
    }
#endif

    SDL_Window* window = SDL_CreateWindow(
        "CyberMatris - Programmatic Retro Tetris",
        SDL_WINDOWPOS_CENTERED,
        SDL_WINDOWPOS_CENTERED,
        win_w, win_h,
        win_flags
    );
    if (window == nullptr) {
        std::cerr << "Window could not be created! SDL_Error: " << SDL_GetError() << std::endl;
        SDL_Quit();
        return -1;
    }

    // 3. Create GPU Hardware Accelerated Renderer with VSync
    SDL_Renderer* renderer = SDL_CreateRenderer(
        window, -1,
        SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC
    );
#ifdef MIYOO_BUILD
    if (renderer != nullptr) {
        std::cerr << "[MIYOO] Hardware accelerated renderer OK" << std::endl;
    }
#endif
    if (renderer == nullptr) {
        std::cerr << "Renderer could not be created! SDL_Error: " << SDL_GetError() << std::endl;
        SDL_DestroyWindow(window);
        SDL_Quit();
        return -1;
    }

    // 4. Initialize Procedural Audio Synthesizer
    Synth synth;
    if (!synth.init()) {
        std::cerr << "Warning: Could not initialize programmatic audio synthesizer! SDL_Error: " << SDL_GetError() << std::endl;
    }

    // 5. Initialize Game Logic and Renderer
    Game game;
    Renderer gameRenderer;
    if (!gameRenderer.init(renderer, win_w, win_h)) {
        std::cerr << "Failed to build procedural graphics textures!" << std::endl;
        SDL_DestroyRenderer(renderer);
        SDL_DestroyWindow(window);
        SDL_Quit();
        return -1;
    }

    bool quit = false;
    SDL_Event event;

    // Track frame timing using high-precision performance counters
    uint64_t lastTime = SDL_GetPerformanceCounter();
    double freq = static_cast<double>(SDL_GetPerformanceFrequency());

    float softDropTimer = 0.0f;

    // Flush initial queued events (e.g., from OnionOS menu launch/button presses)
    std::cout << "[INFO] Flushing initial event queue..." << std::endl;
    SDL_Event trashEvent;
    int flushedCount = 0;
    while (SDL_PollEvent(&trashEvent)) {
        flushedCount++;
    }
    std::cout << "[INFO] Flushed " << flushedCount << " initial events." << std::endl;

    // 6. Execution Loop
    while (!quit) {
        // A. Calculate frame delta-time (dt)
        uint64_t currentTime = SDL_GetPerformanceCounter();
        float dt = static_cast<float>((currentTime - lastTime) / freq);
        lastTime = currentTime;

        // Cap dt to prevent massive jumps during window drags or lags
        if (dt > 0.1f) dt = 0.1f;

        // B. Handle Inputs & Events
        while (SDL_PollEvent(&event) != 0) {
            if (event.type == SDL_QUIT) {
                std::cout << "[EVENT] Received SDL_QUIT signal." << std::endl;
                quit = true;
            } else if (event.type == SDL_KEYDOWN) {
                SDL_Keycode sym = event.key.keysym.sym;
                std::cout << "[EVENT] Key Down: " << sym << " (" << SDL_GetKeyName(sym) << ")" << std::endl;
                
                if (sym == SDLK_s) {
                    gameRenderer.takeScreenshot("screenshot.bmp");
                    std::cout << "[INFO] Screenshot captured to screenshot.bmp" << std::endl;
                }
                
                // START Screen Inputs
                if (game.getState() == GameState::START) {
                    if (sym == SDLK_RETURN || sym == SDLK_KP_ENTER || sym == SDLK_LALT) {
                        std::cout << "[INPUT] Start/Confirm game triggered." << std::endl;
                        game.setState(GameState::PLAYING);
                        game.reset();
                        synth.playBGM(true);
                    } else if (sym == SDLK_ESCAPE) {
                        // Cooldown check (1000ms) to prevent immediate exit due to leftover events on boot
                        Uint32 currentTicks = SDL_GetTicks();
                        if (currentTicks > 1000) {
                            std::cout << "[INPUT] Quit game requested via ESCAPE/SELECT (ticks: " << currentTicks << ")" << std::endl;
                            quit = true;
                        } else {
                            std::cout << "[INPUT] Blocked early ESCAPE/SELECT quit request (cooldown ticks: " << currentTicks << ")" << std::endl;
                        }
                    }
                }
                // PLAYING State Inputs
                else if (game.getState() == GameState::PLAYING) {
                    switch (sym) {
                        case SDLK_LEFT:
                            game.moveLeft();
                            break;
                        case SDLK_RIGHT:
                            game.moveRight();
                            break;
                        case SDLK_UP:
                        case SDLK_x:
                        case SDLK_LALT: // Gamepad A (Rotate CW)
                            game.rotate(1); // Clockwise rotation
                            break;
                        case SDLK_z:
                        case SDLK_LCTRL: // Gamepad B (Rotate CCW)
                            game.rotate(-1); // Counter-Clockwise rotation
                            break;
                        case SDLK_SPACE:
                            game.hardDrop();
                            break;
                        case SDLK_c:
                        case SDLK_LSHIFT:
                            game.holdPiece();
                            break;
                        case SDLK_p:
                            game.setState(GameState::PAUSED);
                            synth.playBGM(false);
                            break;
                        case SDLK_r:
                            synth.stopAllSFX();
                            game.reset();
                            synth.playBGM(true);
                            break;
                        case SDLK_ESCAPE:
                            synth.stopAllSFX();
                            game.setState(GameState::START);
                            synth.playBGM(false);
                            break;
                        default:
                            break;
                    }
                }
                // PAUSED State Inputs
                else if (game.getState() == GameState::PAUSED) {
                    if (sym == SDLK_p) {
                        game.setState(GameState::PLAYING);
                        synth.playBGM(true);
                    } else if (sym == SDLK_ESCAPE) {
                        synth.stopAllSFX();
                        game.setState(GameState::START);
                        synth.playBGM(false);
                    }
                }
                // GAME OVER State Inputs
                else if (game.getState() == GameState::GAME_OVER) {
                    if (sym == SDLK_r) {
                        synth.stopAllSFX();
                        game.setState(GameState::PLAYING);
                        game.reset();
                        synth.playBGM(true);
                    } else if (sym == SDLK_ESCAPE || sym == SDLK_RETURN || sym == SDLK_KP_ENTER || sym == SDLK_LALT) {
                        synth.stopAllSFX();
                        game.setState(GameState::START);
                        synth.playBGM(false);
                    }
                }
            }
        }

        // C. Continuous Keyboard Polling for Smooth Soft-Drop sliding
        if (game.getState() == GameState::PLAYING) {
            const Uint8* keyboardState = SDL_GetKeyboardState(nullptr);
            if (keyboardState[SDL_SCANCODE_DOWN]) {
                softDropTimer += dt;
                if (softDropTimer >= 0.04f) { // Soft drop tick speed (every 40ms)
                    softDropTimer = 0.0f;
                    game.softDrop();
                }
            } else {
                softDropTimer = 0.0f;
            }
        }

        // D. Update Game Logic (gravity timing)
        bool lineCleared = game.update(dt);
        if (lineCleared) {
            // Trigger glorious pixel explosion of sparks on cleared rows
            gameRenderer.spawnLineClearParticles(game);
        }

        // E. Bridge Game Events to Synth Sound Triggers and Particle Emitters
        if (game.flagMoveSFX) {
            synth.triggerSFX(SFXType::MOVE);
            game.flagMoveSFX = false;
        }
        if (game.flagRotateSFX) {
            synth.triggerSFX(SFXType::ROTATE);
            game.flagRotateSFX = false;
        }
        if (game.flagLandSFX) {
            synth.triggerSFX(SFXType::LAND);
            
            // Spawn subtle white-gray impact smoke clouds at bottom row of contact
            auto lockedCells = game.mLastLockedCells;
            if (!lockedCells.empty()) {
                int lowestY = -100;
                for (const auto& p : lockedCells) {
                    if (p.y > lowestY) lowestY = p.y;
                }
                for (const auto& p : lockedCells) {
                    if (p.y == lowestY) {
                        gameRenderer.spawnLandDustParticles(p.x, p.y, game.getActivePieceType());
                    }
                }
            }
            game.flagLandSFX = false;
        }
        if (game.flagLineClearSFX) {
            synth.triggerSFX(SFXType::LINE_CLEAR);
            game.flagLineClearSFX = false;
        }
        if (game.flagTetrisClearSFX) {
            synth.triggerSFX(SFXType::TETRIS_CLEAR);
            game.flagTetrisClearSFX = false;
        }
        if (game.flagLevelUpSFX) {
            synth.triggerSFX(SFXType::LEVEL_UP);
            game.flagLevelUpSFX = false;
        }
        if (game.flagGameOverSFX) {
            synth.triggerSFX(SFXType::GAME_OVER);
            synth.playBGM(false);
            game.flagGameOverSFX = false;
        }

        // F. Update Parallax Background and Particle physics
        gameRenderer.update(dt);

        // G. Render active frame (automatically uploads backbuffer and calls SDL_RenderPresent)
        gameRenderer.render(game, synth);

        // H. Automatic periodic screenshot disabled on Miyoo (FAT32 write-during-render issues)
#ifndef MIYOO_BUILD
        static float autoScreenshotTimer = 0.0f;
        autoScreenshotTimer += dt;
        if (autoScreenshotTimer >= 2.0f) {
            autoScreenshotTimer = 0.0f;
            gameRenderer.takeScreenshot("screenshot.bmp");
        }
#endif
    }

    // 7. Cleanup and close resources
    synth.playBGM(false);
    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);
    SDL_Quit();

    return 0;
}