use crate::audio_mixer::AudioMixer;
use crate::fs_desktop_backend::HostDirBackend;
use crate::log_sink::HostConsoleSink;
use cpal::traits::{DeviceTrait, HostTrait, StreamTrait};
use pixels::{Pixels, SurfaceTexture};
use prometeu_core::firmware::Firmware;
use prometeu_core::hardware::{AudioCommand, InputSignals, OUTPUT_SAMPLE_RATE};
use prometeu_core::Hardware;
use ringbuf::traits::{Consumer, Producer, Split};
use ringbuf::HeapRb;
use std::sync::Arc;
use std::time::{Duration, Instant};
use winit::application::ApplicationHandler;
use winit::dpi::LogicalSize;
use winit::event::{ElementState, MouseButton, WindowEvent};
use winit::event_loop::{ActiveEventLoop, ControlFlow};
use winit::keyboard::{KeyCode, PhysicalKey};
use winit::window::{Window, WindowAttributes, WindowId};

use prometeu_core::telemetry::CertificationConfig;

pub struct PrometeuRunner {
    window: Option<&'static Window>,
    pixels: Option<Pixels<'static>>,

    hardware: Hardware,
    firmware: Firmware,

    input_signals: InputSignals,
    fs_root: Option<String>,

    log_sink: HostConsoleSink,

    frame_target_dt: Duration,
    last_frame_time: Instant,
    accumulator: Duration,

    last_stats_update: Instant,
    frames_since_last_update: u64,
    current_fps: f64,

    overlay_enabled: bool,

    audio_load_accum_us: u64,
    audio_load_samples: u64,
    audio_perf_consumer: Option<ringbuf::wrap::CachingCons<Arc<HeapRb<u64>>>>,

    audio_producer: Option<ringbuf::wrap::CachingProd<Arc<HeapRb<AudioCommand>>>>,
    _audio_stream: Option<cpal::Stream>,
}

impl PrometeuRunner {
    pub(crate) fn new(fs_root: Option<String>, cap_config: Option<CertificationConfig>) -> Self {
        let target_fps = 60;

        let mut firmware = Firmware::new(cap_config);
        if let Some(root) = &fs_root {
            let backend = HostDirBackend::new(root);
            firmware.os.mount_fs(Box::new(backend));
        }

        Self {
            window: None,
            pixels: None,
            hardware: Hardware::new(),
            firmware,
            input_signals: InputSignals::default(),
            fs_root,
            log_sink: HostConsoleSink::new(),
            frame_target_dt: Duration::from_nanos(1_000_000_000 / target_fps),
            last_frame_time: Instant::now(),
            accumulator: Duration::ZERO,

            last_stats_update: Instant::now(),
            frames_since_last_update: 0,
            current_fps: 0.0,
            overlay_enabled: false,
            audio_load_accum_us: 0,
            audio_load_samples: 0,
            audio_perf_consumer: None,

            audio_producer: None,
            _audio_stream: None,
        }
    }

    fn init_audio(&mut self) {
        let host = cpal::default_host();
        let device = host
            .default_output_device()
            .expect("no output device available");

        let config = cpal::StreamConfig {
            channels: 2,
            sample_rate: cpal::SampleRate(OUTPUT_SAMPLE_RATE),
            buffer_size: cpal::BufferSize::Default,
        };

        let rb = HeapRb::<AudioCommand>::new(1024);
        let (prod, mut cons) = rb.split();

        self.audio_producer = Some(prod);

        let mut mixer = AudioMixer::new();

        // Para passar dados de performance da thread de áudio para a principal
        let audio_perf_rb = HeapRb::<u64>::new(64);
        let (mut perf_prod, perf_cons) = audio_perf_rb.split();

        let stream = device
            .build_output_stream(
                &config,
                move |data: &mut [f32], _: &cpal::OutputCallbackInfo| {
                    // Consome comandos da ringbuffer
                    while let Some(cmd) = cons.try_pop() {
                        mixer.process_command(cmd);
                    }
                    // Mixa áudio
                    mixer.fill_buffer(data);
                    // Envia tempo de processamento em microssegundos
                    let _ = perf_prod.try_push(mixer.last_processing_time.as_micros() as u64);
                },
                |err| eprintln!("audio stream error: {}", err),
                None,
            )
            .expect("failed to build audio stream");

        stream.play().expect("failed to play audio stream");
        self._audio_stream = Some(stream);
        self.audio_perf_consumer = Some(perf_cons);
    }

    fn window(&self) -> &'static Window {
        self.window.expect("window not created yet")
    }

    // fn pixels_mut(&mut self) -> &mut Pixels<'static> {
    //     self.pixels.as_mut().expect("pixels not created yet")
    // }

    fn resize_surface(&mut self, width: u32, height: u32) {
        if let Some(p) = self.pixels.as_mut() {
            let _ = p.resize_surface(width, height);
        }
    }

    fn request_redraw(&self) {
        if let Some(w) = self.window.as_ref() {
            w.request_redraw();
        }
    }
}

impl ApplicationHandler for PrometeuRunner {
    fn resumed(&mut self, event_loop: &ActiveEventLoop) {
        let attrs = WindowAttributes::default()
            .with_title(format!(
                "PROMETEU | GFX: {:.1} KB | FPS: {:.1} | Load: {:.1}% (C) + {:.1}% (A) | Frame: tick {} logical {}",
                0.0, 0.0, 0.0, 0, 0, 0))
            .with_inner_size(LogicalSize::new(960.0, 540.0))
            .with_min_inner_size(LogicalSize::new(320.0, 180.0));

        let window = event_loop.create_window(attrs).expect("failed to create window");

        // 🔥 Leak: Window vira &'static Window (bootstrap)
        let window: &'static Window = Box::leak(Box::new(window));
        self.window = Some(window);

        let size = window.inner_size();
        let surface_texture = SurfaceTexture::new(size.width, size.height, window);

        let mut pixels = Pixels::new(Hardware::W as u32, Hardware::H as u32, surface_texture)
            .expect("failed to create Pixels");

        pixels.frame_mut().fill(0);

        self.pixels = Some(pixels);

        self.init_audio();

        event_loop.set_control_flow(ControlFlow::Poll);
    }


    fn window_event(&mut self, event_loop: &ActiveEventLoop, _id: WindowId, event: WindowEvent) {
        match event {
            WindowEvent::CloseRequested => event_loop.exit(),

            WindowEvent::Resized(size) => {
                self.resize_surface(size.width, size.height);
            }

            WindowEvent::ScaleFactorChanged { .. } => {
                let size = self.window().inner_size();
                self.resize_surface(size.width, size.height);
            }

            WindowEvent::RedrawRequested => {
                // Pegue o Pixels diretamente do campo (não via helper que pega &mut self inteiro)
                let pixels = self.pixels.as_mut().expect("pixels not initialized");

                {
                    // Borrow mutável do frame (dura só dentro deste bloco)
                    let frame = pixels.frame_mut();

                    // Borrow imutável do prometeu-core (campo diferente, ok)
                    let src = self.hardware.gfx.front_buffer();

                    draw_rgb565_to_rgba8(src, frame);
                } // <- frame borrow termina aqui

                if pixels.render().is_err() {
                    event_loop.exit();
                }
            }


            WindowEvent::KeyboardInput { event, .. } => {
                if let PhysicalKey::Code(code) = event.physical_key {
                    let is_down = event.state == ElementState::Pressed;
                    match code {
                        KeyCode::ArrowUp => self.input_signals.up_signal = is_down,
                        KeyCode::ArrowDown => self.input_signals.down_signal = is_down,
                        KeyCode::ArrowLeft => self.input_signals.left_signal = is_down,
                        KeyCode::ArrowRight => self.input_signals.right_signal = is_down,

                        // A/B (troque depois como quiser)
                        KeyCode::KeyA => self.input_signals.a_signal = is_down,
                        KeyCode::KeyD => self.input_signals.b_signal = is_down,
                        KeyCode::KeyW => self.input_signals.x_signal = is_down,
                        KeyCode::KeyS => self.input_signals.y_signal = is_down,
                        KeyCode::KeyQ => self.input_signals.l_signal = is_down,
                        KeyCode::KeyE => self.input_signals.r_signal = is_down,

                        KeyCode::KeyZ => self.input_signals.start_signal = is_down,
                        KeyCode::ShiftLeft | KeyCode::ShiftRight => self.input_signals.select_signal = is_down,

                        KeyCode::F1 => {
                            if is_down {
                                self.overlay_enabled = !self.overlay_enabled;
                            }
                        }

                        _ => {}
                    }
                }
            }

            WindowEvent::CursorMoved { position, .. } => {
                let v = window_to_fb(position.x as f32, position.y as f32, self.window());
                self.input_signals.x_pos = v.0;
                self.input_signals.y_pos = v.1;
            }

            WindowEvent::MouseInput { state, button, .. } => {
                if button == MouseButton::Left {
                    match state {
                        ElementState::Pressed => {
                            self.input_signals.f_signal = true;
                        }
                        ElementState::Released => {
                            self.input_signals.f_signal = false;
                        }
                    }
                }
            }

            _ => {}
        }
    }

    fn about_to_wait(&mut self, _event_loop: &ActiveEventLoop) {
        // Atualiza estado do Filesystem no OS (específico do host-desktop)
        if let Some(root) = &self.fs_root {
            use prometeu_core::fs::FsState;
            if matches!(self.firmware.os.fs_state, FsState::Unmounted | FsState::Error(_)) {
                if std::path::Path::new(root).exists() {
                    let backend = HostDirBackend::new(root);
                    self.firmware.os.mount_fs(Box::new(backend));
                }
            }
        }

        let now = Instant::now();
        let mut frame_delta = now.duration_since(self.last_frame_time);

        // Limitador para evitar a "espiral da morte" se o SO travar (máximo de 100ms por volta)
        if frame_delta > Duration::from_millis(100) {
            frame_delta = Duration::from_millis(100);
        }

        self.last_frame_time = now;
        self.accumulator += frame_delta;

        // 🔥 O coração do determinismo: consome o tempo em fatias exatas de 60Hz
        while self.accumulator >= self.frame_target_dt {
            self.firmware.step_frame(&self.input_signals, &mut self.hardware);

            // Envia comandos de áudio gerados neste frame para a thread de áudio
            if let Some(producer) = &mut self.audio_producer {
                for cmd in self.hardware.audio.commands.drain(..) {
                    let _ = producer.try_push(cmd);
                }
            }

            self.accumulator -= self.frame_target_dt;
            self.frames_since_last_update += 1;
        }

        // Drena tempos de performance do áudio
        if let Some(cons) = &mut self.audio_perf_consumer {
            while let Some(us) = cons.try_pop() {
                self.audio_load_accum_us += us;
                self.audio_load_samples += 1;
            }
        }

        // Atualiza estatísticas a cada 1 segundo real
        let stats_elapsed = now.duration_since(self.last_stats_update);
        if stats_elapsed >= Duration::from_secs(1) {
            self.current_fps = self.frames_since_last_update as f64 / stats_elapsed.as_secs_f64();
            if let Some(window) = self.window {
                let kb = self.hardware.gfx.memory_usage_bytes() as f64 / 1024.0;

                // comparação fixa sempre contra 60Hz, manter mesmo quando fazer teste de stress na CPU
                let frame_budget_us = 16666.0;
                let cpu_load_core = (self.firmware.os.last_frame_cpu_time_us as f64 / frame_budget_us) * 100.0;

                let cpu_load_audio = if self.audio_load_samples > 0 {
                    // O load real é (tempo total processando) / (tempo total de parede).
                    (self.audio_load_accum_us as f64 / stats_elapsed.as_micros() as f64) * 100.0
                } else {
                    0.0
                };

                let title = format!(
                    "PROMETEU | GFX: {:.1} KB | FPS: {:.1} | Load: {:.1}% (C) + {:.1}% (A) | Frame: tick {} logical {}",
                    kb, self.current_fps, cpu_load_core, cpu_load_audio, self.firmware.os.tick_index, self.firmware.os.logical_frame_index
                );
                window.set_title(&title);
            }

            self.last_stats_update = now;
            self.frames_since_last_update = 0;
            self.audio_load_accum_us = 0;
            self.audio_load_samples = 0;
        }

        // Processa logs do sistema
        let last_seq = self.log_sink.last_seq().unwrap_or(u64::MAX);
        let new_events = if last_seq == u64::MAX {
            self.firmware.os.log_service.get_recent(4096)
        } else {
            self.firmware.os.log_service.get_after(last_seq)
        };
        self.log_sink.process_events(new_events);

        // Overlay de Telemetria
        if self.overlay_enabled {
            self.hardware.gfx.present(); // Traz o front para o back para desenhar por cima

            let tel = &self.firmware.os.telemetry_last;
            let color_text = prometeu_core::model::Color::WHITE;
            let color_bg = prometeu_core::model::Color::INDIGO; // Azul escuro para destacar
            let color_warn = prometeu_core::model::Color::RED;

            self.hardware.gfx.fill_rect(5, 5, 140, 65, color_bg);
            self.hardware.gfx.draw_text(10, 10, &format!("FPS: {:.1}", self.current_fps), color_text);
            self.hardware.gfx.draw_text(10, 18, &format!("HOST: {:.2}MS", tel.host_cpu_time_us as f64 / 1000.0), color_text);
            self.hardware.gfx.draw_text(10, 26, &format!("STEPS: {}", tel.vm_steps), color_text);
            self.hardware.gfx.draw_text(10, 34, &format!("SYSC: {}", tel.syscalls), color_text);
            self.hardware.gfx.draw_text(10, 42, &format!("CYC: {}", tel.cycles_used), color_text);
            
            let cert_color = if tel.violations > 0 { color_warn } else { color_text };
            self.hardware.gfx.draw_text(10, 50, &format!("CERT LAST: {}", tel.violations), cert_color);
            
            if tel.violations > 0 {
                 if let Some(event) = self.firmware.os.log_service.get_recent(10).into_iter().rev().find(|e| e.tag >= 0xCA01 && e.tag <= 0xCA03) {
                     let mut msg = event.msg.clone();
                     if msg.len() > 30 { msg.truncate(30); }
                     self.hardware.gfx.draw_text(10, 58, &msg, color_warn);
                 }
            }

            self.hardware.gfx.present(); // Devolve para o front com o overlay aplicado
        }

        self.request_redraw();
    }
}

/// Mapeamento simples: window coords -> framebuffer coords (stretch).
/// Depois podemos fazer letterbox/aspect-ratio correto.
fn window_to_fb(wx: f32, wy: f32, window: &Window) -> (i32, i32) {
    let size = window.inner_size();
    let fb_w = Hardware::W as f32;
    let fb_h = Hardware::H as f32;

    let x = (wx * fb_w / size.width as f32).floor() as i32;
    let y = (wy * fb_h / size.height as f32).floor() as i32;

    (x.clamp(0, Hardware::W as i32 - 1), y.clamp(0, Hardware::H as i32 - 1))
}

/// Copia RGB565 (u16) -> RGBA8888 (u8[4]) para o frame do pixels.
/// Formato do pixels: RGBA8.
fn draw_rgb565_to_rgba8(src: &[u16], dst_rgba: &mut [u8]) {
    for (i, &px) in src.iter().enumerate() {
        let (r8, g8, b8) = rgb565_to_rgb888(px);
        let o = i * 4;
        dst_rgba[o] = r8;
        dst_rgba[o + 1] = g8;
        dst_rgba[o + 2] = b8;
        dst_rgba[o + 3] = 0xFF;
    }
}

/// Expande RGB565 para RGB888 (replicação de bits altos).
#[inline(always)]
fn rgb565_to_rgb888(px: u16) -> (u8, u8, u8) {
    let r5 = ((px >> 11) & 0x1F) as u8;
    let g6 = ((px >> 5) & 0x3F) as u8;
    let b5 = (px & 0x1F) as u8;

    let r8 = (r5 << 3) | (r5 >> 2);
    let g8 = (g6 << 2) | (g6 >> 4);
    let b8 = (b5 << 3) | (b5 >> 2);

    (r8, g8, b8)
}