use crate::audio::HostAudio;
use crate::fs_backend::HostDirBackend;
use crate::log_sink::HostConsoleSink;
use crate::debugger::HostDebugger;
use crate::stats::HostStats;
use crate::input::HostInputHandler;
use crate::utilities::draw_rgb565_to_rgba8;
use pixels::{Pixels, SurfaceTexture};
use prometeu_core::firmware::{BootTarget, Firmware};
use prometeu_core::Hardware;
use std::time::{Duration, Instant};
use winit::application::ApplicationHandler;
use winit::dpi::LogicalSize;
use winit::event::{ElementState, 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 HostRunner {
    window: Option<&'static Window>,
    pixels: Option<Pixels<'static>>,

    hardware: Hardware,
    firmware: Firmware,

    input: HostInputHandler,
    fs_root: Option<String>,

    log_sink: HostConsoleSink,

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

    stats: HostStats,
    debugger: HostDebugger,

    overlay_enabled: bool,

    audio: HostAudio,
}

impl HostRunner {
    pub(crate) fn set_boot_target(&mut self, boot_target: BootTarget) {
        self.firmware.boot_target = boot_target.clone();
        self.debugger.setup_boot_target(&boot_target, &mut self.firmware);
    }

    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: HostInputHandler::new(),
            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,

            stats: HostStats::new(),
            debugger: HostDebugger::new(),
            overlay_enabled: false,
            audio: HostAudio::new(),
        }
    }

    fn window(&self) -> &'static Window {
        self.window.expect("window 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();
        }
    }

    fn display_dbg_overlay(&mut self) {
        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.stats.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);
            }
        }
    }
}

impl ApplicationHandler for HostRunner {
    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.audio.init();

        event_loop.set_control_flow(ControlFlow::Poll);
    }


    fn window_event(&mut self, event_loop: &ActiveEventLoop, _id: WindowId, event: WindowEvent) {
        self.input.handle_event(&event, self.window());

        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;

                    if is_down && code == KeyCode::KeyD && self.debugger.waiting_for_start {
                        self.debugger.waiting_for_start = false;
                        println!("[Debugger] Execution started!");
                    }

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

            _ => {}
        }
    }

    fn about_to_wait(&mut self, _event_loop: &ActiveEventLoop) {
        self.debugger.check_commands(&mut self.firmware, &mut self.hardware);

        // 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 {
            if !self.debugger.waiting_for_start {
                self.firmware.step_frame(&self.input.signals, &mut self.hardware);
            }

            self.audio.send_commands(&mut self.hardware.audio.commands);

            self.accumulator -= self.frame_target_dt;
            self.stats.record_frame();
        }

        self.audio.update_stats(&mut self.stats);

        // Atualiza estatísticas a cada 1 segundo real
        self.stats.update(now, self.window, &self.hardware, &self.firmware);

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

        self.request_redraw();
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use prometeu_core::firmware::BootTarget;
    use prometeu_core::debugger_protocol::DEVTOOLS_PROTOCOL_VERSION;
    use std::net::TcpStream;
    use std::io::{Read, Write};

    #[test]
    fn test_debug_port_opens() {
        let mut runner = HostRunner::new(None, None);
        let port = 9999;
        runner.set_boot_target(BootTarget::Cartridge {
            path: "dummy.bin".to_string(),
            debug: true,
            debug_port: port,
        });

        assert!(runner.debugger.waiting_for_start);
        assert!(runner.debugger.listener.is_some());

        // Verifica se conseguimos conectar
        {
            let mut stream = TcpStream::connect(format!("127.0.0.1:{}", port)).expect("Deve conectar");
            // Pequeno sleep para garantir que o SO processe
            std::thread::sleep(std::time::Duration::from_millis(100));
            
            // Simula o loop para aceitar a conexão
            runner.debugger.check_commands(&mut runner.firmware, &mut runner.hardware);
            assert!(runner.debugger.stream.is_some(), "Stream deve ter sido mantido aberto");

            // Verifica Handshake
            let mut buf = [0u8; 2048];
            let n = stream.read(&mut buf).expect("Deve ler handshake");
            let resp: serde_json::Value = serde_json::from_slice(&buf[..n]).expect("Handshake deve ser JSON válido");
            assert_eq!(resp["type"], "handshake");
            assert_eq!(resp["protocol_version"], DEVTOOLS_PROTOCOL_VERSION);

            // Envia start via JSON
            stream.write_all(b"{\"type\":\"start\"}\n").expect("Conexão deve estar aberta para escrita");
            std::thread::sleep(std::time::Duration::from_millis(50));
            
            // Processa o comando recebido
            runner.debugger.check_commands(&mut runner.firmware, &mut runner.hardware);
            assert!(!runner.debugger.waiting_for_start, "Execução deve ter iniciado após comando start");
            assert!(runner.debugger.listener.is_some(), "Listener deve permanecer aberto para reconexões");
        }
        
        // Agora que o stream saiu do escopo do teste, o runner deve detectar o fechamento no próximo check
        std::thread::sleep(std::time::Duration::from_millis(50));
        runner.debugger.check_commands(&mut runner.firmware, &mut runner.hardware);
        assert!(runner.debugger.stream.is_none(), "Stream deve ter sido fechado após o cliente desconectar");
    }

    #[test]
    fn test_debug_reconnection() {
        let mut runner = HostRunner::new(None, None);
        let port = 9998;
        runner.set_boot_target(BootTarget::Cartridge {
            path: "dummy.bin".to_string(),
            debug: true,
            debug_port: port,
        });

        // 1. Conecta e inicia
        {
            let mut stream = TcpStream::connect(format!("127.0.0.1:{}", port)).expect("Deve conectar 1");
            std::thread::sleep(std::time::Duration::from_millis(50));
            runner.debugger.check_commands(&mut runner.firmware, &mut runner.hardware);
            assert!(runner.debugger.stream.is_some());

            stream.write_all(b"{\"type\":\"start\"}\n").expect("Deve escrever start");
            std::thread::sleep(std::time::Duration::from_millis(50));
            runner.debugger.check_commands(&mut runner.firmware, &mut runner.hardware);
            assert!(!runner.debugger.waiting_for_start);
            // Atualmente o listener é fechado aqui.
        }

        // 2. Desconecta (limpa o stream no runner)
        std::thread::sleep(std::time::Duration::from_millis(50));
        runner.debugger.check_commands(&mut runner.firmware, &mut runner.hardware);
        assert!(runner.debugger.stream.is_none());

        // 3. Tenta reconectar - DEVE FALHAR atualmente, mas queremos que FUNCIONE
        let stream2 = TcpStream::connect(format!("127.0.0.1:{}", port));
        assert!(stream2.is_ok(), "Deve aceitar nova conexão mesmo após o start");
        
        std::thread::sleep(std::time::Duration::from_millis(50));
        runner.debugger.check_commands(&mut runner.firmware, &mut runner.hardware);
        assert!(runner.debugger.stream.is_some(), "Stream deve ter sido aceito na reconexão");
    }

    #[test]
    fn test_debug_refuse_second_connection() {
        let mut runner = HostRunner::new(None, None);
        let port = 9997;
        runner.set_boot_target(BootTarget::Cartridge {
            path: "dummy.bin".to_string(),
            debug: true,
            debug_port: port,
        });

        // 1. Primeira conexão
        let mut _stream1 = TcpStream::connect(format!("127.0.0.1:{}", port)).expect("Deve conectar 1");
        std::thread::sleep(std::time::Duration::from_millis(50));
        runner.debugger.check_commands(&mut runner.firmware, &mut runner.hardware);
        assert!(runner.debugger.stream.is_some());

        // 2. Segunda conexão
        let mut stream2 = TcpStream::connect(format!("127.0.0.1:{}", port)).expect("Deve conectar 2 (SO aceita)");
        std::thread::sleep(std::time::Duration::from_millis(50));
        runner.debugger.check_commands(&mut runner.firmware, &mut runner.hardware); // Deve aceitar e fechar stream2
        
        // Verifica se stream2 foi fechado pelo servidor
        let mut buf = [0u8; 10];
        stream2.set_read_timeout(Some(std::time::Duration::from_millis(100))).unwrap();
        let res = stream2.read(&mut buf);
        assert!(matches!(res, Ok(0)) || res.is_err(), "Segunda conexão deve ser fechada pelo servidor");
        
        assert!(runner.debugger.stream.is_some(), "Primeira conexão deve continuar ativa");
    }

    #[test]
    fn test_get_state_returns_response() {
        let mut runner = HostRunner::new(None, None);
        let port = 9996;
        runner.set_boot_target(BootTarget::Cartridge {
            path: "dummy.bin".to_string(),
            debug: true,
            debug_port: port,
        });

        let stream = TcpStream::connect(format!("127.0.0.1:{}", port)).expect("Deve conectar");
        std::thread::sleep(std::time::Duration::from_millis(100));
        runner.debugger.check_commands(&mut runner.firmware, &mut runner.hardware);

        use std::io::BufRead;
        let mut reader = std::io::BufReader::new(stream);
        
        let mut line = String::new();
        reader.read_line(&mut line).expect("Deve ler handshake");
        assert!(line.contains("handshake"));

        // Envia getState
        reader.get_mut().write_all(b"{\"type\":\"getState\"}\n").expect("Deve escrever getState");
        std::thread::sleep(std::time::Duration::from_millis(100));
        
        runner.debugger.check_commands(&mut runner.firmware, &mut runner.hardware);

        // Verifica se recebeu resposta (pode haver eventos/logs antes)
        loop {
            line.clear();
            reader.read_line(&mut line).expect("Deve ler linha");
            if line.is_empty() { break; }
            
            if let Ok(resp) = serde_json::from_str::<serde_json::Value>(&line) {
                if resp["type"] == "getState" {
                    return;
                }
            }
        }
        panic!("Não recebeu resposta getState");
    }

    #[test]
    fn test_debug_resume_on_disconnect() {
        let mut runner = HostRunner::new(None, None);
        let port = 9995;
        runner.set_boot_target(BootTarget::Cartridge {
            path: "dummy.bin".to_string(),
            debug: true,
            debug_port: port,
        });

        // 1. Conecta e pausa
        {
            let mut stream = TcpStream::connect(format!("127.0.0.1:{}", port)).expect("Deve conectar");
            std::thread::sleep(std::time::Duration::from_millis(50));
            runner.debugger.check_commands(&mut runner.firmware, &mut runner.hardware);
            
            stream.write_all(b"{\"type\":\"pause\"}\n").expect("Deve escrever pause");
            std::thread::sleep(std::time::Duration::from_millis(50));
            runner.debugger.check_commands(&mut runner.firmware, &mut runner.hardware);
            assert!(runner.firmware.os.paused, "VM deve estar pausada");
        }

        // 2. Desconecta (stream sai de escopo)
        std::thread::sleep(std::time::Duration::from_millis(50));
        runner.debugger.check_commands(&mut runner.firmware, &mut runner.hardware);
        
        // 3. Verifica se despausou
        assert!(!runner.firmware.os.paused, "VM deve ter despausado após desconexão");
        assert!(!runner.debugger.waiting_for_start, "VM deve ter saído do estado waiting_for_start");
    }
}