use serde::{Deserialize, Serialize};
use std::io::Read;
use std::fs::{self, File};
use std::io::Write as IoWrite;
use std::path::PathBuf;
use std::pin::Pin;
use std::process::Command;

use base64::{Engine as _, engine::general_purpose::STANDARD as BASE64};
use cube_lib::websocket::{WebSocketClient, WebSocketConfig};

// ===================== 文件下载状态 =====================
struct DownloadState {
    filename: String,
    offset: u64,
    temp_path: Option<PathBuf>,
    file: Option<File>,
}

impl Default for DownloadState {
    fn default() -> Self {
        Self {
            filename: String::new(),
            offset: 0,
            temp_path: None,
            file: None,
        }
    }
}

static DOWNLOAD_STATE: std::sync::Mutex<DownloadState> = std::sync::Mutex::new(DownloadState {
    filename: String::new(),
    offset: 0,
    temp_path: None,
    file: None,
});

// ===================== 版本比较与下载 =====================
/// 获取 Updater 数据目录（X:\AppData\，存放 BootLoader.exe 等）
fn get_updater_data_dir() -> PathBuf {
    let exe_path = std::env::current_exe().expect("Failed to get executable path");
    let drive = exe_path
        .parent()
        .and_then(|p| p.as_os_str().to_str())
        .and_then(|s| s.split('\\').next())
        .unwrap_or("C:");
    let appdata = PathBuf::from(format!("{}/AppData", drive));
    let _ = fs::create_dir_all(&appdata);
    appdata
}

/// 获取本地文件版本号（使用 PowerShell 获取 PE 文件版本信息）
fn get_local_file_version(filename: &str) -> String {
    let file_path = get_updater_data_dir().join(filename);

    if !file_path.exists() {
        return "0.0.0".to_string();
    }

    #[cfg(windows)]
    {
        let path_str = file_path.to_string_lossy().to_string();
        let ps_script = format!(
            "(Get-Item -LiteralPath '{}' -ErrorAction SilentlyContinue).VersionInfo.FileVersion",
            path_str.replace("'", "''")
        );

        let output = Command::new("powershell")
            .args(["-NoProfile", "-NonInteractive", "-Command", &ps_script])
            .output();

        if let Ok(output) = output {
            let stdout = String::from_utf8_lossy(&output.stdout);
            let version = stdout.trim();
            if !version.is_empty() && version != "0" && !version.contains("没有版本") {
                return version.to_string();
            }
        }

        // 备用：使用文件修改时间作为"版本"
        if let Ok(metadata) = fs::metadata(&file_path) {
            use std::time::UNIX_EPOCH;
            if let Ok(modified) = metadata.modified() {
                let duration = modified.duration_since(UNIX_EPOCH).unwrap_or_default();
                return format!("{}.{}", duration.as_secs(), duration.subsec_nanos() / 1_000_000);
            }
        }

        "0.0.0".to_string()
    }

    #[cfg(not(windows))]
    {
        "0.0.0".to_string()
    }
}

/// 比较两个版本号（a < b 返回 true）
fn version_less_than(a: &str, b: &str) -> bool {
    let parse_v = |v: &str| -> Vec<u32> {
        v.split(|c: char| !c.is_ascii_digit() && c != '.')
            .filter(|s| !s.is_empty())
            .filter_map(|s| s.parse().ok())
            .collect()
    };
    let a_parts: Vec<u32> = parse_v(a);
    let b_parts: Vec<u32> = parse_v(b);
    let max_len = a_parts.len().max(b_parts.len());

    for i in 0..max_len {
        let av = if i < a_parts.len() { a_parts[i] } else { 0 };
        let bv = if i < b_parts.len() { b_parts[i] } else { 0 };
        if av < bv {
            return true;
        }
        if av > bv {
            return false;
        }
    }
    false
}

/// 计算本地文件前 N 字节的 MD5 hash（字节数为 0 表示全部）
fn compute_file_hash(filename: &str, bytes: u64, _debug: bool) -> Option<String> {

    let file_path = get_updater_data_dir().join(filename);
    if !file_path.exists() {
        return None;
    }

    let mut file = File::open(&file_path).ok()?;
    let file_size = file.metadata().ok()?.len();

    // 如果 bytes=0 或超过文件大小，则计算整个文件
    let read_bytes = if bytes == 0 || bytes > file_size {
        file_size
    } else {
        bytes
    };

    // 读取前 read_bytes 字节
    let mut buffer = vec![0u8; read_bytes as usize];
    file.read_exact(&mut buffer).ok()?;

    let hash = md5::compute(&buffer);
    Some(format!("{:x}", hash))
}

/// 获取临时文件的当前大小（字节数）
fn get_tmp_file_size(filename: &str) -> u64 {
    let tmp_path = get_updater_data_dir().join(format!("{}.tmp", filename));
    tmp_path.metadata().map(|m| m.len()).unwrap_or(0)
}

/// 发送 GetFileMd5 请求
fn request_file_md5(sender: &cube_lib::websocket::MessageSender, filename: &str, bytes: u64, debug: bool) {
    let msg_str = format!(
        r#"{{"Type":"GetFileMd5","Data":{{"filename":"{}","bytes":{}}}}}"#,
        filename, bytes
    );
    if debug {
        let ts = chrono::Local::now().format("%Y-%m-%d %H:%M:%S%.3f");
        println!("{} 发送消息：{}", ts, msg_str);
    }
    sender.send(msg_str);
}

/// 发送文件下载请求（断点续传）
fn request_download(sender: &cube_lib::websocket::MessageSender, filename: &str, offset: u64, debug: bool) {
    let msg_str = format!(
        r#"{{"Type":"DownloadFile","Data":{{"filename":"{}","offset":{}}}}}"#,
        filename, offset
    );
    if debug {
        let ts = chrono::Local::now().format("%Y-%m-%d %H:%M:%S%.3f");
        println!("{} 发送消息：{}", ts, msg_str);
    }
    sender.send(msg_str);
}

/// 处理收到的文件块
fn handle_file_chunk(data: &serde_json::Map<std::string::String, serde_json::Value>, debug: bool) {
    let filename = data.get("filename").and_then(|v| v.as_str()).unwrap_or("");
    let offset = data.get("offset").and_then(|v| v.as_u64()).unwrap_or(0);
    let chunk_data = data.get("data").and_then(|v| v.as_str()).unwrap_or("");
    let is_last = data.get("is_last").and_then(|v| v.as_bool()).unwrap_or(false);

    let mut state = DOWNLOAD_STATE.lock().unwrap();

    // 如果是新文件或 offset=0，重置状态
    if state.filename != filename || offset == 0 {
        // 关闭旧文件
        if let Some(f) = state.file.take() {
            drop(f);
        }
        // 删除旧临时文件
        if let Some(ref tp) = state.temp_path {
            let _ = fs::remove_file(tp);
        }

        // 使用 AppData/Updater/ 作为数据目录
        let data_dir = get_updater_data_dir();
        let temp_path = data_dir.join(format!("{}.tmp", filename));

        // 创建临时文件（截断）
        match File::create(&temp_path) {
            Ok(file) => {
                state.filename = filename.to_string();
                state.offset = 0;
                state.temp_path = Some(temp_path);
                state.file = Some(file);
            }
            Err(_) => {
                if debug {
                    eprintln!("[下载] 无法创建临时文件: {}", filename);
                }
                return;
            }
        }
    }

    // 解码并追加数据
    let current_offset = state.offset;
    if offset == current_offset {
        if let Some(ref mut file) = state.file {
            match BASE64.decode(chunk_data) {
                Ok(decoded) => {
                    match file.write_all(&decoded) {
                        Ok(_) => {
                            let _ = file.flush();
                            state.offset += decoded.len() as u64;
                        }
                        Err(e) => {
                            if debug {
                                eprintln!("[下载] 写入失败: {}", e);
                            }
                        }
                    }
                }
                Err(e) => {
                    if debug {
                        eprintln!("[下载] Base64 解码失败: {}", e);
                    }
                }
            }
        }
    } else {
        if debug {
            eprintln!("[下载] 偏移不匹配: 期望 {}, 收到 {}", current_offset, offset);
        }
    }

    // 最后一块：重命名临时文件为正式文件
    if is_last {
        let temp_path = state.temp_path.clone();
        let final_offset = state.offset;

        // 关闭文件句柄
        if let Some(f) = state.file.take() {
            drop(f);
        }

        if let Some(ref temp) = temp_path {
            let data_dir = get_updater_data_dir();
            let final_path = data_dir.join(filename);

            // 原子重命名
            if let Err(e) = fs::rename(temp, &final_path) {
                if debug {
                    eprintln!("[下载] 重命名失败: {}", e);
                }
                // 尝试直接覆盖写入
                let _ = fs::copy(temp, &final_path);
                let _ = fs::remove_file(temp);
            }

            if debug {
                let ts = chrono::Local::now().format("%Y-%m-%d %H:%M:%S%.3f");
                println!("{} [下载] {} 下载完成，共 {} 字节", ts, filename, final_offset);
            }
        }

        // 重置状态
        state.filename = String::new();
        state.offset = 0;
        state.temp_path = None;
        state.file = None;
    }
}

/// 处理下载完成消息
fn handle_download_complete(data: &serde_json::Map<std::string::String, serde_json::Value>, debug: bool) {
    let filename = data.get("filename").and_then(|v| v.as_str()).unwrap_or("");
    let size = data.get("size").and_then(|v| v.as_u64()).unwrap_or(0);

    if debug {
        let ts = chrono::Local::now().format("%Y-%m-%d %H:%M:%S%.3f");
        println!("{} [下载] {} 下载完成，最终大小: {} 字节", ts, filename, size);
    }

    let mut state = DOWNLOAD_STATE.lock().unwrap();
    state.filename = String::new();
    state.offset = 0;
    state.temp_path = None;
    state.file = None;
}

/// Updater 自身配置（AppData/Updater/config.json）
/// 只负责 Updater 自己的行为参数，连接地址从公共 config.json 加载
#[derive(Debug, Serialize, Deserialize)]
struct Config {
    /// 调试模式：true 时保留控制台窗口并输出日志
    debug_mode: bool,
}

impl Default for Config {
    fn default() -> Self {
        Self { debug_mode: false }
    }
}

/// 获取 Updater 自身配置路径 AppData/Updater/config.json
fn get_updater_config_path() -> PathBuf {
    get_updater_data_dir().join("Updater").join("config.json")
}

/// 获取公共配置路径 AppData/config.json（与 BootLoader 同级）
fn get_public_config_path() -> PathBuf {
    let exe_path = std::env::current_exe().expect("Failed to get executable path");
    let drive = exe_path
        .parent()
        .and_then(|p| p.as_os_str().to_str())
        .and_then(|s| s.split('\\').next())
        .unwrap_or("C:");
    PathBuf::from(format!("{}/AppData/config.json", drive))
}

/// 加载 Updater 自身配置；若文件不存在则写入默认值
fn load_updater_config() -> Config {
    let config_path = get_updater_config_path();
    if config_path.exists() {
        if let Ok(content) = fs::read_to_string(&config_path) {
            if let Ok(config) = serde_json::from_str::<Config>(&content) {
                return config;
            }
        }
    }
    // 文件不存在或解析失败 → 写入默认值
    let default_config = Config::default();
    if let Ok(content) = serde_json::to_string_pretty(&default_config) {
        let _ = fs::write(&config_path, content);
    }
    default_config
}

/// 从公共 config.json 读取 ServerUrl 字段
fn resolve_ws_url() -> String {
    let config_path = get_public_config_path();
    if let Ok(content) = fs::read_to_string(&config_path) {
        if let Ok(json) = serde_json::from_str::<serde_json::Value>(&content) {
            if let Some(url) = json.get("ServerUrl").and_then(|v| v.as_str()) {
                return url.to_string();
            }
        }
    }
    // 读取失败 → 降级到默认值
    "ws://127.0.0.1:8087/ws".to_string()
}

/// 从公共 config.json 读取 DeviceNumber 字段
fn resolve_device_number() -> String {
    let config_path = get_public_config_path();
    if let Ok(content) = fs::read_to_string(&config_path) {
        if let Ok(json) = serde_json::from_str::<serde_json::Value>(&content) {
            // 尝试多个可能的字段名
            if let Some(id) = json.get("DeviceNumber").and_then(|v| v.as_str()) {
                if !id.is_empty() {
                    return id.to_string();
                }
            }
            if let Some(id) = json.get("StationId").and_then(|v| v.as_str()) {
                if !id.is_empty() {
                    return id.to_string();
                }
            }
            if let Some(id) = json.get("Station").and_then(|v| v.as_str()) {
                if !id.is_empty() {
                    return id.to_string();
                }
            }
        }
    }
    // 读取失败 → 降级到默认值
    "UNKNOWN".to_string()
}

fn is_process_running(process_name: &str) -> bool {
    use std::process::id;

    let current_pid = id().to_string();
    let output = Command::new("tasklist")
        .args(["/FI", &format!("IMAGENAME eq {}", process_name), "/FO", "CSV"])
        .output()
        .expect("Failed to execute tasklist");

    let output_str = String::from_utf8_lossy(&output.stdout);
    let lines: Vec<&str> = output_str.lines().collect();
    let mut count = 0;

    for line in lines {
        if line.contains(&format!("\"{}\"", process_name)) && !line.contains(&current_pid) {
            count += 1;
        }
    }

    count > 0
}

/// 运行 Updater（使用 CubeLib 内置的自动重连）
async fn run_updater(debug_mode: bool) {
    // 加载初始 URL
    let server_url = resolve_ws_url();

    if debug_mode {
        println!("========================================");
        println!("Updater 启动 (调试模式)");
        println!("服务器地址: {}", server_url);
        println!("自动重连: 启用 (指数退避: 1s - 30s)");
        println!("========================================");
    }

    // 创建 WebSocket 配置（启用自动重连）
    let config = WebSocketConfig::new(&server_url)
        .with_client_type("Updater")
        .with_debug(debug_mode)
        .with_reconnect(true) // 启用自动重连
        .with_reconnect_delay(1000) // 初始延迟 1s
        .with_max_reconnect_delay(30000); // 最大延迟 30s

    // 创建 WebSocket 客户端
    let mut client = WebSocketClient::new(config);

    // 设置连接成功回调
    let debug_connected = debug_mode;
    client.on_connected(move |url| {
        if debug_connected {
            let ts = chrono::Local::now().format("%Y-%m-%d %H:%M:%S%.3f");
            println!("{} 收到消息：{}", ts, url);
        }
    });

    // 设置消息接收回调
    let debug_msg = debug_mode;
    let device_number = resolve_device_number();
    client.on_message(move |msg_type, data, sender| {
        let ts = chrono::Local::now().format("%Y-%m-%d %H:%M:%S%.3f");
        if debug_msg {
            // 收到消息日志：data 是完整 parsed 对象，取其中的 Data 字段打印
            let actual_data = data.get("Data").unwrap_or(&serde_json::Value::Null);
            let data_str = serde_json::to_string(actual_data).unwrap_or_else(|_| "{}".to_string());
            println!("{} 收到消息：{{\"Type\":{},\"Data\":{}}}",
                ts,
                serde_json::to_string(&msg_type).unwrap_or_default(),
                data_str
            );
        }

        // 收到 welcome 后，发送 GetFileVer
        if msg_type == "welcome" {
            if !device_number.is_empty() && device_number != "UNKNOWN" {
                let msg_str = format!(
                    r#"{{"Type":"GetFileVer","Data":{{"DeviceNumber":"{}","file_list":["BootLoader.exe"]}}}}"#,
                    device_number
                );
                if debug_msg {
                    let ts2 = chrono::Local::now().format("%Y-%m-%d %H:%M:%S%.3f");
                    println!("{} 发送消息：{}", ts2, msg_str);
                }
                sender.send(msg_str);
            }
        }

        // 处理 FileVer 响应
        if msg_type == "FileVer" {
            if let Some(file_versions) = data.get("Data").and_then(|d| d.get("file_versions")).and_then(|v| v.as_object()) {
                for (filename, server_ver) in file_versions {
                    let server_version = server_ver.as_str().unwrap_or("0.0.0");
                    let local_version = get_local_file_version(filename);
                    let tmp_size = get_tmp_file_size(filename);

                    if debug_msg {
                        let ts = chrono::Local::now().format("%Y-%m-%d %H:%M:%S%.3f");
                        println!("{} [版本] {}: 服务端={}, 本地={}, tmp大小={}", 
                            ts, filename, server_version, local_version, tmp_size);
                    }

                    // 比较版本：如果本地不存在或比服务端旧，则下载
                    let need_update = local_version == "0.0.0" || version_less_than(&local_version, server_version);
                    if need_update {
                        if tmp_size > 0 {
                            // 有临时文件，请求 hash 校验
                            if debug_msg {
                                let ts = chrono::Local::now().format("%Y-%m-%d %H:%M:%S%.3f");
                                println!("{} [续传] {} 发现未完成下载，请求 hash 校验...", ts, filename);
                            }
                            request_file_md5(&sender, filename, tmp_size, debug_msg);
                        } else {
                            // 无临时文件，从头下载
                            if debug_msg {
                                let ts = chrono::Local::now().format("%Y-%m-%d %H:%M:%S%.3f");
                                println!("{} [升级] {} 需要更新，开始下载...", ts, filename);
                            }
                            request_download(&sender, filename, 0, debug_msg);
                        }
                    }
                }
            }
        }

        // 处理 Md5 响应
        if msg_type == "Md5" {
            if let Some(md5_data) = data.get("Data").and_then(|v| v.as_object()) {
                let filename = md5_data.get("filename").and_then(|v| v.as_str()).unwrap_or("");
                let server_md5 = md5_data.get("md5").and_then(|v| v.as_str()).unwrap_or("");
                let bytes = md5_data.get("bytes").and_then(|v| v.as_u64()).unwrap_or(0);
                let tmp_filename = format!("{}.tmp", filename);

                // 计算本地 tmp 文件前 bytes 字节的 md5
                let local_md5 = compute_file_hash(&tmp_filename, bytes, debug_msg);

                if debug_msg {
                    let ts = chrono::Local::now().format("%Y-%m-%d %H:%M:%S%.3f");
                    if let Some(ref lm) = local_md5 {
                        println!("{} [续传] {} md5对比: 本地={}, 服务端={}", ts, filename, lm, server_md5);
                    } else {
                        println!("{} [续传] {} 无法计算本地md5，重新下载", ts, filename);
                    }
                }

                // 比较 md5
                if local_md5.as_deref() == Some(server_md5) {
                    // md5 相同，从 offset bytes 处续传
                    if debug_msg {
                        let ts = chrono::Local::now().format("%Y-%m-%d %H:%M:%S%.3f");
                        println!("{} [续传] {} md5匹配，从 {} 字节处续传", ts, filename, bytes);
                    }
                    request_download(&sender, filename, bytes, debug_msg);
                } else {
                    // md5 不同，删除临时文件，重新下载
                    if debug_msg {
                        let ts = chrono::Local::now().format("%Y-%m-%d %H:%M:%S%.3f");
                        println!("{} [续传] {} md5不匹配，重新下载", ts, filename);
                    }
                    let tmp_path = get_updater_data_dir().join(&tmp_filename);
                    let _ = fs::remove_file(&tmp_path);
                    request_download(&sender, filename, 0, debug_msg);
                }
            }
        }

        // 处理文件块
        if msg_type == "FileChunk" {
            if let Some(data_obj) = data.get("Data").and_then(|v| v.as_object()) {
                handle_file_chunk(data_obj, debug_msg);
            }
        }

        // 处理下载完成
        if msg_type == "DownloadComplete" {
            if let Some(data_obj) = data.get("Data").and_then(|v| v.as_object()) {
                handle_download_complete(data_obj, debug_msg);
            }
        }
    });

    // 设置断开连接回调
    let debug_disconnect = debug_mode;
    client.on_disconnected(move || {
        if debug_disconnect {
            let ts = chrono::Local::now().format("%Y-%m-%d %H:%M:%S%.3f");
            println!("{} [断开] 连接已断开", ts);
        }
    });

    // 设置错误回调
    client.on_error(|error| {
        eprintln!("[错误] WebSocket: {}", error);
    });

    // 设置首次连接回调（GetFileVer 改到收到 welcome 后发送）
    let debug_first = debug_mode;
    let device_number_first = resolve_device_number();
    client.on_first_connect(move |_url, _sender| {
        let device_number = device_number_first.clone();
        Box::pin(async move {
            let ts = chrono::Local::now().format("%Y-%m-%d %H:%M:%S%.3f");
            if device_number.is_empty() || device_number == "UNKNOWN" {
                if debug_first {
                    println!("{} [连接] 已连接，未配置设备号，仅维持心跳", ts);
                }
            } else {
                if debug_first {
                    println!("{} [连接] 已连接，等待服务器欢迎消息...", ts);
                }
            }
        }) as Pin<Box<dyn std::future::Future<Output = ()> + Send + Sync>>
    });

    // 设置重连回调
    let debug_reconnect = debug_mode;
    client.on_reconnecting(move |attempt, url_arc| {
        Box::pin(async move {
            if debug_reconnect {
                let ts = chrono::Local::now().format("%Y-%m-%d %H:%M:%S%.3f");
                println!("{} [重连] 第 {} 次重连中...", ts, attempt);
            }
            let new_url = resolve_ws_url();
            *url_arc.lock().await = new_url.clone();
            if debug_reconnect {
                let ts = chrono::Local::now().format("%Y-%m-%d %H:%M:%S%.3f");
                println!("{} [重连] 配置已更新，服务器: {}", ts, new_url);
            }
        }) as Pin<Box<dyn std::future::Future<Output = ()> + Send + Sync>>
    });

    // 设置重连成功回调
    let debug_reconnected = debug_mode;
    let device_number_reconn = resolve_device_number();
    client.on_reconnected(move |_url, _sender| {
        let device_number = device_number_reconn.clone();
        Box::pin(async move {
            let ts = chrono::Local::now().format("%Y-%m-%d %H:%M:%S%.3f");
            if device_number.is_empty() || device_number == "UNKNOWN" {
                if debug_reconnected {
                    println!("{} [重连] 已重连，未配置设备号", ts);
                }
            } else {
                if debug_reconnected {
                    println!("{} [重连] 已重连，等待服务器欢迎消息...", ts);
                }
            }
        }) as Pin<Box<dyn std::future::Future<Output = ()> + Send + Sync>>
    });

    // 连接（CubeLib 会自动处理重连）
    if debug_mode {
        println!("[启动] 开始连接...");
    }
    client.connect().await;
    if debug_mode {
        println!("[启动] 连接已结束");
        println!("Updater 已停止");
    }
}

#[tokio::main]
async fn main() {
    // 检查是否已有 Updater 进程在运行
    if is_process_running("Updater.exe") {
        return;
    }

    // 加载 Updater 自身配置（debug_mode）
    let config = load_updater_config();

    // 非 debug 模式下释放控制台，后台静默运行
    if !config.debug_mode {
        #[cfg(windows)]
        {
            use windows::Win32::System::Console;
            use windows::Win32::Foundation::HWND;
            unsafe {
                let console = Console::GetConsoleWindow();
                if console != HWND::default() {
                    let _ = Console::FreeConsole();
                }
            }
        }
    }

    // 运行 Updater
    run_updater(config.debug_mode).await;

    if config.debug_mode {
        println!("Updater 已退出");
    }
}