use serde::Serialize;
use specta::Type;
use std::collections::HashMap;
use std::process::{Child, Command, Stdio};
use std::sync::Mutex;
use std::thread;
use std::time::Duration;
use tauri::{AppHandle, Emitter, Manager};

// Windows 平台用于隐藏控制台窗口的标志位
// CREATE_NO_WINDOW = 0x08000000，阻止子进程创建新的控制台窗口
#[cfg(windows)]
pub const CREATE_NO_WINDOW: u32 = 0x08000000;
// CREATE_NEW_CONSOLE = 0x00000010，强制为控制台类子进程新开一个可见控制台窗口。
// 从 GUI 宿主（无控制台）直接 spawn cmd/powershell 等控制台程序时若不设置，
// 子进程会挂到隐藏控制台/不显示窗口，表现为"点击没反应"。
#[cfg(windows)]
pub const CREATE_NEW_CONSOLE: u32 = 0x00000010;

// Windows Job Object 相关常量，用于异常退出时自动清理子进程
#[cfg(windows)]
#[allow(non_snake_case, non_upper_case_globals, non_camel_case_types)]
mod winapi {
    pub const JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE: u32 = 0x2000;
    pub type HANDLE = *mut std::ffi::c_void;
    pub type BOOL = i32;
    pub type DWORD = u32;
    pub type ULONG_PTR = usize;

    #[repr(C)]
    pub struct IO_COUNTERS {
        pub ReadOperationCount: ULONG_PTR,
        pub WriteOperationCount: ULONG_PTR,
        pub OtherOperationCount: ULONG_PTR,
        pub ReadTransferCount: ULONG_PTR,
        pub WriteTransferCount: ULONG_PTR,
        pub OtherTransferCount: ULONG_PTR,
    }

    #[repr(C)]
    pub struct JOBOBJECT_EXTENDED_LIMIT_INFORMATION {
        pub BasicLimitInformation: JOBOBJECT_BASIC_LIMIT_INFORMATION,
        pub IoInfo: IO_COUNTERS,
        pub ProcessMemoryLimit: ULONG_PTR,
        pub JobMemoryLimit: ULONG_PTR,
        pub PeakProcessMemoryUsed: ULONG_PTR,
        pub PeakJobMemoryUsed: ULONG_PTR,
    }

    #[repr(C)]
    pub struct JOBOBJECT_BASIC_LIMIT_INFORMATION {
        pub PerProcessUserTimeLimit: i64,
        pub PerJobUserTimeLimit: i64,
        pub LimitFlags: DWORD,
        pub MinimumWorkingSetSize: ULONG_PTR,
        pub MaximumWorkingSetSize: ULONG_PTR,
        pub ActiveProcessLimit: DWORD,
        pub Affinity: ULONG_PTR,
        pub PriorityClass: DWORD,
        pub SchedulingClass: DWORD,
    }

    pub const JobObjectExtendedLimitInformation: DWORD = 9;

    extern "system" {
        pub fn CreateJobObjectW(lpJobAttributes: *mut std::ffi::c_void, lpName: *const u16) -> HANDLE;
        pub fn SetInformationJobObject(
            hJob: HANDLE,
            JobObjectInformationClass: DWORD,
            lpJobObjectInformation: *mut std::ffi::c_void,
            cbJobObjectInformationLength: DWORD,
        ) -> BOOL;
        pub fn AssignProcessToJobObject(hJob: HANDLE, hProcess: HANDLE) -> BOOL;
    }
}

/// 全局 Job Object 句柄（lazy 初始化，所有子进程都加入此 job）
/// 当主进程退出（包括崩溃）时，OS 自动终止 job 内所有子进程
/// 用 usize 存储指针以绕过 Send 约束（句柄本身是进程级资源，线程间共享安全）
#[cfg(windows)]
static JOB_HANDLE: std::sync::OnceLock<usize> = std::sync::OnceLock::new();

#[cfg(windows)]
fn get_job_handle() -> Option<winapi::HANDLE> {
    let addr = *JOB_HANDLE.get_or_init(|| {
        unsafe {
            let h = winapi::CreateJobObjectW(std::ptr::null_mut(), std::ptr::null());
            if h.is_null() {
                crate::logger::log_error("process", "CreateJobObjectW 失败，异常退出时子进程可能残留");
                return 0;
            }
            // 设置 KILL_ON_JOB_CLOSE：主进程退出时自动终止所有子进程
            let mut info: winapi::JOBOBJECT_EXTENDED_LIMIT_INFORMATION = std::mem::zeroed();
            info.BasicLimitInformation.LimitFlags = winapi::JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE;
            let ok = winapi::SetInformationJobObject(
                h,
                winapi::JobObjectExtendedLimitInformation,
                &mut info as *mut _ as *mut std::ffi::c_void,
                std::mem::size_of::<winapi::JOBOBJECT_EXTENDED_LIMIT_INFORMATION>() as u32,
            );
            if ok == 0 {
                crate::logger::log_error("process", "SetInformationJobObject 失败");
                return 0;
            }
            h as usize
        }
    });
    if addr == 0 {
        None
    } else {
        Some(addr as winapi::HANDLE)
    }
}

/// 为 Command 设置平台特定的创建标志（Windows 上隐藏控制台窗口）
/// 公开以便其他模块（如 mihomo_manager 调用 mihomo -v 查询版本）复用
#[cfg(windows)]
pub fn setup_creation_flags(cmd: &mut Command) {
    use std::os::windows::process::CommandExt;
    cmd.creation_flags(CREATE_NO_WINDOW);
}

#[cfg(not(windows))]
pub fn setup_creation_flags(_cmd: &mut Command) {
    // 非 Windows 平台无需处理
}

/// 将已启动的子进程加入 Job Object（异常退出时自动清理）
/// 在 Windows 上调用，非 Windows 平台为空操作
/// pub(crate)：音乐模块的桥接进程（自管 stdio，不走 ProcessManager）也需加入 Job
#[cfg(windows)]
pub(crate) fn assign_to_job(child: &Child) {
    use std::os::windows::io::AsRawHandle;
    if let Some(job) = get_job_handle() {
        let child_handle = child.as_raw_handle() as winapi::HANDLE;
        unsafe {
            let _ = winapi::AssignProcessToJobObject(job, child_handle);
        }
    }
}

#[cfg(not(windows))]
fn assign_to_job(_child: &Child) {}

/// 进程状态枚举
#[derive(Serialize, Clone, Debug, Type)]
#[serde(rename_all = "lowercase")]
pub enum ProcessStatus {
    Running,
    Stopped,
    Crashed,
    #[allow(dead_code)]
    Starting,
}

/// 进程信息（返回给前端）
#[derive(Serialize, Clone, Type)]
#[serde(rename_all = "camelCase")]
pub struct ProcessInfo {
    pub id: String,
    pub name: String,
    pub status: ProcessStatus,
    pub pid: Option<u32>,
    pub restart_count: u32,
}

/// 进程启动参数（从前端传入）
#[derive(serde::Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct StartProcessParams {
    pub id: String,
    pub executable: String,
    #[serde(default)]
    pub args: Vec<String>,
    #[serde(default)]
    pub cwd: Option<String>,
    pub name: String,
    #[serde(default)]
    pub restart_on_crash: bool,
    #[serde(default = "default_max_restarts")]
    pub max_restarts: u32,
}

fn default_max_restarts() -> u32 {
    3
}

/// 内部进程条目
struct ProcessEntry {
    child: Child,
    name: String,
    restart_count: u32,
    max_restarts: u32,
    restart_on_crash: bool,
    executable: String,
    args: Vec<String>,
    cwd: Option<String>,
}

/// 进程管理器 —— 管理子进程的完整生命周期
pub struct ProcessManager {
    processes: Mutex<HashMap<String, ProcessEntry>>,
}

impl ProcessManager {
    pub fn new() -> Self {
        Self {
            processes: Mutex::new(HashMap::new()),
        }
    }

    /// 启动一个子进程
    pub fn start(&self, params: StartProcessParams) -> Result<ProcessInfo, String> {
        let mut processes = self.processes.lock().map_err(|e| e.to_string())?;

        // 如果已有同名进程且仍在运行，返回错误
        if let Some(entry) = processes.get_mut(&params.id) {
            if entry.child.try_wait().map_err(|e| e.to_string())?.is_none() {
                return Err(format!("进程 '{}' 已在运行中", params.id));
            }
            // 进程已退出，移除旧记录
            processes.remove(&params.id);
        }

        let mut cmd = Command::new(&params.executable);
        cmd.args(&params.args);
        if let Some(ref dir) = params.cwd {
            cmd.current_dir(dir);
        }
        // 子进程的 stdout/stderr/stdin 不继承主进程
        cmd.stdout(Stdio::null())
            .stderr(Stdio::null())
            .stdin(Stdio::null());
        // Windows 上隐藏控制台窗口（mihomo.exe 是控制台程序，否则会弹黑框）
        setup_creation_flags(&mut cmd);

        let child = cmd
            .spawn()
            .map_err(|e| format!("启动进程 '{}' 失败: {}", params.id, e))?;
        let pid = child.id();
        // 将子进程加入 Job Object，主进程异常退出时由 OS 自动清理
        assign_to_job(&child);

        let entry = ProcessEntry {
            child,
            name: params.name.clone(),
            restart_count: 0,
            max_restarts: params.max_restarts,
            restart_on_crash: params.restart_on_crash,
            executable: params.executable,
            args: params.args,
            cwd: params.cwd,
        };

        processes.insert(params.id.clone(), entry);

        Ok(ProcessInfo {
            id: params.id,
            name: params.name,
            status: ProcessStatus::Running,
            pid: Some(pid),
            restart_count: 0,
        })
    }

    /// 停止指定进程
    /// kill 在主线程执行（快速），wait 移到后台线程执行避免阻塞前端
    /// Windows 上 kill 后 wait 可能需要等待子进程清理资源，有几十毫秒到几百毫秒延迟
    pub fn stop(&self, id: &str) -> Result<(), String> {
        let mut processes = self.processes.lock().map_err(|e| e.to_string())?;

        if let Some(mut entry) = processes.remove(id) {
            entry
                .child
                .kill()
                .map_err(|e| format!("终止进程 '{}' 失败: {}", id, e))?;
            // 后台等待子进程退出，避免阻塞当前调用线程（前端会感知卡顿）
            // child 已 move 进闭包，wait 在后台完成
            thread::spawn(move || {
                let _ = entry.child.wait();
            });
            Ok(())
        } else {
            Err(format!("进程 '{}' 不存在", id))
        }
    }

    /// 停止所有进程（应用退出时调用）
    /// 同步 kill + 带超时的 wait，确保子进程在主进程退出前真正终止
    pub fn stop_all(&self) {
        if let Ok(mut processes) = self.processes.lock() {
            for (id, mut entry) in processes.drain() {
                let _ = entry.child.kill();
                // 带超时的 wait，避免子进程卡住导致主进程无法退出
                // 最长等 3 秒，超时则放弃等待（Job Object 兜底会清理）
                let deadline = std::time::Instant::now() + Duration::from_secs(3);
                loop {
                    match entry.child.try_wait() {
                        Ok(Some(_)) => break,
                        Ok(None) => {
                            if std::time::Instant::now() >= deadline {
                                crate::logger::log_warn("process", &format!("进程 {} 等待退出超时（3s），放弃等待", id));
                                break;
                            }
                            std::thread::sleep(Duration::from_millis(50));
                        }
                        Err(_) => break,
                    }
                }
                crate::logger::log_info("process", &format!("已停止进程: {}", id));
            }
        }
    }

    /// 获取单个进程状态
    pub fn get_status(&self, id: &str) -> Option<ProcessInfo> {
        let mut processes = self.processes.lock().ok()?;
        let entry = processes.get_mut(id)?;

        let (status, pid) = match entry.child.try_wait() {
            Ok(None) => (ProcessStatus::Running, Some(entry.child.id())),
            Ok(Some(_)) => (ProcessStatus::Crashed, None),
            Err(_) => (ProcessStatus::Stopped, None),
        };

        Some(ProcessInfo {
            id: id.to_string(),
            name: entry.name.clone(),
            status,
            pid,
            restart_count: entry.restart_count,
        })
    }

    /// 获取所有进程状态
    pub fn get_all_status(&self) -> Vec<ProcessInfo> {
        let mut result = Vec::new();

        if let Ok(mut processes) = self.processes.lock() {
            for (id, entry) in processes.iter_mut() {
                let (status, pid) = match entry.child.try_wait() {
                    Ok(None) => (ProcessStatus::Running, Some(entry.child.id())),
                    Ok(Some(_)) => (ProcessStatus::Crashed, None),
                    Err(_) => (ProcessStatus::Stopped, None),
                };

                result.push(ProcessInfo {
                    id: id.clone(),
                    name: entry.name.clone(),
                    status,
                    pid,
                    restart_count: entry.restart_count,
                });
            }
        }

        result
    }

    /// 检查所有进程，处理崩溃的进程（自动重启或移除）
    /// 返回状态发生变化的进程列表
    /// 注意：kill/wait/sleep(800ms) 等阻塞操作一律在锁外执行，
    /// 锁内仅做非阻塞的 try_wait 判定，避免阻塞其他进程的状态查询
    pub fn check_and_cleanup(&self) -> Vec<ProcessInfo> {
        let mut changes = Vec::new();
        // 需要重启的条目（锁外执行 kill + sleep + spawn）
        let mut restarts: Vec<(String, ProcessEntry)> = Vec::new();

        // 阶段 1：锁内快速判定（仅非阻塞 try_wait），收集重启/移除决策
        {
            let mut processes = match self.processes.lock() {
                Ok(p) => p,
                Err(_) => return changes,
            };

            let ids: Vec<String> = processes.keys().cloned().collect();

            for id in ids {
                let Some(entry) = processes.get_mut(&id) else { continue };
                match entry.child.try_wait() {
                    Ok(None) => {
                        // 仍在运行，无需处理
                    }
                    Ok(Some(_)) => {
                        // 进程已退出
                        if entry.restart_on_crash
                            && (entry.max_restarts == 0
                                || entry.restart_count < entry.max_restarts)
                        {
                            // 需要自动重启：从 map 移除，锁外执行
                            if let Some(mut e) = processes.remove(&id) {
                                e.restart_count += 1;
                                restarts.push((id.clone(), e));
                            }
                        } else {
                            // 不自动重启，移除记录
                            let name = entry.name.clone();
                            let restart_count = entry.restart_count;
                            processes.remove(&id);
                            changes.push(ProcessInfo {
                                id: id.clone(),
                                name,
                                status: ProcessStatus::Stopped,
                                pid: None,
                                restart_count,
                            });
                        }
                    }
                    Err(_) => {
                        // try_wait 出错
                        let name = entry.name.clone();
                        let restart_count = entry.restart_count;
                        processes.remove(&id);
                        changes.push(ProcessInfo {
                            id: id.clone(),
                            name,
                            status: ProcessStatus::Stopped,
                            pid: None,
                            restart_count,
                        });
                    }
                }
            }
        } // 锁在此释放

        // 阶段 2：锁外执行重启（kill + wait + 端口释放等待 + spawn，不阻塞进程状态查询）
        for (id, mut entry) in restarts {
            // 先终止旧进程
            let _ = entry.child.kill();
            let _ = entry.child.wait();
            // 等待 TCP 端口释放（Windows 上 kill 后端口释放有延迟）
            std::thread::sleep(std::time::Duration::from_millis(800));

            // 重新启动
            let mut cmd = Command::new(&entry.executable);
            cmd.args(&entry.args);
            if let Some(ref dir) = entry.cwd {
                cmd.current_dir(dir);
            }
            cmd.stdout(Stdio::null())
                .stderr(Stdio::null())
                .stdin(Stdio::null());
            setup_creation_flags(&mut cmd);

            let name = entry.name.clone();
            let restart_count = entry.restart_count;
            match cmd.spawn() {
                Ok(new_child) => {
                    let pid = new_child.id();
                    entry.child = new_child;
                    if let Ok(mut processes) = self.processes.lock() {
                        processes.insert(id.clone(), entry);
                    }
                    changes.push(ProcessInfo {
                        id: id.clone(),
                        name,
                        status: ProcessStatus::Running,
                        pid: Some(pid),
                        restart_count,
                    });
                }
                Err(e) => {
                    crate::logger::log_error(
                        "process",
                        &format!("重启进程 '{}' 失败: {}", id, e),
                    );
                    changes.push(ProcessInfo {
                        id: id.clone(),
                        name,
                        status: ProcessStatus::Crashed,
                        pid: None,
                        restart_count,
                    });
                }
            }
        }

        changes
    }
}

// ===== Tauri 命令 =====

#[tauri::command]
pub fn process_start(
    state: tauri::State<'_, ProcessManager>,
    params: StartProcessParams,
) -> Result<ProcessInfo, String> {
    state.start(params)
}

#[tauri::command]
pub fn process_stop(
    state: tauri::State<'_, ProcessManager>,
    id: String,
) -> Result<(), String> {
    state.stop(&id)
}

#[tauri::command]
pub fn process_status(
    state: tauri::State<'_, ProcessManager>,
    id: String,
) -> Option<ProcessInfo> {
    state.get_status(&id)
}

#[tauri::command]
pub fn process_all_status(
    state: tauri::State<'_, ProcessManager>,
) -> Vec<ProcessInfo> {
    state.get_all_status()
}

#[tauri::command]
pub fn process_stop_all(state: tauri::State<'_, ProcessManager>) {
    state.stop_all()
}

/// 启动后台监控线程，定期检查进程状态并向前端发送事件
pub fn start_monitoring_thread(app: AppHandle) {
    thread::spawn(move || {
        loop {
            thread::sleep(Duration::from_secs(3));

            let state = app.state::<ProcessManager>();
            let changes = state.check_and_cleanup();

            for change in changes {
                let _ = app.emit(crate::constants::events::PROCESS_STATUS_CHANGED, &change);
            }
        }
    });
}