use std::fs;
use std::path::PathBuf;
use std::time::Duration;
#[cfg(windows)]
use std::time::Instant;

use chromiumoxide::async_process::{Child as BrowserChild, ChildStderr as BrowserChildStderr};
use chromiumoxide::browser::{Browser, BrowserConfig};
use chromiumoxide::handler::HandlerConfig;
use futures::{AsyncBufReadExt, FutureExt, StreamExt};
use tempfile::{Builder as TempDirBuilder, TempDir};

use super::cdp::run_browser_validation;
use super::discovery::discover_chrome_or_edge;
use super::evidence::{
    browser_validation_result_for_report, prepare_evidence_root, unix_time_ms, write_json_report,
};
use super::model::{
    BrowserIdentity, BrowserValidationInput, BrowserValidationResult, BROWSER_TIMEOUT,
};
use super::network_policy::{preview_proxy_bypass_list, validate_input};
#[cfg(windows)]
use crate::process_session::WindowsProcessJob;

pub(super) const BROWSER_TEMP_PREFIX: &str = "ga-browser-";

pub(super) fn browser_process_temp_root() -> PathBuf {
    #[cfg(unix)]
    {
        PathBuf::from("/tmp")
    }
    #[cfg(not(unix))]
    {
        std::env::temp_dir()
    }
}

pub(super) fn create_browser_process_temp_dir() -> Result<TempDir, String> {
    TempDirBuilder::new()
        .prefix(BROWSER_TEMP_PREFIX)
        .tempdir_in(browser_process_temp_root())
        .map_err(|error| format!("创建浏览器临时目录失败：{error}"))
}

fn browser_config(
    executable: &std::path::Path,
    temporary: &TempDir,
    bypass: &str,
) -> Result<BrowserConfig, String> {
    let profile_path = temporary.path().join("profile");
    fs::create_dir(&profile_path)
        .map_err(|error| format!("创建浏览器临时 Profile 失败：{error}"))?;
    BrowserConfig::builder()
        .chrome_executable(executable)
        .user_data_dir(profile_path)
        .env("TMPDIR", temporary.path().to_string_lossy().into_owned())
        .new_headless_mode()
        .enable_request_intercept()
        .disable_cache()
        .disable_https_first()
        .request_timeout(BROWSER_TIMEOUT)
        .launch_timeout(BROWSER_TIMEOUT)
        .window_size(1280, 720)
        .arg(("proxy-server", "http://127.0.0.1:9"))
        .arg(("proxy-bypass-list", bypass))
        .arg("block-new-web-contents")
        .arg("deny-permission-prompts")
        .arg("disable-notifications")
        .arg("disable-service-worker")
        .build()
        .map_err(|error| format!("构建浏览器配置失败：{error}"))
}

const BROWSER_CLOSE_TIMEOUT: Duration = Duration::from_secs(5);
const MAX_LAUNCH_STDERR_BYTES: usize = 64 * 1024;
const MAX_WS_URL_LEN: usize = 512;

/// 必须与 browser_config 的 builder 调用保持一致：request_timeout /
/// enable_request_intercept / disable_cache 在这里逐项镜像；其余字段
/// （ignore_https_errors / ignore_invalid_messages / viewport）与
/// BrowserConfigBuilder 默认值相同，沿用 HandlerConfig::default()。
fn handler_config() -> HandlerConfig {
    let mut config = HandlerConfig::default();
    config.request_timeout = BROWSER_TIMEOUT;
    config.request_intercept = true;
    config.cache_enabled = false;
    config
}

/// 从浏览器 stderr 行提取 DevTools ws 地址；只接受 loopback 端点，
/// 避免伪造输出把 CDP 连接引导到任意地址。
fn parse_devtools_ws_url(line: &str) -> Option<String> {
    let (_, ws) = line.rsplit_once("listening on ")?;
    let ws = ws.trim();
    if ws.is_empty() || ws.len() > MAX_WS_URL_LEN || !ws.contains("devtools/browser") {
        return None;
    }
    let authority = ws.strip_prefix("ws://")?.split('/').next()?;
    let (host, port) = authority.rsplit_once(':')?;
    if !matches!(host, "127.0.0.1" | "localhost" | "[::1]")
        || port.is_empty()
        || !port.bytes().all(|byte| byte.is_ascii_digit())
    {
        return None;
    }
    Some(ws.to_string())
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum OwnedBrowserLaunchError {
    SpawnFailed,
    WsTimeout,
    WsFailed,
    ConnectTimeout,
    ConnectFailed,
}

impl OwnedBrowserLaunchError {
    fn is_timeout(self) -> bool {
        matches!(self, Self::WsTimeout | Self::ConnectTimeout)
    }

    fn code(self) -> &'static str {
        match self {
            Self::SpawnFailed => "browser-spawn-failed",
            Self::WsTimeout => "browser-ws-timeout",
            Self::WsFailed => "browser-ws-failed",
            Self::ConnectTimeout => "browser-cdp-connect-timeout",
            Self::ConnectFailed => "browser-cdp-connect-failed",
        }
    }
}

type BrowserStderrReader = futures::io::BufReader<BrowserChildStderr>;

/// 复刻 chromiumoxide 私有 ws_url_from_output 的语义（读 stderr 直到
/// DevTools listening 行、提前退出即失败、整体有界），但 root 进程始终
/// 留在调用方手里，并把 stderr reader 交还给调用方持续排空。
async fn devtools_ws_url_from_stderr(
    child: &mut BrowserChild,
    timeout: Duration,
) -> Result<(String, BrowserStderrReader), OwnedBrowserLaunchError> {
    let stderr = child
        .stderr
        .take()
        .ok_or(OwnedBrowserLaunchError::SpawnFailed)?;
    let mut reader = futures::io::BufReader::new(stderr);
    let mut captured: Vec<u8> = Vec::new();
    let mut exited = Box::pin(child.wait()).fuse();
    let read = async {
        loop {
            let mut line = Vec::new();
            futures::select! {
                _status = exited => return Err(OwnedBrowserLaunchError::WsFailed),
                result = reader.read_until(b'\n', &mut line).fuse() => {
                    let count = result.map_err(|_| OwnedBrowserLaunchError::WsFailed)?;
                    if count == 0 {
                        return Err(OwnedBrowserLaunchError::WsFailed);
                    }
                    captured.extend_from_slice(&line);
                    if captured.len() > MAX_LAUNCH_STDERR_BYTES {
                        return Err(OwnedBrowserLaunchError::WsFailed);
                    }
                    let Ok(text) = std::str::from_utf8(&line) else {
                        return Err(OwnedBrowserLaunchError::WsFailed);
                    };
                    if let Some(url) = parse_devtools_ws_url(text) {
                        return Ok(url);
                    }
                }
            }
        }
    };
    match tokio::time::timeout(timeout, read).await {
        Ok(Ok(url)) => Ok((url, reader)),
        Ok(Err(error)) => Err(error),
        Err(_) => Err(OwnedBrowserLaunchError::WsTimeout),
    }
}

fn spawn_stderr_drain(mut reader: BrowserStderrReader) -> tokio::task::JoinHandle<()> {
    // 持续排空 stderr：浏览器日志写满管道会整体 stall。内容有界、不留存。
    tokio::spawn(async move {
        let mut buffer = Vec::with_capacity(4096);
        loop {
            buffer.clear();
            match reader.read_until(b'\n', &mut buffer).await {
                Ok(0) | Err(_) => break,
                Ok(_) => {}
            }
        }
    })
}

/// 自持浏览器进程：root 从 spawn 起归本结构所有；Windows 下整树挂进
/// KILL_ON_JOB_CLOSE 的 Job——失败路径、遗忘 shutdown、甚至宿主进程
/// 被杀，整棵树都会被回收，不再留下无父进程的无头浏览器。
struct BrowserProcessGuard {
    child: BrowserChild,
    #[cfg(windows)]
    job: Option<WindowsProcessJob>,
}

impl BrowserProcessGuard {
    /// 整树收割：Job 终止全树，再 kill+wait root 兜底（Unix 与 Job
    /// 绑定前逸出的极早期子进程依赖 root 死亡的级联退出）。
    async fn reap(&mut self) {
        #[cfg(windows)]
        if let Some(job) = &self.job {
            let _ = job.terminate();
        }
        let _ = tokio::time::timeout(BROWSER_CLOSE_TIMEOUT, self.child.kill()).await;
        let _ = tokio::time::timeout(BROWSER_CLOSE_TIMEOUT, self.child.wait()).await;
    }

    async fn confirm_reaped(&self) -> Result<(), String> {
        #[cfg(windows)]
        if let Some(job) = &self.job {
            let deadline = Instant::now() + BROWSER_CLOSE_TIMEOUT;
            loop {
                if job
                    .is_empty()
                    .map_err(|_| "browser-tree-reap-unconfirmed".to_string())?
                {
                    return Ok(());
                }
                if Instant::now() >= deadline {
                    return Err("browser-tree-reap-unconfirmed".into());
                }
                tokio::time::sleep(Duration::from_millis(20)).await;
            }
        }
        Ok(())
    }
}

impl Drop for BrowserProcessGuard {
    fn drop(&mut self) {
        // Windows：Job 句柄关闭触发 KILL_ON_JOB_CLOSE 收掉整树；
        // Unix：tokio kill_on_drop 终止 root，子进程随 IPC 断开级联退出。
    }
}

struct OwnedBrowser {
    browser: Browser,
    process: BrowserProcessGuard,
    handler_task: tokio::task::JoinHandle<()>,
    drain_task: tokio::task::JoinHandle<()>,
}

impl OwnedBrowser {
    fn browser(&self) -> &Browser {
        &self.browser
    }

    /// 优雅收束：CDP close → wait；失败则整树终止并确认收割。
    async fn shutdown(mut self) -> Result<(), String> {
        let close = tokio::time::timeout(BROWSER_CLOSE_TIMEOUT, self.browser.close()).await;
        let waited = tokio::time::timeout(BROWSER_CLOSE_TIMEOUT, self.process.child.wait()).await;
        self.handler_task.abort();
        self.drain_task.abort();
        if matches!(close, Ok(Ok(_))) && matches!(waited, Ok(Ok(_))) {
            return Ok(());
        }
        self.process.reap().await;
        self.process.confirm_reaped().await
    }
}

impl Drop for OwnedBrowser {
    fn drop(&mut self) {
        self.handler_task.abort();
        self.drain_task.abort();
        // 进程侧由 BrowserProcessGuard 的 Drop 兜底。
    }
}

/// 自拉浏览器并完成 CDP 连接。spawn 与 Job 绑定之间存在极小的逸出
/// 窗口：绑定前产生的子进程未入 Job，随 root 死亡级联退出；绑定之后
/// 的一切子进程由 Job 全覆盖。
async fn launch_owned_browser(
    config: BrowserConfig,
    executable: &std::path::Path,
    temp_root: &std::path::Path,
) -> Result<OwnedBrowser, OwnedBrowserLaunchError> {
    let child = config
        .launch()
        .map_err(|_| OwnedBrowserLaunchError::SpawnFailed)?;
    // 无法证明整树可收割时拒绝放行浏览器；child 随 drop 由 kill_on_drop 收尾。
    #[cfg(windows)]
    let job = match WindowsProcessJob::assign_tokio(&child.inner) {
        Ok(job) => Some(job),
        Err(_) => return Err(OwnedBrowserLaunchError::SpawnFailed),
    };
    let mut process = BrowserProcessGuard {
        child,
        #[cfg(windows)]
        job,
    };
    // 跨会话清扫的身份锚点：写入失败时该目录之后按旧残留只删不杀。
    if let Some(pid) = process.child.inner.id() {
        super::sweep::write_browser_process_owner(temp_root, pid, executable);
    }
    let (url, reader) = match devtools_ws_url_from_stderr(&mut process.child, BROWSER_TIMEOUT).await
    {
        Ok(pair) => pair,
        Err(error) => {
            process.reap().await;
            return Err(error);
        }
    };
    let drain_task = spawn_stderr_drain(reader);
    let connected = tokio::time::timeout(
        BROWSER_TIMEOUT,
        Browser::connect_with_config(url, handler_config()),
    )
    .await;
    let (browser, mut handler) = match connected {
        Ok(Ok(pair)) => pair,
        Ok(Err(_)) => {
            drain_task.abort();
            process.reap().await;
            return Err(OwnedBrowserLaunchError::ConnectFailed);
        }
        Err(_) => {
            drain_task.abort();
            process.reap().await;
            return Err(OwnedBrowserLaunchError::ConnectTimeout);
        }
    };
    let handler_task = tokio::spawn(async move {
        while let Some(message) = handler.next().await {
            if message.is_err() {
                break;
            }
        }
    });
    Ok(OwnedBrowser {
        browser,
        process,
        handler_task,
        drain_task,
    })
}

/// 仅验证浏览器启动和真实 CDP，不加载项目、不生成试玩凭证。
/// 每次独立 profile；既不串行化其它工具，也不继承 Codex 的临时 HOME。
pub(crate) async fn check_browser_health() -> Result<BrowserIdentity, String> {
    let discovered = discover_chrome_or_edge().map_err(|_| "browser-not-found")?;
    let temporary = create_browser_process_temp_dir().map_err(|_| "browser-temp-unavailable")?;
    let config = browser_config(&discovered.executable_path, &temporary, "<-loopback>")
        .map_err(|_| "browser-config-invalid")?;
    let owned = launch_owned_browser(config, &discovered.executable_path, temporary.path())
        .await
        .map_err(|error| {
            if error.is_timeout() {
                "browser-start-timeout"
            } else {
                "browser-start-failed"
            }
        })?;
    let version = tokio::time::timeout(Duration::from_secs(5), owned.browser().version()).await;
    if owned.shutdown().await.is_err() {
        return Err("browser-cleanup-failed".into());
    }
    let version = version
        .map_err(|_| "browser-cdp-timeout")?
        .map_err(|_| "browser-cdp-failed")?;
    if !safe_version_label(&version.product) || !safe_version_label(&version.protocol_version) {
        return Err("browser-version-invalid".into());
    }
    Ok(BrowserIdentity {
        kind: discovered.kind,
        product: version.product,
        protocol_version: version.protocol_version,
    })
}

fn safe_version_label(value: &str) -> bool {
    !value.is_empty()
        && value.len() <= 128
        && value
            .bytes()
            .all(|byte| byte.is_ascii_alphanumeric() || matches!(byte, b'.' | b'/' | b'-' | b'_'))
}

pub async fn validate_local_preview_in_browser(
    input: BrowserValidationInput,
) -> Result<BrowserValidationResult, String> {
    validate_local_preview_in_browser_with_interaction(input, false).await
}

/// Runs the same restricted Chromium validation, optionally adding one bounded,
/// advisory click on a visible enabled control. The interaction is evidence for
/// the direct Codex reviewer; it is not a fixed gameplay contract and never
/// changes the deterministic browser safety checks.
pub async fn validate_local_preview_in_browser_with_interaction(
    input: BrowserValidationInput,
    advisory_interaction: bool,
) -> Result<BrowserValidationResult, String> {
    validate_local_preview_in_browser_with_cancellation(input, advisory_interaction, None).await
}

pub(crate) async fn validate_local_preview_in_browser_with_cancellation(
    input: BrowserValidationInput,
    advisory_interaction: bool,
    cancellation: Option<std::sync::Arc<std::sync::atomic::AtomicBool>>,
) -> Result<BrowserValidationResult, String> {
    if cancellation
        .as_ref()
        .is_some_and(|flag| flag.load(std::sync::atomic::Ordering::Acquire))
    {
        return Err("宿主已停止本轮浏览器验证".into());
    }
    let preview_url = validate_input(&input)?;
    prepare_evidence_root(&input.evidence_root)?;
    let browser_executable = discover_chrome_or_edge()?;
    let browser_temp = create_browser_process_temp_dir()?;
    let proxy_bypass_list = preview_proxy_bypass_list(&preview_url);
    let config = browser_config(
        &browser_executable.executable_path,
        &browser_temp,
        &proxy_bypass_list,
    )?;

    let owned = launch_owned_browser(
        config,
        &browser_executable.executable_path,
        browser_temp.path(),
    )
    .await
    .map_err(|error| {
        if error.is_timeout() {
            "启动浏览器超时".to_string()
        } else {
            format!("启动浏览器失败：{}", error.code())
        }
    })?;

    let work = run_browser_validation(
        owned.browser(),
        &browser_executable,
        &preview_url,
        &input,
        advisory_interaction,
    );
    let cancelled = async {
        let Some(flag) = cancellation else {
            std::future::pending::<()>().await;
            return;
        };
        while !flag.load(std::sync::atomic::Ordering::Acquire) {
            tokio::time::sleep(Duration::from_millis(50)).await;
        }
    };
    let validation = tokio::select! {
        result=work => result,
        _=cancelled => Err("宿主已停止本轮浏览器验证".to_string()),
    };

    if owned.shutdown().await.is_err() {
        return Err(
            "browser-cleanup-unconfirmed: 浏览器收束后无法证明退出，请核对本轮验证进程".into(),
        );
    }
    drop(browser_temp);
    let mut result = validation?;
    result.completed_at_unix_ms = unix_time_ms();
    let persisted_result = browser_validation_result_for_report(&result)?;
    write_json_report(&result.evidence.report_path, &persisted_result)?;
    Ok(result)
}

#[cfg(test)]
mod health_tests {
    use super::*;

    #[test]
    fn health_launch_uses_isolated_profiles_and_same_restricted_configuration() {
        let first = create_browser_process_temp_dir().unwrap();
        let second = create_browser_process_temp_dir().unwrap();
        let executable = std::env::current_exe().unwrap();
        let first_config = browser_config(&executable, &first, "<-loopback>").unwrap();
        let second_config = browser_config(&executable, &second, "<-loopback>").unwrap();
        assert_ne!(first_config.user_data_dir, second_config.user_data_dir);
        assert!(first_config.user_data_dir.unwrap().is_dir());
        assert!(!safe_version_label("Chrome/123\nTOKEN=secret"));
        assert!(safe_version_label("HeadlessChrome/140.0.1.2"));
    }

    #[test]
    fn devtools_ws_url_only_accepts_loopback_browser_endpoints() {
        assert_eq!(
            parse_devtools_ws_url(
                "DevTools listening on ws://127.0.0.1:53317/devtools/browser/abc-123\r\n"
            )
            .as_deref(),
            Some("ws://127.0.0.1:53317/devtools/browser/abc-123")
        );
        assert!(parse_devtools_ws_url(
            "DevTools listening on ws://localhost:9222/devtools/browser/x"
        )
        .is_some());
        assert!(
            parse_devtools_ws_url("DevTools listening on ws://[::1]:9222/devtools/browser/x")
                .is_some()
        );
        // 非 loopback、非 ws 协议、非 browser 端点、非法端口一律拒绝。
        assert!(parse_devtools_ws_url(
            "DevTools listening on ws://evil.example.com:9222/devtools/browser/x"
        )
        .is_none());
        assert!(parse_devtools_ws_url(
            "DevTools listening on http://127.0.0.1:9222/devtools/browser/x"
        )
        .is_none());
        assert!(
            parse_devtools_ws_url("DevTools listening on ws://127.0.0.1:9222/devtools/page/x")
                .is_none()
        );
        assert!(parse_devtools_ws_url(
            "DevTools listening on ws://127.0.0.1:notaport/devtools/browser/x"
        )
        .is_none());
        assert!(parse_devtools_ws_url("random browser log line").is_none());
        let overlong = format!(
            "DevTools listening on ws://127.0.0.1:9222/devtools/browser/{}",
            "a".repeat(MAX_WS_URL_LEN)
        );
        assert!(parse_devtools_ws_url(&overlong).is_none());
    }

    #[test]
    fn handler_config_mirrors_browser_config_builder() {
        let config = handler_config();
        assert_eq!(config.request_timeout, BROWSER_TIMEOUT);
        assert!(config.request_intercept);
        assert!(!config.cache_enabled);
        // 其余字段必须与 BrowserConfigBuilder 默认值保持一致。
        assert!(config.ignore_https_errors);
        assert!(config.ignore_invalid_messages);
        assert!(config.viewport.is_none());
    }

    #[tokio::test]
    #[ignore = "requires an installed Chrome/Chromium/Edge; local CDP only"]
    async fn real_browser_health_checks_can_run_concurrently() {
        let (first, second) = tokio::join!(check_browser_health(), check_browser_health());
        assert!(!first.unwrap().product.is_empty());
        assert!(!second.unwrap().protocol_version.is_empty());
    }

    #[tokio::test]
    #[ignore = "requires an installed browser; verifies cancellation after the real page is requested and cleanup completes"]
    async fn real_browser_budget_cancellation_closes_an_already_started_validation() {
        let page_requested = std::sync::Arc::new(tokio::sync::Notify::new());
        let observed = std::sync::Arc::clone(&page_requested);
        let app=axum::Router::new().route("/",axum::routing::get(move || {
            let observed=std::sync::Arc::clone(&observed);
            async move { observed.notify_one(); axum::response::Html("<!doctype html><canvas id='game' width='100' height='100'></canvas><script>game.getContext('2d').fillRect(0,0,100,100)</script>") }
        }));
        let listener = tokio::net::TcpListener::bind((std::net::Ipv4Addr::LOCALHOST, 0))
            .await
            .unwrap();
        let address = listener.local_addr().unwrap();
        let server = tokio::spawn(async move { axum::serve(listener, app).await.unwrap() });
        let cancellation = std::sync::Arc::new(std::sync::atomic::AtomicBool::new(false));
        let flag = std::sync::Arc::clone(&cancellation);
        let cancel = tokio::spawn(async move {
            tokio::time::timeout(Duration::from_secs(20), page_requested.notified())
                .await
                .expect("real browser requested page");
            flag.store(true, std::sync::atomic::Ordering::Release);
        });
        let temp = tempfile::tempdir().unwrap();
        let result = validate_local_preview_in_browser_with_cancellation(
            BrowserValidationInput {
                url: format!("http://{address}/"),
                viewports: vec![
                    crate::browser::BrowserValidationViewport::Desktop,
                    crate::browser::BrowserValidationViewport::Mobile,
                ],
                expected_text: Vec::new(),
                settle_ms: 4000,
                fail_on_console_error: true,
                playtest_scenario: None,
                evidence_root: temp.path().join("evidence"),
            },
            false,
            Some(cancellation),
        )
        .await;
        cancel.await.unwrap();
        server.abort();
        let _ = server.await;
        assert_eq!(result.unwrap_err(), "宿主已停止本轮浏览器验证");
    }
}