//! BrowserManager — Start, connect, and manage lifecycle of the camoufox-browser daemon.
//!
//! Uses `camoufox-js@0.11.0` (pinned, not @latest) for fetching the browser binary,
//! and `camoufox-browser@0.1.0` (pinned) for the daemon Unix socket protocol.
//!
//! Pinning rationale:
//! - `camoufox-browser@0.1.0` bundles `camoufox-js@0.9.3` which downloads BROKEN
//!   alpha macOS builds (v150.0.2-alpha.26, missing libmozglue.dylib)
//! - `camoufox-js@0.11.0` (latest, Jun 4 2026) downloads STABLE browser binaries
//! - Both packages share the same cache directory (~/Library/Caches/camoufox/).
//!   We use the pinned `camoufox-js` for fetch, `camoufox-browser` for daemon.

use std::process::Stdio;
use std::time::Duration;

use tokio::process::Command;
use tracing::{info, warn};

use gyandoot_browser::{check_daemon_socket, default_socket_path, BrowserClient};

// ─── Pinned Versions ─────────────────────────────────────────────────────
// These are pinned to specific versions to avoid upstream breakage.
// Update ONLY after testing the new version on both macOS and Linux.

/// Version of camoufox-js for downloading the browser binary.
/// v0.11.0 (Jun 4 2026) — latest stable, downloads correct macOS arm64/x64 builds.
const CAMOUFOX_JS_VERSION: &str = "0.11.0";

/// Version of camoufox-browser for daemon IPC protocol.
/// v0.1.0 (Mar 15 2026) — the only published version, daemon protocol is stable.
const CAMOUFOX_BROWSER_VERSION: &str = "0.1.0";

/// Default session name.
const DEFAULT_SESSION: &str = "default";

/// Maximum time to wait for the daemon socket to appear.
const DAEMON_STARTUP_TIMEOUT_SECS: u64 = 30;

/// Poll interval while waiting for daemon to start.
const DAEMON_POLL_MS: u64 = 500;

/// Result of browser initialization.
#[derive(Debug)]
pub enum BrowserInitResult {
    Ready(BrowserClient),
    Unavailable(String),
}

/// Resolve the npx executable name, respecting config and platform.
fn resolve_npx(node_path: Option<&str>) -> &str {
    if let Some(p) = node_path {
        if !p.is_empty() {
            return p;
        }
    }
    if cfg!(target_os = "windows") {
        "npx.cmd"
    } else {
        "npx"
    }
}

/// Cache directory for the Camoufox browser binary.
fn browser_cache_dir() -> std::path::PathBuf {
    let home = dirs::home_dir().unwrap_or_else(|| std::path::PathBuf::from("/tmp"));
    if cfg!(target_os = "macos") {
        home.join("Library").join("Caches").join("camoufox")
    } else {
        home.join(".cache").join("camoufox")
    }
}

/// Check if the Camoufox browser binary is installed and appears intact.
fn is_browser_installed() -> bool {
    let cache = browser_cache_dir();
    if !cache.exists() {
        return false;
    }
    // Check for the version marker file (written by camoufox-js fetch)
    if !cache.join("version.json").exists() {
        return false;
    }
    if cfg!(target_os = "macos") {
        cache.join("Camoufox.app").join("Contents").join("MacOS").join("camoufox").exists()
    } else {
        cache.join("camoufox").exists()
    }
}

/// Check for known error patterns in daemon stderr.
fn check_known_errors(log: &str) -> Option<&'static str> {
    let lower = log.to_lowercase();
    if lower.contains("libmozglue.dylib") {
        return Some("Browser binary corrupted (missing libmozglue.dylib). Re-run 'gyandoot run' to re-download with the pinned version.");
    }
    if lower.contains("error while loading shared libraries") {
        return Some("Missing Linux system libraries.");
    }
    if lower.contains("sigkill") {
        return Some("macOS Gatekeeper killed the browser (SIGKILL). Run: xattr -dr com.apple.quarantine ~/Library/Caches/camoufox");
    }
    None
}

/// Remove macOS quarantine attribute from the Camoufox cache directory.
/// Gatekeeper kills unsigned headless browsers with SIGKILL on Apple Silicon.
async fn remove_macos_quarantine() {
    if !cfg!(target_os = "macos") {
        return;
    }
    let cache = browser_cache_dir();
    if !cache.exists() {
        return;
    }
    let output = Command::new("xattr")
        .args(&["-dr", "com.apple.quarantine", &cache.to_string_lossy()])
        .stdout(Stdio::null())
        .stderr(Stdio::null())
        .output()
        .await;
    match output {
        Ok(o) if o.status.success() => {
            info!("Removed macOS quarantine from {}", cache.display());
        }
        _ => {
            warn!("Could not remove quarantine (xattr not available or failed)");
        }
    }
}

/// Initialize the browser daemon and return a ready client.
///
/// Steps:
/// 1. Ensure browser binary is downloaded using pinned `camoufox-js@0.11.0`
/// 2. Ensure npm package is available for daemon
/// 3. Start daemon via pinned `camoufox-browser@0.1.0`
/// 4. Connect to Unix socket
pub async fn init_browser(node_path: Option<&str>) -> BrowserInitResult {
    let session = DEFAULT_SESSION;
    let socket_path = default_socket_path(session);
    let npx = resolve_npx(node_path);

    // 1. Already running?
    if check_daemon_socket(session).await {
        info!("Camoufox daemon already running on socket: {}", socket_path.display());
        return BrowserInitResult::Ready(BrowserClient::new().with_session(session));
    }

    info!("Camoufox daemon not running, starting up...");

    // 2. Download browser binary if missing (using PINNED camoufox-js)
    if !is_browser_installed() {
        info!("Downloading Camoufox browser using camoufox-js@{}...", CAMOUFOX_JS_VERSION);
        match run_fetch(npx, CAMOUFOX_JS_VERSION).await {
            Ok(msg) => {
                info!("Camoufox browser fetch: {}", msg);
                // On macOS, remove Gatekeeper quarantine immediately after download
                remove_macos_quarantine().await;
            }
            Err(e) => {
                return BrowserInitResult::Unavailable(format!(
                    "Failed to download Camoufox browser: {}\n\n\
                     Try manually: {} camoufox-js@{} fetch",
                    e, npx, CAMOUFOX_JS_VERSION
                ));
            }
        }
    }

    // On macOS, always try to remove Gatekeeper quarantine from cached binary
    // (even if it was already installed — prior npx downloads may have set it)
    remove_macos_quarantine().await;

    // 3. Ensure the `camoufox-browser` npm package is globally installed for daemon
    if !is_npm_package_installed(npx, "camoufox-browser", CAMOUFOX_BROWSER_VERSION).await {
        info!("Installing camoufox-browser@{} (daemon)...", CAMOUFOX_BROWSER_VERSION);
        match install_npm_package(npx, "camoufox-browser", CAMOUFOX_BROWSER_VERSION).await {
            Ok(_) => info!("camoufox-browser@{} installed", CAMOUFOX_BROWSER_VERSION),
            Err(e) => {
                return BrowserInitResult::Unavailable(format!(
                    "Failed to install camoufox-browser: {}\n\n\
                     Try manually: npm install -g camoufox-browser@{}",
                    e, CAMOUFOX_BROWSER_VERSION
                ));
            }
        }
    }

    // 4. Trigger daemon start
    match trigger_daemon_start(npx, session).await {
        Ok(()) => {
            info!("Waiting for daemon socket...");
            match wait_for_socket(session).await {
                Ok(true) => {
                    info!("Camoufox daemon ready");
                    tokio::time::sleep(Duration::from_millis(1000)).await;
                    BrowserInitResult::Ready(BrowserClient::new().with_session(session))
                }
                Ok(false) => {
                    let msg = format!(
                        "Daemon did not start within {}s.\n\n\
                         Possible causes:\n  \
                         1. Missing Linux system libraries (WSL/Ubuntu):\n    \
                            sudo apt-get update && sudo apt-get install -y \\\n    \
                            libgtk-3-0 libnss3 libnspr4 libatk1.0-0t64 \\\n    \
                            libatk-bridge2.0-0t64 libcups2t64 libdrm2 \\\n    \
                            libxkbcommon0 libxcomposite1 libxdamage1 \\\n    \
                            libxfixes3 libxrandr2 libgbm1 libpango-1.0-0 \\\n    \
                            libcairo2 libasound2t64 libxcb-shm0\n  \
                         2. Try debugging: {} camoufox-browser@{} tab_list --session default\n  \
                            Log: {}",
                        DAEMON_STARTUP_TIMEOUT_SECS,
                        npx, CAMOUFOX_BROWSER_VERSION, socket_path.display()
                    );
                    warn!("{}", msg);
                    BrowserInitResult::Unavailable(msg)
                }
                Err(e) => BrowserInitResult::Unavailable(format!("Daemon error: {}", e)),
            }
        }
        Err(e) => {
            let mut msg = format!(
                "Camoufox daemon failed to start.\n\n{}\n\n",
                e
            );
            if let Some(hint) = check_known_errors(&msg) {
                msg.push_str(hint);
                msg.push_str(&format!(
                    "\n\nTry: rm -rf ~/Library/Caches/camoufox && {} gyandoot run",
                    npx
                ));
            } else {
                msg.push_str(&format!(
                    "Debug: {} camoufox-browser@{} tab_list --session default",
                    npx, CAMOUFOX_BROWSER_VERSION
                ));
            }
            warn!("{}", msg);
            BrowserInitResult::Unavailable(msg)
        }
    }
}

/// Fetch the browser binary using pinned camoufox-js.
async fn run_fetch(npx: &str, js_version: &str) -> Result<String, String> {
    let output = Command::new(npx)
        .args(&["--yes", &format!("camoufox-js@{}", js_version), "fetch"])
        .output()
        .await
        .map_err(|e| format!("'{} camoufox-js' not found: {}", npx, e))?;

    let stdout = String::from_utf8_lossy(&output.stdout).trim().to_string();
    let stderr = String::from_utf8_lossy(&output.stderr).trim().to_string();

    if !output.status.success() {
        let detail = if !stderr.is_empty() {
            stderr.lines().filter(|l| l.contains("Error") || l.contains("error")).last().unwrap_or("(check output)")
        } else {
            stdout.lines().last().unwrap_or("(unknown)")
        };
        return Err(format!("exit {}: {}", output.status.code().unwrap_or(-1), detail));
    }

    Ok(stdout.lines().filter(|l| l.contains("complete") || l.contains("Installed") || l.contains("Downloaded"))
        .last()
        .unwrap_or("Fetch completed")
        .to_string())
}

/// Check if an npm package is already installed globally.
async fn is_npm_package_installed(npx: &str, package: &str, version: &str) -> bool {
    Command::new(npx)
        .args(&["--yes", &format!("{package}@{version}"), "--version"])
        .output()
        .await
        .map(|o| o.status.success())
        .unwrap_or(false)
}

/// Install an npm package globally.
async fn install_npm_package(_npx: &str, package: &str, version: &str) -> Result<String, String> {
    let output = Command::new("npm")
        .args(&["install", "-g", &format!("{package}@{version}")])
        .output()
        .await
        .map_err(|e| format!("npm not found: {}", e))?;

    if !output.status.success() {
        let stderr = String::from_utf8_lossy(&output.stderr).trim().to_string();
        return Err(stderr.lines().last().unwrap_or("(unknown)").to_string());
    }

    Ok(format!("{package}@{version} installed"))
}

/// Trigger daemon startup via `npx camoufox-browser@<pinned> tab_list`.
async fn trigger_daemon_start(npx: &str, session: &str) -> Result<(), String> {
    let home = dirs::home_dir().ok_or("Cannot determine home directory")?;
    let log_dir = home.join(".gyandoot");
    std::fs::create_dir_all(&log_dir)
        .map_err(|e| format!("Cannot create {}: {}", log_dir.display(), e))?;
    let log_file = log_dir.join("camoufox-daemon-spawn.log");

    let output = Command::new(npx)
        .args(&[
            "--yes",
            &format!("camoufox-browser@{}", CAMOUFOX_BROWSER_VERSION),
            "tab_list",
            "--session", session,
        ])
        .output()
        .await
        .map_err(|e| format!("{} not found: {}", npx, e))?;

    if !output.status.success() {
        let stderr = String::from_utf8_lossy(&output.stderr).trim().to_string();
        let stdout = String::from_utf8_lossy(&output.stdout).trim().to_string();
        let details = if !stderr.is_empty() { stderr } else { stdout };

        let _ = std::fs::write(
            &log_file,
            format!(
                "exit_code: {}\nstderr:\n{}\nstdout:\n{}\n",
                output.status.code().unwrap_or(-1),
                String::from_utf8_lossy(&output.stderr),
                String::from_utf8_lossy(&output.stdout),
            ),
        );

        return Err(format!("{}\n  Log: {}", details, log_file.display()));
    }

    Ok(())
}

async fn wait_for_socket(session: &str) -> Result<bool, String> {
    let deadline = tokio::time::Instant::now() + Duration::from_secs(DAEMON_STARTUP_TIMEOUT_SECS);
    while tokio::time::Instant::now() < deadline {
        if check_daemon_socket(session).await {
            return Ok(true);
        }
        tokio::time::sleep(Duration::from_millis(DAEMON_POLL_MS)).await;
    }
    Ok(false)
}