//! BrowserManager — Start, connect, and manage lifecycle of the camoufox-browser daemon.
//!
//! The `camoufox-browser@0.1.0` CLI auto-starts a background daemon
//! (Node.js process) on any command. The daemon listens on a Unix socket at
//! `~/.camoufox-browser/<session>.sock` and auto-launches the camoufox browser
//! on the first browser-dependent command.
//!
//! On `gyandoot run`, the BrowserManager:
//! 1. Checks if the daemon socket already exists and is connected
//! 2. If not, runs a quick CLI command to trigger daemon auto-start
//! 3. Waits for the Unix socket to appear (up to 30 seconds)
//! 4. Returns a ready-to-use `BrowserClient`

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};

/// 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 {
    /// Browser daemon is running and client is ready.
    Ready(BrowserClient),
    /// Could not start daemon.
    Unavailable(String),
}

/// Initialize the camoufox-browser daemon and return a ready client.
pub async fn init_browser() -> BrowserInitResult {
    let session = DEFAULT_SESSION;
    let socket_path = default_socket_path(session);

    // 1. Quick check — is the daemon already running?
    if check_daemon_socket(session).await {
        info!("Camoufox daemon already running on socket: {}", socket_path.display());
        let client = BrowserClient::new().with_session(session);
        return BrowserInitResult::Ready(client);
    }

    info!("Camoufox daemon not running, triggering startup...");

    // 2. Trigger daemon auto-start via CLI
    //    The CLI calls `ensureDaemonRunning()` internally which spawns the daemon
    match trigger_daemon_start(session).await {
        Ok(()) => {
            // 3. Wait for socket to appear
            info!("Waiting for daemon socket at {}...", socket_path.display());
            match wait_for_socket(session).await {
                Ok(true) => {
                    info!("Camoufox daemon started successfully");
                    let client = BrowserClient::new().with_session(session);
                    // Brief pause for daemon to fully initialize
                    tokio::time::sleep(Duration::from_millis(1000)).await;
                    BrowserInitResult::Ready(client)
                }
                Ok(false) => {
                    let msg = format!(
                        "Daemon did not start within {}s — socket not found at {}",
                        DAEMON_STARTUP_TIMEOUT_SECS,
                        socket_path.display()
                    );
                    warn!("{}", msg);
                    BrowserInitResult::Unavailable(msg)
                }
                Err(e) => {
                    let msg = format!("Daemon socket error: {}", e);
                    warn!("{}", msg);
                    BrowserInitResult::Unavailable(msg)
                }
            }
        }
        Err(e) => {
            let msg = format!(
                "Could not start camoufox daemon: {}\n\n\
                 Make sure Node.js v20+ and the package are installed:\n  \
                 npm install -g camoufox-browser\n  \
                 npx camoufox-browser@latest install\n\n\
                 Then try again.",
                e
            );
            warn!("{}", msg);
            BrowserInitResult::Unavailable(msg)
        }
    }
}

/// Trigger daemon startup by running a quick CLI command.
///
/// The `camoufox-browser@latest` CLI auto-starts the daemon via
/// `ensureDaemonRunning()` on any command. We run a harmless
/// `tab_list` which spawns the daemon in the background and
/// returns once complete.
async fn trigger_daemon_start(session: &str) -> Result<(), String> {
    // Create log directory for any stderr output
    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 log = std::fs::File::create(&log_file)
        .map_err(|e| format!("Cannot create log file: {}", e))?;

    // Run a command — the CLI auto-starts the daemon as a side effect
    let _output = Command::new("npx")
        .args(&[
            "camoufox-browser@latest",
            "tab_list",
            "--session", session,
        ])
        .stdout(Stdio::from(log.try_clone().map_err(|e| e.to_string())?))
        .stderr(Stdio::from(log))
        .output()
        .await
        .map_err(|e| format!("npx failed: {}. Is Node.js installed?", e))?;

    // Return immediately — socket polling in the caller will detect the daemon
    Ok(())
}

/// Poll for the daemon Unix socket to appear.
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)
}