magellan 4.13.0

//! Watch command implementation

use anyhow::{Context, Result};
use std::path::PathBuf;
use std::sync::atomic::AtomicBool;
use std::sync::Arc;

use crate::generate_execution_id;

use magellan::backend_router::MagellanBackend;
use magellan::graph::validation;
use magellan::WatchPipelineConfig;
use magellan::WatcherConfig;
use serde_json::json;

/// Synchronous helper: send JSON-RPC watch request to daemon
fn send_watch_request(req_line: &str, exec_id: &str) -> Result<()> {
    use std::io::{Read, Write};
    use std::os::unix::net::UnixStream;
    use std::time::Duration;

    let socket_path = std::path::PathBuf::from(crate::service::socket_path());
    let mut stream = UnixStream::connect(&socket_path)
        .with_context(|| format!("Daemon socket unreachable at {}", socket_path.display()))?;
    let _ = stream.set_read_timeout(Some(Duration::from_millis(500)));
    let _ = stream.set_write_timeout(Some(Duration::from_millis(500)));

    let req_with_newline = format!("{}\n", req_line);
    if let Err(e) = stream.write_all(req_with_newline.as_bytes()) {
        return Err(anyhow::anyhow!(
            "Failed to write watch request to daemon socket: {}",
            e
        ));
    }
    let _ = stream.shutdown(std::net::Shutdown::Write);

    let mut buf = [0u8; 4096];
    match stream.read(&mut buf) {
        Ok(n) if n > 0 => {
            let resp = String::from_utf8_lossy(&buf[..n]);
            if resp.contains(r#""error""#) {
                return Err(anyhow::anyhow!("Daemon refused watch request: {}", resp));
            }
            println!(
                "Watch request dispatched to daemon ({}) — response: {}",
                exec_id,
                resp.trim()
            );
            Ok(())
        }
        Ok(_) => Err(anyhow::anyhow!("Daemon socket closed before response")),
        Err(e) => Err(anyhow::anyhow!("Failed to read daemon response: {}", e)),
    }
}

pub fn run_watch(
    root_path: PathBuf,
    db_path: PathBuf,
    config: WatcherConfig,
    scan_initial: bool,
    validate: bool,
    validate_only: bool,
    compile_commands: Option<std::path::PathBuf>,
) -> Result<()> {
    // Build args for execution tracking
    let mut args = vec![
        "watch".to_string(),
        "--root".to_string(),
        root_path.to_string_lossy().to_string(),
        "--db".to_string(),
        db_path.to_string_lossy().to_string(),
    ];
    if !scan_initial {
        args.push("--watch-only".to_string());
    }
    if validate {
        args.push("--validate".to_string());
    }
    if validate_only {
        args.push("--validate-only".to_string());
    }
    args.push("--debounce-ms".to_string());
    args.push(config.debounce_ms.to_string());

    let exec_id = generate_execution_id();

    // svc-8: if daemon is running, signal it instead of local watch
    if crate::service::is_daemon_running() {
        return send_watch_request(
            &json!({
                "id": exec_id,
                "method": "watch",
                "tag": root_path.to_string_lossy(),
                "paths": [root_path.to_string_lossy().to_string()],
            })
            .to_string(),
            &exec_id,
        );
    }

    let root_str = root_path.to_string_lossy().to_string();
    let db_path_str = db_path.to_string_lossy().to_string();

    // Open the backend for execution logging
    let mut backend = Some(MagellanBackend::open_or_create(&db_path)?);

    // Start execution log if supported (SQLite only)
    if let Some(MagellanBackend::SQLite(ref mut graph)) = &mut backend {
        graph.execution_log().start_execution(
            &exec_id,
            env!("CARGO_PKG_VERSION"),
            &args,
            Some(&root_str),
            &db_path_str,
        )?;
    }

    // Pre-run validation if enabled (SQLite only)
    if validate || validate_only {
        if let Some(MagellanBackend::SQLite(ref mut graph)) = &mut backend {
            // Phase: pre_validation
            graph
                .telemetry()
                .record_phase_start(&exec_id, "pre_validation")?;
            let input_paths = vec![root_path.clone()];
            match validation::pre_run_validate(&db_path, &root_path, &input_paths) {
                Ok(report) if !report.passed => {
                    let error_count = report.errors.len();
                    let error_msg = format!("Pre-validation failed: {} errors", error_count);
                    graph
                        .telemetry()
                        .record_phase_end(&exec_id, "pre_validation")?;
                    graph.execution_log().finish_execution(
                        &exec_id,
                        "error",
                        Some(&error_msg),
                        0,
                        0,
                        0,
                    )?;
                    return Err(anyhow::anyhow!("Pre-validation failed"));
                }
                Ok(_) => {}
                Err(e) => return Err(e),
            }
            graph
                .telemetry()
                .record_phase_end(&exec_id, "pre_validation")?;
            if validate_only {
                graph
                    .execution_log()
                    .finish_execution(&exec_id, "success", None, 0, 0, 0)?;
                return Ok(());
            }
        }
    }

    // Create shutdown flag
    let shutdown = Arc::new(AtomicBool::new(false));
    let shutdown_clone = shutdown.clone();

    // Register signal handlers for SIGINT and SIGTERM
    #[cfg(unix)]
    {
        use signal_hook::consts::signal;
        use signal_hook::flag;
        let _ = flag::register(signal::SIGINT, shutdown_clone.clone())?;
        let _ = flag::register(signal::SIGTERM, shutdown_clone.clone())?;
    }

    // Warmup parsers
    let _ = magellan::ingest::pool::warmup_parsers();

    // Create pipeline configuration
    let mut pipeline_config =
        WatchPipelineConfig::new(root_path, db_path.clone(), config, scan_initial);
    pipeline_config.compile_commands_path = compile_commands;

    // Run the deterministic watch pipeline
    let result = magellan::run_watch_pipeline(pipeline_config, shutdown);

    // Record execution completion (SQLite only)
    if let Some(MagellanBackend::SQLite(ref mut graph)) = &mut backend {
        let outcome = if result.is_ok() { "success" } else { "error" };
        let error_msg = result.as_ref().err().map(|e| e.to_string());
        let _ = graph.execution_log().finish_execution(
            &exec_id,
            outcome,
            error_msg.as_deref(),
            0,
            0,
            0,
        );
    }

    match result {
        Ok(count) => {
            println!("SHUTDOWN");
            println!("Watch session complete. Processed {} events.", count);
            Ok(())
        }
        Err(e) => {
            println!("SHUTDOWN");
            Err(e)
        }
    }
}