//! Shared helpers for integration tests: spawn the real daemon binary on
//! ephemeral paths and speak the JSON-lines protocol to it.

// Each test binary compiles its own copy of this module and none of them
// uses every helper.
#![allow(dead_code)]

use std::io::{BufRead, BufReader, Write};
use std::os::unix::net::UnixStream;
use std::path::{Path, PathBuf};
use std::process::{Child, Command};
use std::time::{Duration, Instant};

use varde_proto::{Envelope, Request};

/// A running daemon process, killed on drop.
pub struct DaemonProc {
    pub child: Child,
    pub socket: PathBuf,
    pub store: PathBuf,
    // Kept alive so the store/socket dirs survive as long as the daemon.
    _dir: Option<tempfile::TempDir>,
}

impl DaemonProc {
    /// SIGKILL the daemon — no cleanup handlers run, simulating a crash.
    pub fn kill_dash_nine(&mut self) {
        let _ = self.child.kill();
        let _ = self.child.wait();
    }
}

impl Drop for DaemonProc {
    fn drop(&mut self) {
        let _ = self.child.kill();
        let _ = self.child.wait();
    }
}

/// Spawn the compiled varde-daemon on a fresh tempdir.
pub fn spawn_daemon() -> DaemonProc {
    let dir = tempfile::tempdir().expect("tempdir");
    let mut proc = spawn_daemon_at(dir.path());
    proc._dir = Some(dir);
    proc
}

/// Spawn the daemon against an existing directory (for restart tests).
pub fn spawn_daemon_at(dir: &Path) -> DaemonProc {
    spawn_daemon_with_env(dir, &[])
}

/// Spawn the daemon with extra environment variables (config overrides).
pub fn spawn_daemon_with_env(dir: &Path, envs: &[(&str, &str)]) -> DaemonProc {
    let socket = dir.join("varde.sock");
    let store = dir.join("store");
    let mut command = Command::new(env!("CARGO_BIN_EXE_varde-daemon"));
    command
        .arg("--user")
        .arg("--socket")
        .arg(&socket)
        .arg("--store")
        .arg(&store)
        // Isolate from any config file on the developer's machine.
        .env("VARDE_CONFIG", dir.join("no-config.toml"))
        .env("VARDE_DISCOVERY", "false");
    for (key, value) in envs {
        command.env(key, value);
    }
    let child = command.spawn().expect("spawning varde-daemon");
    // An explicitly named config must exist for the daemon to start.
    std::fs::write(dir.join("no-config.toml"), "").expect("writing empty config");

    let proc = DaemonProc {
        child,
        socket,
        store,
        _dir: None,
    };
    wait_for_socket(&proc.socket);
    proc
}

fn wait_for_socket(path: &Path) {
    let deadline = Instant::now() + Duration::from_secs(10);
    while Instant::now() < deadline {
        if UnixStream::connect(path).is_ok() {
            return;
        }
        std::thread::sleep(Duration::from_millis(20));
    }
    panic!("daemon socket {} never appeared", path.display());
}

/// One connected API client.
pub struct Client {
    reader: BufReader<UnixStream>,
    writer: UnixStream,
}

impl Client {
    pub fn connect(socket: &Path) -> Client {
        let stream = UnixStream::connect(socket).expect("connecting to daemon");
        let reader = BufReader::new(stream.try_clone().expect("cloning stream"));
        Client {
            reader,
            writer: stream,
        }
    }

    /// Send a request and read the response envelope.
    pub fn request(&mut self, req: &Request) -> Envelope {
        let mut line = serde_json::to_string(req).expect("serializing request");
        line.push('\n');
        self.writer
            .write_all(line.as_bytes())
            .expect("writing request");
        self.read_envelope()
    }

    /// Send a raw line (for malformed-input tests).
    pub fn send_raw(&mut self, raw: &str) -> Envelope {
        self.writer
            .write_all(raw.as_bytes())
            .expect("writing raw line");
        self.writer.write_all(b"\n").expect("writing newline");
        self.read_envelope()
    }

    fn read_envelope(&mut self) -> Envelope {
        let mut reply = String::new();
        self.reader.read_line(&mut reply).expect("reading reply");
        assert!(
            !reply.is_empty(),
            "daemon closed connection without replying"
        );
        serde_json::from_str(&reply).expect("parsing reply envelope")
    }

    /// Bound how long reads may block (applies to the shared socket).
    pub fn set_read_timeout(&mut self, timeout: Duration) {
        self.writer
            .set_read_timeout(Some(timeout))
            .expect("setting read timeout");
    }

    /// Read one line of the event stream (after Subscribe).
    pub fn read_event_line(&mut self) -> Option<String> {
        let mut line = String::new();
        match self.reader.read_line(&mut line) {
            Ok(0) => None,
            Ok(_) => Some(line),
            Err(e) => panic!("reading event line: {e}"),
        }
    }
}