//! Notification chimes for room events (join / peer-join / peer-leave, with more
//! events in later phases).
//!
//! The WAVs are embedded in the binary (`include_bytes!`) so a deployed single
//! binary is self-contained — no asset directory to ship alongside it. On first
//! use each sound is written once to a temp file, then played fire-and-forget
//! via `pw-play` (PipeWire-native; falls back to `paplay`/`aplay`). Playback runs
//! on a detached thread that waits on the child, so it never blocks the UI and
//! never leaves a zombie. Any failure (no player, no audio) is silent by design —
//! a missing chime should never disrupt a call.

use std::collections::HashMap;
use std::path::{Path, PathBuf};
use std::process::{Command, Stdio};
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::{Mutex, OnceLock};

static ENABLED: AtomicBool = AtomicBool::new(true);

/// Enable or disable all notification chimes globally.
pub fn set_enabled(enabled: bool) {
    ENABLED.store(enabled, Ordering::Relaxed);
}

/// Check if notifications are enabled.
pub fn is_enabled() -> bool {
    ENABLED.load(Ordering::Relaxed)
}


/// A notification event with a distinct chime.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum Sound {
    /// You joined a room.
    SelfJoin,
    /// Another participant joined.
    PeerJoin,
    /// A participant left.
    PeerLeave,
    /// Reconnecting to a peer.
    ReconnectAttempt,
    /// Reconnected to a peer.
    Reconnected,
    /// You left a room.
    SelfLeave,
    /// Mic mute/unmute toggle.
    MicToggle,
    /// Reconnect failed / peer evicted.
    ReconnectFailed,
}

impl Sound {
    /// Embedded WAV bytes for this sound.
    fn bytes(self) -> &'static [u8] {
        match self {
            Sound::SelfJoin => include_bytes!("../assets/sounds/self-join.wav"),
            Sound::PeerJoin => include_bytes!("../assets/sounds/peer-join.wav"),
            Sound::PeerLeave => include_bytes!("../assets/sounds/peer-leave.wav"),
            Sound::ReconnectAttempt => include_bytes!("../assets/sounds/reconnect-attempt.wav"),
            Sound::Reconnected => include_bytes!("../assets/sounds/reconnected.wav"),
            Sound::SelfLeave => include_bytes!("../assets/sounds/self-leave.wav"),
            Sound::MicToggle => include_bytes!("../assets/sounds/mic-toggle.wav"),
            Sound::ReconnectFailed => include_bytes!("../assets/sounds/reconnect-failed.wav"),
        }
    }

    /// Stable file stem for the cached temp file.
    fn name(self) -> &'static str {
        match self {
            Sound::SelfJoin => "self-join",
            Sound::PeerJoin => "peer-join",
            Sound::PeerLeave => "peer-leave",
            Sound::ReconnectAttempt => "reconnect-attempt",
            Sound::Reconnected => "reconnected",
            Sound::SelfLeave => "self-leave",
            Sound::MicToggle => "mic-toggle",
            Sound::ReconnectFailed => "reconnect-failed",
        }
    }
}

/// Helper to expand `~` at the start of a path to the user's home directory.
pub fn expand_tilde(path_str: &str) -> PathBuf {
    let trimmed = path_str.trim();
    if trimmed == "~" {
        dirs::home_dir().unwrap_or_else(|| PathBuf::from(trimmed))
    } else if let Some(stripped) = trimmed.strip_prefix("~/") {
        dirs::home_dir()
            .map(|home| home.join(stripped))
            .unwrap_or_else(|| PathBuf::from(trimmed))
    } else {
        PathBuf::from(trimmed)
    }
}

/// Check if a custom path is valid (i.e. if it exists and is a file).
/// Returns `None` if empty/whitespace, `Some(true)` if valid, `Some(false)` if invalid.
pub fn validate_custom_path(path_str: &str) -> Option<bool> {
    if path_str.trim().is_empty() {
        None
    } else {
        let path = expand_tilde(path_str);
        Some(path.exists() && path.is_file())
    }
}

/// Play a notification chime, fire-and-forget. Never blocks; never errors out.
pub fn play(sound: Sound, custom_path: Option<&str>) {
    if !is_enabled() {
        return;
    }
    let custom_path = custom_path.map(String::from);
    std::thread::spawn(move || {
        if let Some(ref path_str) = custom_path
            && !path_str.trim().is_empty()
        {
            let path = expand_tilde(path_str);
            if path.exists() && path.is_file() {
                spawn_player(&path);
                return;
            }
        }
        if let Some(path) = cached_path(sound) {
            spawn_player(&path);
        }
    });
}

/// Materialize the embedded WAV to a temp file the first time it's needed and
/// cache the path. Returns `None` only if the file can't be written.
fn cached_path(sound: Sound) -> Option<PathBuf> {
    static CACHE: OnceLock<Mutex<HashMap<&'static str, PathBuf>>> = OnceLock::new();
    let cache = CACHE.get_or_init(|| Mutex::new(HashMap::new()));

    let mut guard = cache.lock().unwrap();
    if let Some(path) = guard.get(sound.name()) {
        return Some(path.clone());
    }
    let path = std::env::temp_dir().join(format!("peerspeak-{}.wav", sound.name()));
    if std::fs::write(&path, sound.bytes()).is_err() {
        return None;
    }
    guard.insert(sound.name(), path.clone());
    Some(path)
}

/// Try each available player in turn, waiting on the first that starts (which
/// reaps the child). Runs on a detached thread, so the wait is harmless.
fn spawn_player(path: &Path) {
    for player in ["pw-play", "paplay", "aplay"] {
        let started = Command::new(player)
            .arg(path)
            .stdin(Stdio::null())
            .stdout(Stdio::null())
            .stderr(Stdio::null())
            .status();
        // `status()` errors only if the player binary isn't present; on a real
        // playback error it still returns (non-zero), so a started player ends
        // the loop either way — we don't want to double-play through fallbacks.
        if started.is_ok() {
            return;
        }
    }
}

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

    #[test]
    fn test_expand_tilde() {
        if let Some(home) = dirs::home_dir() {
            // bare `~` -> home dir
            assert_eq!(expand_tilde("~"), home);
            // `~/sub/dir/file.wav` -> home joined with `sub/dir/file.wav`
            assert_eq!(expand_tilde("~/sub/dir/file.wav"), home.join("sub/dir/file.wav"));
        }
        // absolute path (`/etc/foo.wav`) -> unchanged
        assert_eq!(expand_tilde("/etc/foo.wav"), PathBuf::from("/etc/foo.wav"));
        // relative path (`foo/bar.wav`) -> unchanged
        assert_eq!(expand_tilde("foo/bar.wav"), PathBuf::from("foo/bar.wav"));
        // a tilde not at the start (`/opt/~/x.wav`) -> unchanged
        assert_eq!(expand_tilde("/opt/~/x.wav"), PathBuf::from("/opt/~/x.wav"));
        // `~username` style (`~bob/x.wav`) -> unchanged
        assert_eq!(expand_tilde("~bob/x.wav"), PathBuf::from("~bob/x.wav"));
        // leading/trailing whitespace is trimmed
        if let Some(home) = dirs::home_dir() {
            assert_eq!(expand_tilde("  ~  "), home);
            assert_eq!(expand_tilde("  ~/sub/dir/file.wav  "), home.join("sub/dir/file.wav"));
        }
        assert_eq!(expand_tilde("  /etc/foo.wav  "), PathBuf::from("/etc/foo.wav"));
        assert_eq!(expand_tilde("  foo/bar.wav  "), PathBuf::from("foo/bar.wav"));
    }

    #[test]
    fn test_validate_custom_path() {
        // empty and whitespace-only -> None
        assert_eq!(validate_custom_path(""), None);
        assert_eq!(validate_custom_path("   "), None);
        // a path that does not exist -> Some(false)
        assert_eq!(validate_custom_path("/non/existent/file.wav"), Some(false));
        // a real existing file -> Some(true)
        let existing_file = concat!(env!("CARGO_MANIFEST_DIR"), "/Cargo.toml");
        assert_eq!(validate_custom_path(existing_file), Some(true));
        // an existing directory -> Some(false)
        let existing_dir = env!("CARGO_MANIFEST_DIR");
        assert_eq!(validate_custom_path(existing_dir), Some(false));
        // a `~`-prefixed path that resolves to a non-existent file -> Some(false)
        assert_eq!(validate_custom_path("~/non/existent/file.wav"), Some(false));
    }
}