//! Audio player for voice messages.
//!
//! Uses ffplay (from FFmpeg) for reliable Opus/OGG playback.
//! Pause/resume implemented via SIGSTOP/SIGCONT signals.

use std::path::Path;
use std::process::Command;
use std::sync::{Arc, Mutex};
use std::time::Duration;

/// Audio player state and controls
pub struct AudioPlayer {
    /// PID of current playback process (if any)
    current_pid: Arc<Mutex<Option<u32>>>,
    /// Whether the process is currently paused (SIGSTOP)
    paused: Arc<Mutex<bool>>,
    /// Path to the currently playing file (for restart with seek)
    current_path: Arc<Mutex<Option<std::path::PathBuf>>>,
    /// True between play_from() call and ffplay actually starting (race window)
    starting: Arc<Mutex<bool>>,
}

impl AudioPlayer {
    /// Creates a new AudioPlayer
    pub fn new() -> Result<Self, String> {
        Command::new("which")
            .arg("ffplay")
            .stdout(std::process::Stdio::null())
            .stderr(std::process::Stdio::null())
            .output()
            .map_err(|_| "ffplay not found (install ffmpeg)".to_string())?;

        Ok(Self {
            current_pid: Arc::new(Mutex::new(None)),
            paused: Arc::new(Mutex::new(false)),
            current_path: Arc::new(Mutex::new(None)),
            starting: Arc::new(Mutex::new(false)),
        })
    }

    /// Plays an audio file from the given path
    pub fn play<P: AsRef<Path>>(&self, path: P) -> Result<(), String> {
        self.play_from(path, 0.0)
    }

    /// Plays an audio file starting from the given position (seconds)
    pub fn play_from<P: AsRef<Path>>(&self, path: P, start_secs: f32) -> Result<(), String> {
        self.stop();

        let path_owned = path.as_ref().to_path_buf();
        *self.current_path.lock().unwrap() = Some(path_owned.clone());
        *self.starting.lock().unwrap() = true;
        let current_pid = self.current_pid.clone();
        let paused = self.paused.clone();
        let starting = self.starting.clone();

        std::thread::spawn(move || {
            let mut cmd = Command::new("ffplay");
            cmd.arg("-nodisp")
                .arg("-autoexit")
                .arg("-loglevel")
                .arg("quiet");

            if start_secs > 0.0 {
                cmd.arg("-ss").arg(format!("{:.1}", start_secs));
            }

            if let Ok(mut child) = cmd
                .arg(&path_owned)
                .stdout(std::process::Stdio::null())
                .stderr(std::process::Stdio::null())
                .spawn()
            {
                let pid = child.id();
                *current_pid.lock().unwrap() = Some(pid);
                *paused.lock().unwrap() = false;
                *starting.lock().unwrap() = false;

                let _ = child.wait();

                // Обнуляем только если это наш pid (новый play мог уже заменить его)
                let mut pid_guard = current_pid.lock().unwrap();
                if *pid_guard == Some(pid) {
                    *pid_guard = None;
                    *paused.lock().unwrap() = false;
                }
            } else {
                *starting.lock().unwrap() = false;
            }
        });

        Ok(())
    }

    /// Pauses playback via SIGSTOP
    pub fn pause(&self) {
        if let Some(pid) = *self.current_pid.lock().unwrap() {
            let _ = Command::new("kill")
                .arg("-STOP")
                .arg(pid.to_string())
                .output();
            *self.paused.lock().unwrap() = true;
        }
    }

    /// Resumes playback via SIGCONT (from the same position)
    pub fn resume(&self) {
        if let Some(pid) = *self.current_pid.lock().unwrap() {
            let _ = Command::new("kill")
                .arg("-CONT")
                .arg(pid.to_string())
                .output();
            *self.paused.lock().unwrap() = false;
        }
    }

    /// Resumes playback from a specific position (restarts ffplay with -ss)
    pub fn resume_from(&self, position_secs: f32) -> Result<(), String> {
        let path = self.current_path.lock().unwrap().clone();
        if let Some(path) = path {
            self.play_from(&path, position_secs)
        } else {
            Err("No file to resume".to_string())
        }
    }

    /// Stops playback (kills the process)
    pub fn stop(&self) {
        *self.starting.lock().unwrap() = false;
        if let Some(pid) = self.current_pid.lock().unwrap().take() {
            // Resume first if paused, then kill
            let _ = Command::new("kill")
                .arg("-CONT")
                .arg(pid.to_string())
                .output();
            let _ = Command::new("kill").arg(pid.to_string()).output();
        }
        *self.paused.lock().unwrap() = false;
    }

    /// Returns true if a process is active (playing or paused)
    #[allow(dead_code)]
    pub fn is_playing(&self) -> bool {
        self.current_pid.lock().unwrap().is_some() && !*self.paused.lock().unwrap()
    }

    /// Returns true if paused
    #[allow(dead_code)]
    pub fn is_paused(&self) -> bool {
        self.current_pid.lock().unwrap().is_some() && *self.paused.lock().unwrap()
    }

    /// Returns true if no active process and not starting a new one
    pub fn is_stopped(&self) -> bool {
        self.current_pid.lock().unwrap().is_none() && !*self.starting.lock().unwrap()
    }

    #[allow(dead_code)]
    pub fn set_volume(&self, _volume: f32) {}
    #[allow(dead_code)]
    pub fn adjust_volume(&self, _delta: f32) {}

    pub fn volume(&self) -> f32 {
        1.0
    }

    #[allow(dead_code)]
    pub fn seek(&self, _delta: Duration) -> Result<(), String> {
        Err("Seeking not supported".to_string())
    }
}

impl Drop for AudioPlayer {
    fn drop(&mut self) {
        self.stop();
    }
}

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

    #[test]
    fn test_audio_player_creation() {
        if let Ok(player) = AudioPlayer::new() {
            assert!(player.is_stopped());
            assert!(!player.is_playing());
            assert!(!player.is_paused());
        }
    }

    #[test]
    fn test_volume() {
        if let Ok(player) = AudioPlayer::new() {
            assert_eq!(player.volume(), 1.0);
        }
    }
}