//! Reading recorded segments with FFmpeg: clip export (remuxing without
//! re-encoding) and decoding for playback.
//!
//! FFmpeg is linked dynamically: the system's libraries on Linux (the OBS
//! runtime already depends on them) and, on Windows, the FFmpeg DLLs shipped
//! in the official OBS release that scripts/obs/assemble-windows.sh bundles.

use std::{path::Path, sync::Once, time::Duration};

pub use ffmpeg_next as ffmpeg;

/// Initialises FFmpeg once per process.
pub fn init() {
    static INIT: Once = Once::new();
    INIT.call_once(|| {
        let _ = ffmpeg::init();
        ffmpeg::log::set_level(ffmpeg::log::Level::Error);
    });
}

/// Basic facts about a segment file.
#[derive(Debug, Clone, PartialEq)]
pub struct Probe {
    pub duration: Duration,
    pub video_codec: String,
    pub width: u32,
    pub height: u32,
    pub audio_tracks: usize,
}

pub fn probe(path: &Path) -> Result<Probe, ffmpeg::Error> {
    init();
    let input = ffmpeg::format::input(path)?;
    let video = input
        .streams()
        .best(ffmpeg::media::Type::Video)
        .ok_or(ffmpeg::Error::StreamNotFound)?;
    let decoder = ffmpeg::codec::context::Context::from_parameters(video.parameters())?
        .decoder()
        .video()?;
    let micros = input.duration().max(0) as u64;
    Ok(Probe {
        duration: Duration::from_micros(micros),
        video_codec: decoder.id().name().to_owned(),
        width: decoder.width(),
        height: decoder.height(),
        audio_tracks: input
            .streams()
            .filter(|stream| stream.parameters().medium() == ffmpeg::media::Type::Audio)
            .count(),
    })
}

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

    /// Set CLIPBIN_TEST_SEGMENT to a recorded segment to run this.
    #[test]
    fn probes_a_recorded_segment() {
        let Some(path) = std::env::var_os("CLIPBIN_TEST_SEGMENT") else {
            return;
        };
        let probe = probe(Path::new(&path)).unwrap();
        assert!(probe.duration > Duration::ZERO);
        assert!(probe.width > 0 && probe.height > 0);
        println!("{probe:?}");
    }
}

pub mod audio;
pub mod decode;
pub mod export;
pub mod player;
pub mod thumbnail;

mod priority;
#[cfg(windows)]
#[allow(unsafe_code)]
mod windows_priority;