extern crate mp4;

use mp4::TrackType;
use std::env;
use std::fs::File;

fn main() {
    let args: Vec<String> = env::args().collect();

    match args.len() {
        2 => {
            let filename = &args[1];
            let f = File::open(filename).unwrap();

            let bmff = mp4::read_mp4(f).unwrap();
            let moov = bmff.moov.unwrap();

            // Print results.
            println!("File:");
            println!("  file size:  {}", bmff.size);
            println!(
                "  brands:     {:?} {:?}\n",
                bmff.ftyp.major_brand, bmff.ftyp.compatible_brands
            );

            println!("Movie:");
            println!("  version:       {:?}", moov.mvhd.version);
            println!(
                "  creation time: {}",
                creation_time(moov.mvhd.creation_time)
            );
            println!("  duration:      {:?}", moov.mvhd.duration);
            println!("  timescale:     {:?}\n", moov.mvhd.timescale);

            println!("Found {} Tracks", moov.traks.len());
            for trak in moov.traks.iter() {
                let tkhd = trak.tkhd.as_ref().unwrap();
                println!("Track: {:?}", tkhd.track_id);
                println!("  flags:    {:?}", tkhd.flags);
                println!("  id:       {:?}", tkhd.track_id);
                println!("  duration: {:?}", tkhd.duration);
                if tkhd.width != 0 && tkhd.height != 0 {
                    println!("    width:    {:?}", tkhd.width);
                    println!("    height:   {:?}", tkhd.height);
                }
                if let Some(ref mdia) = trak.mdia {
                    let hdlr = mdia.hdlr.as_ref().unwrap();
                    let mdhd = mdia.mdhd.as_ref().unwrap();
                    let stts = mdia
                        .minf
                        .as_ref()
                        .map(|m| m.stbl.as_ref().map(|s| s.stts.as_ref()).flatten())
                        .flatten();

                    println!(
                        "  type:     {:?}",
                        get_handler_type(hdlr.handler_type.value.as_ref())
                    );
                    println!("  language: {:?}", mdhd.language_string);

                    println!("  media:");
                    if let Some(ref s) = stts {
                        println!("    sample count: {:?}", s.sample_counts[0]);
                    }
                    println!("    timescale:    {:?}", mdhd.timescale);
                    println!(
                        "    duration:     {:?} (media timescale units)",
                        mdhd.duration
                    );
                    println!(
                        "    duration:     {:?} (ms)",
                        get_duration_ms(mdhd.duration, mdhd.timescale)
                    );
                    if get_handler_type(hdlr.handler_type.value.as_ref()) == TrackType::Video {
                        if let Some(ref s) = stts {
                            println!(
                                "    frame rate: (computed): {:?}",
                                get_framerate(&s.sample_counts, mdhd.duration, mdhd.timescale)
                            );
                        }
                    }
                }
            }
        }
        _ => {
            println!("Usage: mp4info <filename>");
        }
    }
}

fn get_handler_type(handler: &str) -> TrackType {
    let mut typ: TrackType = TrackType::Unknown;
    match handler {
        "vide" => typ = TrackType::Video,
        "soun" => typ = TrackType::Audio,
        "meta" => typ = TrackType::Unknown,
        _ => (),
    }
    return typ;
}

fn get_duration_ms(duration: u32, timescale: u32) -> String {
    let ms = (duration as f64 / timescale as f64) * 1000.0;
    return format!("{:.2}", ms.floor());
}

fn get_framerate(sample_counts: &Vec<u32>, duration: u32, timescale: u32) -> String {
    let sc = (sample_counts[0] as f64) * 1000.0;
    let ms = (duration as f64 / timescale as f64) * 1000.0;
    return format!("{:.2}", sc / ms.floor());
}

fn creation_time(creation_time: u32) -> u32 {
    // convert from MP4 epoch (1904-01-01) to Unix epoch (1970-01-01)
    if creation_time >= 2082844800 {
        creation_time - 2082844800
    } else {
        creation_time
    }
}