//! Each extension format's reader holds its declared duration to the reader limits it
//! shares with SPEC §2 (`wai::limits`): samples, counting every channel, for a score,
//! a haptic signal and an audio scene's stereo floor; frames for a splat4d clip, a film
//! and a reel's shots together. Rendering allocates in proportion to the declaration,
//! and nothing bounded it: a few bytes could ask a renderer for more memory than any
//! machine has.
//!
//! For each, a committed vector's contract is rewritten to declare exactly the limit,
//! which must still read, and one past it, which must be refused by name
//! (`duration_too_long`). A film whose last tick passes 2^64 - 1 is refused too: its
//! tick arithmetic used to wrap in release builds and panic in debug ones.
#![cfg(all(
    feature = "world",
    feature = "audio_scene",
    feature = "film",
    feature = "score",
    feature = "haptic",
    feature = "splat4d"
))]

use std::path::PathBuf;

use wai::limits::{RENDER_MAX_FRAMES, RENDER_MAX_SAMPLES};

fn vector(rel: &str) -> Vec<u8> {
    let p = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("..").join(rel);
    std::fs::read(&p).unwrap_or_else(|e| panic!("read {}: {e}", p.display()))
}

/// The sections of a container in the layout these formats share: a magic, a `u16`
/// count, a table of `(kind u8, offset u32, length u32)`, then the bodies.
fn sections(b: &[u8]) -> Vec<(u8, Vec<u8>)> {
    let n = u16::from_le_bytes([b[4], b[5]]) as usize;
    let body = &b[6 + 9 * n..];
    (0..n)
        .map(|i| {
            let e = &b[6 + 9 * i..6 + 9 * (i + 1)];
            let off = u32::from_le_bytes(e[1..5].try_into().unwrap()) as usize;
            let len = u32::from_le_bytes(e[5..9].try_into().unwrap()) as usize;
            (e[0], body[off..off + len].to_vec())
        })
        .collect()
}

fn build(magic: &[u8], secs: &[(u8, Vec<u8>)]) -> Vec<u8> {
    let mut out = magic[..4].to_vec();
    out.extend_from_slice(&(secs.len() as u16).to_le_bytes());
    let mut off = 0u32;
    for (k, body) in secs {
        out.push(*k);
        out.extend_from_slice(&off.to_le_bytes());
        out.extend_from_slice(&(body.len() as u32).to_le_bytes());
        off += body.len().div_ceil(8) as u32 * 8;
    }
    for (_, body) in secs {
        out.extend_from_slice(body);
        out.resize(out.len() + (body.len().div_ceil(8) * 8 - body.len()), 0);
    }
    out
}

/// The container with its contract (section 0x01) rewritten by `edit`.
fn with_contract(b: &[u8], edit: impl Fn(&mut serde_json::Map<String, serde_json::Value>)) -> Vec<u8> {
    let mut secs = sections(b);
    let c = secs.iter_mut().find(|(k, _)| *k == 0x01).expect("a contract section");
    let mut v: serde_json::Value = serde_json::from_slice(&c.1).expect("the contract parses");
    edit(v.as_object_mut().unwrap());
    c.1 = serde_json::to_vec(&v).unwrap();
    build(b, &secs)
}

fn set(key: &'static str, value: u64) -> impl Fn(&mut serde_json::Map<String, serde_json::Value>) {
    move |o| {
        o.insert(key.into(), value.into());
    }
}

fn channels(b: &[u8]) -> u64 {
    let secs = sections(b);
    let c = &secs.iter().find(|(k, _)| *k == 0x01).unwrap().1;
    let v: serde_json::Value = serde_json::from_slice(c).unwrap();
    v["channels"].as_u64().unwrap_or(1).max(1)
}

fn refused<E: std::fmt::Debug>(what: &str, r: Result<impl Sized, E>) {
    let e = format!("{:?}", r.err().unwrap_or_else(|| panic!("{what}: past the limit, and read")));
    assert!(e.contains("duration_too_long:"), "{what}: refused for another reason: {e}");
}

#[test]
fn audio_formats_are_held_to_the_sample_limit_counting_every_channel() {
    let score = vector("score-conformance/vectors/arp.wscr");
    let at = RENDER_MAX_SAMPLES / channels(&score);
    wai::score::Score::from_bytes(&with_contract(&score, set("duration", at))).expect("a score at the limit reads");
    refused("score", wai::score::Score::from_bytes(&with_contract(&score, set("duration", at + 1))));

    let haptic = vector("haptic-conformance/vectors/ramp.whap");
    let at = RENDER_MAX_SAMPLES / channels(&haptic);
    wai::haptic::HapticSignal::from_bytes(&with_contract(&haptic, set("duration", at))).expect("a signal at the limit reads");
    refused("haptic", wai::haptic::HapticSignal::from_bytes(&with_contract(&haptic, set("duration", at + 1))));

    // A scene's floor is stereo: two samples for every one of `duration`.
    let scene = vector("wai-web/demo/audio/moving.wscn");
    let at = RENDER_MAX_SAMPLES / 2;
    wai::audio_scene::SpatialScene::from_bytes(&with_contract(&scene, set("duration", at))).expect("a scene at the limit reads");
    refused("audio scene", wai::audio_scene::SpatialScene::from_bytes(&with_contract(&scene, set("duration", at + 1))));
}

#[test]
fn frame_formats_are_held_to_the_frame_limit() {
    let clip = vector("volumetric-conformance/vectors/morph.w4ds");
    wai::splat4d::Splat4dClipData::from_bytes(&with_contract(&clip, set("n_frames", RENDER_MAX_FRAMES)))
        .expect("a clip at the limit reads");
    refused("splat4d", wai::splat4d::Splat4dClipData::from_bytes(&with_contract(&clip, set("n_frames", RENDER_MAX_FRAMES + 1))));

    let film = vector("film-conformance/vectors/rise.wflm");
    wai::film::Film::from_bytes(&with_contract(&film, set("frames", RENDER_MAX_FRAMES))).expect("a film at the limit reads");
    refused("film", wai::film::Film::from_bytes(&with_contract(&film, set("frames", RENDER_MAX_FRAMES + 1))));

    // The reel: the first shot's frames (the first u64 after the shot count) set so the
    // shots together are exactly at the limit, then one past it.
    let reel = vector("film-conformance/vectors/coverage.wrel");
    let secs = sections(&reel);
    let shots = &secs.iter().find(|(k, _)| *k == 0x03).expect("a shots section").1;
    let n = u32::from_le_bytes(shots[..4].try_into().unwrap()) as usize;
    let mut others = 0u64;
    let mut p = 4;
    let mut firsts = Vec::new();
    for i in 0..n {
        let frames = u64::from_le_bytes(shots[p..p + 8].try_into().unwrap());
        firsts.push(p);
        if i > 0 {
            others += frames;
        }
        let keys = u32::from_le_bytes(shots[p + 24..p + 28].try_into().unwrap()) as usize;
        p += 24 + 4 + keys * 72;
    }
    let with_first = |frames: u64| {
        let mut s = secs.clone();
        let body = &mut s.iter_mut().find(|(k, _)| *k == 0x03).unwrap().1;
        body[firsts[0]..firsts[0] + 8].copy_from_slice(&frames.to_le_bytes());
        build(&reel, &s)
    };
    wai::film::Reel::from_bytes(&with_first(RENDER_MAX_FRAMES - others)).expect("a reel at the limit reads");
    refused("reel", wai::film::Reel::from_bytes(&with_first(RENDER_MAX_FRAMES - others + 1)));
}

#[test]
fn a_film_whose_last_tick_passes_u64_is_refused() {
    let film = vector("film-conformance/vectors/rise.wflm");
    let past = with_contract(&film, |o| {
        o.insert("frames".into(), 3u64.into());
        o.insert("start_tick".into(), (u64::MAX - 1).into());
        o.insert("ticks_per_frame".into(), 1u64.into());
    });
    let e = format!("{:?}", wai::film::Film::from_bytes(&past).err().expect("refused"));
    assert!(e.contains("last tick passes"), "{e}");
    let at = with_contract(&film, |o| {
        o.insert("frames".into(), 2u64.into());
        o.insert("start_tick".into(), (u64::MAX - 1).into());
        o.insert("ticks_per_frame".into(), 1u64.into());
    });
    let f = wai::film::Film::from_bytes(&at).expect("a schedule ending at 2^64 - 1 reads");
    assert_eq!(f.frame_tick(1), u64::MAX);
}