//! A re-pack from a parent (packaging §11.5): a pack that takes every piece's base and
//! refinements from an earlier package instead of coding them. The golden
//! `video-repack-01` takes `video-base-01`'s bases under two floors; its files are those of
//! a pack that codes, but for its receipt's parent and `LISTING`; a parent that does not
//! verify, is not this source's, or is coded in other rungs is refused by name; and a
//! verifier holding the parent checks the re-pack against it.

use std::collections::BTreeMap;
use std::path::{Path, PathBuf};
use wai_pack::files::FileSet;

type Files = BTreeMap<String, Vec<u8>>;

fn corpus() -> PathBuf {
    Path::new(env!("CARGO_MANIFEST_DIR")).join("../pack-conformance")
}

fn held(p: &Path) -> Files {
    wai::pin::read_dir_set(p).unwrap()
}

fn package(name: &str) -> Files {
    held(&corpus().join("packs").join(name).join("package"))
}

fn policy() -> String {
    String::from_utf8(std::fs::read(corpus().join("packs/video-repack-01/policy.toml")).unwrap()).unwrap()
}

/// Pack `policy` over `source` with the re-pack golden's floor and key, taking the bases
/// from `parent` when given.
fn pack(policy: &str, source: Vec<u8>, parent: Option<Files>) -> Result<wai_pack::pack::PackOutput, wai_pack::pack::PackError> {
    let d = corpus().join("packs/video-repack-01");
    let key = ed25519_dalek::SigningKey::from_bytes(&wai_pack::unhex(std::fs::read_to_string(d.join("key.hex")).unwrap().trim()).unwrap().try_into().unwrap());
    let id = wai::signer_id::did_key(&key.verifying_key().to_bytes());
    let mut o = wai_pack::pack::PackOpts::new(key, id, held(&d.join("floor")));
    o.base_from = parent.map(FileSet::Memory);
    let mut src = BTreeMap::new();
    src.insert("v".to_string(), source);
    wai_pack::pack::pack(policy.as_bytes(), &src, &mut o)
}

fn fixture() -> Vec<u8> {
    wai_pack::fixture::generate("video-base-01").unwrap()
}

fn code(r: Result<wai_pack::pack::PackOutput, wai_pack::pack::PackError>) -> String {
    r.map(|_| "ok".to_string()).unwrap_or_else(|e| e.code)
}

fn receipt(f: &Files) -> wai::package::PackageReceiptV2 {
    wai::package::PackageReceiptV2::from_json(std::str::from_utf8(&f["package.receipt.json"]).unwrap()).unwrap()
}

/// The re-pack takes the parent's objects: its files are a coding pack's of the same
/// policy, but for the receipt, which names the parent, and `LISTING`; and it verifies
/// against its parent, and against no other package.
#[test]
fn a_repack_is_a_coding_pack_with_its_parent_named() {
    let parent = package("video-base-01");
    let re = pack(&policy(), fixture(), Some(parent.clone())).unwrap();
    assert_eq!(re.files, package("video-repack-01"), "the golden");
    let coded = pack(&policy(), fixture(), None).unwrap();
    let differ: Vec<&String> = re.files.keys().filter(|k| coded.files.get(*k) != Some(&re.files[*k])).collect();
    assert_eq!(differ, vec!["LISTING", "package.receipt.json"]);
    assert_eq!(re.files.keys().collect::<Vec<_>>(), coded.files.keys().collect::<Vec<_>>());
    assert_eq!(re.receipt.parent, wai::package::Parent::RePack(receipt(&parent).receipt_hash()));
    assert_eq!(coded.receipt.parent, wai::package::Parent::None);
    wai_pack::verify::verify_repack(&re.files, &parent).unwrap();
    let codes = |r: Result<wai_pack::verify::VerifyReport, Vec<wai_pack::verify::Reason>>| r.err().unwrap_or_default().into_iter().map(|x| x.code).collect::<Vec<_>>();
    assert_eq!(codes(wai_pack::verify::verify_repack(&re.files, &package("video-ladder-01"))), vec!["repack-parent-mismatch"], "a parent it does not name");
    assert_eq!(codes(wai_pack::verify::verify_repack(&coded.files, &parent)), vec!["repack-parent-mismatch"], "a pack that names no parent");
}

/// §11.5's refusals, each before anything is written: a parent that does not verify, one
/// whose pieces are another source's, one coded under other base parameters, and a source
/// one sample from the parent's.
#[test]
fn a_parent_that_is_not_this_source_s_is_refused() {
    let parent = package("video-base-01");
    // An object of the parent altered, its LISTING written again: it does not verify.
    let mut corrupt = parent.clone();
    let obj = corrupt.keys().find(|k| k.starts_with("objects/")).unwrap().clone();
    let b = corrupt.get_mut(&obj).unwrap();
    let last = b.len() - 1;
    b[last] ^= 1;
    corrupt.remove("LISTING");
    let view: BTreeMap<String, &[u8]> = corrupt.iter().map(|(k, v)| (k.clone(), v.as_slice())).collect();
    let l = wai::pin::listing_from(&view).unwrap();
    corrupt.insert("LISTING".into(), l);
    assert_eq!(code(pack(&policy(), fixture(), Some(corrupt))), "repack-parent-invalid");
    // Another fixture's package: other pieces.
    assert_eq!(code(pack(&policy(), fixture(), Some(package("video-staged-01")))), "repack-parent-mismatch");
    // This policy's base under other parameters than the parent's.
    let other = policy().replace("q_candidates = [16, 12, 8]", "q_candidates = [16, 12]");
    assert_ne!(other, policy());
    assert_eq!(code(pack(&other, fixture(), Some(parent.clone()))), "repack-parent-mismatch");
    // One luma sample of frame 30 changed: the same pieces and kinds, another source.
    let mut src = fixture();
    let head = src.iter().position(|&c| c == b'\n').unwrap() + 1;
    let frame = 64 * 36 + 2 * 32 * 18;
    let at = head + 30 * (6 + frame) + 6 + 64 * 10 + 20;
    src[at] = src[at].wrapping_add(40);
    assert_eq!(code(pack(&policy(), src, Some(parent))), "repack-source-mismatch");
}

/// The command line: `pack --base-from` writes the re-pack, and `verify --parent` checks it
/// against the parent it names.
#[test]
fn the_command_line_repacks_and_verifies_against_the_parent() {
    let dir = std::env::temp_dir().join(format!("wai-pack-repack-{}", std::process::id()));
    let _ = std::fs::remove_dir_all(&dir);
    std::fs::create_dir_all(&dir).unwrap();
    let g = corpus().join("packs/video-repack-01");
    std::fs::write(dir.join("v.y4m"), fixture()).unwrap();
    let bin = env!("CARGO_BIN_EXE_wai-pack");
    let out = std::process::Command::new(bin)
        .args(["pack", "--policy"]).arg(g.join("policy.toml"))
        .arg("--out").arg(dir.join("out"))
        .arg("--key").arg(g.join("key.hex"))
        .arg("--source").arg(format!("v={}", dir.join("v.y4m").display()))
        .arg("--floor").arg(g.join("floor"))
        .arg("--base-from").arg(corpus().join("packs/video-base-01/package"))
        .output()
        .unwrap();
    assert!(out.status.success(), "{}", String::from_utf8_lossy(&out.stderr));
    assert_eq!(held(&dir.join("out")), package("video-repack-01"));
    let verify = |parent: &str| {
        std::process::Command::new(bin).arg("verify").arg(dir.join("out")).arg("--parent").arg(corpus().join("packs").join(parent).join("package")).output().unwrap()
    };
    assert!(verify("video-base-01").status.success());
    let wrong = verify("video-ladder-01");
    assert!(!wrong.status.success() && String::from_utf8_lossy(&wrong.stderr).contains("repack-parent-mismatch"));
    let _ = std::fs::remove_dir_all(&dir);
}