//! End-to-end: a real server on a loopback port, clients over HTTP.

use oxy_core::repo::{Repo, SignatureStatus};
use std::fs;
use std::net::TcpListener;
use std::path::Path;

fn write(root: &Path, rel: &str, content: &[u8]) {
    let p = root.join(rel);
    fs::create_dir_all(p.parent().unwrap()).unwrap();
    fs::write(p, content).unwrap();
}

/// Point `$OXY_HOME` at a throwaway directory once per test process so no
/// test reads or writes the developer's real user configuration or keys.
fn hermetic() {
    static ONCE: std::sync::Once = std::sync::Once::new();
    static DIR: std::sync::OnceLock<tempfile::TempDir> = std::sync::OnceLock::new();
    ONCE.call_once(|| {
        let d = tempfile::tempdir().unwrap();
        std::env::set_var("OXY_HOME", d.path());
        DIR.set(d).ok();
    });
}

fn start(root: &Path, tokens: Vec<String>) -> String {
    start_with(root, tokens, None)
}

fn start_with(root: &Path, tokens: Vec<String>, tls: Option<oxy_server::TlsFiles>) -> String {
    let listener = TcpListener::bind("127.0.0.1:0").unwrap();
    let port = listener.local_addr().unwrap().port();
    let scheme = if tls.is_some() { "https" } else { "http" };
    let cfg = oxy_server::ServerConfig { root: root.to_path_buf(), tokens, tls };
    std::thread::spawn(move || oxy_server::run_blocking(listener, cfg).unwrap());
    // Give the acceptor a moment; the first request otherwise races the bind.
    std::thread::sleep(std::time::Duration::from_millis(50));
    format!("{scheme}://127.0.0.1:{port}")
}

/// A self-signed certificate for 127.0.0.1 written to `dir`: (cert, key).
fn self_signed(dir: &Path) -> (std::path::PathBuf, std::path::PathBuf) {
    fs::create_dir_all(dir).unwrap();
    let ck = rcgen::generate_simple_self_signed(vec!["127.0.0.1".into(), "localhost".into()]).unwrap();
    let cert = dir.join("cert.pem");
    let key = dir.join("key.pem");
    fs::write(&cert, ck.cert.pem()).unwrap();
    fs::write(&key, ck.signing_key.serialize_pem()).unwrap();
    (cert, key)
}

#[test]
fn clone_push_pull_over_http() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let served = root.join("served");
    Repo::init(&served.join("origin")).unwrap();
    let base = start(&served, vec![]);
    let url = format!("{base}/origin");

    let mut a = Repo::clone(&url, &root.join("a")).unwrap().with_home(root.join("home"));
    let (key, _) = a.create_identity("Ada", "ada@example.org", oxy_core::repo::IdentityScope::Repo).unwrap();
    write(&root.join("a"), "f.txt", b"hello\n");
    let h1 = a.commit("hello", &[]).unwrap();
    let r = a.push("origin", false).unwrap();
    assert!(r[0].ok, "{}", r[0].reason);

    let origin = Repo::open(&served.join("origin")).unwrap();
    assert_eq!(origin.bookmark_heads().unwrap(), vec![h1]);
    assert!(matches!(origin.authenticate_change(&h1).unwrap(), SignatureStatus::Valid { key: k, sealed: true, .. } if k == key));

    let b = Repo::clone(&url, &root.join("b")).unwrap();
    assert_eq!(fs::read(root.join("b/f.txt")).unwrap(), b"hello\n");
    write(&root.join("b"), "g.txt", b"g\n");
    let h2 = b.commit("g", &[]).unwrap();
    assert!(b.push("origin", false).unwrap()[0].ok);

    let pr = a.pull("origin").unwrap();
    assert!(pr.changed && pr.checked_out);
    assert_eq!(fs::read(root.join("a/g.txt")).unwrap(), b"g\n");
    let mut heads = a.bookmark_heads().unwrap();
    heads.sort();
    let mut want = vec![h1, h2];
    want.sort();
    assert_eq!(heads, want);

    // Unknown repositories and names the server refuses are surfaced as errors.
    let err = Repo::clone(&format!("{base}/nope"), &root.join("c")).unwrap_err().to_string();
    assert!(err.contains("404"), "{err}");
    fs::create_dir_all(served.join(".hidden/.oxy")).unwrap();
    assert!(Repo::clone(&format!("{base}/.hidden"), &root.join("d")).unwrap_err().to_string().contains("404"));
}

#[test]
fn objects_endpoint_serves_lazy_blobs() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let served = root.join("served");
    let origin = Repo::init(&served.join("origin")).unwrap();
    let big: Vec<u8> = (0..300_000u32).map(|i| (i % 253) as u8).collect(); // has NUL bytes: opaque
    write(&served.join("origin"), "big.bin", &big);
    write(&served.join("origin"), "t.txt", b"t\n");
    origin.commit("big", &[]).unwrap();
    let base = start(&served, vec![]);
    let url = format!("{base}/origin");
    let a = Repo::clone_with(&url, &root.join("a"), Some(1000), &[]).unwrap();
    assert_eq!(fs::read(root.join("a/big.bin")).unwrap(), big, "fetched through the objects endpoint during checkout");
    assert!(!a.snapshot("status").unwrap().changed);
}

#[test]
fn push_requires_a_token_when_configured() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let served = root.join("served");
    Repo::init(&served.join("origin")).unwrap();
    let base = start(&served, vec!["s3cret".into()]);
    let url = format!("{base}/origin");

    // Reads are open.
    let mut a = Repo::clone(&url, &root.join("a")).unwrap();
    write(&root.join("a"), "f.txt", b"x\n");
    a.commit("x", &[]).unwrap();
    let err = a.push("origin", false).unwrap_err().to_string();
    assert!(err.contains("401"), "{err}");

    a.config.set("remote.origin.token", "wrong").unwrap();
    a.save_config().unwrap();
    assert!(a.push("origin", false).unwrap_err().to_string().contains("401"));

    a.config.set("remote.origin.token", "s3cret").unwrap();
    a.save_config().unwrap();
    assert!(a.push("origin", false).unwrap()[0].ok);
    let origin = Repo::open(&served.join("origin")).unwrap();
    assert_eq!(origin.bookmark_heads().unwrap().len(), 1);
}

#[test]
fn https_with_a_self_signed_certificate() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let served = root.join("served");
    Repo::init(&served.join("origin")).unwrap();
    let (cert, key) = self_signed(root);
    let base = start_with(&served, vec![], Some(oxy_server::TlsFiles { cert: cert.clone(), key }));
    let url = format!("{base}/origin");

    // Without trusting the certificate the clone fails; with `OXY_CA` it works.
    let err = Repo::clone(&url, &root.join("untrusted")).err().unwrap().to_string();
    assert!(err.contains("certificate") || err.contains("tls") || err.contains("TLS") || err.contains("handshake"), "{err}");
    std::env::set_var("OXY_CA", &cert);
    let mut a = Repo::clone(&url, &root.join("a")).unwrap();
    std::env::remove_var("OXY_CA");
    // Persist the trust for this remote so later commands need no env var.
    a.config.set("remote.origin.ca", cert.to_str().unwrap()).unwrap();
    a.save_config().unwrap();
    write(&root.join("a"), "f.txt", b"tls\n");
    let h = a.commit("over tls", &[]).unwrap();
    assert!(a.push("origin", false).unwrap()[0].ok);
    let origin = Repo::open(&served.join("origin")).unwrap();
    assert_eq!(origin.bookmark_heads().unwrap(), vec![h]);
    // A wrong CA is refused.
    let (other_cert, _) = self_signed(&root.join("other"));
    a.config.set("remote.origin.ca", other_cert.to_str().unwrap()).unwrap();
    a.save_config().unwrap();
    assert!(a.fetch("origin").is_err());
}

/// Eight clones push independent changes at the same moment. The server
/// serialises pushes per repository, so every push either lands or is
/// refused because the bookmark moved, and a pull-then-push retry lands it.
#[test]
fn concurrent_pushes_are_serialised() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let served = root.join("served");
    Repo::init(&served.join("origin")).unwrap();
    let base = start(&served, vec![]);
    let url = format!("{base}/origin");
    const N: usize = 8;
    let mut clones = Vec::new();
    for i in 0..N {
        let path = root.join(format!("c{i}"));
        Repo::clone(&url, &path).unwrap();
        clones.push(path);
    }
    let barrier = std::sync::Arc::new(std::sync::Barrier::new(N));
    let mut handles = Vec::new();
    for (i, path) in clones.into_iter().enumerate() {
        let barrier = barrier.clone();
        handles.push(std::thread::spawn(move || {
            let repo = Repo::open(&path).unwrap();
            write(&path, &format!("file-{i}.txt"), format!("from clone {i}\n").as_bytes());
            let h = repo.commit(&format!("change {i}"), &[]).unwrap();
            barrier.wait();
            // A push is refused either up front (the remote moved since the
            // clone's last fetch) or by the server's compare-and-swap; both
            // are answered by pulling and pushing again.
            for attempt in 0..(N * 4) {
                match repo.push("origin", false) {
                    Ok(r) if r.iter().all(|x| x.ok) => return (h, attempt),
                    Ok(_) => {}
                    Err(e) if e.to_string().contains("pull first") || e.to_string().contains("moved") => {}
                    Err(e) => panic!("clone {i}: {e}"),
                }
                repo.pull("origin").unwrap_or_else(|e| panic!("clone {i} pull: {e}"));
            }
            panic!("clone {i} never managed to push");
        }));
    }
    let mut hashes = Vec::new();
    let mut total_rejected = 0;
    for h in handles {
        let (hash, attempts) = h.join().unwrap();
        hashes.push(hash);
        total_rejected += attempts;
    }
    let origin = Repo::open(&served.join("origin")).unwrap();
    let mut heads = origin.bookmark_heads().unwrap();
    heads.sort();
    hashes.sort();
    assert_eq!(heads, hashes, "every independent change is a head");
    let snap = origin.load_state(&heads).unwrap().materialize();
    for i in 0..N {
        assert!(snap.files.contains_key(&format!("file-{i}.txt")));
    }
    assert!(!snap.is_conflicted());
    eprintln!("{total_rejected} pushes were refused for a moved bookmark and retried");
    // The operation log is a single chain: each accepted push builds on the last.
    let ops = origin.op_log().unwrap();
    assert!(ops.len() > N);
}