use super::*;
use crate::Session;

fn fresh_dir(name: &str) -> PathBuf {
    let d = std::env::temp_dir().join(format!("fieldcraft-crash-test-{name}-{}", std::process::id()));
    let _ = fs::remove_dir_all(&d);
    d
}

fn build() -> Build {
    Build { version: "9.9.9", commit: "abc1234" }
}

fn node(label: u32) -> Value {
    json!({"label": label, "xyz": [f64::from(label), 0.0, 0.0]})
}

/// The child half of the process tests: does nothing unless a parent asks, then installs the
/// hook and crashes the way `FIELDCRAFT_CRASH_CHILD` says.
#[test]
fn child() {
    let (Some(dir), Ok(mode)) = (std::env::var_os("FIELDCRAFT_CRASH_CHILD_DIR"), std::env::var("FIELDCRAFT_CRASH_CHILD")) else {
        return;
    };
    let dir = PathBuf::from(dir);
    if mode == "replay" {
        // Replay the one report (in a process of its own: the replay replaces the panic hook).
        let id = list(&dir)[0].id.clone();
        let r = replay(&read(&dir, &id).unwrap(), &std::env::temp_dir()).unwrap();
        let steps: Vec<_> = r.steps.iter().map(|(c, r)| json!({"command": c, "ok": r.is_ok()})).collect();
        println!("REPLAY {}", json!({"reproduced": r.reproduced, "nodes": r.session.model.nodes().len(), "steps": steps}));
        return;
    }
    let fresh = install(dir.clone(), build());
    println!("FRESH {}", serde_json::to_string(&fresh).unwrap());
    if mode == "idle" {
        end_session();
        return;
    }
    let mut s = Session { crash_journal: true, ..Default::default() };
    s.execute("mesh.node.add", &node(1)).unwrap();
    s.execute("mesh.node.add", &node(2)).unwrap();
    // Commands that only read are not kept.
    for _ in 0..50 {
        s.execute("model.info", &json!({})).unwrap();
    }
    match mode.as_str() {
        "command" => {
            for _ in 0..3 {
                let r = s.execute("diagnostics.crash_test", &json!({"mode": "panic"}));
                assert!(matches!(r, Err(crate::EngineError::Internal { .. })), "{r:?}");
            }
            assert_eq!(s.model.nodes().len(), 2, "the model is unchanged");
        }
        "recovered" => {
            assert_eq!(s.execute("diagnostics.crash_test", &json!({"mode": "recovered"})).unwrap()["caught"], true);
        }
        "thread" => {
            let r = std::thread::Builder::new()
                .name("worker".into())
                .spawn(|| std::panic::panic_any(String::from("worker thread 42 failed")))
                .unwrap()
                .join();
            assert!(r.is_err());
        }
        "abort" => {
            activity("control ui.capture");
            let _ = s.execute("diagnostics.crash_test", &json!({"mode": "abort"}));
        }
        "autosave" => {
            // The journal starts again from each autosave.
            let mut a = crate::autosave::Autosaver::new(&dir.join("recovery")).unwrap();
            assert!(a.save(&s).unwrap());
            s.execute("mesh.node.add", &node(3)).unwrap();
            activity("control ui.capture");
            std::process::abort();
        }
        _ => {}
    }
    end_session();
}

/// Run [`child`] in a new process; returns its stdout and whether it succeeded.
fn run_child(dir: &Path, mode: &str) -> (String, bool) {
    let out = std::process::Command::new(std::env::current_exe().unwrap())
        .args(["--exact", "crash::tests::child", "--test-threads=1", "--nocapture"])
        .env("FIELDCRAFT_CRASH_CHILD_DIR", dir)
        .env("FIELDCRAFT_CRASH_CHILD", mode)
        .env("FIELDCRAFT_CRASH_TEST", "1")
        .env("RUST_BACKTRACE", "0")
        .output()
        .unwrap();
    (String::from_utf8_lossy(&out.stdout).into_owned(), out.status.success())
}

fn printed(out: &str, tag: &str) -> Value {
    let line = out.lines().find_map(|l| l.split_once(tag).map(|(_, rest)| rest)).unwrap_or_else(|| panic!("no {tag} in {out}"));
    serde_json::from_str(line.trim()).unwrap()
}

fn only_report(dir: &Path) -> (Summary, Value) {
    let all = list(dir);
    assert_eq!(all.len(), 1, "{all:?}");
    let s = all.into_iter().next().unwrap();
    let v = read(dir, &s.id).unwrap();
    (s, v)
}

fn nodes_in(model: &str) -> usize {
    let mut s = Session::default();
    s.execute("file.open", &json!({"path": model})).unwrap();
    s.model.nodes().len()
}

#[test]
fn a_command_panic_is_reported_once_with_the_model_and_the_command_and_replays() {
    let d = fresh_dir("command");
    let (_, ok) = run_child(&d, "command");
    assert!(ok, "the panics were caught");
    let (s, v) = only_report(&d);
    assert_eq!(s.kind, "command_panic");
    assert_eq!(s.count, 3, "repeats are counted, not written again");
    assert_eq!(s.command.as_deref(), Some("diagnostics.crash_test"));
    assert!(s.replayable);
    assert_eq!(v["format"], FORMAT);
    assert_eq!(v["app"]["version"], "9.9.9");
    assert_eq!(v["system"]["os"], std::env::consts::OS);
    assert!(v["message"].as_str().unwrap().contains("an internal error in a command"), "{v}");
    assert!(v["location"].as_str().unwrap().contains("diagnostics.rs"), "{v}");
    let bt = v["backtrace"].as_array().unwrap();
    assert!(bt.iter().any(|f| f.as_str().unwrap().contains("crash_test")), "{bt:?}");
    assert!(!bt.iter().any(|f| f.as_str().unwrap().contains("crash::hook")), "the hook's own frames are dropped: {bt:?}");
    assert_eq!(v["recent_commands"][0]["command"], "mesh.node.add");
    assert_eq!(v["recent_commands"].as_array().unwrap().len(), 3, "read-only commands are not kept: {v}");
    assert_eq!(v["recent_commands"][2]["ok"], false);
    // The model from before the command, and the command: together they reproduce the crash.
    assert_eq!(nodes_in(v["model_path"].as_str().unwrap()), 2);
    let replay: Value = serde_json::from_slice(&fs::read(v["replay_path"].as_str().unwrap()).unwrap()).unwrap();
    assert_eq!(replay["commands"], json!([{"command": "diagnostics.crash_test", "params": {"mode": "panic"}}]));
    assert_eq!(v["reproduce"], format!("fieldcraft-cli crashes replay {}", s.id));
    assert!(fs::read_dir(d.join("sessions")).unwrap().next().is_none(), "a clean exit leaves no journal");
    // The replay reaches the same internal error, from the same model.
    let (out, ok) = run_child(&d, "replay");
    assert!(ok, "{out}");
    let r = printed(&out, "REPLAY ");
    assert_eq!(r["reproduced"], true, "{r}");
    assert_eq!(r["nodes"], 2, "the replay ends in the state the crash left: {r}");
    let _ = fs::remove_dir_all(&d);
}

#[test]
fn a_panic_caught_inside_a_command_is_reported_as_recovered() {
    let d = fresh_dir("recovered");
    let (_, ok) = run_child(&d, "recovered");
    assert!(ok);
    let (s, v) = only_report(&d);
    assert_eq!(s.kind, "recovered_panic");
    assert!(!s.replayable, "the command did not fail");
    assert!(v["message"].as_str().unwrap().contains("caught inside"), "{v}");
    let _ = fs::remove_dir_all(&d);
}

#[test]
fn a_panic_outside_commands_is_reported_from_the_journal() {
    let d = fresh_dir("thread");
    let (_, ok) = run_child(&d, "thread");
    assert!(ok);
    let (s, v) = only_report(&d);
    assert_eq!(s.kind, "panic");
    assert_eq!(v["thread"], "worker");
    assert!(s.message.contains("worker thread 42 failed"));
    // The journal's commands from a new model rebuild it.
    let replay: Value = serde_json::from_slice(&fs::read(v["replay_path"].as_str().unwrap()).unwrap()).unwrap();
    assert_eq!(replay["commands"].as_array().unwrap().len(), 2, "{replay}");
    // A panic the hook reported is no unclean exit at the next start.
    let (out, _) = run_child(&d, "abort");
    let fresh = printed(&out, "FRESH ");
    assert_eq!(fresh.as_array().unwrap().len(), 1, "the earlier report, seen once: {fresh}");
    let _ = fs::remove_dir_all(&d);
}

#[test]
fn an_unclean_exit_is_found_at_the_next_start_with_its_commands() {
    let d = fresh_dir("abort");
    let (_, ok) = run_child(&d, "abort");
    assert!(!ok, "the child aborted");
    assert!(list(&d).is_empty(), "nothing wrote a report while it died");
    assert_eq!(fs::read_dir(d.join("sessions")).unwrap().count(), 1, "its journal is left behind");
    let (out, ok) = run_child(&d, "idle");
    assert!(ok);
    let fresh = printed(&out, "FRESH ");
    assert_eq!(fresh[0]["kind"], "unclean_exit", "{fresh}");
    let (s, v) = only_report(&d);
    assert_eq!(s.command.as_deref(), Some("diagnostics.crash_test"), "the command in flight");
    assert!(s.message.contains("ended without a clean exit while running `diagnostics.crash_test`"), "{}", s.message);
    assert_eq!(v["last_activity"], "control ui.capture");
    let replay: Value = serde_json::from_slice(&fs::read(v["replay_path"].as_str().unwrap()).unwrap()).unwrap();
    let ids: Vec<&str> = replay["commands"].as_array().unwrap().iter().map(|c| c["command"].as_str().unwrap()).collect();
    assert_eq!(ids, ["mesh.node.add", "mesh.node.add", "diagnostics.crash_test"]);
    assert!(fs::read_dir(d.join("sessions")).unwrap().next().is_none(), "the dead journal is gone");
    // Told once: the next start offers nothing new.
    let (out, _) = run_child(&d, "idle");
    assert_eq!(printed(&out, "FRESH "), json!([]));
    let _ = fs::remove_dir_all(&d);
}

#[test]
fn an_unclean_exit_after_an_autosave_starts_from_the_autosave() {
    let d = fresh_dir("autosave");
    let (_, ok) = run_child(&d, "autosave");
    assert!(!ok);
    run_child(&d, "idle");
    let (s, v) = only_report(&d);
    assert_eq!(s.kind, "unclean_exit");
    assert!(s.message.contains("between commands (last: control ui.capture)"), "{}", s.message);
    assert_eq!(nodes_in(v["model_path"].as_str().unwrap()), 2, "the autosaved model");
    let replay: Value = serde_json::from_slice(&fs::read(v["replay_path"].as_str().unwrap()).unwrap()).unwrap();
    assert_eq!(replay["commands"], json!([{"command": "mesh.node.add", "params": node(3)}]), "only what came after the autosave");
    let (out, ok) = run_child(&d, "replay");
    assert!(ok, "{out}");
    assert_eq!(printed(&out, "REPLAY ")["nodes"], 3, "the replay rebuilds the model the app had");
    let _ = fs::remove_dir_all(&d);
}

#[test]
fn journals_parse_and_hostile_ids_are_refused() {
    let text = [
        r#"{"start":"x","pid":1,"version":"1"}"#,
        r#"{"base":"new"}"#,
        r#"{"run":"a","params":{}}"#,
        r#"{"ok":true}"#,
        r#"{"activity":"control ui.capture"}"#,
        r#"{"run":"b","params":{"x":1}}"#,
        r#"{"ok":false,"error":"no"}"#,
        "not json",
        r#"{"run":"c","params":{}}"#,
    ]
    .join("\n");
    let j = parse_journal(&text);
    assert_eq!(j.replay, vec![json!({"command": "a", "params": {}})]);
    assert_eq!(j.recent.len(), 2);
    assert_eq!(j.in_flight, Some(json!({"command": "c", "params": {}})));
    assert_eq!(j.activity.as_deref(), Some("control ui.capture"));
    assert!(j.complete && !j.reported);
    let d = fresh_dir("hostile");
    fs::create_dir_all(&d).unwrap();
    for id in ["", "../x", "a/b", &"f".repeat(65)] {
        assert!(read(&d, id).is_err(), "{id}");
        assert_eq!(clear(&d, Some(id)), 0);
    }
    let _ = fs::remove_dir_all(&d);
}

#[test]
fn signatures_ignore_numbers() {
    assert_eq!(signature("a.rs:1", "node 12 of 400"), signature("a.rs:1", "node 7 of 3"));
    assert_ne!(signature("a.rs:1", "node 12"), signature("a.rs:2", "node 12"));
    assert_eq!(utc(0), "1970-01-01T00:00:00Z");
    assert_eq!(stamp(1_760_436_000), "20251014-100000");
}

#[test]
fn reports_are_pruned_to_the_limits() {
    let d = fresh_dir("prune");
    for i in 0..(MAX_REPORTS + 5) {
        let id = format!("20261014-1000{:02}-{:016x}", i % 60, i + 1);
        fs::create_dir_all(d.join(&id)).unwrap();
        let kind = if i == MAX_REPORTS + 4 { "recovered_panic" } else { "panic" };
        fs::write(d.join(&id).join("report.json"), json!({"kind": kind, "message": "m"}).to_string()).unwrap();
    }
    prune(&d, now());
    let left = list(&d);
    assert_eq!(left.len(), MAX_REPORTS);
    assert!(left.iter().all(|r| r.kind == "panic"), "recovered ones go first");
    assert_eq!(clear(&d, None), MAX_REPORTS);
    let _ = fs::remove_dir_all(&d);
}