//! E2E coverage for the CLI surface of the canonical-type-names
//! validator. The unit tests in `workspace.rs` already prove the
//! validator fires; these tests prove the diagnostic survives the
//! `WorkspaceLoadError -> Diagnostic` translation in
//! `crates/ail/src/main.rs::workspace_error_to_diagnostic` AND is
//! observable on the CLI in both `--json` and human modes (exit code
//! + diagnostic code in the output stream).
//!
//! Companion to the happy-path test below: post-migration
//! `examples/ordering_match.ail.json` must `ail check` cleanly. If
//! someone reverts the migration (or breaks the canonical-form
//! acceptance path in the registry), that test goes red.

use ailang_test_support::examples_dir;
use std::path::PathBuf;
use std::process::Command;

fn ail_bin() -> PathBuf {
    // CARGO_BIN_EXE_<name> is set by cargo when building integration tests.
    PathBuf::from(env!("CARGO_BIN_EXE_ail"))
}

/// Property: a workspace whose entry module contains a bare
/// cross-module Type::Con / Term::Ctor reference — here `Mystery_Type`,
/// a name no module in the workspace declares (post-prep.1: in-scope
/// bare names are accepted, so the fixture uses an unresolvable name
/// to keep firing the diagnostic) — is rejected by `ail check --json`
/// with diagnostic code `bare-cross-module-type-ref` and non-zero
/// exit. Guards against `workspace_error_to_diagnostic` losing the
/// `BareCrossModuleTypeRef` arm or the validator no longer firing
/// through the CLI loader path.
#[test]
fn check_json_emits_bare_cross_module_type_ref() {
    let fixture = examples_dir().join("test_ct1_bare_xmod_rejected.ail.json");
    let output = Command::new(ail_bin())
        .args(["check", "--json", fixture.to_str().unwrap()])
        .output()
        .expect("ail binary must launch");
    assert!(
        !output.status.success(),
        "ail check must fail on bare cross-module ref; stdout={} stderr={}",
        String::from_utf8_lossy(&output.stdout),
        String::from_utf8_lossy(&output.stderr),
    );
    let stdout = String::from_utf8(output.stdout).expect("stdout is utf-8");
    let diags: serde_json::Value =
        serde_json::from_str(&stdout).expect("--json mode emits a JSON array on stdout");
    let arr = diags.as_array().expect("diagnostics is a JSON array");
    assert!(
        arr.iter().any(|d| d["code"] == "bare-cross-module-type-ref"),
        "expected `bare-cross-module-type-ref` in diagnostics array; got {stdout}"
    );
}

/// Property: a qualified `<owner>.<name>` Type::Con where `<owner>` is
/// not a known module is rejected by `ail check --json` with
/// diagnostic code `bad-cross-module-type-ref` and non-zero exit.
/// Guards against `workspace_error_to_diagnostic` losing the
/// `BadCrossModuleTypeRef` arm.
#[test]
fn check_json_emits_bad_cross_module_type_ref() {
    let fixture = examples_dir().join("test_ct1_bad_qualifier.ail.json");
    let output = Command::new(ail_bin())
        .args(["check", "--json", fixture.to_str().unwrap()])
        .output()
        .expect("ail binary must launch");
    assert!(
        !output.status.success(),
        "ail check must fail on unknown qualifier; stdout={} stderr={}",
        String::from_utf8_lossy(&output.stdout),
        String::from_utf8_lossy(&output.stderr),
    );
    let stdout = String::from_utf8(output.stdout).expect("stdout is utf-8");
    let diags: serde_json::Value =
        serde_json::from_str(&stdout).expect("--json mode emits a JSON array on stdout");
    let arr = diags.as_array().expect("diagnostics is a JSON array");
    assert!(
        arr.iter().any(|d| d["code"] == "bad-cross-module-type-ref"),
        "expected `bad-cross-module-type-ref` in diagnostics array; got {stdout}"
    );
}

/// Property: with class references in canonical form, a qualified class name in an `InstanceDef.class`
/// field is the canonical form, not a rejection. The
/// `test_ct1_qualified_class_rejected` fixture (declares
/// `instance prelude.Eq Int` outside prelude and outside Int's
/// defining module) is now rejected by the downstream coherence
/// check with `orphan-instance` instead of the pre-canonical-class-form
/// `qualified-class-name`. Guards against
/// `workspace_error_to_diagnostic` losing the OrphanInstance arm
/// AND against any regression that would reintroduce
/// `qualified-class-name` on a referencing field.
#[test]
fn check_json_emits_orphan_instance_on_xmod_class_without_coherence_post_mq1() {
    let fixture = examples_dir().join("test_ct1_qualified_class_rejected.ail.json");
    let output = Command::new(ail_bin())
        .args(["check", "--json", fixture.to_str().unwrap()])
        .output()
        .expect("ail binary must launch");
    assert!(
        !output.status.success(),
        "ail check must fail; stdout={} stderr={}",
        String::from_utf8_lossy(&output.stdout),
        String::from_utf8_lossy(&output.stderr),
    );
    let stdout = String::from_utf8(output.stdout).expect("stdout is utf-8");
    let diags: serde_json::Value =
        serde_json::from_str(&stdout).expect("--json mode emits a JSON array on stdout");
    let arr = diags.as_array().expect("diagnostics is a JSON array");
    assert!(
        arr.iter().any(|d| d["code"] == "orphan-instance"),
        "expected `orphan-instance` in diagnostics array; got {stdout}"
    );
    assert!(
        !arr.iter().any(|d| d["code"] == "qualified-class-name"),
        "must NOT fire `qualified-class-name` on a referencing field post-canonical-class-form; got {stdout}"
    );
}

/// Property: in non-JSON (human) mode `ail check` exits non-zero on a
/// canonical-type-form validator failure and writes an actionable error message to
/// stderr — naming both the offending type and the migration command
/// the author should run. Pinning the human-mode path separately
/// because in this mode the loader error short-circuits via `anyhow`
/// (no diagnostic-code prefix) and is formatted by the
/// `WorkspaceLoadError`'s `thiserror` Display impl rather than by
/// `workspace_error_to_diagnostic`. A regression that left `--json`
/// working but stripped the actionable hint from the human path
/// would otherwise ship unnoticed. The bare-cross-module fixture is
/// the representative case; the property — actionable hint in the
/// Display impl — is named per-variant.
#[test]
fn check_human_mode_emits_actionable_message_to_stderr() {
    let fixture = examples_dir().join("test_ct1_bare_xmod_rejected.ail.json");
    let output = Command::new(ail_bin())
        .args(["check", fixture.to_str().unwrap()])
        .output()
        .expect("ail binary must launch");
    assert!(
        !output.status.success(),
        "ail check (human mode) must fail on bare cross-module ref"
    );
    let stderr = String::from_utf8(output.stderr).expect("stderr is utf-8");
    assert!(
        stderr.contains("Mystery_Type"),
        "expected the offending type name in stderr; got {stderr}"
    );
    assert!(
        stderr.contains("not in scope"),
        "expected the narrowed not-in-scope wording in stderr; got {stderr}"
    );
}

/// Property: the post-migration `examples/ordering_match.ail.json`
/// (Term::Ctor `Ordering` -> `prelude.Ordering`) typechecks cleanly
/// through the CLI — `ail check` exits 0 with no diagnostics.
/// Guards against (a) a revert of the canonical-form migration, (b) a
/// regression in `Registry::normalize_type_for_lookup` that would make
/// the canonical (qualified) form fail to dispatch where the bare
/// form used to succeed.
#[test]
fn check_ordering_match_post_migration_is_clean() {
    let fixture = examples_dir().join("ordering_match.ail");
    let output = Command::new(ail_bin())
        .args(["check", "--json", fixture.to_str().unwrap()])
        .output()
        .expect("ail binary must launch");
    assert!(
        output.status.success(),
        "ail check must succeed on migrated ordering_match; stdout={} stderr={}",
        String::from_utf8_lossy(&output.stdout),
        String::from_utf8_lossy(&output.stderr),
    );
    let stdout = String::from_utf8(output.stdout).expect("stdout is utf-8");
    let diags: serde_json::Value =
        serde_json::from_str(&stdout).expect("--json mode emits a JSON array on stdout");
    let arr = diags.as_array().expect("diagnostics is a JSON array");
    assert!(
        arr.is_empty(),
        "expected zero diagnostics on migrated fixture; got {stdout}"
    );
}

/// Property: in non-JSON (human) mode, the human-stderr formatter
/// prepends the diagnostic code exactly once as the canonical
/// `[code]` bracket prefix (the cli-diag-human format). The
/// `loop-binder-captured-by-lambda` `CheckError` Display body must
/// NOT also embed `[code] ` inside its `thiserror` Display body,
/// which would render the bracketed code TWICE in the user-visible
/// stderr line (`error: [code] fn: [code] message`).
///
/// This pins the *observable* doubling on the real CLI human path
/// (`crates/ail/src/main.rs` non-JSON `Cmd::Check` arm), not the raw
/// Display string of the variant in isolation: it counts occurrences
/// of the literal `[<code>]` token in the rendered stderr and
/// requires exactly one (the formatter supplies it; the Display body
/// must not also embed it).
#[test]
fn check_human_mode_renders_loop_binder_diagnostic_code_exactly_once() {
    let cases = [
        (
            "test_loop_binder_captured_by_lambda.ail.json",
            "loop-binder-captured-by-lambda",
        ),
    ];
    for (fixture_name, code) in cases {
        let fixture = examples_dir().join(fixture_name);
        let output = Command::new(ail_bin())
            .args(["check", fixture.to_str().unwrap()])
            .output()
            .expect("ail binary must launch");
        assert!(
            !output.status.success(),
            "ail check (human mode) must fail on {fixture_name}"
        );
        let stderr = String::from_utf8(output.stderr).expect("stderr is utf-8");
        // The canonical cli-diag-human prefix is `[<code>]`. It must
        // appear exactly once in the rendered human diagnostic — the
        // formatter supplies it; the Display body must not also embed it.
        let needle = format!("[{code}]");
        let occurrences = stderr.matches(&needle).count();
        assert_eq!(
            occurrences, 1,
            "expected `[{code}]` exactly once in human stderr, found {occurrences}; \
             full stderr:\n{stderr}"
        );
    }
}

/// loop-recur iter 2: the four `Recur*` Display bodies must be
/// bracket-`[code]`-free (F2 convention) — the human-mode
/// formatter supplies `[<code>]` exactly once. Same observable
/// property as the mut sibling, over the four recur negatives.
#[test]
fn check_human_mode_renders_recur_diagnostic_code_exactly_once() {
    let cases = [
        ("test_recur_outside_loop.ail.json", "recur-outside-loop"),
        ("test_recur_arity_mismatch.ail.json", "recur-arity-mismatch"),
        ("test_recur_type_mismatch.ail.json", "recur-type-mismatch"),
        (
            "test_recur_not_in_tail_position.ail.json",
            "recur-not-in-tail-position",
        ),
    ];
    for (fixture_name, code) in cases {
        let fixture = examples_dir().join(fixture_name);
        let output = Command::new(ail_bin())
            .args(["check", fixture.to_str().unwrap()])
            .output()
            .expect("ail binary must launch");
        assert!(
            !output.status.success(),
            "ail check (human mode) must fail on {fixture_name}"
        );
        let stderr = String::from_utf8(output.stderr).expect("stderr is utf-8");
        let needle = format!("[{code}]");
        let occurrences = stderr.matches(&needle).count();
        assert_eq!(
            occurrences, 1,
            "expected `[{code}]` exactly once in human stderr, found {occurrences}; \
             full stderr:\n{stderr}"
        );
    }
}

/// Property: `ail check --json` on a `.ail` (Form A) source file with
/// a syntax error returns a structured `surface-parse-error`
/// diagnostic (non-empty diagnostics array, exit code != 0), rather
/// than crashing with the misleading JSON-parse fall-through that
/// ext-cli.1 was built to eliminate. Guards against
/// `workspace_error_to_diagnostic` losing the `SurfaceParse` arm or
/// the surface dispatcher silently swallowing the parse error.
#[test]
fn ail_check_json_on_ail_with_syntax_error_returns_structured_diagnostic() {
    let tmp = tempfile::tempdir().expect("tempdir");
    let bad = tmp.path().join("bad.ail");
    // Deliberately broken — missing closing paren in the module header.
    std::fs::write(&bad, "(module bad\n").expect("write");

    let output = Command::new(ail_bin())
        .args(["check", "--json", bad.to_str().unwrap()])
        .output()
        .expect("run ail check --json");

    // ail check --json on a bad .ail should NOT crash with the misleading
    // JSON-parse fall-through; it should return exit code != 0 and emit a
    // parseable JSON diagnostic on stdout.
    assert!(
        !output.status.success(),
        "expected non-zero exit on bad source; stdout={} stderr={}",
        String::from_utf8_lossy(&output.stdout),
        String::from_utf8_lossy(&output.stderr),
    );

    let stdout = String::from_utf8(output.stdout).expect("stdout is UTF-8");
    let parsed: serde_json::Value = serde_json::from_str(&stdout)
        .unwrap_or_else(|e| panic!("stdout not valid JSON: {e}\ngot:\n{stdout}"));

    let diags = parsed.as_array().expect("diagnostics array");
    assert!(!diags.is_empty(), "at least one diagnostic emitted");
    let first = &diags[0];
    assert_eq!(first["code"].as_str(), Some("surface-parse-error"));
    // The offending path goes into the ctx payload (matching the
    // shape every other workspace-error diagnostic uses, e.g.
    // `schema-mismatch` puts `expected`/`actual` there).
    assert!(first["ctx"]["path"].is_string(), "ctx.path is the file path");
    assert!(first["message"].is_string(), "message is the formatted ParseError");
}
