//! Workspace-load pin tests, relocated from `ailang-core/src/workspace.rs`
//! `#[cfg(test)] mod tests` to a `tests/*` integration crate in iter
//! form-a.1 Task 5. The relocation switches each test from
//! `ailang_core::load_workspace` (the JSON-only loader) to
//! `ailang_surface::load_workspace` (the extension-dispatching superset),
//! so the post-iter `.ail` corpus is loaded from Form A rather than the
//! deleted `.ail.json` siblings.
//!
//! pd.2 extension: the second batch (10 tests at the end of this file)
//! is relocated from `ailang-core/src/workspace.rs::tests` because pd.2
//! deletes the `load_workspace_with` shim those tests depended on.
//! Their post-pd.2 successor is `ailang_surface::load_workspace`, which
//! is unreachable from `ailang-core` lib-tests due to the dev-dep cycle
//! (`ailang-core` dev-deps `ailang-surface` which depends on
//! `ailang-core` — fine for integration tests, breaks lib-tests). The
//! integration-test crate is the right home: it consumes both crates
//! against the same `ailang-core` artefact, so the cycle never
//! materialises.

use ailang_core::workspace::{Registry, RegistryEntry, WorkspaceLoadError};
use ailang_surface::load_workspace;
use ailang_test_support::examples_dir;
use std::path::{Path, PathBuf};

// Adapter so this integration crate can call `load_modules_with` with
// the same Io/Schema mapping the in-mod test helper used.
fn load_one_adapter(path: &Path) -> Result<ailang_core::ast::Module, WorkspaceLoadError> {
    match ailang_core::load_module(path) {
        Ok(m) => Ok(m),
        Err(ailang_core::Error::Io(e)) => Err(WorkspaceLoadError::Io {
            path: path.to_path_buf(),
            source: e,
        }),
        Err(e) => Err(WorkspaceLoadError::Schema {
            path: path.to_path_buf(),
            source: e,
        }),
    }
}


#[test]
fn loads_example_workspace_happy_path() {
    let entry = examples_dir().join("ws_main.ail");
    let ws = load_workspace(&entry).expect("load workspace");
    assert_eq!(ws.entry, "ws_main");
    assert!(ws.modules.contains_key("ws_main"));
    assert!(ws.modules.contains_key("ws_lib"));
    // the loader auto-injects two built-in kernel-tier modules
    // (`prelude` and `raw_buf`, the first real-payload kernel
    // extension, raw-buf.4), so the count is the user's two modules
    // plus those two.
    assert_eq!(ws.modules.len(), 4);
    assert!(ws.modules.contains_key("prelude"));
    assert!(ws.modules.contains_key("raw_buf"));
}

#[test]
fn loads_workspace_auto_injects_prelude() {
    // the prelude module is implicitly part of every
    // workspace, regardless of whether the user's modules import
    // it. Loading any well-formed workspace must result in
    // `ws.modules["prelude"]` being present with the Ordering
    // type def.
    let entry = examples_dir().join("ws_main.ail");
    let ws = load_workspace(&entry).expect("load workspace");
    assert!(
        ws.modules.contains_key("prelude"),
        "prelude module must be auto-injected; modules present: {:?}",
        ws.modules.keys().collect::<Vec<_>>()
    );
    let prelude = &ws.modules["prelude"];
    assert_eq!(prelude.name, "prelude");
    assert!(
        prelude.defs.iter().any(|d| matches!(
            d,
            ailang_core::ast::Def::Type(t) if t.name == "Ordering"
        )),
        "prelude must contain Ordering type def"
    );

    // prelude also ships the `Eq` class plus three
    // primitive instances (Eq Int, Eq Bool, Eq Str).
    assert!(
        prelude.defs.iter().any(|d| matches!(
            d,
            ailang_core::ast::Def::Class(c) if c.name == "Eq"
        )),
        "prelude must contain Eq class def"
    );
    let eq_instance_types: Vec<&str> = prelude
        .defs
        .iter()
        .filter_map(|d| match d {
            ailang_core::ast::Def::Instance(i) if i.class == "Eq" => {
                if let ailang_core::ast::Type::Con { name, .. } = &i.type_ {
                    Some(name.as_str())
                } else {
                    None
                }
            }
            _ => None,
        })
        .collect();
    assert!(
        eq_instance_types.contains(&"Int"),
        "prelude must contain `instance Eq Int`; saw Eq instances on: {eq_instance_types:?}"
    );
    assert!(
        eq_instance_types.contains(&"Bool"),
        "prelude must contain `instance Eq Bool`; saw Eq instances on: {eq_instance_types:?}"
    );
    assert!(
        eq_instance_types.contains(&"Str"),
        "prelude must contain `instance Eq Str`; saw Eq instances on: {eq_instance_types:?}"
    );

    // prelude also ships the `Ord` class plus three
    // primitive instances (Ord Int, Ord Bool, Ord Str).
    assert!(
        prelude.defs.iter().any(|d| matches!(
            d,
            ailang_core::ast::Def::Class(c) if c.name == "Ord"
        )),
        "prelude must contain Ord class def"
    );
    let ord_instance_types: Vec<&str> = prelude
        .defs
        .iter()
        .filter_map(|d| match d {
            ailang_core::ast::Def::Instance(i) if i.class == "Ord" => {
                if let ailang_core::ast::Type::Con { name, .. } = &i.type_ {
                    Some(name.as_str())
                } else {
                    None
                }
            }
            _ => None,
        })
        .collect();
    assert!(
        ord_instance_types.contains(&"Int"),
        "prelude must contain `instance Ord Int`; saw: {ord_instance_types:?}"
    );
    assert!(
        ord_instance_types.contains(&"Bool"),
        "prelude must contain `instance Ord Bool`; saw: {ord_instance_types:?}"
    );
    assert!(
        ord_instance_types.contains(&"Str"),
        "prelude must contain `instance Ord Str`; saw: {ord_instance_types:?}"
    );
}

#[test]
fn iter22b1_workspace_with_no_classes_has_empty_registry() {
    let entry = examples_dir().join("sum.ail");
    let ws = load_workspace(&entry).expect("sum.ail loads");
    assert!(
        ws.registry.entries.values().all(|e: &RegistryEntry| e.defining_module == "prelude"),
        "pre-22b fixture has no class/instance defs of its own; \
         all registry entries must come from the auto-injected prelude. \
         got non-prelude entries: {:?}",
        ws.registry.entries.values()
            .filter(|e| e.defining_module != "prelude")
            .map(|e| &e.defining_module)
            .collect::<Vec<_>>()
    );
    // Silence unused-import warning for `Registry`; the type is named
    // in the test only via the field-access path above.
    let _: Option<&Registry> = None;
}

#[test]
fn iter22b1_instance_in_class_module_loads_clean() {
    let entry = examples_dir().join("test_22b1_orphan_class.ail");
    let ws = load_workspace(&entry).expect("coherent instance loads");
    let fixture_entries: Vec<_> = ws.registry.entries.iter()
        .filter(|(_, e)| e.defining_module != "prelude")
        .collect();
    assert_eq!(fixture_entries.len(), 1);
    let (key, entry) = fixture_entries[0];
    // registry key is keyed by the qualified class name.
    // 24.2: class renamed `Show` → `TShow` workspace-wide.
    assert_eq!(&key.0, "test_22b1_orphan_class.TShow");
    assert_eq!(entry.defining_module, "test_22b1_orphan_class");
    // `instance.class` carries the canonical-form on-disk value
    // (bare for same-module per the canonical-form rule).
    assert_eq!(entry.instance.class, "TShow");
}

/// an instance declared in a module that is neither
/// the class's module nor the type's module fires `OrphanInstance`.
#[test]
fn iter22b1_orphan_instance_fires_diagnostic() {
    let entry = examples_dir().join("test_22b1_orphan_third.ail");
    let err = load_workspace(&entry).expect_err("must fire orphan");
    match err {
        WorkspaceLoadError::OrphanInstance {
            class,
            type_repr,
            defining_module,
            ..
        } => {
            assert_eq!(class, "test_22b1_orphan_third_classmod.TShow");
            assert_eq!(type_repr, "Int");
            assert_eq!(defining_module, "test_22b1_orphan_third");
        }
        other => panic!("expected OrphanInstance, got {other:?}"),
    }
}

/// two instances of the same `(class, type)` pair
/// collide on the registry's uniqueness check. Post-canonical-class-form both
/// instances must live in the class's or the type's module (see
/// fixture).
#[test]
fn iter22b1_duplicate_instance_fires_diagnostic() {
    let entry = examples_dir().join("test_22b1_dup_same_module.ail");
    let err = load_workspace(&entry).expect_err("must fire duplicate");
    match err {
        WorkspaceLoadError::DuplicateInstance {
            class,
            type_repr,
            first_module,
            second_module,
        } => {
            assert_eq!(class, "TShow");
            assert_eq!(type_repr, "Int");
            assert_eq!(first_module, "test_22b1_dup_same_module");
            assert_eq!(second_module, "test_22b1_dup_same_module");
        }
        other => panic!("expected DuplicateInstance, got {other:?}"),
    }
}

/// an instance that omits a required (non-default) method
/// of its class fires `MissingMethod`.
#[test]
fn iter22b1_missing_method_fires_diagnostic() {
    let entry = examples_dir().join("test_22b1_missing_method.ail");
    let err = load_workspace(&entry).expect_err("must fire missing-method");
    match err {
        WorkspaceLoadError::MissingMethod {
            class,
            type_repr,
            method,
        } => {
            assert_eq!(class, "TEq");
            assert_eq!(type_repr, "Int");
            assert_eq!(method, "teq");
        }
        other => panic!("expected MissingMethod, got {other:?}"),
    }
}

/// an instance that specifies a body for a method name the
/// class never declared must fire `OverridingNonExistentMethod`.
/// (`test_22b2_overriding_nonexistent` is NOT a §C4 carve-out — it
/// stays as a `.ail`-loadable fixture.)
#[test]
fn instance_overriding_nonexistent_method_fires() {
    let entry = examples_dir().join("test_22b2_overriding_nonexistent.ail");
    let err = load_workspace(&entry)
        .expect_err("must fire overriding-non-existent-method");
    match err {
        WorkspaceLoadError::OverridingNonExistentMethod {
            class, type_repr, method,
        } => {
            assert_eq!(class, "TEq");
            assert_eq!(type_repr, "Int");
            assert_eq!(method, "ne");
        }
        other => panic!("expected OverridingNonExistentMethod, got {other:?}"),
    }
}

/// an instance `C T` whose class `C` declares a superclass
/// `S` requires that `instance S T` also exist in the workspace.
#[test]
fn instance_without_superclass_instance_fires() {
    let entry = examples_dir().join("test_22b2_missing_superclass_instance.ail");
    let err = load_workspace(&entry)
        .expect_err("must fire missing-superclass-instance");
    match err {
        WorkspaceLoadError::MissingSuperclassInstance {
            class, superclass, type_repr,
        } => {
            assert_eq!(class, "test_22b2_missing_superclass_instance.TOrd");
            assert_eq!(superclass, "TEq");
            assert_eq!(type_repr, "Int");
        }
        other => panic!("expected MissingSuperclassInstance, got {other:?}"),
    }
}

/// positive on-disk pair where `Constraint.class` references a
/// class in an imported module via the qualified form loads cleanly.
#[test]
fn mq1_xmod_constraint_class_fixture_loads() {
    let entry = examples_dir().join("mq1_xmod_constraint_class.ail");
    let ws = load_workspace(&entry)
        .expect("workspace must load with qualified Constraint.class");
    assert!(ws.modules.contains_key("mq1_xmod_constraint_class"));
    assert!(ws.modules.contains_key("mq1_xmod_constraint_class_dep"));
}

// ---------------------------------------------------------------------
// pd.2 relocations from `ailang-core/src/workspace.rs::tests` (the
// post-shim-retirement batch). Each test below was a `load_workspace_with`
// caller in the in-mod tests; post-pd.2 the shim is gone and these
// tests now go through `ailang_surface::load_workspace` (which composes
// `load_modules_with` + caller-side prelude inject + `build_workspace`).
//
// `tmp_dir` + `write_module` helpers are inlined per-test to keep each
// test self-contained at integration-test scope.
// ---------------------------------------------------------------------

fn write_simple_module_json(dir: &Path, name: &str, imports: &[&str]) -> PathBuf {
    use std::fs;
    let imports_json: Vec<serde_json::Value> = imports
        .iter()
        .map(|m| serde_json::json!({ "module": m }))
        .collect();
    let module = serde_json::json!({
        "schema": "ailang/v0",
        "name": name,
        "imports": imports_json,
        "defs": [],
    });
    let path = dir.join(format!("{name}.ail.json"));
    fs::write(&path, serde_json::to_vec_pretty(&module).unwrap()).unwrap();
    path
}

/// the loader auto-injects a module named
/// "prelude", so a user module that also claims that name would collide
/// silently. The collision is caught explicitly with `ReservedModuleName`.
#[test]
fn user_module_named_prelude_is_rejected() {
    let dir = tempfile::tempdir().unwrap();
    let entry = write_simple_module_json(dir.path(), "prelude", &[]);

    let err = load_workspace(&entry).expect_err("must reject user prelude");
    match err {
        WorkspaceLoadError::ReservedModuleName { name } => {
            assert_eq!(name, "prelude");
        }
        other => panic!("expected ReservedModuleName, got: {other:?}"),
    }
}

/// pd.2 relocation: workspace import-cycle detection.
#[test]
fn detects_import_cycle() {
    let dir = tempfile::tempdir().unwrap();
    write_simple_module_json(dir.path(), "a", &["b"]);
    write_simple_module_json(dir.path(), "b", &["a"]);
    let entry = dir.path().join("a.ail.json");

    let err = load_workspace(&entry).expect_err("must error on cycle");
    match err {
        WorkspaceLoadError::Cycle { path } => {
            assert!(path.contains(&"a".to_string()));
            assert!(path.contains(&"b".to_string()));
        }
        other => panic!("expected Cycle, got {other:?}"),
    }
}

/// pd.2 relocation: a missing imported module yields a structured
/// `ModuleNotFound` error naming the absent name + the path that was
/// searched.
#[test]
fn module_not_found_yields_structured_error() {
    let dir = tempfile::tempdir().unwrap();
    write_simple_module_json(dir.path(), "main", &["does_not_exist"]);
    let entry = dir.path().join("main.ail.json");

    let err = load_workspace(&entry).expect_err("must error on missing module");
    match err {
        WorkspaceLoadError::ModuleNotFound { name, expected_path } => {
            assert_eq!(name, "does_not_exist");
            assert!(expected_path.ends_with("does_not_exist.ail.json"));
        }
        other => panic!("expected ModuleNotFound, got {other:?}"),
    }
}

/// pd.2 relocation: §C4 (a) carve-out fixture
/// `test_22b2_kind_mismatch.ail.json` — class param appearing in
/// applied position fires the canonical-form rejection
/// (`BareCrossModuleTypeRef`).
#[test]
fn class_param_in_applied_position_fires_canonical_form_rejection() {
    let entry = examples_dir().join("test_22b2_kind_mismatch.ail.json");
    let err = load_workspace(&entry)
        .expect_err("must fire canonical-form rejection");
    match err {
        WorkspaceLoadError::BareCrossModuleTypeRef { module, name, .. } => {
            assert_eq!(module, "test_22b2_kind_mismatch");
            assert_eq!(name, "f");
        }
        other => panic!(
            "expected BareCrossModuleTypeRef (validator now fires first), got {other:?}",
        ),
    }
}

/// pd.2 relocation: §C4 (a) carve-out fixture
/// `test_22b2_invalid_superclass_param.ail.json` — `class Ord a extends
/// Eq b` shape fires `InvalidSuperclassParam`.
#[test]
fn superclass_with_wrong_param_fires_invalid_superclass_param() {
    let entry = examples_dir().join("test_22b2_invalid_superclass_param.ail.json");
    let err = load_workspace(&entry)
        .expect_err("must fire invalid-superclass-param");
    match err {
        WorkspaceLoadError::InvalidSuperclassParam {
            class, superclass, expected_param, got_type,
        } => {
            assert_eq!(class, "Ord");
            assert_eq!(superclass, "Eq");
            assert_eq!(expected_param, "a");
            assert_eq!(got_type, "b");
        }
        other => panic!("expected InvalidSuperclassParam, got {other:?}"),
    }
}

/// pd.2 relocation: §C4 (a) carve-out fixture
/// `test_22b2_unbound_constraint_var.ail.json` — class method
/// `Type::Forall.constraints` referencing an unbound type var fires
/// `UnboundConstraintTypeVar`.
#[test]
fn constraint_with_unbound_var_fires_unbound_constraint_type_var() {
    let entry = examples_dir().join("test_22b2_unbound_constraint_var.ail.json");
    let err = load_workspace(&entry)
        .expect_err("must fire constraint-references-unbound-type-var");
    match err {
        WorkspaceLoadError::UnboundConstraintTypeVar {
            class, method, var, ..
        } => {
            assert_eq!(class, "Foo");
            assert_eq!(method, "foo");
            assert_eq!(var, "z");
        }
        other => panic!("expected UnboundConstraintTypeVar, got {other:?}"),
    }
}

/// pd.2 relocation, prep.1 fixture-flip: §C4 (a) carve-out fixture
/// `test_ct1_bare_xmod_rejected.ail.json`. Pre-prep.1 the fixture used
/// bare `Ordering` and the validator caught it via prelude-as-candidate.
/// Post-prep.1 a bare in-scope type-name (`Ordering` from implicit
/// prelude) is ACCEPTED, so the fixture was switched to a name no
/// module declares (`Mystery_Type`); the rejection path still fires
/// `BareCrossModuleTypeRef` but the candidates list is empty.
#[test]
fn ct1_fixture_bare_xmod_rejected() {
    let entry = examples_dir().join("test_ct1_bare_xmod_rejected.ail.json");
    let err = load_workspace(&entry).expect_err("must reject bare Mystery_Type");
    match err {
        WorkspaceLoadError::BareCrossModuleTypeRef { module, name, candidates } => {
            assert_eq!(module, "test_ct1_bare_xmod_rejected");
            assert_eq!(name, "Mystery_Type");
            assert!(
                candidates.is_empty(),
                "no module declares Mystery_Type => candidates empty; got {candidates:?}"
            );
        }
        other => panic!("expected BareCrossModuleTypeRef, got {other:?}"),
    }
}

/// pd.2 relocation: §C4 (a) carve-out fixture
/// `test_ct1_bad_qualifier.ail.json` — qualified `Mystery.Type` with
/// `Mystery` not a known module fires `BadCrossModuleTypeRef`.
#[test]
fn ct1_fixture_bad_qualifier() {
    let entry = examples_dir().join("test_ct1_bad_qualifier.ail.json");
    let err = load_workspace(&entry).expect_err("must reject Mystery.Type");
    match err {
        WorkspaceLoadError::BadCrossModuleTypeRef { module, name } => {
            assert_eq!(module, "test_ct1_bad_qualifier");
            assert_eq!(name, "Mystery.Type");
        }
        other => panic!("expected BadCrossModuleTypeRef, got {other:?}"),
    }
}

/// pd.2 relocation: §C4 (a) carve-out fixture
/// `test_ct1_qualified_class_rejected.ail.json` — declares
/// `instance prelude.Eq Int` outside the prelude AND outside Int's
/// defining module; post-canonical-class-form the qualified class-ref is schema-valid
/// and the downstream coherence check rejects with `OrphanInstance`.
#[test]
fn ct1_fixture_qualified_class_orphan_post_mq1() {
    let entry = examples_dir().join("test_ct1_qualified_class_rejected.ail.json");
    let err = load_workspace(&entry).expect_err("must reject (now as Orphan)");
    match err {
        WorkspaceLoadError::OrphanInstance {
            class, type_repr, defining_module, ..
        } => {
            assert_eq!(class, "prelude.Eq");
            assert_eq!(type_repr, "Int");
            assert_eq!(defining_module, "test_ct1_qualified_class_rejected");
        }
        other => panic!("expected OrphanInstance, got {other:?}"),
    }
}

/// pd.1 Task 2 + pd.3 Task 1 relocation: `build_workspace` accepts a
/// pre-assembled modules map (with the caller having already injected
/// any implicit modules) and runs the three-stage validation pipeline.
/// The `implicit_imports` slice is what the diagnostic helpers consult
/// for fallback candidate suggestions. Relocated from the in-mod
/// `tests` of `ailang-core/src/workspace.rs` because the caller-side
/// prelude inject now uses `ailang_surface::parse_prelude()`, which
/// only typechecks across the dev-dep edge from the integration-test
/// crate (the lib-test crate sees two distinct `ailang-core`
/// compilations and fails to unify the `Module` types).
#[test]
fn build_workspace_accepts_assembled_modules_and_runs_validation() {
    let dir = tempfile::tempdir().unwrap();
    write_simple_module_json(dir.path(), "main", &[]);
    let entry = dir.path().join("main.ail.json");

    let (entry_name, root_dir, mut modules) =
        ailang_core::workspace::load_modules_with(&entry, load_one_adapter)
            .expect("load");

    // Caller-side prelude inject — surface owns the production inject
    // path; this test consumes it via the dev-dep edge to demonstrate
    // the caller-injects pattern with the same source of truth.
    let prelude = ailang_surface::parse_prelude();
    modules.insert("prelude".to_string(), prelude);

    let ws = ailang_core::workspace::build_workspace(
        entry_name,
        root_dir,
        modules,
        &["prelude"],
    )
    .expect("build");

    assert_eq!(ws.entry, "main");
    assert!(ws.modules.contains_key("main"));
    assert!(ws.modules.contains_key("prelude"));
}