//! IR deserialization tests against the AFI fixture (KDL).
//!
//! The fixture is captured from `cores/mizan-python/src/mizan_core/ir.py::build_ir()`
//! against `tests/afi/fixture.py`. Each test exercises a different facet
//! of the IR — function set, per-function field decoding, context-param
//! elevation, and named-type presence — to confirm the typed Rust structs
//! match the KDL shape the backend emits.

use std::path::PathBuf;

use mizan_codegen::fetch::parse_ir_from_str;
use mizan_codegen::ir::{AffectKind, IsContext, NamedType, Primitive, Transport};


fn load_fixture() -> mizan_codegen::ir::MizanIR {
    let path = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
        .join("tests/fixtures/afi_ir.kdl");
    let raw = std::fs::read_to_string(&path)
        .unwrap_or_else(|e| panic!("read {}: {e}", path.display()));
    parse_ir_from_str(&raw).unwrap_or_else(|e| panic!("parse IR: {e}"))
}


#[test]
fn afi_fixture_deserializes_function_set() {
    let ir = load_fixture();
    let names: Vec<&str> = ir.functions.iter().map(|f| f.name.as_str()).collect();

    assert_eq!(ir.functions.len(), 7, "expected 7 functions, got {}: {names:?}", ir.functions.len());

    for expected in [
        "echo", "whoami",
        "user_profile", "user_orders",
        "update_profile", "find_user", "rename_user",
    ] {
        assert!(names.contains(&expected), "missing function {expected:?} in {names:?}");
    }
}


#[test]
fn afi_fixture_function_field_decode() {
    let ir = load_fixture();
    let echo = ir.functions.iter().find(|f| f.name == "echo").unwrap();
    assert_eq!(echo.camel_name, "echo");
    assert!(echo.has_input);
    assert_eq!(echo.input_type.as_deref(), Some("echoInput"));
    assert_eq!(echo.output_type, "echoOutput");
    assert!(!echo.output_nullable);
    assert_eq!(echo.transport, Transport::Http);
    assert_eq!(echo.is_context, IsContext::No);

    let whoami = ir.functions.iter().find(|f| f.name == "whoami").unwrap();
    assert!(!whoami.has_input);

    // `find_user` returns `ProfileOutput | None` — outputNullable must be true.
    let find_user = ir.functions.iter().find(|f| f.name == "find_user").unwrap();
    assert!(find_user.output_nullable, "find_user must be outputNullable");

    // Context-typed function picks up the context name.
    let user_profile = ir.functions.iter().find(|f| f.name == "user_profile").unwrap();
    assert_eq!(user_profile.is_context.as_str(), Some("user"));

    // Mutation with `affects="user"` lands in `affects` as a context target.
    let update_profile = ir.functions.iter().find(|f| f.name == "update_profile").unwrap();
    assert_eq!(update_profile.affects.len(), 1);
    assert_eq!(update_profile.affects[0].kind, AffectKind::Context);
    assert_eq!(update_profile.affects[0].name, "user");

    // Mutation with `merge="user"`.
    let rename_user = ir.functions.iter().find(|f| f.name == "rename_user").unwrap();
    assert_eq!(rename_user.merge, vec!["user".to_string()]);
}


#[test]
fn afi_fixture_context_param_elevation() {
    let ir = load_fixture();
    let user = ir.contexts.get("user").expect("user context group");

    // Both context functions share `user_id` as a required param.
    let user_id = user.params.get("user_id").expect("user_id param");
    assert_eq!(user_id.ty, Primitive::Integer);
    assert!(user_id.required, "user_id is required (declared by every fn in the group)");
    assert!(user_id.shared_by.contains(&"user_profile".to_string()));
    assert!(user_id.shared_by.contains(&"user_orders".to_string()));
}


#[test]
fn afi_fixture_named_types_present() {
    let ir = load_fixture();
    // Every IR function references its <camelName>Input / <camelName>Output
    // type by name; the IR's `type` section must declare each as a named
    // type (struct, alias to a list, etc.).
    for expected in [
        "echoInput", "echoOutput",
        "whoamiOutput",
        "userProfileInput", "userProfileOutput",
        "userOrdersInput",
        "updateProfileInput", "updateProfileOutput",
        "findUserInput", "findUserOutput",
        "renameUserInput", "renameUserOutput",
    ] {
        let ty = ir.types.get(expected)
            .unwrap_or_else(|| panic!("missing type {expected:?}"));
        // Each named type is one of the four KDL shapes — sanity-check
        // we round-tripped a non-trivial declaration.
        match ty {
            NamedType::Struct(_) | NamedType::List(_) | NamedType::Enum(_) | NamedType::Alias(_) => {}
        }
    }
}
