use nxc_frontend::{analyze, Lexer, Parser};

fn analyze_source(source: &str) -> nxc_frontend::SemanticResult {
    let lexed = Lexer::new(source).lex();
    assert!(
        lexed.diagnostics.is_empty(),
        "unexpected lexer diagnostics: {:?}",
        lexed.diagnostics
    );

    let parsed = Parser::new(lexed.tokens).parse_module();
    assert!(
        parsed.diagnostics.is_empty(),
        "unexpected parser diagnostics: {:?}",
        parsed.diagnostics
    );

    analyze(&parsed.module)
}

fn messages(result: &nxc_frontend::SemanticResult) -> Vec<String> {
    result
        .diagnostics
        .iter()
        .map(|diagnostic| diagnostic.message.clone())
        .collect()
}

#[test]
fn rejects_duplicate_function_names() {
    let result = analyze_source(
        "\
fn main() -> Int:
    return 0

fn main() -> Int:
    return 1
",
    );

    assert!(messages(&result).iter().any(|msg| msg.contains("duplicate function `main`")));
}

#[test]
fn rejects_duplicate_parameter_names() {
    let result = analyze_source(
        "\
fn main(value: Int, value: Int) -> Int:
    return value
",
    );

    assert!(messages(&result)
        .iter()
        .any(|msg| msg.contains("duplicate parameter `value`")));
}

#[test]
fn rejects_duplicate_local_bindings_in_same_scope() {
    let result = analyze_source(
        "\
fn main() -> Int:
    let value = 1
    let value = 2
    return value
",
    );

    assert!(messages(&result)
        .iter()
        .any(|msg| msg.contains("duplicate binding `value`")));
}

#[test]
fn rejects_unknown_identifiers() {
    let result = analyze_source(
        "\
fn main() -> Int:
    return missing
",
    );

    assert!(messages(&result)
        .iter()
        .any(|msg| msg.contains("unknown identifier `missing`")));
}

#[test]
fn rejects_unknown_function_calls() {
    let result = analyze_source(
        "\
fn main() -> Int:
    return missing(1)
",
    );

    assert!(messages(&result)
        .iter()
        .any(|msg| msg.contains("unknown function `missing`")));
}

#[test]
fn rejects_invalid_unary_operator_types() {
    let result = analyze_source(
        "\
fn main() -> Int:
    return -true
",
    );

    assert!(messages(&result)
        .iter()
        .any(|msg| msg.contains("unary `-` expects `Int` or `Float`")));
}

#[test]
fn rejects_invalid_binary_operator_types() {
    let result = analyze_source(
        "\
fn main() -> Int:
    return true + 1
",
    );

    assert!(messages(&result)
        .iter()
        .any(|msg| msg.contains("operator `+` expects numeric operands")));
}

#[test]
fn rejects_invalid_if_condition_types() {
    let result = analyze_source(
        "\
fn main() -> Int:
    if 1:
        return 0
    else:
        return 1
",
    );

    assert!(messages(&result)
        .iter()
        .any(|msg| msg.contains("if condition must be `Bool`")));
}

#[test]
fn rejects_wrong_call_arity() {
    let result = analyze_source(
        "\
fn add(a: Int, b: Int) -> Int:
    return a + b

fn main() -> Int:
    return add(1)
",
    );

    assert!(messages(&result)
        .iter()
        .any(|msg| msg.contains("expects 2 argument(s), found 1")));
}

#[test]
fn rejects_wrong_call_argument_types() {
    let result = analyze_source(
        "\
fn negate(value: Int) -> Int:
    return -value

fn main() -> Int:
    return negate(true)
",
    );

    assert!(messages(&result)
        .iter()
        .any(|msg| msg.contains("parameter `value` expects `Int`, found `Bool`")));
}

#[test]
fn rejects_return_type_mismatch() {
    let result = analyze_source(
        "\
fn main() -> Int:
    return true
",
    );

    assert!(messages(&result)
        .iter()
        .any(|msg| msg.contains("return type mismatch: expected `Int`, found `Bool`")));
}

#[test]
fn rejects_missing_return_in_non_void_function() {
    let result = analyze_source(
        "\
fn main() -> Int:
    let value = 1
",
    );

    assert!(messages(&result)
        .iter()
        .any(|msg| msg.contains("may exit without returning `Int`")));
}

#[test]
fn allows_shadowing_in_nested_scopes() {
    let result = analyze_source(
        "\
fn main(value: Int) -> Int:
    if true:
        let value = 2
        return value
    else:
        return value
",
    );

    assert!(result.diagnostics.is_empty(), "{:?}", result.diagnostics);
}