use endor_core::{
    CodeLayout, CompareOp, EndorBaseExceptionObject, EndorCode, EndorDictObject,
    EndorFunctionObject, EndorInteger, EndorNativeFunctionObject, EndorNumber, EndorNumberObject,
    EndorReal, EndorStringObject, EndorTracebackEntry, Instruction, Opcode, Value, Vm, VmError,
};

fn text(value: &str) -> Value {
    Value::Text(value.into())
}

#[test]
fn numbers_preserve_large_digits_decimal_scale_exponents_and_fraction_parts() {
    let huge = "123456789012345678901234567890123456789012345678901234567890";
    assert_eq!(EndorNumber::integer(huge).unwrap().to_string(), huge);
    assert_eq!(EndorNumber::integer("-000").unwrap().to_string(), "0");
    assert_eq!(EndorNumber::integer("+0012").unwrap().as_i64(), Some(12));
    assert_eq!(EndorNumber::integer(huge).unwrap().as_i64(), None);
    for literal in [
        "-0.0000",
        "1.2300000000000000000001",
        ".5",
        "1.",
        "2e+999999999999999999999999999999",
    ] {
        assert_eq!(EndorNumber::decimal(literal).unwrap().to_string(), literal);
    }
    assert_ne!(
        EndorNumber::decimal("1.00").unwrap(),
        EndorNumber::decimal("1.0").unwrap()
    );
    assert_eq!(
        EndorNumber::rational("2", "-6").unwrap().to_string(),
        "-2/6"
    );
    assert_eq!(EndorNumber::rational("0", "-6").unwrap().to_string(), "0/6");
    assert!(EndorNumber::rational("1", "0").is_err());
    for invalid in ["", "+", " 1", "1 ", "1_000", "１２", "1.0"] {
        assert!(EndorNumber::integer(invalid).is_err(), "{invalid}");
    }
    for invalid in ["", ".", "1.2.3", "1e", "1e+", "1e2e3", "nan", " 0.1", "--1"] {
        assert!(EndorNumber::decimal(invalid).is_err(), "{invalid}");
    }
}

#[test]
fn number_objects_preserve_ieee_bits_and_reject_undefined_numeric_operations() {
    let mut vm = Vm::new().unwrap();
    let bits = 0x7ff8_0000_0000_0042;
    let nan = EndorNumber::binary_float(f64::from_bits(bits));
    assert_eq!(nan.as_real(), Some(&EndorReal::BinaryFloat(bits)));
    assert_ne!(
        EndorNumber::binary_float(-0.0),
        EndorNumber::binary_float(0.0)
    );
    assert!(!EndorNumber::binary_float(f64::INFINITY).is_zero());
    let zero = vm
        .new_number(EndorNumber::decimal("-0.000e99999999999").unwrap())
        .unwrap();
    assert!(!vm.is_true(zero).unwrap());
    let complex = EndorNumber::complex(
        EndorReal::Integer(EndorInteger::parse("3").unwrap()),
        EndorNumber::rational("1", "3")
            .unwrap()
            .as_real()
            .unwrap()
            .clone(),
    );
    let object = vm.new_number(complex).unwrap();
    assert_eq!(vm.str(object).unwrap(), "(3 + (1/3)i)");
    assert_eq!(
        vm.hash(object),
        Err(VmError::UnsupportedOperation("numeric hash"))
    );
    assert_eq!(
        vm.compare(object, zero, CompareOp::Eq),
        Err(VmError::UnsupportedOperation("numeric comparison"))
    );
    assert!(
        vm.payload::<EndorNumberObject>(object, "number")
            .unwrap()
            .value()
            .as_real()
            .is_none()
    );
}

#[test]
fn strings_use_unicode_characters_and_content_equality() {
    let mut vm = Vm::new().unwrap();
    let a = vm.new_string("Endor中文🦀").unwrap();
    let b = vm.new_string("Endor中文🦀").unwrap();
    let empty = vm.new_string("").unwrap();
    let string = vm.payload::<EndorStringObject>(a, "string").unwrap();
    assert_eq!(string.char_count(), 8);
    assert_eq!(string.char_at(7), Some('🦀'));
    assert_eq!(string.char_at(8), None);
    assert!(vm.compare(a, b, CompareOp::Eq).unwrap());
    assert_eq!(vm.hash(a).unwrap(), vm.hash(b).unwrap());
    assert_eq!(vm.str(a).unwrap(), "Endor中文🦀");
    assert!(!vm.is_true(empty).unwrap());
}

#[test]
fn dictionaries_keep_order_and_first_key_and_own_keys_and_values() {
    let mut vm = Vm::new().unwrap();
    let dict = vm.new_dict().unwrap();
    let key = vm.new_string("answer").unwrap();
    let old = vm.new_object().unwrap();
    vm.dict_set(dict, Value::Object(key), Value::Object(old))
        .unwrap();
    vm.release(key).unwrap();
    vm.release(old).unwrap();
    vm.dict_set(dict, text("second"), Value::Nil).unwrap();
    vm.dict_set(dict, text("answer"), text("replacement"))
        .unwrap();
    assert_eq!(
        vm.dict_get(dict, &text("answer")).unwrap(),
        Some(text("replacement"))
    );
    assert_eq!(vm.dict_items(dict).unwrap()[0].0, Value::Object(key));
    assert_eq!(vm.dict_items(dict).unwrap().len(), 2);
    assert!(matches!(vm.object(old), Err(VmError::InvalidHandle)));
    assert!(vm.dict_delete(dict, &text("answer")).unwrap());
    assert!(matches!(vm.object(key), Err(VmError::InvalidHandle)));
    assert!(!vm.dict_delete(dict, &text("missing")).unwrap());
    vm.dict_clear(dict).unwrap();
    assert!(!vm.is_true(dict).unwrap());
}

#[test]
fn failed_container_writes_leave_values_and_counts_unchanged() {
    let mut vm = Vm::new().unwrap();
    let mut other = Vm::new().unwrap();
    let foreign = other.new_object().unwrap();
    let dict = vm.new_dict().unwrap();
    let child = vm.new_object().unwrap();
    vm.dict_set(dict, text("x"), Value::Object(child)).unwrap();
    assert_eq!(
        vm.dict_set(dict, text("x"), Value::Object(foreign)),
        Err(VmError::ForeignHandle)
    );
    assert_eq!(
        vm.dict_get(dict, &text("x")).unwrap(),
        Some(Value::Object(child))
    );
    assert_eq!(vm.ref_count(child).unwrap(), 2);
    assert_eq!(
        vm.dict_set(dict, Value::Number(1_i64.into()), Value::Nil),
        Err(VmError::UnsupportedOperation("numeric hash"))
    );
    assert_eq!(
        vm.dict_set(dict, Value::Object(dict), Value::Nil),
        Err(VmError::UnsupportedOperation("dict hash"))
    );
    let cell = vm.new_cell(Some(Value::Object(child))).unwrap();
    assert_eq!(
        vm.cell_set(cell, Value::Object(foreign)),
        Err(VmError::ForeignHandle)
    );
    assert_eq!(vm.cell_get(cell).unwrap(), Value::Object(child));
    let dead = vm.new_object().unwrap();
    vm.release(dead).unwrap();
    assert_eq!(
        vm.cell_set(cell, Value::Object(dead)),
        Err(VmError::InvalidHandle)
    );
    assert_eq!(vm.ref_count(child).unwrap(), 3);
    assert_eq!(
        vm.dict_clear(child),
        Err(VmError::ObjectKindMismatch("dict"))
    );
}

#[test]
fn cells_share_rebinding_distinguish_empty_and_none_and_keep_stable_objects() {
    let mut vm = Vm::new().unwrap();
    let cell = vm.new_cell(None).unwrap();
    assert_eq!(vm.cell_get(cell), Err(VmError::EmptyCell));
    vm.cell_set(cell, Value::Nil).unwrap();
    assert_eq!(vm.cell_get(cell).unwrap(), Value::Nil);
    let child = vm.new_object().unwrap();
    vm.cell_set(cell, Value::Object(child)).unwrap();
    vm.release(child).unwrap();
    vm.cell_set(cell, Value::Object(child)).unwrap();
    assert_eq!(vm.ref_count(child).unwrap(), 1);
    vm.cell_clear(cell).unwrap();
    assert!(matches!(vm.object(child), Err(VmError::InvalidHandle)));
    assert_eq!(vm.cell_get(cell), Err(VmError::EmptyCell));
}

#[test]
fn container_cycles_and_duplicate_edges_are_collected() {
    let mut vm = Vm::new().unwrap();
    let dict = vm.new_dict().unwrap();
    let cell = vm.new_cell(Some(Value::Object(dict))).unwrap();
    vm.dict_set(dict, text("a"), Value::Object(cell)).unwrap();
    vm.dict_set(dict, text("b"), Value::Object(cell)).unwrap();
    assert_eq!(vm.ref_count(cell).unwrap(), 3);
    vm.release(dict).unwrap();
    vm.release(cell).unwrap();
    assert_eq!(vm.collect_cycles(), 2);
    assert_eq!(vm.object_count(), 0);
}

#[test]
fn functions_retain_globals_constants_defaults_and_shared_closure_cells() {
    let mut vm = Vm::new().unwrap();
    let globals = vm.new_dict().unwrap();
    let constant = vm.new_string("constant").unwrap();
    let cell = vm.new_cell(Some(text("first"))).unwrap();
    let code = EndorCode::from_instructions(
        &[
            Instruction::new(Opcode::LoadDeref, 1),
            Instruction::simple(Opcode::ReturnValue),
        ],
        vec![Value::Object(constant)],
        CodeLayout {
            parameters: vec!["argument".into()],
            locals: vec!["argument".into()],
            free_variables: vec!["captured".into()],
            ..CodeLayout::default()
        },
    )
    .unwrap();
    let code = vm.new_code(code).unwrap();
    let function = vm
        .new_function(
            "read",
            code,
            globals,
            vec![Value::Object(constant)],
            vec![cell],
        )
        .unwrap();
    let second = vm
        .new_function("read_again", code, globals, vec![], vec![cell])
        .unwrap();
    assert_eq!(vm.ref_count(constant).unwrap(), 3);
    vm.release(code).unwrap();
    vm.release(constant).unwrap();
    vm.release(cell).unwrap();
    vm.cell_set(cell, text("updated")).unwrap();
    for reference in [function, second] {
        let f = vm
            .payload::<EndorFunctionObject>(reference, "function")
            .unwrap();
        assert_eq!(vm.cell_get(f.closure()[0]).unwrap(), text("updated"));
    }
    assert_eq!(vm.call(function, &[]).unwrap(), text("updated"));
    vm.dict_set(globals, text("read"), Value::Object(function))
        .unwrap();
    vm.release(globals).unwrap();
    vm.release(function).unwrap();
    vm.release(second).unwrap();
    assert_eq!(vm.collect_cycles(), 5);
}

#[test]
fn malformed_function_environments_are_rejected_without_retaining_any_edges() {
    let mut vm = Vm::new().unwrap();
    let globals = vm.new_object().unwrap();
    let instructions = [
        Instruction::new(Opcode::LoadConst, 0),
        Instruction::simple(Opcode::ReturnValue),
    ];
    let code = EndorCode::from_instructions(&instructions, vec![Value::Nil], CodeLayout::default())
        .unwrap();
    let code = vm.new_code(code).unwrap();
    assert_eq!(
        vm.new_function("bad", code, globals, vec![], vec![]),
        Err(VmError::ObjectKindMismatch("dict"))
    );
    assert_eq!(vm.ref_count(globals).unwrap(), 1);
    assert_eq!(vm.ref_count(code).unwrap(), 1);
    assert!(EndorCode::new(vec![], vec![], vec!["x".into(), "x".into()], vec![]).is_err());
    let code = EndorCode::from_instructions(
        &instructions,
        vec![Value::Nil],
        CodeLayout {
            free_variables: vec!["x".into()],
            ..CodeLayout::default()
        },
    )
    .unwrap();
    let code = vm.new_code(code).unwrap();
    let globals = vm.new_dict().unwrap();
    assert!(
        vm.new_function("bad", code, globals, vec![], vec![])
            .is_err()
    );
    assert_eq!(vm.ref_count(code).unwrap(), 1);
}

#[test]
fn exceptions_preserve_arguments_chains_notes_and_traceback_without_type_classes() {
    let mut vm = Vm::new().unwrap();
    let argument = vm.new_string("detail").unwrap();
    let cause = vm
        .allocate(EndorBaseExceptionObject::new(
            "ValueError",
            vec![Value::Object(argument)],
        ))
        .unwrap();
    let exception = vm
        .allocate(
            EndorBaseExceptionObject::new("RuntimeError", vec![text("failed")])
                .with_cause(cause)
                .with_context(cause)
                .with_note("while loading")
                .with_traceback(EndorTracebackEntry {
                    function: "load".into(),
                    file: "demo.endor".into(),
                    line: 12,
                }),
        )
        .unwrap();
    assert_eq!(vm.ref_count(cause).unwrap(), 3);
    vm.release(argument).unwrap();
    vm.release(cause).unwrap();
    let data = vm
        .payload::<EndorBaseExceptionObject>(exception, "exception")
        .unwrap();
    assert!(data.context_suppressed());
    assert_eq!(data.notes(), &["while loading"]);
    assert_eq!(data.traceback()[0].line, 12);
    assert_eq!(vm.str(exception).unwrap(), "failed");
    vm.release(exception).unwrap();
    assert_eq!(vm.object_count(), 0);
    let wrong = vm.new_dict().unwrap();
    assert_eq!(
        vm.allocate(EndorBaseExceptionObject::new("Error", vec![]).with_cause(wrong)),
        Err(VmError::ObjectKindMismatch("exception"))
    );
}

fn echo(arguments: &[Value]) -> Result<Value, VmError> {
    match arguments {
        [value] => Ok(value.clone()),
        _ => Err(VmError::InvalidArgument("expected one value")),
    }
}

#[test]
fn native_functions_pass_lossless_numbers_and_return_owned_objects() {
    let mut vm = Vm::new().unwrap();
    let function = vm
        .allocate(EndorNativeFunctionObject::new("echo", echo))
        .unwrap();
    let number = Value::Number(EndorNumber::decimal("12345678901234567890.000100").unwrap());
    assert_eq!(
        vm.call(function, std::slice::from_ref(&number)).unwrap(),
        number
    );
    let dict = vm.new_dict().unwrap();
    let returned = vm.call(function, &[Value::Object(dict)]).unwrap();
    assert_eq!(returned, Value::Object(dict));
    assert_eq!(vm.ref_count(dict).unwrap(), 2);
    vm.release_value(returned).unwrap();
    assert_eq!(vm.ref_count(dict).unwrap(), 1);
    assert_eq!(
        vm.payload::<EndorDictObject>(dict, "dict").unwrap().len(),
        0
    );
}