#![cfg(test)]

use crate::SmallInt;
use crate::SmallUint;
use core::fmt::Debug;

#[cfg(feature = "num-bigint")]
use num_bigint::{BigInt, BigUint, Sign};

macro_rules! conversion_tests {
    ($t:ty, $i:ident) => {
        #[test]
        fn $i() {
            let i = <$t>::MAX;
            let s = SmallInt::from(i);
            assert_eq!(<$t>::try_from(s).unwrap(), i);

            let i = <$t>::MIN;
            let s = SmallInt::from(i);
            assert_eq!(<$t>::try_from(s).unwrap(), i);
        }
    };
}

conversion_tests!(u8, test_u8);
conversion_tests!(i8, test_i8);
conversion_tests!(u16, test_u16);
conversion_tests!(i16, test_i16);
conversion_tests!(u32, test_u32);
conversion_tests!(i32, test_i32);
conversion_tests!(u64, test_u64);
conversion_tests!(i64, test_i64);
conversion_tests!(u128, test_u128);
conversion_tests!(i128, test_i128);

#[cfg(feature = "num-bigint")]
fn run_tests_u_inner(test: impl Fn(BigUint)) {
    for i in 0u8..=7 {
        test(BigUint::from(i));
    }
    for shift_scale in 1..=16 {
        for shift_offset in -2..=2 {
            let shift: i16 = (shift_scale * 32) + shift_offset;
            test(BigUint::from(1u8) << shift);
            for offset in 1u8..=7 {
                test((BigUint::from(1u8) << shift) + BigUint::from(offset));
                test((BigUint::from(1u8) << shift) - BigUint::from(offset));
            }
        }
    }
    test(BigUint::new(vec![3, 9, 8, 3, 1]));
    test(BigUint::new(vec![5, 4, 9, 3, 1, 81]));
}

#[allow(dead_code)]
#[cfg(feature = "num-bigint")]
fn run_tests_u_1<T: Eq + Debug>(small: impl Fn(SmallUint) -> T, big: impl Fn(&BigUint) -> T) {
    run_tests_u_inner(|i| {
        let small_result = small(SmallUint::from(&i));
        let big_result = big(&i);
        assert_eq!(
            small_result,
            big_result,
            "{:#x}", i
        );
    });
}

#[cfg(feature = "num-bigint")]
fn run_tests_u_2<T: Eq + Debug>(
    small: impl Fn(SmallUint, SmallUint) -> T,
    big: impl Fn(&BigUint, &BigUint) -> T
) {
    run_tests_u_inner(|i| run_tests_u_inner(|k| {
        let small_result = small(SmallUint::from(&i), SmallUint::from(&k));
        let big_result = big(&i, &k);
        assert_eq!(
            small_result,
            big_result,
            "{:#x} {:#x}", i, k
        );
    }));
}

#[cfg(feature = "num-bigint")]
fn run_tests_i_inner(test: impl Fn(BigInt)) {
    run_tests_u_inner(|value| {
        test(BigInt::from_biguint(Sign::Plus, value.clone()));
        test(BigInt::from_biguint(Sign::Minus, value));
    });
}

#[cfg(feature = "num-bigint")]
fn run_tests_i_1<T: Eq + Debug>(small: impl Fn(SmallInt) -> T, big: impl Fn(&BigInt) -> T) {
    run_tests_i_inner(|i| {
        let small_result = small(SmallInt::from(&i));
        let big_result = big(&i);
        assert_eq!(
            small_result,
            big_result,
            "{:#x}", i
        );
    });
}

#[cfg(feature = "num-bigint")]
fn run_tests_i_2<T: Eq + Debug>(
    small: impl Fn(SmallInt, SmallInt) -> T,
    big: impl Fn(&BigInt, &BigInt) -> T
) {
    run_tests_i_inner(|i| run_tests_i_inner(|k| {
        let small_result = small(SmallInt::from(&i), SmallInt::from(&k));
        let big_result = big(&i, &k);
        assert_eq!(
            small_result,
            big_result,
            "{:#x} {:#x}", i, k
        );
    }));
}

#[test]
#[cfg(feature = "num-bigint")]
fn test_convert_biguint() {
    run_tests_u_1(|i| BigUint::from(&i), |i| i.clone());
    run_tests_u_1(|i| i, |i| SmallUint::from(i));
}

#[test]
#[cfg(feature = "num-bigint")]
fn test_convert_bigint() {
    run_tests_i_1(|i| BigInt::from(&i), |i| i.clone());
    run_tests_i_1(|i| i, |i| SmallInt::from(i));
}

#[test]
#[cfg(feature = "num-bigint")]
fn test_cmp_u() {
    run_tests_u_2(
        |i, k| i.partial_cmp(&k),
        |i, k| i.partial_cmp(&k),
    );
}

#[test]
#[cfg(feature = "num-bigint")]
fn test_cmp_i() {
    run_tests_i_2(
        |i, k| i.partial_cmp(&k),
        |i, k| i.partial_cmp(&k),
    );
}

#[test]
#[cfg(feature = "num-bigint")]
fn test_op_add_u() {
    run_tests_u_2(
        |i, k| BigUint::from(&(i + k)),
        |i, k| i + k,
    );
}

#[test]
#[cfg(feature = "num-bigint")]
fn test_op_add_i() {
    run_tests_i_2(
        |i, k| BigInt::from(&(i + k)),
        |i, k| i + k,
    );
}

#[test]
#[cfg(feature = "num-bigint")]
fn test_op_mul_u() {
    run_tests_u_2(
        |i, k| BigUint::from(&(i * k)),
        |i, k| i * k,
    );
}

#[test]
#[cfg(feature = "num-bigint")]
fn test_op_mul_i() {
    run_tests_i_2(
        |i, k| BigInt::from(&(i * k)),
        |i, k| i * k,
    );
}

#[test]
#[cfg(feature = "num-bigint")]
fn test_op_sub_u() {
    run_tests_u_2(
        |i, k| (i >= k).then(|| BigUint::from(&(i - k))),
        |i, k| (i >= k).then(|| i - k),
    );
}

#[test]
#[cfg(feature = "num-bigint")]
fn test_op_sub_i() {
    run_tests_i_2(
        |i, k| BigInt::from(&(i - k)),
        |i, k| i - k,
    );
}

#[test]
#[cfg(feature = "num-bigint")]
fn test_op_and_u() {
    run_tests_u_2(
        |i, k| BigUint::from(&(i & k)),
        |i, k| i & k,
    );
}

#[test]
#[cfg(feature = "num-bigint")]
fn test_op_and_i() {
    run_tests_i_2(
        |i, k| BigInt::from(&(i & k)),
        |i, k| i & k,
    );
}

#[test]
#[cfg(feature = "num-bigint")]
fn test_op_or_u() {
    run_tests_u_2(
        |i, k| BigUint::from(&(i | k)),
        |i, k| i | k,
    );
}

// #[test]
// #[cfg(feature = "num-bigint")]
// fn test_op_or_i() {
//     run_tests_i_2(
//         |i, k| BigInt::from(&(i | k)),
//         |i, k| i | k,
//     );
// }

#[test]
#[cfg(feature = "num-bigint")]
fn test_op_xor_u() {
    run_tests_u_2(
        |i, k| BigUint::from(&(i ^ k)),
        |i, k| i ^ k,
    );
}

#[test]
#[cfg(feature = "num-bigint")]
fn test_op_neg() {
    run_tests_i_1(|i| BigInt::from(&-i), |i| -i.clone());
}

#[test]
#[cfg(feature = "num-bigint")]
fn test_conversion_sign_drop() {
    run_tests_i_1(
        |i| BigUint::from(&SmallUint::from_smallint_unsigned(i)),
        |i| i.magnitude().clone()
    );
}

#[test]
#[cfg(feature = "num-bigint")]
fn test_bigint() {
    let i = BigInt::new(Sign::Plus, vec![5, 4, 8, 3, 2, 9, 3]);
    let s = SmallInt::from(&i);
    assert_eq!(
        BigInt::from(&s).to_u32_digits(),
        (Sign::Plus, vec![5, 4, 8, 3, 2, 9, 3])
    );
}