use eschac::board::*;
use eschac::position::*;
use eschac::san::*;
use eschac::setup::*;

static P1: &'static str = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq -";
static P2: &'static str = "r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq -";
static P3: &'static str = "8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - -";
static P4: &'static str = "r3k2r/Pppp1ppp/1b3nbN/nP6/BBP1P3/q4N2/Pp1P2PP/R2Q1RK1 w kq -";
static P5: &'static str = "rnbq1k1r/pp1Pbppp/2p5/8/2B5/8/PPP1NnPP/RNBQK2R w KQ -";
static P6: &'static str = "r4rk1/1pp1qppp/p1np1n2/2b1p1B1/2B1P1b1/P1NP1N2/1PP1QPPP/R4RK1 w - -";

fn recursive_check_aux(position: Position, depth: usize) {
    assert_eq!(
        position,
        position
            .as_setup()
            .to_string()
            .parse::<Setup>()
            .unwrap()
            .validate()
            .unwrap(),
    );

    if let Some(passed) = position.pass() {
        let mut position = position.clone();
        position.remove_en_passant_target_square();
        assert_eq!(position, passed.pass().unwrap());
    }

    let computed_mirror = {
        let mut setup = Setup::new();
        for square in Square::all() {
            setup.set(
                square.mirror(),
                position.get(square).map(|piece| Piece {
                    role: piece.role,
                    color: !piece.color,
                }),
            );
        }
        setup.set_turn(!position.turn());
        for color in Color::all() {
            for side in CastlingSide::all() {
                setup.set_castling_rights(!color, side, position.castling_rights(color, side));
            }
        }
        setup.set_en_passant_target_square(
            position
                .en_passant_target_square()
                .map(|square| square.mirror()),
        );
        setup.validate().unwrap()
    };
    let expected_mirror = position.mirror();
    assert_eq!(computed_mirror, expected_mirror);
    assert_eq!(expected_mirror.mirror(), position);

    match depth.checked_sub(1) {
        None => (),
        Some(depth) => {
            position.legal_moves().into_iter().for_each(|m| {
                let uci = m.to_uci();
                assert_eq!(uci, uci.to_move(&position).unwrap().to_uci());
                let san: San = m.to_san();
                match san.to_move(&position) {
                    Ok(m) => assert_eq!(san, m.to_san()),
                    Err(err) => {
                        panic!("{san} is {err} on {position:?}")
                    }
                };
                recursive_check_aux(m.make(), depth)
            });
        }
    }
}
fn recursive_check(record: &str) {
    recursive_check_aux(record.parse::<Setup>().unwrap().validate().unwrap(), 4);
}
#[test]
fn recursive_check_1() {
    recursive_check(P1);
}
#[test]
fn recursive_check_2() {
    recursive_check(P2);
}
#[test]
fn recursive_check_3() {
    recursive_check(P3);
}
#[test]
fn recursive_check_4() {
    recursive_check(P4);
}
#[test]
fn recursive_check_5() {
    recursive_check(P5);
}
#[test]
fn recursive_check_6() {
    recursive_check(P6);
}

#[test]
fn setup() {
    assert_eq!(Position::new().as_setup().to_string(), P1);
    assert_eq!(Setup::new().to_string(), "8/8/8/8/8/8/8/8 w - -");
    assert_eq!(
        "8/8/8/8/1Pp5/8/R1k5/K7 w - b3"
            .parse::<Setup>()
            .unwrap()
            .to_string(),
        "8/8/8/8/1Pp5/8/R1k5/K7 w - b3",
    );

    for (record, err) in [
        ("", ParseSetupError::InvalidBoard),
        (" w - -", ParseSetupError::InvalidBoard),
        ("8/8/8/8/8/8/8 w - -", ParseSetupError::InvalidBoard),
        ("1/1/1/1/1/1/1/1 w - -", ParseSetupError::InvalidBoard),
        (
            "44/44/44/44/44/44/44/44 w - -",
            ParseSetupError::InvalidBoard,
        ),
        ("8/8/8/8/8/8/8/8/8 w - -", ParseSetupError::InvalidBoard),
        ("p8/8/8/8/8/8/8/8 w - -", ParseSetupError::InvalidBoard),
        ("8/8/8/8/8/8/8/8 - - - ", ParseSetupError::InvalidTurn),
        (
            "8/8/8/8/8/8/8/8 w QQQQ -",
            ParseSetupError::InvalidCastlingRights,
        ),
    ] {
        assert_eq!(record.parse::<Setup>(), Err(err), "{record}");
    }
    for (record, reason) in [
        (
            "8/8/8/8/8/8/8/8 w KQkq -",
            IllegalPositionReason::MissingKing,
        ),
        (
            "3kk3/8/8/8/8/8/8/3KK3 w KQkq -",
            IllegalPositionReason::TooManyKings,
        ),
        (
            "4k3/8/8/1Q6/8/8/8/4K3 w - -",
            IllegalPositionReason::HangingKing,
        ),
        (
            "4k3/8/3N4/8/8/8/8/4K3 w - -",
            IllegalPositionReason::HangingKing,
        ),
        (
            "4k3/8/8/8/8/8/8/4K2R w KQ -",
            IllegalPositionReason::InvalidCastlingRights,
        ),
        (
            "4k3/8/8/8/8/8/8/P3K3 w KQ -",
            IllegalPositionReason::PawnOnBackRank,
        ),
        (
            "p3k3/8/8/8/8/8/8/4K3 w KQ -",
            IllegalPositionReason::PawnOnBackRank,
        ),
        (
            "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR b KQkq e3",
            IllegalPositionReason::InvalidEnPassant,
        ),
        (
            "rnbqkbnr/pppppppp/8/8/8/4P3/PPPP1PPP/RNBQKBNR b KQkq e3",
            IllegalPositionReason::InvalidEnPassant,
        ),
        (
            "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e3",
            IllegalPositionReason::InvalidEnPassant,
        ),
        (
            "8/8/8/5B2/4P3/3k4/8/4K3 b - e3",
            IllegalPositionReason::ImpossibleEnPassantPin,
        ),
        (
            "8/8/8/3k4/4P3/5B2/8/4K3 b - e3",
            IllegalPositionReason::ImpossibleEnPassantPin,
        ),
        (
            "rnbqkbnr/pppppppp/8/8/4B3/8/PPPPPPPP/RNBQKBNR b KQkq -",
            IllegalPositionReason::TooMuchMaterial,
        ),
        (
            "rnbqkbnr/pppppppp/8/8/8/QBNP4/PPPPPPP1/RNBQKBNR b KQkq -",
            IllegalPositionReason::TooMuchMaterial,
        ),
    ] {
        assert!(
            record.parse::<Setup>().map(|record| record.to_string()) == Ok(record.to_string()),
            "{record}",
        );
        assert!(
            record
                .parse::<Setup>()
                .unwrap()
                .validate()
                .is_err_and(|e| e.reasons().contains(reason)),
            "{record} should be invalid because of {reason:?}",
        );
    }

    for record in [
        "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPB/RNBQKBNR b KQkq -",
        "rnbqkbnr/pppppppp/8/8/8/8/NNNNNNNN/RNBQKBNR b KQkq -",
        "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3",
        "3kr3/8/8/8/4P3/8/8/4K3 b - e3",
        "8/8/8/3k4/3P4/8/8/3RK3 b - d3",
    ] {
        assert!(record.parse::<Setup>().is_ok(), "{record}");
    }
}

#[test]
fn mirror() {
    assert_eq!(Position::new().pass(), Some(Position::new().mirror()));
    let position = "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b Kq e3"
        .parse::<Setup>()
        .unwrap()
        .validate()
        .unwrap();
    let mirror = "rnbqkbnr/pppp1ppp/8/4p3/8/8/PPPPPPPP/RNBQKBNR w Qk e6"
        .parse::<Setup>()
        .unwrap()
        .validate()
        .unwrap();
    assert_eq!(mirror, position.mirror());
}

fn perft_aux(record: &str, tests: &[u128]) {
    let position = record.parse::<Setup>().unwrap().validate().unwrap();
    for (depth, value) in tests.iter().copied().enumerate() {
        assert_eq!(
            position.perft(depth),
            value,
            "\"{record}\" at depth {depth}",
        );
    }
}
#[test]
fn perft_1() {
    perft_aux(P1, &[1, 20, 400, 8_902, 197_281, 4_865_609, 119_060_324]);
}
#[test]
fn perft_2() {
    perft_aux(P2, &[1, 48, 2039, 97_862, 4_085_603, 193_690_690]);
}
#[test]
fn perft_3() {
    perft_aux(
        P3,
        &[1, 14, 191, 2_812, 43_238, 674_624, 11_030_083, 178_633_661],
    );
}
#[test]
fn perft_4() {
    perft_aux(P4, &[1, 6, 264, 9_467, 422_333, 15_833_292]);
}
#[test]
fn perft_5() {
    perft_aux(P5, &[1, 44, 1_486, 62_379, 2_103_487, 89_941_194]);
}
#[test]
fn perft_6() {
    perft_aux(P6, &[1, 46, 2_079, 89_890, 3_894_594, 164_075_551]);
}

#[test]
fn san() {
    let position = "8/2KN1p2/5p2/3N1B1k/5PNp/7P/7P/8 w - -"
        .parse::<Setup>()
        .unwrap()
        .validate()
        .unwrap();
    let san1 = "N7xf6#".parse::<San>().unwrap();
    let m1 = san1.to_move(&position).unwrap();
    let san2 = "N5xf6#".parse::<San>().unwrap();
    let m2 = san2.to_move(&position).unwrap();
    let san3 = "Ngxf6+".parse::<San>().unwrap();
    let m3 = san3.to_move(&position).unwrap();
    assert_eq!(m1.to_san(), san1);
    assert_eq!(m2.to_san(), san2);
    assert_eq!(m3.to_san(), san3);
    assert_eq!(
        "Nd7f6"
            .parse::<San>()
            .unwrap()
            .to_move(&position)
            .unwrap()
            .to_san(),
        san1,
    );
    assert_eq!(
        "Nf6".parse::<San>().unwrap().to_move(&position).map(|_| ()),
        Err(InvalidSan::Ambiguous),
    );
}