import ctypes
from test.base import ChessLibTestBase
from test.chess_ffi import gen_white_pawn_quiet_pushes
from test.chess_ffi import gen_white_pawn_push_promotions
from test.chess_ffi import gen_white_pawn_capture_promotions
from test.chess_ffi import gen_white_pawn_captures
from test.chess_ffi import gen_knight_moves
from test.chess_ffi import Move
from test.chess_ffi import Board


MAX_MOVES = 256


class TestPseudoMoveGeneration(ChessLibTestBase):
    def test_knight_move_gen(self):
        all_move_types = [
            ("8/8/8/8/3N4/8/8/8 w - - 0 1", 8, "center d4: 8 moves"),
            ("8/8/8/8/N7/8/8/8 w - - 0 1",   4, "edge a4: 4 moves"),
            ("8/8/8/8/8/8/8/N7 w - - 0 1",   2, "corner a1: 2 moves"),
            ("8/8/8/8/8/8/8/1N6 w - - 0 1",  3, "b1: 3 moves"),
            
            # own pieces on destinations reduce count
            ("8/8/8/5P2/3N4/1P6/2P5/8 w - - 0 1", 5, "d4 with own pawns on f5,b3,c2 -> 8-3=5"),
            
            # two knights
            ("8/8/8/8/8/8/8/1N4N1 w - - 0 1", 6, "b1 & g1, empty board: 3+3"),
            
            # all 8 destinations occupied by black (still 8 total moves, all as captures)
            ("8/8/2p1p3/1p3p2/3N4/1p3p2/2p1p3/8 w - - 0 1", 8, "enemy on all 8 targets"),
            
            # corner with one capture and one friendly block
            ("8/8/8/8/8/1p6/2P5/N7 w - - 0 1", 1, "a1, b3 black (capture), c2 white (blocked)"),
        ]

        captures_only = False
        for fen, expected, msg in all_move_types:
            with self.subTest(msg=msg, fen=fen):
                cnt = ctypes.c_int(0)
                moves = (Move * MAX_MOVES)()
                b = Board()

                self.load_fen(fen, board=b)
                gen_knight_moves(b, moves, ctypes.byref(cnt), captures_only)

                self.assertEqual(expected, cnt.value)

        cases_knight_captures = [
            ("8/8/8/8/3N4/8/8/8 w - - 0 1", 0, "center d4 but no enemies"),
            ("8/8/2p5/1p6/3N4/5p2/8/8 w - - 0 1", 3, "d4 capturing c6,b5,f3"),
            ("8/8/8/8/3N4/1P3p2/4P3/8 w - - 0 1", 1, "d4 with f3 black (1 cap), b3/e2 white (not capturable)"),
            ("8/8/2p1p3/1p3p2/3N4/1p3p2/2p1p3/8 w - - 0 1", 8, "d4 with all 8 targets black: 8 captures"),
        ]

        captures_only = True
        for fen, expected, msg in cases_knight_captures:
            with self.subTest(msg=msg, fen=fen):
                cnt = ctypes.c_int(0)
                moves = (Move * MAX_MOVES)()
                b = Board()

                self.load_fen(fen, board=b)
                gen_knight_moves(b, moves, ctypes.byref(cnt), captures_only)

                self.assertEqual(expected, cnt.value)


    def test_bishop_move_gen(self):
        pass


    def test_rook_move_gen(self):
        pass


    def test_queen_move_gen(self):
        pass


    def test_king_move_gen(self):
        pass


    def test_quiet_pawn_pushes_white(self):
        cases = [
            ("8/pppppppp/8/8/8/8/PPPPPPPP/8 w - - 0 1", 16, "open ranks"),
            ("8/8/8/8/8/8/P7/8 w - - 0 1", 2, "single pawn open"),
            ("8/8/8/8/8/p7/P7/8 w - - 0 1", 0, "blocked single enemy"),
            ("8/8/8/8/8/n7/P7/8 w - - 0 1", 0, "blocked single friendly"),
            # Although legal move, we have a separate function that calculates this move type.
            ("8/9P/8/8/8/8/8/8 w - - 0 1", 0, "no promotion push"),
        ]

        for fen, expected, msg in cases:
            with self.subTest(msg=msg, fen=fen):
                cnt = ctypes.c_int(0)
                moves = (Move * MAX_MOVES)()
                b = Board()

                self.load_fen(fen, board=b)
                gen_white_pawn_quiet_pushes(b, moves, ctypes.byref(cnt))

                self.assertEqual(expected, cnt.value)


    def test_quiet_pawn_promotions_white(self):
        cases = [
            ("8/PPPPPPPP/8/8/8/8/8/8 w - - 0 1", 8, "all open on 7th rank"),
            ("8/8/7P/8/8/8/8/8 w - - 0 1", 0, "no promotions"),
            ("7n/7P/8/8/8/8/8/8 w - - 0 1", 0, "blocked by enemy"),
            ("7N/7P/8/8/8/8/8/8 w - - 0 1", 0, "blocked by friendly"),
        ]

        for fen, expected, msg in cases:
            with self.subTest(msg=msg, fen=fen):
                cnt = ctypes.c_int(0)
                moves = (Move * MAX_MOVES)()
                b = Board()

                self.load_fen(fen, board=b)
                gen_white_pawn_push_promotions(b, moves, ctypes.byref(cnt))

                self.assertEqual(expected, cnt.value)


    def test_capture_pawn_promotions_white(self):
        cases = [
            ("6n1/7P/8/8/8/8/8/8 w - - 0 1", 1, "one capture"),
            ("5n1n/6P1/8/8/8/8/8/8 w - - 0 1", 2, "two captures"),
            ("8/7P/8/8/8/8/8/8 w - - 0 1", 0, "no capture"),
        ]

        for fen, expected, msg in cases:
            with self.subTest(msg=msg, fen=fen):
                cnt = ctypes.c_int(0)
                moves = (Move * MAX_MOVES)()
                b = Board()

                self.load_fen(fen, board=b)
                gen_white_pawn_capture_promotions(b, moves, ctypes.byref(cnt))

                self.assertEqual(expected, cnt.value)


    def test_capture_pawn_white(self):
        cases = [
            # normal diagonal captures
            ("8/8/8/3n4/4P3/8/8/8 w - - 0 1", 1, "e4xd5"),
            ("8/8/8/3n1n2/4P3/8/8/8 w - - 0 1", 2, "e4xd5 and e4xf5"),
            ("8/8/8/1p6/P7/8/8/8 w - - 0 1", 1, "edge file: a4xb5"),
            ("8/7P/8/8/8/8/8/8 w - - 0 1", 0, "no capture"),

            # en passant
            ("8/8/8/3pP3/8/8/8/8 w - d6 0 1", 1, "EP available: e5xd6 e.p. (black pawn on d5)"),
            ("8/8/5n2/3pP3/8/8/8/8 w - d6 0 1", 2, "EP e5xd6 and normal e5xf6"),
            ("8/8/8/3p4/8/4P3/8/8 w - d6 0 1", 0, "EP square present but no white pawn can take"),
        ]

        for fen, expected, msg in cases:
            with self.subTest(msg=msg, fen=fen):
                cnt = ctypes.c_int(0)
                moves = (Move * MAX_MOVES)()
                b = Board()

                self.load_fen(fen, board=b)
                gen_white_pawn_captures(b, moves, ctypes.byref(cnt))

                self.assertEqual(expected, cnt.value)