from abc import ABC, abstractmethod
from dataclasses import dataclass

from gbso.cpu import CPU
from gbso.regs import R16, R8


class Insn(ABC):
    @abstractmethod
    def exec(self, cpu: CPU) -> None:
        pass

    # TODO: Make abstract once all subclasses implement
    def pretty(self) -> str:
        return ""


@dataclass
class LD_R_R(Insn):
    dst: R8
    src: R8

    def exec(self, cpu: CPU) -> None:
        cpu.set_reg8(self.dst, cpu.get_reg8(self.src))
        cpu.cycles += 4

    def pretty(self) -> str:
        return f"LD {self.dst}, {self.src}"


@dataclass
class LD_R_N8(Insn):
    dst: R8
    imm: int

    def exec(self, cpu: CPU) -> None:
        cpu.set_reg8(self.dst, self.imm)
        cpu.cycles += 8

    def pretty(self) -> str:
        return f"LD {self.dst}, {hex(self.imm)}"


@dataclass
class LD_R_HL(Insn):
    dst: R8

    def exec(self, cpu: CPU) -> None:
        cpu.set_reg8(self.dst, cpu.get_mem8(cpu.get_reg16(R16.HL)))
        cpu.cycles += 8

    def pretty(self) -> str:
        return f"LD {self.dst}, (HL)"


@dataclass
class LD_HL_R(Insn):
    src: R8

    def exec(self, cpu: CPU) -> None:
        cpu.deref_hl_set(cpu.get_reg8(self.src))
        cpu.cycles += 8

    def pretty(self) -> str:
        return f"LD (HL), {self.src}"


@dataclass
class LD_HL_N(Insn):
    imm: int

    def exec(self, cpu: CPU) -> None:
        cpu.set_mem8(cpu.get_reg16(R16.HL), self.imm)
        cpu.cycles += 12

    def pretty(self) -> str:
        return f"LD (HL), {hex(self.imm & 0xff)}"


@dataclass
class LD_A_BC(Insn):
    def exec(self, cpu: CPU) -> None:
        cpu.set_reg8(R8.A, cpu.get_mem8(cpu.get_reg16(R16.BC)))
        cpu.cycles += 8

    def pretty(self) -> str:
        return "LD A, (BC)"


@dataclass
class LD_A_DE(Insn):
    def exec(self, cpu: CPU) -> None:
        cpu.set_reg8(R8.A, cpu.get_mem8(cpu.get_reg16(R16.DE)))
        cpu.cycles += 8

    def pretty(self) -> str:
        return "LD A, (DE)"


@dataclass
class LD_A_NN(Insn):
    nn: int

    def exec(self, cpu: CPU) -> None:
        cpu.set_reg8(R8.A, cpu.get_mem8(self.nn))
        cpu.cycles += 16

    def pretty(self) -> str:
        return f"LD A, ({hex(self.nn)})"


@dataclass
class LD_BC_A(Insn):
    def exec(self, cpu: CPU) -> None:
        cpu.set_mem8(cpu.get_reg16(R16.BC), cpu.get_reg8(R8.A))
        cpu.cycles += 8

    def pretty(self) -> str:
        return "LD (BC), A"


@dataclass
class LD_DE_A(Insn):
    def exec(self, cpu: CPU) -> None:
        cpu.set_mem8(cpu.get_reg16(R16.DE), cpu.get_reg8(R8.A))
        cpu.cycles += 8

    def pretty(self) -> str:
        return "LD (DE), A"


@dataclass
class LD_NN_A(Insn):
    nn: int

    def exec(self, cpu: CPU) -> None:
        cpu.set_mem8(self.nn, cpu.get_reg8(R8.A))
        cpu.cycles += 16

    def pretty(self) -> str:
        return f"LD ({hex(self.nn)}), A"


@dataclass
class LD_A_FF_N(Insn):
    n: int

    def exec(self, cpu: CPU) -> None:
        cpu.set_reg8(R8.A, cpu.get_mem8(0xFF00 + self.n))
        cpu.cycles += 12

    def pretty(self) -> str:
        return f"LD A, (0xFF00 + {hex(self.n)})"


@dataclass
class LD_FF_N_A(Insn):
    n: int

    def exec(self, cpu: CPU) -> None:
        cpu.set_mem8(0xFF00 + self.n, cpu.get_reg8(R8.A))
        cpu.cycles += 12

    def pretty(self) -> str:
        return f"LD (0xFF00 + {hex(self.n)}), A"


@dataclass
class LD_A_FF_C(Insn):
    def exec(self, cpu: CPU) -> None:
        cpu.set_reg8(R8.A, cpu.get_mem8(0xFF00 + cpu.get_reg8(R8.C)))
        cpu.cycles += 8

    def pretty(self) -> str:
        return "LD A, (0xFF00 + C)"


@dataclass
class LD_FF_C_A(Insn):
    def exec(self, cpu: CPU) -> None:
        cpu.set_mem8(0xFF00 + cpu.get_reg8(R8.C), cpu.get_reg8(R8.A))
        cpu.cycles += 8

    def pretty(self) -> str:
        return "LD (0xFF00 + C), A"


@dataclass
class LDI_HL_A(Insn):
    def exec(self, cpu: CPU) -> None:
        hl = cpu.get_reg16(R16.HL)
        cpu.set_mem8(hl, cpu.get_reg8(R8.A))
        cpu.set_reg16(R16.HL, hl + 1)
        cpu.cycles += 8

    def pretty(self) -> str:
        return "LDI (HL), A"


@dataclass
class LDI_A_HL(Insn):
    def exec(self, cpu: CPU) -> None:
        hl = cpu.get_reg16(R16.HL)
        cpu.set_reg8(R8.A, cpu.get_mem8(hl))
        cpu.set_reg16(R16.HL, hl + 1)
        cpu.cycles += 8

    def pretty(self) -> str:
        return "LDI A, (HL)"


@dataclass
class LDD_HL_A(Insn):
    def exec(self, cpu: CPU) -> None:
        hl = cpu.get_reg16(R16.HL)
        cpu.set_mem8(hl, cpu.get_reg8(R8.A))
        cpu.set_reg16(R16.HL, hl - 1)
        cpu.cycles += 8

    def pretty(self) -> str:
        return "LDD (HL), A"


@dataclass
class LDD_A_HL(Insn):
    def exec(self, cpu: CPU) -> None:
        hl = cpu.get_reg16(R16.HL)
        cpu.set_reg8(R8.A, cpu.get_mem8(hl))
        cpu.set_reg16(R16.HL, hl - 1)
        cpu.cycles += 8

    def pretty(self) -> str:
        return "LDD A, (HL)"


@dataclass
class LD_RR_NN(Insn):
    rr: R16
    nn: int

    def exec(self, cpu: CPU) -> None:
        cpu.set_reg16(self.rr, self.nn)

    def pretty(self) -> str:
        return f"LD {self.rr.value}, {hex(self.nn)}"


@dataclass
class LD_NN_SP(Insn):
    nn: int

    def exec(self, cpu: CPU) -> None:
        cpu.set_mem16(self.nn, cpu.get_reg16(R16.SP))


@dataclass
class LD_SP_HL(Insn):
    def exec(self, cpu: CPU) -> None:
        cpu.set_reg16(R16.SP, cpu.get_reg16(R16.HL))


@dataclass
class PUSH_RR(Insn):
    rr: R16

    def exec(self, cpu: CPU) -> None:
        sp = cpu.get_reg16(R16.SP)
        cpu.set_reg16(R16.SP, sp - 2)
        cpu.set_mem16(sp - 2, cpu.get_reg16(self.rr))


@dataclass
class POP_RR(Insn):
    rr: R16

    def exec(self, cpu: CPU) -> None:
        sp = cpu.get_reg16(R16.SP)
        cpu.set_reg16(self.rr, cpu.get_mem16(sp))
        cpu.set_reg16(R16.SP, sp + 2)


@dataclass
class ADD_A_R(Insn):
    r: R8

    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A) + cpu.get_reg8(self.r)
        cpu.carry = 1 if a > 0xFF else 0
        cpu.set_reg8(R8.A, a)


@dataclass
class ADD_A_N(Insn):
    n: int

    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A) + self.n
        cpu.carry = 1 if a > 0xFF else 0
        cpu.set_reg8(R8.A, a)


@dataclass
class ADD_A_HL(Insn):
    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A) + cpu.get_mem8(cpu.get_reg16(R16.HL))
        cpu.carry = 1 if a > 0xFF else 0
        cpu.set_reg8(R8.A, a)


@dataclass
class ADC_A_R(Insn):
    r: R8

    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A) + cpu.get_reg8(self.r) + cpu.carry
        cpu.carry = 1 if a > 0xFF else 0
        cpu.set_reg8(R8.A, a)


@dataclass
class ADC_A_N(Insn):
    n: int

    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A) + self.n + cpu.carry
        cpu.carry = 1 if a > 0xFF else 0
        cpu.set_reg8(R8.A, a)


@dataclass
class ADC_A_HL(Insn):
    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A) + cpu.get_mem8(cpu.get_reg16(R16.HL)) + cpu.carry
        cpu.carry = 1 if a > 0xFF else 0
        cpu.set_reg8(R8.A, a)


@dataclass
class SUB_A_R(Insn):
    r: R8

    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A) - cpu.get_reg8(self.r)
        cpu.carry = 1 if a < 0 else 0
        cpu.set_reg8(R8.A, a)


@dataclass
class SUB_A_N(Insn):
    n: int

    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A) - self.n
        cpu.carry = 1 if a < 0 else 0
        cpu.set_reg8(R8.A, a)


@dataclass
class SUB_A_HL(Insn):
    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A) - cpu.get_mem8(cpu.get_reg16(R16.HL))
        cpu.carry = 1 if a < 0 else 0
        cpu.set_reg8(R8.A, a)


@dataclass
class SBC_A_R(Insn):
    r: R8

    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A) - cpu.get_reg8(self.r) - cpu.carry
        cpu.carry = 1 if a < 0 else 0
        cpu.set_reg8(R8.A, a)


@dataclass
class SBC_A_N(Insn):
    n: int

    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A) - self.n - cpu.carry
        cpu.carry = 1 if a < 0 else 0
        cpu.set_reg8(R8.A, a)


@dataclass
class SBC_A_HL(Insn):
    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A) - cpu.get_mem8(cpu.get_reg16(R16.HL)) - cpu.carry
        cpu.carry = 1 if a < 0 else 0
        cpu.set_reg8(R8.A, a)


@dataclass
class AND_A_R(Insn):
    r: R8

    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A) & cpu.get_reg8(self.r)
        cpu.set_reg8(R8.A, a)
        cpu.carry = 0


@dataclass
class AND_A_N(Insn):
    n: int

    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A) & self.n
        cpu.set_reg8(R8.A, a)
        cpu.carry = 0


@dataclass
class AND_A_HL(Insn):
    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A) & cpu.get_mem8(cpu.get_reg16(R16.HL))
        cpu.set_reg8(R8.A, a)
        cpu.carry = 0

    def pretty(self) -> str:
        return "AND A, (HL)"


@dataclass
class CP_A_R(Insn):
    r: R8

    def exec(self, cpu: CPU) -> None:
        cpu.carry = 1 if cpu.get_reg8(R8.A) < cpu.get_reg8(self.r) else 0

    def pretty(self) -> str:
        return f"CP A, {self.r.value}"


@dataclass
class CP_A_N(Insn):
    n: int

    def exec(self, cpu: CPU) -> None:
        cpu.carry = 1 if cpu.get_reg8(R8.A) < self.n else 0

    def pretty(self) -> str:
        return f"CP A, {hex(self.n)}"


@dataclass
class CP_A_HL(Insn):
    def exec(self, cpu: CPU) -> None:
        cpu.carry = 1 if cpu.get_reg8(R8.A) < cpu.get_mem8(cpu.get_reg16(R16.HL)) else 0

    def pretty(self) -> str:
        return "CP A, (HL)"


@dataclass
class INC_R(Insn):
    r: R8

    def exec(self, cpu: CPU) -> None:
        cpu.set_reg8(self.r, cpu.get_reg8(self.r) + 1)

    def pretty(self) -> str:
        return f"INC {self.r.value}"


@dataclass
class INC_HL(Insn):
    r: R8

    def exec(self, cpu: CPU) -> None:
        hl = cpu.get_reg16(R16.HL)
        cpu.set_mem8(hl, cpu.get_mem8(hl) + 1)

    def pretty(self) -> str:
        return "INC (HL)"


@dataclass
class DEC_R(Insn):
    r: R8

    def exec(self, cpu: CPU) -> None:
        cpu.set_reg8(self.r, cpu.get_reg8(self.r) - 1)

    def pretty(self) -> str:
        return f"DEC {self.r.value}"


@dataclass
class DEC_HL(Insn):
    r: R8

    def exec(self, cpu: CPU) -> None:
        hl = cpu.get_reg16(R16.HL)
        cpu.set_mem8(hl, cpu.get_mem8(hl) - 1)

    def pretty(self) -> str:
        return "DEC (HL)"


@dataclass
class CPL(Insn):
    def exec(self, cpu: CPU) -> None:
        cpu.set_reg8(R8.A, cpu.get_reg8(R8.A) ^ 0xFF)


@dataclass
class ADD_HL_RR(Insn):
    rr: R16

    def exec(self, cpu: CPU) -> None:
        hl = cpu.get_reg16(R16.HL) + cpu.get_reg16(self.rr)
        cpu.carry = 1 if hl > 0xFFFF else 0
        cpu.set_reg16(R16.HL, hl)

    def pretty(self) -> str:
        return f"ADD HL, {self.rr.value}"


@dataclass
class INC_RR(Insn):
    rr: R16

    def exec(self, cpu: CPU) -> None:
        cpu.set_reg16(self.rr, cpu.get_reg16(self.rr) + 1)

    def pretty(self) -> str:
        return f"INC {self.rr.value}"


@dataclass
class DEC_RR(Insn):
    rr: R16

    def exec(self, cpu: CPU) -> None:
        cpu.set_reg16(self.rr, cpu.get_reg16(self.rr) - 1)

    def pretty(self) -> str:
        return f"DEC {self.rr.value}"


@dataclass
class ADD_SP_DD(Insn):
    dd: int

    def exec(self, cpu: CPU) -> None:
        sp = cpu.get_reg16(R16.SP) + self.dd
        cpu.carry = 1 if sp > 0xFFFF or sp < 0 else 0
        cpu.set_reg16(R16.SP, sp)

    def pretty(self) -> str:
        return f"ADD SP, {self.dd}"


@dataclass
class LD_HL_SP_DD(Insn):
    dd: int

    def exec(self, cpu: CPU) -> None:
        sp = cpu.get_reg16(R16.SP) + self.dd
        cpu.carry = 1 if sp > 0xFFFF or sp < 0 else 0
        cpu.set_reg16(R16.HL, sp)

    def pretty(self) -> str:
        return f"LD HL, SP + {self.dd}"


@dataclass
class RLCA(Insn):
    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A)
        cpu.carry = (a >> 7) & 1
        cpu.set_reg8(R8.A, ((a << 1) & 0xFF) | cpu.carry)

    def pretty(self) -> str:
        return "RLCA"


@dataclass
class RLA(Insn):
    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A)
        next_carry = (a >> 7) & 1
        cpu.set_reg8(R8.A, ((a << 1) & 0xFF) | cpu.carry)
        cpu.carry = next_carry

    def pretty(self) -> str:
        return "RLA"


@dataclass
class RRCA(Insn):
    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A)
        cpu.carry = a & 1
        cpu.set_reg8(R8.A, (a >> 1) | (cpu.carry << 7))

    def pretty(self) -> str:
        return "RRCA"


@dataclass
class RRA(Insn):
    def exec(self, cpu: CPU) -> None:
        a = cpu.get_reg8(R8.A)
        next_carry = a & 1
        cpu.set_reg8(R8.A, (a >> 1) | (cpu.carry << 7))
        cpu.carry = next_carry

    def pretty(self) -> str:
        return "RRA"


@dataclass
class RLC_R(Insn):
    r: R8

    def exec(self, cpu: CPU) -> None:
        r = cpu.get_reg8(self.r)
        cpu.carry = (r >> 7) & 1
        cpu.set_reg8(self.r, ((r << 1) & 0xFF) | cpu.carry)

    def pretty(self) -> str:
        return f"RLC {self.r}"


@dataclass
class RLC_HL(Insn):
    def exec(self, cpu: CPU) -> None:
        hl = cpu.deref_hl()
        cpu.carry = (hl >> 7) & 1
        cpu.deref_hl_set(((hl << 1) & 0xFF) | cpu.carry)

    def pretty(self) -> str:
        return f"RLC (HL)"


@dataclass
class RL_R(Insn):
    r: R8

    def exec(self, cpu: CPU) -> None:
        r = cpu.get_reg8(self.r)
        next_carry = (r >> 7) & 1
        cpu.set_reg8(self.r, ((r << 1) & 0xFF) | cpu.carry)
        cpu.carry = next_carry

    def pretty(self) -> str:
        return f"RL {self.r}"


@dataclass
class RL_HL(Insn):
    def exec(self, cpu: CPU) -> None:
        hl = cpu.deref_hl()
        next_carry = (hl >> 7) & 1
        cpu.deref_hl_set(((hl << 1) & 0xFF) | cpu.carry)
        cpu.carry = next_carry

    def pretty(self) -> str:
        return "RL (HL)"


@dataclass
class RRC_R(Insn):
    r: R8

    def exec(self, cpu: CPU) -> None:
        r = cpu.get_reg8(self.r)
        cpu.carry = r & 1
        cpu.set_reg8(self.r, (r >> 1) | (cpu.carry << 7))

    def pretty(self) -> str:
        return f"RRC {self.r}"


@dataclass
class RRC_HL(Insn):
    def exec(self, cpu: CPU) -> None:
        hl = cpu.deref_hl()
        cpu.carry = hl & 1
        cpu.deref_hl_set((hl >> 1) | (cpu.carry << 7))

    def pretty(self) -> str:
        return "RRC (HL)"


@dataclass
class RR_R(Insn):
    r: R8

    def exec(self, cpu: CPU) -> None:
        r = cpu.get_reg8(self.r)
        next_carry = r & 1
        cpu.set_reg8(self.r, (r >> 1) | (cpu.carry << 7))
        cpu.carry = next_carry

    def pretty(self) -> str:
        return f"RR {self.r}"


@dataclass
class RR_HL(Insn):
    def exec(self, cpu: CPU) -> None:
        hl = cpu.deref_hl()
        next_carry = hl & 1
        cpu.deref_hl_set((hl >> 1) | (cpu.carry << 7))
        cpu.carry = next_carry

    def pretty(self) -> str:
        return "RR (HL)"


@dataclass
class SLA_R(Insn):
    r: R8

    def exec(self, cpu: CPU) -> None:
        r = cpu.get_reg8(self.r)
        cpu.set_reg8(self.r, (r << 1) & 0xFF)

    def pretty(self) -> str:
        return f"SLA {self.r}"


@dataclass
class SLA_HL(Insn):
    def exec(self, cpu: CPU) -> None:
        hl = cpu.deref_hl()
        cpu.deref_hl_set((hl << 1) & 0xFF)

    def pretty(self) -> str:
        return "SLA (HL)"


@dataclass
class SWAP_R(Insn):
    r: R8

    def exec(self, cpu: CPU) -> None:
        r = cpu.get_reg8(self.r)
        cpu.set_reg8(self.r, ((r << 4) & 0xFF) | (r >> 4))

    def pretty(self) -> str:
        return f"SWAP {self.r}"


@dataclass
class SWAP_HL(Insn):
    def exec(self, cpu: CPU) -> None:
        hl = cpu.deref_hl()
        cpu.deref_hl_set(((hl << 4) & 0xFF) | (hl >> 4))

    def pretty(self) -> str:
        return "SWAP (HL)"


@dataclass
class SRA_R(Insn):
    r: R8

    def exec(self, cpu: CPU) -> None:
        r = cpu.get_reg8(self.r)
        cpu.set_reg8(self.r, (r >> 1) | (r & (1 << 7)))

    def pretty(self) -> str:
        return f"SRA {self.r}"


@dataclass
class SRA_HL(Insn):
    def exec(self, cpu: CPU) -> None:
        hl = cpu.deref_hl()
        cpu.deref_hl_set((hl >> 1) | (hl & (1 << 7)))

    def pretty(self) -> str:
        return "SRA (HL)"


@dataclass
class SRL_R(Insn):
    r: R8

    def exec(self, cpu: CPU) -> None:
        r = cpu.get_reg8(self.r)
        cpu.set_reg8(self.r, r >> 1)

    def pretty(self) -> str:
        return f"SRL {self.r}"


@dataclass
class SRL_HL(Insn):
    def exec(self, cpu: CPU) -> None:
        hl = cpu.deref_hl()
        cpu.deref_hl_set(hl >> 1)

    def pretty(self) -> str:
        return "SRL (HL)"


# TODO: Remaining rotate and shift instructions


@dataclass
class SET_N_R(Insn):
    n: int
    r: R8

    def exec(self, cpu: CPU) -> None:
        cpu.set_reg8(self.r, cpu.get_reg8(self.r) | (1 << self.n))

    def pretty(self) -> str:
        return f"SET {self.n}, (HL)"


@dataclass
class SET_N_HL(Insn):
    n: int

    def exec(self, cpu: CPU) -> None:
        hl = cpu.get_reg16(R16.HL)
        cpu.set_mem8(hl, cpu.get_mem8(hl) | (1 << self.n))

    def pretty(self) -> str:
        return f"SET {self.n}, (HL)"


@dataclass
class RES_N_R(Insn):
    n: int
    r: R8

    def exec(self, cpu: CPU) -> None:
        cpu.set_reg8(self.r, cpu.get_reg8(self.r) & ~(1 << self.n))

    def pretty(self) -> str:
        return f"RES {self.n}, (HL)"


@dataclass
class RES_N_HL(Insn):
    n: int

    def exec(self, cpu: CPU) -> None:
        hl = cpu.get_reg16(R16.HL)
        cpu.set_mem8(hl, cpu.get_mem8(hl) & ~(1 << self.n))

    def pretty(self) -> str:
        return f"RES {self.n}, (HL)"


@dataclass
class CCF(Insn):
    def exec(self, cpu: CPU) -> None:
        cpu.carry = cpu.carry ^ 1

    def pretty(self) -> str:
        return "CCF"


@dataclass
class SCF(Insn):
    def exec(self, cpu: CPU) -> None:
        cpu.carry = 1

    def pretty(self) -> str:
        return "SCF"