use moa_core::{System, MemoryBlock, BusPort, Address, Addressable, wrap_transmutable};

use moa_z80::{Z80, Z80Type};
use moa_z80::state::Register;
use moa_z80::decode::{Instruction, LoadTarget, Target, RegisterPair, IndexRegister, IndexRegisterHalf};

fn init_decode_test() -> (Z80, System) {
    let mut system = System::default();

    // Insert basic initialization
    let data = vec![0; 0x10000];
    let mem = MemoryBlock::new(data);
    system.add_addressable_device(0x0000, wrap_transmutable(mem)).unwrap();

    // Initialize the CPU and make sure it's in the expected state
    let mut cpu = Z80::new(Z80Type::Z80, 4_000_000, BusPort::new(0, 16, 8, system.bus.clone()));
    cpu.init().unwrap();

    (cpu, system)
}

fn load_memory(system: &System, data: &[u8]) {
    for i in 0..data.len() {
        system.get_bus().write_u8(i as Address, data[i]).unwrap();
    }
}

fn run_decode_test(data: &[u8]) -> Instruction {
    let (mut cpu, system) = init_decode_test();
    load_memory(&system, data);
    cpu.decode_next().unwrap();
    cpu.decoder.instruction
}

#[test]
fn run_all_decode_tests() {
    let mut failures = vec![];

    for (data, expected_instruction) in DECODE_TESTS {
        let instruction = run_decode_test(data);
        if instruction != *expected_instruction {
            failures.push((data, instruction, expected_instruction));
        }
    }

    let fails = failures.len();
    for (data, instruction, expected_instruction) in failures {
        println!("for {:?}\nexpected:\t{:?}\nreceived:\t{:?}\n", data, instruction, expected_instruction);
    }

    if fails > 0 {
        panic!("{} decode tests failed", fails);
    }
}

const DECODE_TESTS: &'static [(&[u8], Instruction)] = &[
    (&[0x00],               Instruction::NOP),
    (&[0x01, 0x01, 0x02],   Instruction::LD(LoadTarget::DirectRegWord(RegisterPair::BC), LoadTarget::ImmediateWord(0x0201))),
    (&[0x02],               Instruction::LD(LoadTarget::IndirectRegByte(RegisterPair::BC), LoadTarget::DirectRegByte(Register::A))),
    (&[0x03],               Instruction::INC16(RegisterPair::BC)),
    (&[0x04],               Instruction::INC8(Target::DirectReg(Register::B))),
    (&[0x05],               Instruction::DEC8(Target::DirectReg(Register::B))),

    (&[0xDD, 0x09],         Instruction::ADD16(RegisterPair::IX, RegisterPair::BC)),
    (&[0xDD, 0x44],         Instruction::LD(LoadTarget::DirectRegByte(Register::B), LoadTarget::DirectRegHalfByte(IndexRegisterHalf::IXH))),
    (&[0xDD, 0x66, 0x12],   Instruction::LD(LoadTarget::DirectRegByte(Register::H), LoadTarget::IndirectOffsetByte(IndexRegister::IX, 0x12))),
    (&[0xDD, 0x6E, 0x12],   Instruction::LD(LoadTarget::DirectRegByte(Register::L), LoadTarget::IndirectOffsetByte(IndexRegister::IX, 0x12))),
    (&[0xDD, 0x84],         Instruction::ADDa(Target::DirectRegHalf(IndexRegisterHalf::IXH))),
    (&[0xDD, 0x85],         Instruction::ADDa(Target::DirectRegHalf(IndexRegisterHalf::IXL))),
];