use crate::device;
use crate::ui;

pub const JCMD_STATUS: u8 = 0x00;
pub const JCMD_CONTROLLER_READ: u8 = 0x01;
pub const JCMD_PAK_READ: u8 = 0x02;
pub const JCMD_PAK_WRITE: u8 = 0x03;
//pub const JCMD_VRU_READ: u8 = 0x09;
//pub const JCMD_VRU_WRITE: u8 = 0x0A;
//pub const JCMD_VRU_READ_STATUS: u8 = 0x0B;
//pub const JCMD_VRU_WRITE_CONFIG: u8 = 0x0C;
//pub const JCMD_VRU_WRITE_INIT: u8 = 0x0D;
pub const JCMD_RESET: u8 = 0xff;

//pub const JDT_NONE: u16 = 0x0000;
pub const JDT_JOY_ABS_COUNTERS: u16 = 0x0001; /* joystick with absolute coordinates */
//pub const JDT_JOY_REL_COUNTERS: u16 = 0x0002; /* joystick with relative coordinates (= mouse) */
pub const JDT_JOY_PORT: u16 = 0x0004; /* has port for external paks */
//pub const JDT_VRU: u16 = 0x0100; /* VRU */
pub const PAK_CHUNK_SIZE: usize = 0x20;
pub const CONT_STATUS: u8 = 0;
pub const CONT_FLAVOR: u16 = JDT_JOY_ABS_COUNTERS | JDT_JOY_PORT;

pub fn process(device: &mut device::Device, channel: usize) {
    let cmd = device.pif.ram[device.pif.channels[channel].tx_buf.unwrap()];

    match cmd {
        JCMD_RESET => { /* reset  */ }
        JCMD_STATUS => {
            device.pif.ram[device.pif.channels[channel].rx_buf.unwrap()] = CONT_FLAVOR as u8;
            device.pif.ram[device.pif.channels[channel].rx_buf.unwrap() + 1] =
                (CONT_FLAVOR >> 8) as u8;
            device.pif.ram[device.pif.channels[channel].rx_buf.unwrap() + 2] = CONT_STATUS;
        }
        JCMD_CONTROLLER_READ => {
            let offset = device.pif.channels[channel].rx_buf.unwrap();
            let input = ui::input::get(&mut device.ui, channel);
            device.pif.ram[offset..offset + 4].copy_from_slice(&input.to_ne_bytes());
        }
        JCMD_PAK_READ => pak_read_block(
            device,
            device.pif.channels[channel].tx_buf.unwrap() + 1,
            device.pif.channels[channel].rx_buf.unwrap(),
            device.pif.channels[channel].rx_buf.unwrap() + 32,
        ),
        JCMD_PAK_WRITE => pak_write_block(
            device,
            device.pif.channels[channel].tx_buf.unwrap() + 1,
            device.pif.channels[channel].tx_buf.unwrap() + 3,
            device.pif.channels[channel].rx_buf.unwrap(),
        ),
        _ => println!("unknown controller command {}", cmd),
    }
}

pub fn pak_read_block(device: &mut device::Device, _addr_acrc: usize, data: usize, dcrc: usize) {
    //let address = (device.pif.ram[addr_acrc] << 8) | (device.pif.ram[addr_acrc + 1] & 0xe0);

    //TODO: paks
    device.pif.ram[dcrc] = !pak_data_crc(device, data, PAK_CHUNK_SIZE)
}

pub fn pak_write_block(device: &mut device::Device, _addr_acrc: usize, data: usize, dcrc: usize) {
    //let address = (device.pif.ram[addr_acrc] << 8) | (device.pif.ram[addr_acrc + 1] & 0xe0);

    //TODO: paks
    device.pif.ram[dcrc] = !pak_data_crc(device, data, PAK_CHUNK_SIZE)
}

pub fn pak_data_crc(device: &mut device::Device, data_offset: usize, size: usize) -> u8 {
    let mut i = 0;
    let mut crc = 0;

    while i <= size {
        let mut mask = 0x80;
        while mask >= 1 {
            let xor_tap;
            if crc & 0x80 != 0 {
                xor_tap = 0x85
            } else {
                xor_tap = 0x00
            }
            crc <<= 1;
            if i != size && (device.pif.ram[data_offset + i] & mask) != 0 {
                crc |= 1;
            }
            crc ^= xor_tap;
            mask >>= 1
        }
        i += 1;
    }
    return crc;
}