import asm
import intr.idt as idt
import drivers.serial.uart.serial as serial
import viperstring as string
import t, c


KBD_DATA:    t.CDefine = 0x60
KBD_STATUS:  t.CDefine = 0x64
KBD_COMMAND: t.CDefine = 0x64

KBD_BUF_SIZE: t.CDefine = 1024

KEY_RELEASED: t.CDefine = 0x80

buffer:     t.CArray[t.CUInt8T, KBD_BUF_SIZE]
buf_head:  t.CStatic | t.CUInt32T = 0
buf_tail:  t.CStatic | t.CUInt32T = 0
buf_count: t.CStatic | t.CUInt32T = 0

shift_l:   t.CStatic | t.CUInt8T = 0
shift_r:   t.CStatic | t.CUInt8T = 0
ctrl_l:    t.CStatic | t.CUInt8T = 0
alt_l:     t.CStatic | t.CUInt8T = 0
caps_lock: t.CStatic | t.CUInt8T = 0

scancode_set1: t.CArray[t.CChar, 128] = [
    '\0', '\x1b', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '-', '=', '\b',
    '\t', 'q', 'w', 'e', 'r', 't', 'y', 'u', 'i', 'o', 'p', '[', ']', '\n',
    '\0', 'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';', "'", '`', '\0',
    '\\', 'z', 'x', 'c', 'v', 'b', 'n', 'm', ',', '.', '/', '\0', '\0', '\0', ' ',
    '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '-', '8', '6', '2', '\0',
    '1', '+', '4', '5', '3', '0', '.', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
    '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
    '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
    '\0'
]

scancode_set1_shift: t.CArray[t.CChar, 128] = [
    '\0', '\x1b', '!', '@', '#', '$', '%', '^', '&', '*', '(', ')', '_', '+', '\b',
    '\t', 'Q', 'W', 'E', 'R', 'T', 'Y', 'U', 'I', 'O', 'P', '{', '}', '\n',
    '\0', 'A', 'S', 'D', 'F', 'G', 'H', 'J', 'K', 'L', ':', '"', '~', '\0',
    '|', 'Z', 'X', 'C', 'V', 'B', 'N', 'M', '<', '>', '?', '\0', '\0', '\0', ' ',
    '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '-', '8', '6', '2', '\0',
    '1', '+', '4', '5', '3', '0', '.', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
    '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
    '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
    '\0'
]

def _wait_read():
    timeout: t.CUInt32T = 100000
    while timeout > 0:
        if (asm.inb(KBD_STATUS) & 0x01) != 0: return
        timeout -= 1

def _wait_write():
    timeout: t.CUInt32T = 100000
    while timeout > 0:
        if (asm.inb(KBD_STATUS) & 0x02) == 0: return
        timeout -= 1

def irq_handler() -> t.CInt:
    global buf_head, buf_tail, buf_count
    scancode: t.CUInt8T = asm.inb(KBD_DATA)
    if buf_count < KBD_BUF_SIZE:
        buffer[buf_tail] = scancode
        buf_tail = buf_tail + 1
        if buf_tail >= KBD_BUF_SIZE:
            buf_tail = 0
        buf_count += 1
    return 0

def read_scancode() -> t.CUInt8T:
    global buf_head, buf_count
    asm.cli()
    if buf_count == 0:
        asm.sti()
        return 0
    code: t.CUInt8T = buffer[buf_head]
    buf_head = buf_head + 1
    if buf_head >= KBD_BUF_SIZE:
        buf_head = 0
    buf_count -= 1
    asm.sti()
    return code

def scancode_to_ascii(scancode: t.CUInt8T) -> t.CChar:
    code: t.CUInt8T = scancode & ~t.CUInt8T(KEY_RELEASED)
    if code >= 128: return '\0'
    shifted: bool = (shift_l or shift_r) != 0
    if caps_lock and code >= 0x10 and code <= 0x32:
        shifted = not shifted
    if shifted:
        return scancode_set1_shift[code]
    return scancode_set1[code]

def has_data() -> t.CInt:
    return buf_count

def init():
    drain: t.CUInt32T
    drain = 0
    while (asm.inb(KBD_STATUS) & 0x01) != 0:
        asm.inb(KBD_DATA)
        drain += 1
        if drain > 1000: break

    _wait_write()
    asm.outb(KBD_COMMAND, 0xAD)

    drain = 0
    while (asm.inb(KBD_STATUS) & 0x01) != 0:
        asm.inb(KBD_DATA)
        drain += 1
        if drain > 1000: break

    _wait_write()
    asm.outb(KBD_COMMAND, 0x20)
    _wait_read()
    ccb: t.CUInt8T = asm.inb(KBD_DATA)

    ccb = ccb | 0x01
    ccb = ccb | 0x40
    ccb = ccb & 0xEF

    _wait_write()
    asm.outb(KBD_COMMAND, 0x60)
    _wait_write()
    asm.outb(KBD_DATA, ccb)

    _wait_write()
    asm.outb(KBD_COMMAND, 0xAE)

    drain = 0
    while (asm.inb(KBD_STATUS) & 0x01) != 0:
        asm.inb(KBD_DATA)
        drain += 1
        if drain > 1000: break

    _wait_write()
    asm.outb(KBD_DATA, 0xF4)
    _wait_read()
    asm.inb(KBD_DATA)

    idt.irqInstallHandler(1, irq_handler, "keyboard")