import t, c
import drivers.usb.usb as usb
import drivers.usb.hid.hid as hid
import drivers.usb.uhci as uhci
import drivers.serial.uart.serial as serial

KBD_BUF_SIZE: t.CDefine = 1024
KBD_EVT_PRESS: t.CDefine = 0
KBD_EVT_RELEASE: t.CDefine = 1

class usb_kbd_event(t.CStruct):
    modifier: t.CUInt8T
    keycode: t.CUInt8T
    event_type: t.CUInt8T

kbd_buf: t.CArray[usb_kbd_event, KBD_BUF_SIZE]
kbd_buf_head: t.CInt = 0
kbd_buf_tail: t.CInt = 0
kbd_buf_count: t.CInt = 0
kbd_dev: usb.usb_device | t.CPtr = None
kbd_report: hid.hid_kbd_report
kbd_prev_keycodes: t.CArray[t.CUInt8T, 6]
kbd_initialized: t.CInt = 0
kbd_slot_id: t.CInt = -1

def init() -> t.CInt:
    global kbd_dev, kbd_initialized, kbd_slot_id
    dev: usb.usb_device | t.CPtr = usb.find_hid_device(0x01)
    if dev is None:
        serial.puts("[usb_kbd] no USB keyboard found\n")
        return -1
    kbd_dev = dev
    if hid.init_keyboard(dev) != 0:
        serial.puts("[usb_kbd] init failed\n")
        return -2
    kbd_initialized = 1
    serial.puts("[usb_kbd] initialized\n")
    kbd_slot_id = uhci.register_int_callback(c.Addr(_on_int_complete))
    if kbd_slot_id < 0:
        serial.puts("[usb_kbd] register callback failed\n")
        kbd_initialized = 0
        return -3
    uhci.schedule_int_transfer(kbd_slot_id, dev.addr, dev.ep_in, dev.ls, t.CUInt8T(dev.ep_in_max), dev.ep_in_toggle, c.Addr(kbd_report))
    return 0

def _on_int_complete() -> t.CInt:
    global kbd_buf_head, kbd_buf_tail, kbd_buf_count, kbd_prev_keycodes
    if kbd_initialized == 0: return 0
    i: t.CInt
    j: t.CInt
    for i in range(6):
        code: t.CUInt8T = kbd_report.keycode[i]
        if code == 0: continue
        found: t.CInt = 0
        for j in range(6):
            if code == kbd_prev_keycodes[j]:
                found = 1
                break
        if found == 0:
            if kbd_buf_count < KBD_BUF_SIZE:
                kbd_buf[kbd_buf_tail].modifier = kbd_report.modifier
                kbd_buf[kbd_buf_tail].keycode = code
                kbd_buf[kbd_buf_tail].event_type = KBD_EVT_PRESS
                kbd_buf_tail = kbd_buf_tail + 1
                if kbd_buf_tail >= KBD_BUF_SIZE:
                    kbd_buf_tail = 0
                kbd_buf_count += 1
    for i in range(6):
        prev: t.CUInt8T = kbd_prev_keycodes[i]
        if prev == 0: continue
        found2: t.CInt = 0
        for j in range(6):
            if prev == kbd_report.keycode[j]:
                found2 = 1
                break
        if found2 == 0:
            if kbd_buf_count < KBD_BUF_SIZE:
                kbd_buf[kbd_buf_tail].modifier = kbd_report.modifier
                kbd_buf[kbd_buf_tail].keycode = prev
                kbd_buf[kbd_buf_tail].event_type = KBD_EVT_RELEASE
                kbd_buf_tail = kbd_buf_tail + 1
                if kbd_buf_tail >= KBD_BUF_SIZE:
                    kbd_buf_tail = 0
                kbd_buf_count += 1
    for i in range(6):
        kbd_prev_keycodes[i] = kbd_report.keycode[i]
    dev: usb.usb_device | t.CPtr = kbd_dev
    if dev is not None and kbd_slot_id >= 0:
        uhci.schedule_int_transfer(kbd_slot_id, dev.addr, dev.ep_in, dev.ls, t.CUInt8T(dev.ep_in_max), dev.ep_in_toggle, c.Addr(kbd_report))
    return 0

def has_data() -> t.CInt:
    if kbd_buf_count > 0: return 1
    return 0

def poll() -> t.CInt:
    if kbd_initialized == 0: return 0
    if kbd_buf_count > 0: return 1
    return 0

def read_event(out: usb_kbd_event | t.CPtr) -> t.CInt:
    global kbd_buf_head, kbd_buf_count
    if kbd_buf_count == 0: return -1
    out.modifier = kbd_buf[kbd_buf_head].modifier
    out.keycode = kbd_buf[kbd_buf_head].keycode
    out.event_type = kbd_buf[kbd_buf_head].event_type
    kbd_buf_head = kbd_buf_head + 1
    if kbd_buf_head >= KBD_BUF_SIZE:
        kbd_buf_head = 0
    kbd_buf_count -= 1
    return 0