from linux_input import *
from linux_uinput import *

import array, struct, fcntl, os, sys

def get_input_version(f):
    """
    Returns the input version of a specified fd of a device
    """
    buf = array.array('i', [0])
    r = fcntl.ioctl(f, EVIOCGVERSION, buf)
    v = struct.unpack('@i', buf)[0]
    del buf
    return "%d.%d.%d" % ( v >> 16, (v >> 8) & 0xff, v & 0xff)

def get_input_name(f, l=256):
    """
    Returns the name of a specified fd of a device
    """
    buf = array.array('c', ' ' * l)
    r = fcntl.ioctl(f, EVIOCGNAME(l), buf)
    v = struct.unpack('%ds' % l, buf)[0]
    del buf
    return v[:r]

_bpl = struct.calcsize('@L') * 8
_nbits = lambda x: ((x-1) / _bpl) + 1
_ll = _nbits(KEY_MAX)
test_bit = lambda j, v: (v[j / _bpl] >> (j % _bpl)) & 1

def get_keys(f, ev):
    """
    Get keys of type *f* from a specific input device *f*.
    """
    buf = array.array('L', [0L] * _ll)
    try:
        fcntl.ioctl(f, EVIOCGBIT(ev, KEY_MAX), buf)
    except IOError:
        #print >>sys.stderr, 'Whoops!', rev_events[ev]
        return None

    v = struct.unpack('@%dL' % _ll, buf)
    del buf

    r = []
    for j in range(0, KEY_MAX):
        if test_bit(j, v):
            r.append(j)

    return r


def copy_event(estr):
    """
    Copy event from a string returned by read().
    We return a copy because the string will probably be freed.
    """
    e = ctypes.cast(estr, ctypes.POINTER(input_event))
    ev = e.contents

    return input_event(ev.time, ev.type, ev.code, ev.value)

class InputDevice(object):
    """
    Class for reading input devices in /dev/input/
    """

    def __init__(self, path):
        self._f = os.open(path, os.O_RDONLY)

    def get_version(self):
        """
        Returns the version of the input device.
        """
        return get_input_version(self._f)

    def get_name(self):
        """
        Returns the name of the input device.
        """
        return get_input_name(self._f)

    def get_exposed_events(self):
        """
        Returns all the keys exposed by this input device.
        """
        d = dict()
        for k, v in events.iteritems():
            l = get_keys(self._f, v)
            if l:
                d[k] = []
                for ev in l:
                    try:
                        d[k].append(rev_event_keys[v][ev])
                    except KeyError:
                        pass

        return d

    def next_event(self):
        """
        Read the next event from the input device
        """
        estr = os.read(self._f, ctypes.sizeof(input_event))
        return copy_event(estr)

    def get_fd(self):
        """
        Returns the underlying fd.
        """
        return self._f


    def __del__(self):
        if hasattr(self, '_f'):
            os.close(self._f)


def open_uinput():
    try:
        f = os.open('/dev/uinput',  os.O_WRONLY | os.O_NONBLOCK)
    except OSError:
        try:
            f = os.open('/dev/input/uinput', os.O_WRONLY | os.O_NONBLOCK)
        except OSError:
            print 'FAIL MUCH?'
            return None
    return f

def write_uinput_device_info(f, name):
    """
    Create uinput device
    """

    # Add keys, etc
    #handle_specs(f, specs)

    # Allocate other info
    uidev = uinput_user_dev()

    # TODO: Get from specs
    uidev.name = name
    uidev._id.bustype = 0x03 # BUS_USB (TODO)
    uidev._id.vendor = 0x42
    uidev._id.product = 0xbebe
    uidev._id.version = 1

    buf = buffer(uidev)[:]

    # Write dev info
    os.write(f, buf)

    fcntl.ioctl(f, UI_DEV_CREATE)

    return f

def free_uinput_device(f):
    return fcntl.ioctl(f, UI_DEV_DESTROY)

class UInputDevice(object):

    """
    Class to create input devices using /dev/(input/)?uinput

    """

    def __init__(self):
        self._f = open_uinput()
        if not self._f:
            print 'Failed to open uinput'
            raise OSError

    def setup(self, name):
        """
        Writes initial data and transforms the fd into the input device
        """
        write_uinput_device_info(self._f, name)

    def expose_event_type(self, evt):
        """
        Exposes a specific event type.
        """
        fcntl.ioctl(self._f, UI_SET_EVBIT, evt)

    def expose_event(self, evt, evk):
        """
        Exposes an event; make sure the event type is exposed as well.
        """
        evbit = evbits[evt]
        fcntl.ioctl(self._f, evbit, evk)

    def fire_event(self, ev):
        """
        Fire a new input event.
        """
        os.write(self._f, buffer(ev)[:])

    def __del__(self):
        if hasattr(self, '_f'):
            free_uinput_device(self._f)