from struct import Struct
from array import array
import fcntl

import ioctls

DTV_UNDEFINED = 0
DTV_TUNE = 1
DTV_CLEAR = 2
DTV_FREQUENCY = 3
DTV_MODULATION = 4
DTV_BANDWIDTH_HZ = 5
DTV_INVERSION = 6
DTV_DISEQC_MASTER = 7
DTV_SYMBOL_RATE = 8
DTV_INNER_FEC = 9
DTV_VOLTAGE = 10
DTV_TONE = 11
DTV_PILOT = 12
DTV_ROLLOFF = 13
DTV_DISEQC_SLAVE_REPLY = 14
DTV_FE_CAPABILITY_COUNT = 15
DTV_FE_CAPABILITY = 16
DTV_DELIVERY_SYSTEM = 17
DTV_API_VERSION = 35
DTV_API_VERSION = 35
DTV_CODE_RATE_HP = 36
DTV_CODE_RATE_LP = 37
DTV_GUARD_INTERVAL = 38
DTV_TRANSMISSION_MODE = 39
DTV_HIERARCHY = 40
DTV_MAX_COMMAND = 40

dtv_properties = Struct("IP")
dtv_property_u32 = Struct("I12xI44xPI")
	# The P is unused, but we need it here because we don't know the
	# size of void*
dtv_property_buffer = Struct("I12x32BI12xPI")
dvb_frontend_event = Struct("I32x")
dmx_pes_filter = Struct("HIIII")

def cvt32(i):
	return int(-(i ^ 0xffffffff)-1)

class Property(object):
	def __init__(self, type=DTV_UNDEFINED, value=0, buf=None):
		if buf == None:
			self.type = type
			self.value = value
		else:
			res = dtv_property_u32.unpack(buf)
			self.type = res[0]
			self.value = res[1]
			self.result = res[3]

	def __iter__(self):
		arr = dtv_property_u32.pack(self.type, self.value, 0, 0)
		return iter(arr)

class Properties(list):
	def _properties(self, f, ioctl):
		# Construct an array of the things we want to know
		buf = array('c')
		for p in self:
			buf.extend(p)

		# Get its address
		rladdr, rllen = buf.buffer_info()
		# Create the header to pass to the ioctl
		head = dtv_properties.pack(len(self), rladdr)
		fcntl.ioctl(f, cvt32(ioctl), head)
		# Read the data back into the array
		stride = dtv_property_u32.size
		for i in range(0, len(self)):
			pos = i*stride
			self[i] = Property(buf=buf[pos:pos+stride])

	def get_properties(self, f):
		self._properties(f, ioctls.FE_GET_PROPERTY)

	def set_properties(self, f):
		self._properties(f, ioctls.FE_SET_PROPERTY)