from nmigen.build import *


__all__ = ["I2CResource"]


def I2CResource(*args, sda, scl, conn=None, attrs=None, role="host"):
	assert role in ("host", "device")

	io = []

	# sda line: I/O port for the data line
	io.append(Subsignal("sda", Pins(sda, dir="io", conn=conn, assert_width=1)))

	# sck line: I2C clock signal outputs from master to slave
	if role == "host":
		io.append(Subsignal("scl", Pins(scl, dir="o", conn=conn, assert_width=1)))
	else:	#device
		io.append(Subsignal("scl", Pins(scl, dir="i", conn=conn, assert_width=1)))

	if attrs is not None:
		io.append(attrs)
	return Resource.family(*args, default_name="i2c", ios=io)

'''
# Auto create a resource list given a set of iCE40 pins and STM32 pin names (pins_dict)
def GPIOResources(*args, pins_dict, dir = "o", invert=False, conn=None, attrs=None):

	# Check data integrity: pins_dict must be a dict AND port must be from a to k
	assert isinstance(pins_dict, dict)

	# Debug: dir == "o"
	assert dir == "o"

	# List of resources to be returned
	resources = []
	for STM32_pin, iCE40_pin in pins_dict.items():

		# Set all gpio pins to be output only for the time being

		# TODO: Allow dir argument.
		ios = [Pins(iCE40_pin, dir=dir, invert=invert, conn=conn)]
		if attrs is not None:
			ios.append(attrs)

		# Extract GPIO port and port number from STM32_pin
		# Strip "P" from P<port><port_num>
		if STM32_pin.startswith('P'):
			STM32_pin = STM32_pin[1:]

		# Acquire port from <port><port_num>
		port = STM32_pin[0].lower()
		port_num = int(STM32_pin[1:])

		# Insert gpio<port>.<portNum> into resources list
		resources.append(Resource.family(*args, port_num, default_name=("gpio"+port), ios=ios))
	return resources

# Auto create a resource list for differential I/O
def DiffResources(*args, eem_pins, invert=False, conn=None, attrs=None, dir):
	# TODO: Everything

	# assert dimensionality
	assert isinstance(eem_pins, list)
	assert isinstance(eem_pins[0], list)
	assert isinstance(eem_pins[0][0], list)
	assert isinstance(eem_pins[0][0][0], str)

	# assert direction to be either input or output
	# reject tristate or bidirectional pin
	assert dir in ("i", "o")




if __name__ == "__main__":

	from pin_mapper import *
	eem = diffMapping()
	DiffResources(eem_pins = eem, dir = "o",
		attrs=Attrs(IO_STANDARD="SB_LVCMOS")
	)
'''