import math
from collections import OrderedDict

from migen.fhdl.std import *
from migen.fhdl.decorators import ModuleDecorator
from migen.genlib.resetsync import AsyncResetSynchronizer
from migen.genlib.record import *
from migen.genlib.fsm import FSM, NextState
from migen.genlib.misc import chooser
from migen.flow.actor import *
from migen.flow.plumbing import Buffer
from migen.actorlib.structuring import Converter, Pipeline
from migen.actorlib.fifo import SyncFIFO, AsyncFIFO
from migen.bank.description import *

eth_mtu = 1532
eth_min_len = 46
eth_interpacket_gap = 12
eth_preamble = 0xD555555555555555
buffer_depth = 2**log2_int(eth_mtu, need_pow2=False)

class HField():
	def __init__(self, byte, offset, width):
		self.byte = byte
		self.offset = offset
		self.width = width

ethernet_type_ip = 0x800
ethernet_type_arp = 0x806

mac_header_len = 14
mac_header = {
	"target_mac":		HField(0,  0, 48),
	"sender_mac":		HField(6,  0, 48),
	"ethernet_type":	HField(12, 0, 16)
}

arp_hwtype_ethernet = 0x0001
arp_proto_ip = 0x0800
arp_opcode_request = 0x0001
arp_opcode_reply = 0x0002

arp_header_len = 28
arp_header = {
	"hwtype":			HField( 0,  0, 16),
	"proto":			HField( 2,  0, 16),
	"hwsize":			HField( 4,  0, 8),
	"protosize":		HField( 5,  0, 8),
	"opcode":			HField( 6,  0, 16),
	"sender_mac":		HField( 8,  0, 48),
	"sender_ip":		HField(14,  0, 32),
	"target_mac":		HField(18,  0, 48),
	"target_ip":		HField(24,  0, 32)
}

ipv4_header_len = 20
ipv4_header = {
	"ihl":				HField(0,  0, 4),
	"version":			HField(0,  4, 4),
	"total_length":		HField(2,  0, 16),
	"identification":	HField(4,  0, 16),
	"ttl":				HField(8,  0, 8),
	"protocol":			HField(9,  0, 8),
	"checksum":			HField(10,  0, 16),
	"sender_ip":		HField(12,  0, 32),
	"target_ip":		HField(16,  0, 32)
}

icmp_header_len = 8
icmp_header = {
	"msgtype":		HField( 0,  0, 8),
	"code":			HField( 1,  0, 8),
	"checksum":		HField( 2,  0, 16),
	"quench":		HField( 4,  0, 32)
}
icmp_protocol = 0x01

udp_header_len = 8
udp_header = {
	"src_port":		HField( 0,  0, 16),
	"dst_port":		HField( 2,  0, 16),
	"length":		HField( 4,  0, 16),
	"checksum":		HField( 6,  0, 16)
}

udp_protocol = 0x11

etherbone_magic = 0x4e6f
etherbone_version = 1
etherbone_header_len = 8
etherbone_header = {
	"magic":		HField( 0,  0, 16),
	"portsize":		HField( 2,  0, 4),
	"addrsize":		HField( 2,  4, 4),
	"pf":			HField( 3,  0, 1),
	"version":		HField( 4,  0, 4),

	"wff":			HField( 5,  1, 1),
	"wca":			HField( 5,  2, 1),
	"cyc":			HField( 5,  3, 1),
	"rff":			HField( 5,  5, 1),
	"rca":			HField( 5,  6, 1),
	"bca":			HField( 5,  7, 1),

	"rcount":		HField( 6,  0, 8),

	"wcount":		HField( 7,  0, 8)
}


def reverse_bytes(v):
	n = math.ceil(flen(v)/8)
	r = []
	for i in reversed(range(n)):
		r.append(v[i*8:min((i+1)*8, flen(v))])
	return Cat(iter(r))

# layouts
def _layout_from_header(header):
	_layout = []
	for k, v in sorted(header.items()):
		_layout.append((k, v.width))
	return _layout

def eth_phy_description(dw):
	payload_layout = [
		("data", dw),
		("last_be", dw//8),
		("error", dw//8)
	]
	return EndpointDescription(payload_layout, packetized=True)

def eth_mac_description(dw):
	payload_layout = _layout_from_header(mac_header) + [
		("data", dw),
		("last_be", dw//8),
		("error", dw//8)
	]
	return EndpointDescription(payload_layout, packetized=True)

def eth_arp_description(dw):
	payload_layout = [
		("data", dw),
		("error", dw//8)
	]
	param_layout = _layout_from_header(arp_header)
	return EndpointDescription(payload_layout, param_layout, packetized=True)

arp_table_request_layout = [
	("ip_address", 32)
]

arp_table_response_layout = [
	("failed", 1),
	("mac_address", 48)
]

def eth_ipv4_description(dw):
	payload_layout = [
		("data", dw),
		("error", dw//8)
	]
	param_layout = _layout_from_header(ipv4_header)
	return EndpointDescription(payload_layout, param_layout, packetized=True)

def eth_ipv4_user_description(dw):
	payload_layout = [
		("data", dw),
		("error", dw//8)
	]
	param_layout = [
		("length", 16),
		("protocol", 8),
		("ip_address", 32)
	]
	return EndpointDescription(payload_layout, param_layout, packetized=True)

def convert_ip(s):
	ip = 0
	for e in s.split("."):
		ip = ip << 8
		ip += int(e)
	return ip

def eth_icmp_description(dw):
	payload_layout = [
		("data", dw),
		("error", dw//8)
	]
	param_layout = _layout_from_header(icmp_header)
	return EndpointDescription(payload_layout, param_layout, packetized=True)

def eth_icmp_user_description(dw):
	payload_layout = [
		("data", dw),
		("error", dw//8)
	]
	param_layout = _layout_from_header(icmp_header) + [
		("ip_address", 32),
		("length", 16)
	]
	return EndpointDescription(payload_layout, param_layout, packetized=True)

def eth_udp_description(dw):
	payload_layout = [
		("data", dw),
		("error", dw//8)
	]
	param_layout = _layout_from_header(udp_header)
	return EndpointDescription(payload_layout, param_layout, packetized=True)

def eth_udp_user_description(dw):
	payload_layout = [
		("data", dw),
		("error", dw//8)
	]
	param_layout = [
		("src_port", 16),
		("dst_port", 16),
		("ip_address", 32),
		("length", 16)
	]
	return EndpointDescription(payload_layout, param_layout, packetized=True)

def eth_etherbone_description(dw):
	payload_layout = [
		("data", dw),
		("error", dw//8)
	]
	param_layout = _layout_from_header(etherbone_header)
	return EndpointDescription(payload_layout, param_layout, packetized=True)

def eth_etherbone_description(dw):
	payload_layout = [
		("data", dw),
		("error", dw//8)
	]
	param_layout = _layout_from_header(etherbone_header)
	return EndpointDescription(payload_layout, param_layout, packetized=True)

def eth_etherbone_user_description(dw):
	payload_layout = [
		("data", dw),
		("error", dw//8)
	]
	param_layout = [
		("length", 16),
		("ip_address", 32),
		("wcount", 8),
		("rcount", 8)
	]
	return EndpointDescription(payload_layout, param_layout, packetized=True)


# Generic modules
@DecorateModule(InsertReset)
@DecorateModule(InsertCE)
class FlipFlop(Module):
	def __init__(self, *args, **kwargs):
		self.d = Signal(*args, **kwargs)
		self.q = Signal(*args, **kwargs)
		self.sync += self.q.eq(self.d)

@DecorateModule(InsertReset)
@DecorateModule(InsertCE)
class Counter(Module):
	def __init__(self, signal=None, **kwargs):
		if signal is None:
			self.value = Signal(**kwargs)
		else:
			self.value = signal
		self.width = flen(self.value)
		self.sync += self.value.eq(self.value+1)

@DecorateModule(InsertReset)
@DecorateModule(InsertCE)
class Timeout(Module):
	def __init__(self, length):
		self.reached = Signal()
		###
		value = Signal(max=length)
		self.sync += If(~self.reached, value.eq(value+1))
		self.comb += self.reached.eq(value == (length-1))

class BufferizeEndpoints(ModuleDecorator):
	def __init__(self, submodule, *args):
		ModuleDecorator.__init__(self, submodule)

		endpoints = get_endpoints(submodule)
		sinks = {}
		sources = {}
		for name, endpoint in endpoints.items():
			if name in args or len(args) == 0:
				if isinstance(endpoint, Sink):
					sinks.update({name : endpoint})
				elif isinstance(endpoint, Source):
					sources.update({name : endpoint})

		# add buffer on sinks
		for name, sink in sinks.items():
			buf = Buffer(sink.description)
			self.submodules += buf
			setattr(self, name, buf.d)
			self.comb += Record.connect(buf.q, sink)

		# add buffer on sources
		for name, source in sources.items():
			buf = Buffer(source.description)
			self.submodules += buf
			self.comb += Record.connect(source, buf.d)
			setattr(self, name, buf.q)

class EndpointPacketStatus(Module):
	def __init__(self, endpoint):
		self.start = Signal()
		self.done = Signal()
		self.ongoing = Signal()

		ongoing = Signal()
		self.comb += [
			self.start.eq(endpoint.stb & endpoint.sop & endpoint.ack),
			self.done.eq(endpoint.stb & endpoint.eop & endpoint.ack)
		]
		self.sync += \
			If(self.start,
				ongoing.eq(1)
			).Elif(self.done,
				ongoing.eq(0)
			)
		self.comb += self.ongoing.eq((self.start | ongoing) & ~self.done)

class PacketBuffer(Module):
	def __init__(self, description, data_depth, cmd_depth=4, almost_full=None):
		self.sink = sink = Sink(description)
		self.source = source = Source(description)

		###
		sink_status = EndpointPacketStatus(self.sink)
		source_status = EndpointPacketStatus(self.source)
		self.submodules += sink_status, source_status

		# store incoming packets
		# cmds
		def cmd_description():
			layout = [("error", 1)]
			return EndpointDescription(layout)
		cmd_fifo = SyncFIFO(cmd_description(), cmd_depth)
		self.submodules += cmd_fifo
		self.comb += [
			cmd_fifo.sink.stb.eq(sink_status.done),
			cmd_fifo.sink.error.eq(sink.error)
		]

		# data
		data_fifo = SyncFIFO(description, data_depth, buffered=True)
		self.submodules += data_fifo
		self.comb += [
			Record.connect(self.sink, data_fifo.sink),
			data_fifo.sink.stb.eq(self.sink.stb & cmd_fifo.sink.ack),
			self.sink.ack.eq(data_fifo.sink.ack & cmd_fifo.sink.ack),
		]

		# output packets
		self.fsm = fsm = FSM(reset_state="IDLE")
		self.submodules += fsm
		fsm.act("IDLE",
			If(cmd_fifo.source.stb,
				NextState("SEEK_SOP")
			)
		)
		fsm.act("SEEK_SOP",
			If(~data_fifo.source.sop,
				data_fifo.source.ack.eq(1)
			).Else(
				NextState("OUTPUT")
			)
		)
		fsm.act("OUTPUT",
			Record.connect(data_fifo.source, self.source),
			self.source.error.eq(cmd_fifo.source.error),
			If(source_status.done,
				cmd_fifo.source.ack.eq(1),
				NextState("IDLE")
			)
		)

		# compute almost full
		if almost_full is not None:
			self.almost_full = Signal()
			self.comb += self.almost_full.eq(data_fifo.fifo.level > almost_full)