from migen.fhdl.structure import *
from migen.fhdl.structure import _make_signal_name

class Record:
	def __init__(self, layout, name=None):
		self.name = name or _make_signal_name()
		self.field_order = []
		for f in layout:
			if isinstance(f, tuple):
				if isinstance(f[1], BV):
					setattr(self, f[0], Signal(f[1], self.name + "_" + f[0]))
				elif isinstance(f[1], Signal) or isinstance(f[1], Record):
					setattr(self, f[0], f[1])
				elif isinstance(f[1], list):
					setattr(self, f[0], Record(f[1], self.name + "_" + f[0]))
				else:
					raise TypeError
				self.field_order.append(f[0])
			else:
				setattr(self, f, Signal(BV(1), self.name + "_" + f))
				self.field_order.append(f)

	def layout(self):
		l = []
		for key in self.field_order:
			e = self.__dict__[key]
			if isinstance(e, Signal):
				l.append((key, e.bv))
			elif isinstance(e, Record):
				l.append((key, e.layout()))
		return l
	
	def copy(self, name=None):
		return Record(self.layout(), name or _make_signal_name())
	
	def subrecord(self, *descr):
		fields = []
		for item in descr:
			path = item.split('/')
			last = path.pop()
			pos_self = self
			pos_fields = fields
			for hop in path:
				pos_self = getattr(pos_self, hop)
				lu = list(filter(lambda x: x[0] == hop, pos_fields))
				try:
					pos_fields = lu[0][1]
				except IndexError:
					n = []
					pos_fields.append((hop, n))
					pos_fields = n
				if not isinstance(pos_fields, list):
					raise ValueError
			if len(list(filter(lambda x: x[0] == last, pos_fields))) > 0:
				raise ValueError
			pos_fields.append((last, getattr(pos_self, last)))
		return Record(fields, "subrecord")
	
	def compatible(self, other):
		tpl1 = self.flatten()
		tpl2 = other.flatten()
		return len(tpl1) == len(tpl2)
	
	def flatten(self):
		l = []
		for key in self.field_order:
			e = self.__dict__[key]
			if isinstance(e, Signal):
				l.append(e)
			elif isinstance(e, Record):
				l += e.flatten()
		return l
	
	def __repr__(self):
		return repr(self.layout())