import datetime
from litescope.host.dump import *

class VCDDump(Dump):
	def __init__(self, init_dump=None, timescale="1ps", comment=""):
		Dump.__init__(self)
		if init_dump:
			self.vars = init_dump.vars
		self.timescale = timescale
		self.comment = comment
		self.cnt = -1

	def change(self):
		r = ""
		c = ""
		for var in self.vars:
			c += var.change(self.cnt)
		if c != "":
			r += "#"
			r += str(self.cnt+1)
			r += "\n"
			r += c
		return r

	def generate_date(self):
		now = datetime.datetime.now()
		r = "$date\n"
		r += "\t"
		r += now.strftime("%Y-%m-%d %H:%M")
		r += "\n"
		r += "$end\n"
		return r

	def generate_version(self):
		r  = "$version\n"
		r += "\tmiscope VCD dump\n"
		r += "$end\n"
		return r

	def generate_comment(self):
		r  = "$comment\n"
		r += self.comment
		r += "\n$end\n"
		return r

	def generate_timescale(self):
		r  = "$timescale "
		r += self.timescale
		r += " $end\n"
		return r

	def generate_scope(self):
		r  = "$scope "
		r += self.timescale
		r += " $end\n"
		return r

	def generate_vars(self):
		r = ""
		for var in self.vars:
			r += "$var "
			r += var.type
			r += " "
			r += str(var.width)
			r += " "
			r += var.vcd_id
			r += " "
			r += var.name
			r += " $end\n"
		return r

	def generate_unscope(self):
		r  = "$unscope "
		r += " $end\n"
		return r

	def generate_enddefinitions(self):
		r  = "$enddefinitions "
		r += " $end\n"
		return r

	def generate_dumpvars(self):
		r  = "$dumpvars\n"
		for var in self.vars:
			r += "b"
			r += dec2bin(var.val, var.width)
			r += " "
			r += var.vcd_id
			r+= "\n"
		r += "$end\n"
		return r

	def generate_valuechange(self):
		r = ""
		for i in range(len(self)):
			r += self.change()
			self.cnt += 1
		return r

	def __repr__(self):
		r = ""

		return r

	def write(self, filename):
		f = open(filename, "w")
		f.write(self.generate_date())
		f.write(self.generate_comment())
		f.write(self.generate_timescale())
		f.write(self.generate_scope())
		f.write(self.generate_vars())
		f.write(self.generate_unscope())
		f.write(self.generate_enddefinitions())
		f.write(self.generate_dumpvars())
		f.write(self.generate_valuechange())
		f.close()

	def read(self, filename):
		raise NotImplementedError("VCD files can not (yet) be read, please contribute!")

if __name__ == '__main__':
	dump = VCDDump()
	dump.add(Var("foo1", 1, [0,1,0,1,0,1]))
	dump.add(Var("foo2", 2, [1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0]))
	ramp = [i%128 for i in range(1024)]
	dump.add(Var("ramp", 16, ramp))
	dump.write("dump.vcd")