import os, struct, subprocess
from decimal import Decimal

from migen.fhdl.structure import *

from mibuild.generic_platform import *
from mibuild.crg import CRG, SimpleCRG
from mibuild import tools

def _add_period_constraint(platform, clk, period):
	platform.add_platform_command("""NET "{clk}" TNM_NET = "GRPclk";
TIMESPEC "TSclk" = PERIOD "GRPclk" """+str(period)+""" ns HIGH 50%;""", clk=clk)

class CRG_SE(SimpleCRG):
	def __init__(self, platform, clk_name, rst_name, period):
		SimpleCRG.__init__(self, platform, clk_name, rst_name)
		_add_period_constraint(platform, self.cd.clk, period)

class CRG_DS(CRG):
	def __init__(self, platform, clk_name, rst_name, period):
		self.cd = ClockDomain("sys")
		self._clk = platform.request(clk_name)
		platform.request(rst_name, None, self.cd.rst)
		_add_period_constraint(platform, self._clk.p, period)

	def get_fragment(self):
		ibufg = Instance("IBUFGDS",
			Instance.Input("I", self._clk.p),
			Instance.Input("IB", self._clk.n),
			Instance.Output("O", self.cd.clk)
		)
		return Fragment(instances=[ibufg])

def _format_constraint(c):
	if isinstance(c, Pins):
		return "LOC=" + c.identifiers[0]
	elif isinstance(c, IOStandard):
		return "IOSTANDARD=" + c.name
	elif isinstance(c, Drive):
		return "DRIVE=" + str(c.strength)
	elif isinstance(c, Misc):
		return c.misc

def _format_ucf(signame, pin, others, resname):
	fmt_c = [_format_constraint(c) for c in ([Pins(pin)] + others)]
	fmt_r = resname[0] + ":" + str(resname[1])
	if resname[2] is not None:
		fmt_r += "." + resname[2]
	return "NET \"" + signame + "\" " + " | ".join(fmt_c) + "; # " + fmt_r + "\n"

def _build_ucf(named_sc, named_pc):
	r = ""
	for sig, pins, others, resname in named_sc:
		if len(pins) > 1:
			for i, p in enumerate(pins):
				r += _format_ucf(sig + "(" + str(i) + ")", p, others, resname)
		else:
			r += _format_ucf(sig, pins[0], others, resname)
	if named_pc:
		r += "\n" + "\n\n".join(named_pc)
	return r

def _build(device, sources, named_sc, named_pc, build_name, xilinx_install_path):
	tools.write_to_file(build_name + ".ucf", _build_ucf(named_sc, named_pc))

	prj_contents = ""
	for s in sources:
		prj_contents += s["type"] + " work " + s["path"] + "\n"
	tools.write_to_file(build_name + ".prj", prj_contents)

	xst_contents = """run
-ifn %s.prj
-top top
-ifmt MIXED
-opt_mode SPEED
-reduce_control_sets auto
-ofn %s.ngc
-p %s""" % (build_name, build_name, device)
	tools.write_to_file(build_name + ".xst", xst_contents)

	def is_valid_version(v):
		try: 
			Decimal(v)
			return os.path.isdir(os.path.join(xilinx_install_path, v))
		except:
			return False
	vers = [ver for ver in os.listdir(xilinx_install_path) if is_valid_version(ver)]
	tools_version = max(vers)
	bits = struct.calcsize("P")*8
	xilinx_settings_file = '%s/%s/ISE_DS/settings%d.sh' % (xilinx_install_path, tools_version, bits) 

	build_script_contents = """# Autogenerated by mibuild

set -e

source {xilinx_settings_file}
xst -ifn {build_name}.xst
ngdbuild -uc {build_name}.ucf {build_name}.ngc
map -ol high -w {build_name}.ngd
par -ol high -w {build_name}.ncd {build_name}-routed.ncd
bitgen -g Binary:Yes -w {build_name}-routed.ncd {build_name}.bit
""".format(build_name=build_name, xilinx_settings_file=xilinx_settings_file)
	build_script_file = "build_" + build_name + ".sh"
	tools.write_to_file(build_script_file, build_script_contents)

	r = subprocess.call(["bash", build_script_file])
	if r != 0:
		raise OSError("Subprocess failed")

class XilinxISEPlatform(GenericPlatform):
	def build(self, fragment, clock_domains=None, build_dir="build", build_name="top",
			xilinx_install_path="/opt/Xilinx"):
		tools.mkdir_noerror(build_dir)
		os.chdir(build_dir)

		v_src, named_sc, named_pc = self.get_verilog(fragment, clock_domains)
		v_file = build_name + ".v"
		tools.write_to_file(v_file, v_src)
		sources = [{"type": "verilog", "path": v_file}]
		_build(self.device, sources, named_sc, named_pc, build_name, xilinx_install_path)
		
		os.chdir("..")