#! /usr/bin/env python
# encoding: utf-8

import hashlib
from waflib import Task, TaskGen, Logs

OBJ_NAME = 'YY_Thunks_for_WinXP.obj'
OBJ_SHA256 = '51a13c4b667c82181d357e274a50308a273be63f5f85ae958465774857721573'
DLL_LINKFLAGS = ['-ENTRY:DllMainCRTStartupForYY_Thunks', '-alternatename:_YY_ThunksOriginalDllMainCRTStartup@12=__DllMainCRTStartup@12']

class copy_yy_thunks(Task.Task):
	color = 'CYAN'
	def run(self):
		return self.outputs[0].write(self.inputs[0].read('rb'), 'wb')

@TaskGen.feature('yy_thunks')
def add_yy_thunks_obj(self):
	src = self.path.find_node(OBJ_NAME)
	out = self.path.find_or_declare(OBJ_NAME)
	self.compiled_tasks = [self.create_task('copy_yy_thunks', src, out)]

@TaskGen.feature('cshlib', 'cxxshlib')
@TaskGen.after_method('process_use')
def apply_yy_thunks_dll(self):
	if 'yy_thunks' not in self.to_list(getattr(self, 'use', [])):
		return

	try:
		self.bld.get_tgen_by_name('yy_thunks')
	except Exception:
		return
	self.env.append_value('LINKFLAGS', DLL_LINKFLAGS)

def options(opt):
	pass

def configure(conf):
	if conf.env.DEST_OS != 'win32' or conf.env.COMPILER_CC != 'msvc':
		return

	if conf.env.MSVC_TARGETS[0] not in ['amd64_x86', 'x86']:
		return

	obj = conf.path.find_node(OBJ_NAME)
	if not obj:
		Logs.warn('YY-Thunks: %s not found, XP compatibility disabled' % OBJ_NAME)
		return

	with open(obj.abspath(), 'rb') as f:
		digest = hashlib.sha256(f.read()).hexdigest()

	if digest != OBJ_SHA256:
		conf.fatal('%s checksum mismatch: expected %s, got %s' % (OBJ_NAME, OBJ_SHA256, digest))

	conf.env.YY_THUNKS = True

def build(bld):
	if bld.env.YY_THUNKS:
		bld(name='yy_thunks', features='yy_thunks')