#!/usr/bin/python3
#
# This script applies patches to the UnrealEngine repository.
#
# We don't keep our own unreal engine repository because that
# would be overkill.  Instead, you must check out the standard
# copy of Unreal engine, then we apply a few simple patches.
# The files patched are:
#
#   UnrealEngine/Engine/Saved/UnrealBuildTool/BuildConfiguration.xml
#   UnrealEngine/Engine/Source/Runtime/Core/Private/Logging/LogMacros.cpp
#
# This python program will generate these files as necessary.
#
# It is safe to run this patch program a second time to repair
# any of these files, if necessary.  Doing so will not corrupt
# anything.
#
#--------------------------------------------------------------

import sys, os, json, glob
from pathlib import Path

#
# Some handy utility functions
#

def readfile(fn):
	with open(fn) as f:
		return f.read()

def writefile(fn, str):
	with open(fn, "w") as f:
		f.write(str)

#
# These are some directory paths that we will need.
#

INTEGRATION = os.path.dirname(os.path.abspath(sys.argv[0]))
UNREALENGINE = os.environ["HOME"] + "/UnrealEngine"
if not os.path.isdir(UNREALENGINE): error("No unreal installed in $HOME/UnrealEngine")

#
# Change to the target directory.
# Remove any existing project files.
#

os.chdir(UNREALENGINE)
Path("Engine/Saved/UnrealBuildTool").mkdir(parents=True, exist_ok=True)
Path("Engine/Saved/UnrealBuildTool/BuildConfiguration.xml").unlink(missing_ok=True)
Path("Engine/Source/Runtime/Core/Private/Logging/LogMacros.cpp").unlink(missing_ok=True)

#
# Write BuildConfiguration.xml
#

BUILDCONFIG=readfile(f"{INTEGRATION}/EnginePatches/BuildConfigurationLinux.xml")
writefile("Engine/Saved/UnrealBuildTool/BuildConfiguration.xml", BUILDCONFIG)

#
# Write LogMacros.cpp
#

LOGMACROS=readfile(f"{INTEGRATION}/EnginePatches/LogMacros.cpp")
writefile(f"{UNREALENGINE}/Engine/Source/Runtime/Core/Private/Logging/LogMacros.cpp", LOGMACROS)