#!/usr/bin/python3
#
# This script generates these config files:
#
#   Saved/UnrealBuildTool/BuildConfiguration.xml
#   Integration.uproject
#   Integration.code-workspace
#   Makefile
#   Source/Integration/lpx-paths.hpp
#
# The BuildConfiguration.xml file specifies that this project will
# use visual studio code (on linux) or visual studio (on windows).
# It can't be checked into git because it differs by platform.
#
# Unreal needs "Integration.uproject".  This config file tells
# UnrealBuildTool what version of the unreal engine to link this game
# with.  It also specifies a couple of other game-specific configuration
# settings.  It can't easily be checked into git because it contains
# a GUID which is specific to your local machine. We generate
# Integration.uproject from scratch.  Later, the unreal
# editor will inject the engine GUID into the file.
#
# VSCode needs "Integration.code-workspace," it tells vscode how to
# compile this game and how to run it under the debugger.  It can't
# be checked into git because it contains many hardwired
# paths.
#
# The UnrealBuildTool which is included with the UnrealEngine can
# generate a rough draft of Integration.code-workspace.  However, the
# file it generates is not well-configured for our luprex-related
# needs. This python script uses UnrealBuildTool to generate the rough
# draft, then it loads Integration.code-workspace into RAM, edits it
# in RAM, and writes a new, improved version back out.
#
# We don't really need a Makefile, since Unreal games are build using
# UnrealBuildTool, not make.  But, having a one-liner makefile can at
# least make it obvious what command you're supposed to type to build
# things.  UnrealBuildTool creates a Makefile, but we delete that, and
# replace it with a simple one-liner.
#
# The file lpx-paths.hpp contains hardwired absolute paths of the
# Luprex DLL and Luprex root path.  Eventually, we're going to write
# C++ code to calculate these dynamically, so that they don't need to
# be hardwired in.  But this will do for now.
#

import sys, os, json
from pathlib import Path

#
# Some handy utility functions
#

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"
UNREALBUILDTOOL = f"{UNREALENGINE}/Engine/Binaries/DotNET/UnrealBuildTool/UnrealBuildTool.dll"

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

os.chdir(INTEGRATION)
Path("Saved/UnrealBuildTool").mkdir(parents=True, exist_ok=True)
Path("Saved/UnrealBuildTool/BuildConfiguration.xml").unlink(missing_ok=True)
Path("Integration.uproject").unlink(missing_ok=True)
Path("Integration.code-workspace").unlink(missing_ok=True)
Path("Makefile").unlink(missing_ok=True)
Path("Source/Integration/lpx-paths.hpp").unlink(missing_ok=True)

#
# Write BuildConfiguration.xml
#

writefile("Saved/UnrealBuildTool/Integration.uproject", f"""
<?xml version="1.0" encoding="utf-8" ?>
<Configuration xmlns="https://www.unrealengine.com/BuildConfiguration">
  <ProjectFileGenerator>
    <Format>VisualStudioCode</Format>
  </ProjectFileGenerator>
</Configuration>
""")

#
# Write lpx-paths.hpp.
#

writefile("Source/Integration/lpx-paths.hpp", f"""
#define LUPREX_DLL_PATH "{INTEGRATION}/luprex/build/linux/luprexlib.so"
#define LUPREX_ROOT_PATH "{INTEGRATION}/luprex"
""")

#
# Write Integration.uproject.
#

writefile("Integration.uproject", """
{
	"FileVersion": 3,
	"EngineAssociation": "5.3",
	"Category": "",
	"Description": "",
	"Modules": [
		{
			"Name": "Integration",
			"Type": "Runtime",
			"LoadingPhase": "Default",
			"AdditionalDependencies": [
				"Engine",
				"CoreUObject"
			]
		}
	],
	"Plugins": [
		{
			"Name": "ModelingToolsEditorMode",
			"Enabled": true,
			"TargetAllowList": [
				"Editor"
			]
		}
	]
}
""")



#
# Use UnrealBuildTool to generate a rough draft of Integration.code-workspace.
#

BUILDPROJECTFILES = f'dotnet {UNREALBUILDTOOL} -projectfiles -project="{INTEGRATION}/Integration.uproject" -game'
print(BUILDPROJECTFILES)
os.system(BUILDPROJECTFILES)

#
# Load the rough Integration.code-workspace into RAM, then delete the rough draft.
#

with open("Integration.code-workspace") as original:
    WORKSPACE=json.load(original)
os.remove("Integration.code-workspace")

#
# Configure the correct build task as the default task.
#

for task in WORKSPACE["tasks"]["tasks"]:
    if task["label"] == "IntegrationEditor Linux DebugGame Build":
        task["group"] = { "kind": "build", "isDefault": "true" }

#
# Delete all build tasks that aren't relevant.
#

def goodtask(task):
    return task["label"].startswith("IntegrationEditor Linux DebugGame")

WORKSPACE["tasks"]["tasks"] = [x for x in WORKSPACE["tasks"]["tasks"] if goodtask(x)]

#
# Add a build task for Luprex
#

LUPREXBUILDTASK={}
WORKSPACE["tasks"]["tasks"].append(LUPREXBUILDTASK)
LUPREXBUILDTASK["label"] = "Build Luprex"
LUPREXBUILDTASK["group"] = "build"
LUPREXBUILDTASK["command"] = "make"
LUPREXBUILDTASK["problemMatcher"] = "$msCompile"
LUPREXBUILDTASK["type"] = "shell"
LUPREXBUILDTASK["options"] = {}
LUPREXBUILDTASK["options"]["cwd"] = f"{INTEGRATION}/luprex"

#
# Convert all launch configurations to lldb.
#

LLDBINIT=f"command script import {UNREALENGINE}/Engine/Extras/LLDBDataFormatters/UEDataFormatters_2ByteChars.py"

for config in WORKSPACE["launch"]["configurations"]:
    config["type"] = "lldb"
    config["initCommands"] = [ LLDBINIT ]
    config.pop("visualizerFile", None)
    config.pop("showDisplayString", None)

#
# Delete all but the relevant launch configuration.
#

def goodconf(config):
    return config["name"] == "Launch IntegrationEditor (DebugGame)"

WORKSPACE["launch"]["configurations"] = [x for x in WORKSPACE["launch"]["configurations"] if goodconf(x)]

#
# Write Integration.code-workspace.
#

with open("Integration.code-workspace", "w") as rewritten:
    json.dump(WORKSPACE, rewritten, indent=4)

#
# Write the Makefile
#

writefile("Makefile", f"""
all:
	(cd luprex ; make)
	dotnet {UNREALBUILDTOOL} Integration Linux DebugGame -project="{INTEGRATION}/Integration.uproject"
""")