import argparse
import os
import platform
import subprocess

from utils import pushd, removeall, shellish


def attach_build_runtime(subparsers):
    build = subparsers.add_parser("build-runtime", help="TODO")
    build.add_argument("--release", action="store_true", help="compile Orca in release mode (default is debug)")
    build.set_defaults(func=shellish(build_runtime))


def build_runtime(args):
    try:
        subprocess.run(["clang", "-v"], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
    except FileNotFoundError:
        print("ERROR: clang was not found on your system.")
        if platform.system() == "Windows":
            print("We recommend installing clang via the Visual Studio installer.")
            # TODO(ben): Link to the Visual Studio download page (I have no internet right now)
        elif platform.system() == "Darwin":
            print("Run the following to install it:")
            print()
            print("  brew install llvm")
            print()
        exit(1)

    # TODO(ben): Check for xcode command line tools

    build_milepost("lib", args.release)

def build_milepost(target, release):
    print("Building milepost...")
    with pushd("milepost"):
        os.makedirs("bin", exist_ok=True)
        os.makedirs("lib", exist_ok=True)
        os.makedirs("resources", exist_ok=True)

        if target == "lib":
            if platform.system() == "Darwin":
                build_milepost_lib_mac(release)
            else:
                print(f"ERROR: can't build milepost for unknown platform '{platform.system()}'")
        elif target == "test":
            with pushd("examples/test_app"):
                # TODO?
                subprocess.run(["./build.sh"])
        elif target == "clean":
            removeall("bin")
        else:
            print(f"ERROR: unrecognized milepost target '{target}'")
            exit(1)

def build_milepost_lib_mac(release):
    sdk_dir = "/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk"

    flags = ["-mmacos-version-min=10.15.4", "-maes"]
    cflags = ["-std=c11"]
    debug_flags = ["-O3"] if release else ["-g", "-DDEBUG", "-DLOG_COMPILE_DEBUG"]
    ldflags = [f"-L{sdk_dir}/usr/lib", f"-F{sdk_dir}/System/Library/Frameworks/"]
    includes = ["-Isrc", "-Isrc/util", "-Isrc/platform", "-Iext", "-Iext/angle_headers"]

    # compile metal shader
    subprocess.run([
        "xcrun", "-sdk", "macosx", "metal",
        # TODO: shaderFlagParam
        "-fno-fast-math", "-c",
        "-o", "lib/mtl_renderer.air",
        "src/mtl_renderer.metal",
    ], check=True)
    subprocess.run([
        "xcrun", "-sdk", "macosx", "metallib",
        "-o", "lib/mtl_renderer.metallib",
        "lib/mtl_renderer.air",
    ], check=True)

    # compile milepost. We use one compilation unit for all C code, and one
    # compilation unit for all Objective-C code
    subprocess.run([
        "clang",
        *debug_flags, "-c",
        "-o", "bin/milepost_c.o",
        *cflags, *flags, *includes,
        "src/milepost.c"
    ], check=True)
    subprocess.run([
        "clang",
        *debug_flags, "-c",
        "-o", "bin/milepost_objc.o",
        *flags, *includes,
        "src/milepost.m"
    ], check=True)

    # build dynamic library
    subprocess.run([
        "ld",
        *ldflags, "-dylib",
        "-o", "bin/libmilepost.dylib",
        "bin/milepost_c.o", "bin/milepost_objc.o",
        "-Llib", "-lc",
        "-framework", "Carbon", "-framework", "Cocoa", "-framework", "Metal", "-framework", "QuartzCore",
        "-weak-lEGL", "-weak-lGLESv2",
    ], check=True)

    # change dependent libs path to @rpath
    subprocess.run([
        "install_name_tool",
        "-change", "./libEGL.dylib", "@rpath/libEGL.dylib",
        "bin/libmilepost.dylib",
    ], check=True)
    subprocess.run([
        "install_name_tool",
        "-change", "./libGLESv2.dylib", "@rpath/libGLESv2.dylib",
        "bin/libmilepost.dylib",
    ], check=True)

    # add executable path to rpath. Client executable can still add its own
    # rpaths if needed, e.g. @executable_path/libs/ etc.
    subprocess.run([
        "install_name_tool",
        "-id", "@rpath/libmilepost.dylib",
        "bin/libmilepost.dylib",
    ], check=True)