import argparse
from datetime import datetime
import glob
import os
import platform
import urllib.request
import shutil
import subprocess
from zipfile import ZipFile

import checksum
from log import *
from utils import pushd, removeall


ANGLE_VERSION = "2023-07-09"


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):
    ensure_programs()
    ensure_angle()

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


def build_milepost_lib_win(release):
    # TODO(ben): delete embed_text.py
    embed_text_glsl("src\\glsl_shaders.h", "glsl_", [
        "src\\glsl_shaders\\common.glsl",
        "src\\glsl_shaders\\blit_vertex.glsl",
        "src\\glsl_shaders\\blit_fragment.glsl",
        "src\\glsl_shaders\\path_setup.glsl",
        "src\\glsl_shaders\\segment_setup.glsl",
        "src\\glsl_shaders\\backprop.glsl",
        "src\\glsl_shaders\\merge.glsl",
        "src\\glsl_shaders\\raster.glsl",
    ])

    includes = [
        "/I", "src",
        "/I", "src/util",
        "/I", "src/platform",
        "/I", "ext",
        "/I", "ext/angle_headers",
    ]
    libs = [
        "user32.lib",
        "opengl32.lib",
        "gdi32.lib",
        "shcore.lib",
        "delayimp.lib",
        "dwmapi.lib",
        "comctl32.lib",
        "ole32.lib",
        "shell32.lib",
        "shlwapi.lib",
        "/LIBPATH:./bin",
        "libEGL.dll.lib",
        "libGLESv2.dll.lib",
        "/DELAYLOAD:libEGL.dll",
        "/DELAYLOAD:libGLESv2.dll",
    ]

    subprocess.run([
        "cl",
        "/we4013", "/Zi", "/Zc:preprocessor",
        "/DMP_BUILD_DLL",
        "/std:c11",
        *includes,
        "src/milepost.c", "/Fo:bin/milepost.o",
        "/LD", "/link",
        "/MANIFEST:EMBED", "/MANIFESTINPUT:src/win32_manifest.xml",
        *libs,
        "/OUT:bin/milepost.dll",
        "/IMPLIB:bin/milepost.dll.lib",
    ], check=True)


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)


def ensure_programs():
    if platform.system() == "Windows":
        try:
            subprocess.run(["cl"], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
        except FileNotFoundError:
            msg = log_error("MSVC was not found on your system.")
            msg.more("If you have already installed Visual Studio, make sure you are running in a")
            msg.more("Visual Studio command prompt or you have run vcvarsall.bat. Otherwise, download")
            msg.more("and install Visual Studio: https://visualstudio.microsoft.com/")
            exit(1)

    try:
        subprocess.run(["clang", "-v"], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
    except FileNotFoundError:
        msg = log_error("clang was not found on your system.")
        if platform.system() == "Windows":
            msg.more("We recommend installing clang via the Visual Studio installer.")
        elif platform.system() == "Darwin":
            msg.more("Run the following to install it:")
            msg.more()
            msg.more("  brew install llvm")
            msg.more()
        exit(1)
    # TODO(ben): Check for xcode command line tools


def ensure_angle():
    checkfiles = None
    if platform.system() == "Windows":
        checkfiles = [
            "milepost/lib/libEGL.dll",
            "milepost/lib/libEGL.dll.lib",
            "milepost/lib/libGLESv2.dll",
            "milepost/lib/libGLESv2.dll.lib",
        ]
    elif platform.system() == "Darwin":
        if platform.machine() == "arm64":
            log_warning(f"automated ANGLE builds are not yet available for Apple silicon")
            return
        checkfiles = [
            "milepost/lib/libEGL.dylib",
            "milepost/lib/libGLESv2.dylib",
        ]

    if checkfiles is None:
        log_warning("could not verify if the correct version of ANGLE is present; the build will probably fail.")
        return

    angle_exists = True
    for file in checkfiles:
        if not os.path.isfile(file):
            print(f"Required ANGLE file {file} not found.")
            angle_exists = False
            break
        if not checksum.checkfile(file):
            angle_exists = False
            log_warning("wrong version of ANGLE libraries installed")
            break

    if not angle_exists:
        download_angle()


def download_angle():
    print("Downloading ANGLE...")
    if platform.system() == "Windows":
        build = "windows-2019"
        extensions = ["dll", "lib"]
    elif platform.system() == "Darwin":
        # TODO(ben): make universal dylibs
        build = "macos-12"
        extensions = ["dylib"]
    else:
        log_error(f"could not automatically download ANGLE for unknown platform {platform.system()}")
        return

    os.makedirs("scripts/files", exist_ok=True)
    filename = f"angle-{build}-{ANGLE_VERSION}.zip"
    filepath = f"scripts/files/{filename}"
    url = f"https://github.com/HandmadeNetwork/build-angle/releases/download/{ANGLE_VERSION}/{filename}"
    with urllib.request.urlopen(url) as response:
        with open(filepath, "wb") as out:
            shutil.copyfileobj(response, out)

    if not checksum.checkfile(filepath):
        log_error(f"ANGLE download did not match checksum")
        exit(1)

    print("Extracting ANGLE...")
    with ZipFile(filepath, "r") as anglezip:
        anglezip.extractall(path="scripts/files")

    os.makedirs("milepost/lib", exist_ok=True)
    for angleDir in ["bin", "lib"]:
        for ext in extensions:
            for filepath in glob.glob(f"scripts/files/angle/{angleDir}/*.{ext}"):
                shutil.copy(filepath, "milepost/lib")


def embed_text_glsl(outputpath, prefix, shaders):
    output = open(outputpath, "w")
    output.write("/*********************************************************************\n")
    output.write("*\n")
    output.write("*\tfile: %s\n" % os.path.basename(outputpath))
    output.write("*\tnote: string literals auto-generated by build_runtime.py\n")
    output.write("*\tdate: %s\n" % datetime.now().strftime("%d/%m%Y"))
    output.write("*\n")
    output.write("**********************************************************************/\n")

    outSymbol = (os.path.splitext(os.path.basename(outputpath))[0]).upper()

    output.write("#ifndef __%s_H__\n" % outSymbol)
    output.write("#define __%s_H__\n" % outSymbol)
    output.write("\n\n")

    for fileName in shaders:
        f = open(fileName, "r")
        lines = f.read().splitlines()

        output.write("//NOTE: string imported from %s\n" % fileName)

        stringName = os.path.splitext(os.path.basename(fileName))[0]
        output.write(f"const char* {prefix}{stringName} = ")

        for line in lines:
            output.write("\n\"%s\\n\"" % line)

        output.write(";\n\n")
        f.close()

    output.write("#endif // __%s_H__\n" % outSymbol)

    output.close()