import os
import os.path


def is_desktop(platform):
    return platform in ["windows", "macos", "linuxbsd", "server", "uwp", "haiku"]


def is_unix_like(platform):
    return platform in ["macos", "linuxbsd", "server", "android", "haiku", "ios"]


def module_supports_tools_on(platform):
    return is_desktop(platform)


def configure(env, env_mono):
    # is_android = env["platform"] == "android"
    # is_javascript = env["platform"] == "javascript"
    # is_ios = env["platform"] == "ios"
    # is_ios_sim = is_ios and env["arch"] in ["x86", "x86_64"]

    tools_enabled = env["tools"]

    if tools_enabled and not module_supports_tools_on(env["platform"]):
        raise RuntimeError("This module does not currently support building for this platform with tools enabled")

    if env["tools"] or env["target"] != "release":
        env_mono.Append(CPPDEFINES=["GD_MONO_HOT_RELOAD"])

    app_host_dir = find_dotnet_app_host_dir(env)

    def check_app_host_file_exists(file):
        file_path = os.path.join(app_host_dir, file)
        if not os.path.isfile(file_path):
            raise RuntimeError("File not found: " + file_path)

    # TODO:
    # All libnethost does for us is provide a function to find hostfxr.
    # If we could handle that logic ourselves we could void linking it.

    # nethost file names:
    #   static: libnethost.a/lib
    #   shared: libnethost.a/dylib and nethost.dll
    check_app_host_file_exists("libnethost.lib" if os.name == "nt" else "libnethost.a")
    check_app_host_file_exists("nethost.h")
    check_app_host_file_exists("hostfxr.h")
    check_app_host_file_exists("coreclr_delegates.h")

    env.Append(LIBPATH=[app_host_dir])
    env_mono.Prepend(CPPPATH=app_host_dir)

    libnethost_path = os.path.join(app_host_dir, "libnethost.lib" if os.name == "nt" else "libnethost.a")

    if env["platform"] == "windows":
        env_mono.Append(CPPDEFINES=["NETHOST_USE_AS_STATIC"])

        if env.msvc:
            env.Append(LINKFLAGS="libnethost.lib")
        else:
            env.Append(LINKFLAGS=["-Wl,-whole-archive", libnethost_path, "-Wl,-no-whole-archive"])
    else:
        is_apple = env["platform"] in ["macos", "ios"]
        # is_macos = is_apple and not is_ios

        # if is_ios and not is_ios_sim:
        #     env_mono.Append(CPPDEFINES=["IOS_DEVICE"])

        if is_apple:
            env.Append(LINKFLAGS=["-Wl,-force_load," + libnethost_path])
        else:
            env.Append(LINKFLAGS=["-Wl,-whole-archive", libnethost_path, "-Wl,-no-whole-archive"])


def find_dotnet_app_host_dir(env):
    dotnet_root = env["dotnet_root"]

    if not dotnet_root:
        dotnet_exe = find_executable("dotnet")
        if dotnet_exe:
            dotnet_exe_realpath = os.path.realpath(dotnet_exe)  # Eliminate symbolic links
            dotnet_root = os.path.abspath(os.path.join(dotnet_exe_realpath, os.pardir))
        else:
            raise RuntimeError("Cannot find .NET Core Sdk")

    print("Found .NET Core Sdk root directory: " + dotnet_root)

    dotnet_cmd = os.path.join(dotnet_root, "dotnet.exe" if os.name == "nt" else "dotnet")

    runtime_identifier = determine_runtime_identifier(env)

    # TODO: In the future, if it can't be found this way, we want to obtain it
    # from the runtime.{runtime_identifier}.Microsoft.NETCore.DotNetAppHost NuGet package.
    app_host_search_version = "5.0"
    app_host_version = find_app_host_version(dotnet_cmd, app_host_search_version)
    if not app_host_version:
        raise RuntimeError("Cannot find .NET app host for version: " + app_host_search_version)

    app_host_dir = os.path.join(
        dotnet_root,
        "packs",
        "Microsoft.NETCore.App.Host." + runtime_identifier,
        app_host_version,
        "runtimes",
        runtime_identifier,
        "native",
    )

    return app_host_dir


def determine_runtime_identifier(env):
    names_map = {
        "windows": "win",
        "macos": "osx",
        "linuxbsd": "linux",
        "server": "linux",  # FIXME: Is server linux only, or also macos?
    }

    # .NET RID architectures: x86, x64, arm, or arm64

    platform = env["platform"]

    if is_desktop(platform):
        if env["arch"] in ["arm", "arm32"]:
            rid = "arm"
        elif env["arch"] == "arm64":
            rid = "arm64"
        else:
            bits = env["bits"]
            bit_arch_map = {"64": "x64", "32": "x86"}
            rid = bit_arch_map[bits]
        return "%s-%s" % (names_map[platform], rid)
    else:
        raise NotImplementedError()


def find_app_host_version(dotnet_cmd, search_version):
    import subprocess

    try:
        lines = subprocess.check_output([dotnet_cmd, "--list-runtimes"]).splitlines()

        for line_bytes in lines:
            line = line_bytes.decode("utf-8")
            if not line.startswith("Microsoft.NETCore.App "):
                continue

            parts = line.split(" ")
            if len(parts) < 2:
                continue

            version = parts[1]

            # Look for 6.0.0 or 6.0.0-*
            if version.startswith(search_version + "."):
                return version
    except (subprocess.CalledProcessError, OSError):
        pass
    return ""


ENV_PATH_SEP = ";" if os.name == "nt" else ":"


def find_executable(name):
    is_windows = os.name == "nt"
    windows_exts = os.environ["PATHEXT"].split(ENV_PATH_SEP) if is_windows else None
    path_dirs = os.environ["PATH"].split(ENV_PATH_SEP)

    search_dirs = path_dirs + [os.getcwd()]  # cwd is last in the list

    for dir in search_dirs:
        path = os.path.join(dir, name)

        if is_windows:
            for extension in windows_exts:
                path_with_ext = path + extension

                if os.path.isfile(path_with_ext) and os.access(path_with_ext, os.X_OK):
                    return path_with_ext
        else:
            if os.path.isfile(path) and os.access(path, os.X_OK):
                return path

    return ""