#!/usr/bin/env python3

# Copyright 2025 Google LLC
#
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import argparse
import json
import os
import subprocess
import sys
import sysconfig
import textwrap

EMSDK_ROOT = os.path.join('third_party', 'emsdk')

EMSDK_PATH = os.path.join(EMSDK_ROOT, 'emsdk.py')
EMSDK_CONFIG_PATH = os.path.join(EMSDK_ROOT, '.emscripten')


# Run a subprocess with stderr forwarded to stdout. Raise an exception if it fails.
def run_or_exit(name, args):
    try:
        subprocess.run(args,
                       encoding='utf-8',
                       check=True,
                       stdout=subprocess.PIPE,
                       stderr=subprocess.STDOUT)
    except subprocess.CalledProcessError as ex:
        raise Exception(name + ' failed:\n' + ex.stdout) from ex


def main(args):
    parser = argparse.ArgumentParser()
    parser.add_argument('--get-emsdk-version', help='Print emsdk version and exit.', action='store_true')
    options = parser.parse_args()

    if options.get_emsdk_version:
        # https://github.com/emscripten-core/emsdk/blob/main/emscripten-releases-tags.json
        with open(os.path.join(EMSDK_ROOT, 'emscripten-releases-tags.json')) as f:
            print(json.load(f)['aliases']['latest'])
        return

    # Install and activate the default dependencies for emsdk.
    # 'latest' is a static alias in emsdk for the toolchain corresponding to
    # this emsdk release, so we can use it stably.
    run_or_exit('emsdk install',
                [sys.executable, EMSDK_PATH, 'install', 'latest'])
    run_or_exit('emsdk activate',
                [sys.executable, EMSDK_PATH, 'activate', 'latest'])

    # If we ever need to override the Python, Node, and LLVM binaries used by Emscripten, do that
    # here. See https://dawn-review.googlesource.com/c/dawn/+/238814/4..5 which removed support.


if __name__ == '__main__':
    main(sys.argv)