#!/usr/bin/env python

"""Run the tests."""

import argparse
import glob
import os
import shutil
import subprocess
import sys
import tempfile

def test_no_build_system(build_dir, language, source):
    if language == 'C':
        compiler = os.getenv('CC', 'cc')
    elif language == 'C++':
        compiler = os.getenv('C++', 'c++')
    else:
        print('Unknown language: ' + language)
        return 1
    print('Building ' + source + ' by calling ' + compiler + '...')
    return subprocess.call([compiler, source])


def test_cmake_build_system(build_dir, source):
    shutil.copy(source, build_dir)
    with open('CMakeLists.txt', 'w') as fp:
        fp.write('cmake_minimum_required(VERSION 3.0)\n')
        fp.write('project(test-compiler)\n')
        fp.write('add_executable(a.out ' + os.path.basename(source) + ')\n')
    os.mkdir('build')
    os.chdir('build')
    print('Building ' + source + ' with CMake...')
    if subprocess.call(['cmake', '..']):
        return 1
    if subprocess.call(['make']):
        return 1
    shutil.copy('a.out', build_dir)
    return 0


def test_source(source, language, build_system, emulator):
    result = 0
    cwd = os.getcwd()
    build_dir = tempfile.mkdtemp()
    os.chdir(build_dir)

    if build_system == 'None':
        result += test_no_build_system(build_dir, language, source)
    elif build_system == 'CMake':
        result += test_cmake_build_system(build_dir, source)
    else:
        print('Unknown build system: ' + build_system)
        result += 1

    if emulator:
        cmd = emulator
        cmd += ' ' + os.path.join(build_dir, 'a.out')
        print('Running ' + cmd + '...')
        result += subprocess.call(cmd, shell=True)

    os.chdir(cwd)
    shutil.rmtree(build_dir)
    return result


def test_build_system(test_dir, language, build_system, emulator):
    result = 0
    for source in glob.glob(os.path.join(test_dir, language, '*')):
        result += test_source(source, language, build_system, emulator)
    return result


def test_language(test_dir, language, build_systems, emulator):
    result = 0
    for build_system in build_systems:
        result += test_build_system(test_dir, language, build_system, emulator)
    return result


def run_tests(test_dir, languages=('C', 'C++'), build_systems=('None', 'CMake'),
        emulator=None):
    """Run the tests found in test_dir where each directory corresponds to an
    entry in languages. Every source within a language directory is built. The
    output executable is also run with the emulator if provided."""
    result = 0
    for language in languages:
        result += test_language(test_dir, language, build_systems, emulator)
    return result


if __name__ == '__main__':
    parser = argparse.ArgumentParser(
            description='Test the cross-compiler toolchain.')
    parser.add_argument('--languages', nargs='+', default=['C', 'C++'],
            help='Languages to test. Options: C C++')
    parser.add_argument('--build-systems', nargs='+', default=['None', 'CMake'],
            help='Build systems to test. Options: None CMake')
    parser.add_argument('--emulator', '-e',
            help='Emulator used to test generated executables')
    args = parser.parse_args()

    test_dir = os.path.dirname(os.path.abspath(__file__))

    sys.exit(run_tests(test_dir,
        languages=args.languages,
        build_systems=args.build_systems,
        emulator=args.emulator) != 0)