#!/usr/bin/env python3

# Copyright (c) 2019 Egor Tensin <Egor.Tensin@gmail.com>
# This file is part of the "cmake-common" project.
# For details, see https://github.com/egor-tensin/cmake-common.
# Distributed under the MIT License.

# This script is used basically to invoke the CMake executable in a
# cross-platform way (provided the platform has Python 3, of course).
# The motivation was to merge my Travis and AppVeyor build scripts (largely
# similar, but written in bash and PowerShell, respectively).

import argparse
from contextlib import contextmanager
import logging
from enum import Enum
import os
import os.path
import shutil
import subprocess
import sys
import tempfile


def _run_executable(cmd_line):
    logging.info('Running executable: %s', cmd_line)
    return subprocess.run(cmd_line, check=True)


def _run_cmake(cmake_args):
    _run_executable(['cmake'] + cmake_args)


class Configuration(Enum):
    DEBUG = 'Debug'
    RELEASE = 'Release'

    def __str__(self):
        return self.value


def _parse_configuration(s):
    try:
        return Configuration(s)
    except ValueError:
        raise argparse.ArgumentTypeError(f'invalid configuration: {s}')


@contextmanager
def _create_build_dir(args):
    if args.build_dir is not None:
        logging.info('Build directory: %s', args.build_dir)
        yield args.build_dir
        return

    with tempfile.TemporaryDirectory(dir=os.path.dirname(args.src_dir)) as build_dir:
        logging.info('Build directory: %s', build_dir)
        try:
            yield build_dir
        finally:
            logging.info('Removing build directory: %s', build_dir)
        return


class GenerationPhase:
    def __init__(self, build_dir, args):
        self.build_dir = build_dir
        self.args = args

    def _cmake_args(self):
        return self._to_cmake_args(self.build_dir, self.args)

    @staticmethod
    def _to_cmake_args(build_dir, args):
        result = []
        if args.install_dir is not None:
            result += ['-D', f'CMAKE_INSTALL_PREFIX={args.install_dir}']
        if args.configuration is not None:
            result += ['-D', f'CMAKE_BUILD_TYPE={args.configuration}']
        if args.cmake_args is not None:
            result += args.cmake_args
        result += [f'-B{build_dir}', f'-H{args.src_dir}']
        return result

    def run(self):
        _run_cmake(self._cmake_args())


class BuildPhase:
    def __init__(self, build_dir, args):
        self.build_dir = build_dir
        self.args = args

    def _cmake_args(self):
        return self._to_cmake_args(self.build_dir, self.args)

    @staticmethod
    def _to_cmake_args(build_dir, args):
        result = ['--build', build_dir]
        if args.configuration is not None:
            result += ['--config', str(args.configuration)]
        if args.install_dir is not None:
            result += ['--target', 'install']
        return result

    def run(self):
        _run_cmake(self._cmake_args())


def _parse_dir(s):
    return os.path.abspath(os.path.normpath(s))


def _parse_args(argv=None):
    if argv is None:
        argv = sys.argv[1:]
    logging.info('Command line arguments: %s', argv)

    parser = argparse.ArgumentParser(description='Build a CMake project')
    parser.add_argument('--build', metavar='DIR', dest='build_dir',
                        type=_parse_dir,
                        help='build directory (temporary directory unless specified)')
    parser.add_argument('--install', metavar='DIR', dest='install_dir',
                        type=_parse_dir,
                        help='install directory')
    parser.add_argument('--configuration', metavar='CONFIG',
                        type=_parse_configuration, default=Configuration.DEBUG,
                        help='build configuration (i.e. Debug/Release)')
    parser.add_argument('src_dir', metavar='DIR',
                        type=_parse_dir,
                        help='source directory')
    parser.add_argument('cmake_args', nargs='*', metavar='CMAKE_ARG',
                        help='additional CMake arguments, to be passed verbatim')
    args = parser.parse_args(argv)
    return args


def _setup_logging():
    logging.basicConfig(
        format='%(asctime)s | %(levelname)s | %(message)s',
        level=logging.INFO)


def build(argv=None):
    args = _parse_args(argv)
    with _create_build_dir(args) as build_dir:
        gen_phase = GenerationPhase(build_dir, args)
        gen_phase.run()
        build_phase = BuildPhase(build_dir, args)
        build_phase.run()


def main(argv=None):
    _setup_logging()
    try:
        build(argv)
    except Exception as e:
        logging.exception(e)
        raise


if __name__ == '__main__':
    main()