#!/usr/bin/env python3

import errno
import multiprocessing
import os
import subprocess
import sys

import build_configs

CONFIGS = {config: params for config, params in build_configs.__dict__.items()
           if not config.startswith("_")}
DEFAULT_CONFIG_NAME = CONFIGS.pop("DEFAULT")
DEBUG_CONFIG_NAME = CONFIGS.pop("DEBUG")

CMAKE = "cmake"
DEFAULT_MAKE_PARAMETERS = []
if os.name == "posix":
    MAKE = "make"
    try:
        num_cpus = multiprocessing.cpu_count()
    except NotImplementedError:
        pass
    else:
        DEFAULT_MAKE_PARAMETERS.append('-j{}'.format(num_cpus))
    CMAKE_GENERATOR = "Unix Makefiles"
elif os.name == "nt":
    MAKE = "nmake"
    CMAKE_GENERATOR = "NMake Makefiles"
else:
    print("Unsupported OS: " + os.name)
    sys.exit(1)


def print_usage():
    script_name = os.path.basename(__file__)
    configs = []
    for name, args in sorted(CONFIGS.items()):
        if name == DEFAULT_CONFIG_NAME:
            name += " (default)"
        if name == DEBUG_CONFIG_NAME:
            name += " (default with --debug)"
        configs.append(name + "\n    " + " ".join(args))
    configs_string = "\n  ".join(configs)
    cmake_name = os.path.basename(CMAKE)
    make_name = os.path.basename(MAKE)
    generator_name = CMAKE_GENERATOR.lower()
    default_config_name = DEFAULT_CONFIG_NAME
    debug_config_name = DEBUG_CONFIG_NAME
    print("""Usage: {script_name} [BUILD [BUILD ...]] [--all] [--debug] [MAKE_OPTIONS]

Build one or more predefined build configurations of Fast Downward. Each build
uses {cmake_name} to generate {generator_name} and then uses {make_name} to compile the
code. Build configurations differ in the parameters they pass to {cmake_name}.
By default, the build uses N threads on a machine with N cores if the number of
cores can be determined. Use the "-j" option for {cmake_name} to override this default
behaviour.

Build configurations
  {configs_string}

--all         Alias to build all build configurations.
--debug       Alias to build the default debug build configuration.
--help        Print this message and exit.

Make options
  All other parameters are forwarded to {make_name}.

Example usage:
  ./{script_name}                     # build {default_config_name} in #cores threads
  ./{script_name} -j4                 # build {default_config_name} in 4 threads
  ./{script_name} debug               # build debug
  ./{script_name} --debug             # build {debug_config_name}
  ./{script_name} release debug       # build release and debug configs
  ./{script_name} --all VERBOSE=true  # build all build configs with detailed logs
""".format(**locals()))


def get_project_root_path():
    import __main__
    return os.path.dirname(__main__.__file__)


def get_builds_path():
    return os.path.join(get_project_root_path(), "builds")


def get_src_path():
    return os.path.join(get_project_root_path(), "src")


def get_build_path(config_name):
    return os.path.join(get_builds_path(), config_name)

def try_run(cmd, cwd):
    print('Executing command "{}" in directory "{}".'.format(" ".join(cmd), cwd))
    try:
        subprocess.check_call(cmd, cwd=cwd)
    except OSError as exc:
        if exc.errno == errno.ENOENT:
            print("Could not find '%s' on your PATH. For installation instructions, "
                  "see https://www.fast-downward.org/ObtainingAndRunningFastDownward." %
                  cmd[0])
            sys.exit(1)
        else:
            raise

def build(config_name, cmake_parameters, make_parameters):
    print("Building configuration {config_name}.".format(**locals()))
    build_path = get_build_path(config_name)
    rel_src_path = os.path.relpath(get_src_path(), build_path)
    try:
        os.makedirs(build_path)
    except OSError as exc:
        if exc.errno == errno.EEXIST and os.path.isdir(build_path):
            pass
        else:
            raise

    try_run([CMAKE, "-G", CMAKE_GENERATOR] + cmake_parameters + [rel_src_path],
            cwd=build_path)
    try_run([MAKE] + make_parameters, cwd=build_path)

    print("Built configuration {config_name} successfully.".format(**locals()))


def main():
    config_names = set()
    make_parameters = DEFAULT_MAKE_PARAMETERS
    for arg in sys.argv[1:]:
        if arg == "--help" or arg == "-h":
            print_usage()
            sys.exit(0)
        elif arg == "--debug":
            config_names.add(DEBUG_CONFIG_NAME)
        elif arg == "--all":
            config_names |= set(CONFIGS.keys())
        elif arg in CONFIGS:
            config_names.add(arg)
        else:
            make_parameters.append(arg)
    if not config_names:
        config_names.add(DEFAULT_CONFIG_NAME)
    for config_name in config_names:
        build(config_name, CONFIGS[config_name], make_parameters)


if __name__ == "__main__":
    main()