#!/usr/bin/env python2.7

import argparse
import imp
import utils
import inferlib
import logging
import os
import sys
import platform

CAPTURE_PACKAGE = 'capture'
LIB_FOLDER = os.path.join(
    os.path.dirname(os.path.realpath(__file__)), os.path.pardir, 'lib')

# token that identifies the end of the options for infer and the beginning
# of the compilation command
CMD_MARKER = '--'

# insert here the correspondence between module name and the list of
# compiler/build-systems it handles.
# All supported commands should be listed here
MODULE_TO_COMMAND = {
    'ant': ['ant'],
    'analyze': ['analyze'],
    'buck': ['buck'],
    'gradle': ['gradle', 'gradlew'],
    'javac': ['javac'],
    'make': ['make', 'clang', 'clang++', 'cc', 'gcc', 'g++'],
    'xcodebuild': ['xcodebuild'],
    'mvn': ['mvn']
}

FORMAT = '[%(levelname)s] %(message)s'
LOG_FILE = 'toplevel.log'

def get_commands():
    """Return all commands that are supported."""
    #flatten and dedup the list of commands
    return set(sum(MODULE_TO_COMMAND.values(), []))


def get_module_name(command):
    """ Return module that is able to handle the command. None if
    there is no such module."""
    for module, commands in MODULE_TO_COMMAND.iteritems():
        if command in commands:
            return module
    return None


def load_module(mod_name):
    # load the 'capture' package in lib
    pkg_info = imp.find_module(CAPTURE_PACKAGE, [LIB_FOLDER])
    imported_pkg = imp.load_module(CAPTURE_PACKAGE, *pkg_info)
    # load the requested module (e.g. make)
    mod_file, mod_path, mod_descr = \
        imp.find_module(mod_name, imported_pkg.__path__)
    try:
        return imp.load_module(
            '{pkg}.{mod}'.format(pkg=imported_pkg.__name__, mod=mod_name),
            mod_file, mod_path, mod_descr)
    finally:
        if mod_file:
            mod_file.close()


def split_args_to_parse():
    dd_index = \
        sys.argv.index(CMD_MARKER) if CMD_MARKER in sys.argv else len(sys.argv)
    return sys.argv[1:dd_index], sys.argv[dd_index + 1:]


def create_argparser(parents=[]):
    parser = argparse.ArgumentParser(
        parents=[inferlib.inferJ_parser] + parents,
        add_help=False,
        formatter_class=argparse.RawDescriptionHelpFormatter,
    )
    group = parser.add_argument_group(
        'supported compiler/build-system commands')

    supported_commands = ', '.join(get_commands())
    group.add_argument(
        CMD_MARKER,
        metavar='<cmd>',
        dest='nullarg',
        default=None,
        help=('Command to run the compiler/build-system. '
              'Supported build commands (run `infer --help -- <cmd_name>` for '
              'extra help, e.g. `infer --help -- javac`): ' + supported_commands),
    )
    return parser


def configure_logging(infer_dir, log_to_stderr):
    if log_to_stderr:
        logging.basicConfig(level=logging.INFO, format=FORMAT)
    else:
        logging.basicConfig(level=logging.INFO,
                            format=FORMAT,
                            filename=os.path.join(infer_dir, LOG_FILE),
                            filemode='w')


def main():
    to_parse, cmd = split_args_to_parse()
    # get the module name (if any), then load it
    capture_module_name = os.path.basename(cmd[0]) if len(cmd) > 0 else None
    mod_name = get_module_name(capture_module_name)
    imported_module = None
    if mod_name:
        # There is module that supports the command
        imported_module = load_module(mod_name)

    # get the module's argparser and merge it with the global argparser
    module_argparser = []
    if imported_module:
        module_argparser.append(
            imported_module.create_argparser(capture_module_name)
        )
    global_argparser = create_argparser(module_argparser)

    args = global_argparser.parse_args(to_parse)

    if (imported_module and not args.incremental and
            capture_module_name != 'analyze'):
        inferlib.remove_infer_out(args.infer_out)

    inferlib.create_results_dir(args.infer_out)

    configure_logging(args.infer_out, args.log_to_stderr)
    logging.info('Running command %s', ' '.join(sys.argv))
    logging.info('Path to infer script %s (%s)', __file__,
                 os.path.realpath(__file__))
    logging.info(inferlib.get_infer_version())
    logging.info('Platform: %s', platform.platform())
    logging.info('PATH=%s', os.getenv('PATH'))
    logging.info('SHELL=%s', os.getenv('SHELL'))
    logging.info('PWD=%s', os.getenv('PWD'))

    if imported_module:
        capture_exitcode = imported_module.gen_instance(args, cmd).capture()
        if capture_exitcode != os.EX_OK:
            logging.error('Error during capture phase, exiting')
            exit(capture_exitcode)
        logging.info('Capture phase was successful')
    elif capture_module_name is not None:
        # There was a command, but it's not supported
        print('Command "{cmd}" not recognised'.format(
            cmd='' if capture_module_name is None else capture_module_name))
        global_argparser.print_help()
        sys.exit(1)
    else:
        global_argparser.print_help()
        sys.exit(os.EX_OK)

    if not (mod_name == 'buck' or mod_name == 'javac'):
        # Something should be already captured, otherwise analysis would fail
        if not os.path.exists(os.path.join(args.infer_out, 'captured')):
            print('There was nothing to analyze, exiting')
            exit(os.EX_USAGE)
        analysis = inferlib.Infer(args, [])
        analysis.analyze_and_report()
        analysis.save_stats()

if __name__ == '__main__':
    main()