import os
import yaml
from time import time
from glob import glob

import networkx as nx

from contextlib import contextmanager


def load_network(network_params, dir_path=None):
    path = network_params.get('path', None)
    if path:
        if dir_path and not os.path.isabs(path):
            path = os.path.join(dir_path, path)
        extension = os.path.splitext(path)[1][1:]
        kwargs = {}
        if extension == 'gexf':
            kwargs['version'] = '1.2draft'
            kwargs['node_type'] = int
        try:
            method = getattr(nx.readwrite, 'read_' + extension)
        except AttributeError:
            raise AttributeError('Unknown format')
        return method(path, **kwargs)

    net_args = network_params.copy()
    net_type = net_args.pop('generator')

    method = getattr(nx.generators, net_type)
    return method(**net_args)


def load_file(infile):
    with open(infile, 'r') as f:
        return list(yaml.load_all(f))


def load_files(*patterns):
    for pattern in patterns:
        for i in glob(pattern):
            for config in load_file(i):
                yield config, os.path.abspath(i)


def load_config(config):
    if isinstance(config, dict):
        yield config, None
    else:
        yield from load_files(config)


@contextmanager
def timer(name='task', pre="", function=print, to_object=None):
    start = time()
    yield start
    end = time()
    function('{}Finished {} in {} seconds'.format(pre, name, str(end-start)))
    if to_object:
        to_object.start = start
        to_object.end = end