import contextlib
import os
import textwrap
import time

from oslo_serialization import jsonutils
from oslo_utils import encodeutils
import prettytable
import six


def env(*args, **kwargs):
    """Returns the first environment variable set.

    If all are empty, defaults to '' or keyword arg `default`.
    """
    for arg in args:
        value = os.environ.get(arg)
        if value:
            return value
    return kwargs.get('default', '')


def arg(*args, **kwargs):
    """Decorator for CLI args.

    Example:

    >>> @arg("name", help="Name of the new entity")
    ... def entity_create(args):
    ...     pass
    """

    def _decorator(func):
        add_arg(func, *args, **kwargs)
        return func

    return _decorator


def add_arg(func, *args, **kwargs):
    """Bind CLI arguments to a shell.py `do_foo` function."""

    if not hasattr(func, 'arguments'):
        func.arguments = []

    # NOTE(sirp): avoid dups that can occur when the module is shared across
    # tests.
    if (args, kwargs) not in func.arguments:
        # Because of the semantics of decorator composition if we just append
        # to the options list positional options will appear to be backwards.
        func.arguments.insert(0, (args, kwargs))


def pretty_choice_list(l):
    return ', '.join("'%s'" % i for i in l)


def pretty_choice_dict(d):
    """Returns a formatted dict as 'key=value'."""
    return pretty_choice_list(['%s=%s' % (k, d[k]) for k in sorted(d.keys())])


def print_list(objs, fields, formatters={}, sortby=None, align='c'):
    pt = prettytable.PrettyTable([f for f in fields], caching=False)
    pt.align = align
    for o in objs:
        row = []
        for field in fields:
            if field in formatters:
                if callable(formatters[field]):
                    row.append(formatters[field](o))
                else:
                    row.append(o.get(formatters[field], None))
            else:
                data = o.get(field, None)
                if data is None or data == "":
                    data = '-'
                data = six.text_type(data).replace("\r", "")
                row.append(data)
        pt.add_row(row)
    if sortby is not None and sortby in fields:
        result = encodeutils.safe_encode(pt.get_string(sortby=sortby))
    else:
        result = encodeutils.safe_encode(pt.get_string())

    if six.PY3:
        result = result.decode()

    print(result)


def print_dict(d, dict_property="Property", dict_value="Value", wrap=0):
    pt = prettytable.PrettyTable([dict_property, dict_value], caching=False)
    pt.align = 'l'
    for k, v in sorted(d.items()):
        # convert dict to str to check length
        if isinstance(v, (dict, list)):
            v = jsonutils.dumps(v)
        if wrap > 0:
            v = textwrap.fill(six.text_type(v), wrap)
        # if value has a newline, add in multiple rows
        # e.g. fault with stacktrace
        if v and isinstance(v, six.string_types) and (r'\n' in v or '\r' in v):
            # '\r' would break the table, so remove it.
            if '\r' in v:
                v = v.replace('\r', '')
            lines = v.strip().split(r'\n')
            col1 = k
            for line in lines:
                pt.add_row([col1, line])
                col1 = ''
        else:
            if v is None:
                v = '-'
            pt.add_row([k, v])

    result = encodeutils.safe_encode(pt.get_string())

    if six.PY3:
        result = result.decode()

    print(result)


def safe_issubclass(*args):
    """Like issubclass, but will just return False if not a class."""

    try:
        if issubclass(*args):
            return True
    except TypeError:
        pass

    return False


@contextlib.contextmanager
def record_time(times, enabled, *args):
    """Record the time of a specific action.

    :param times: A list of tuples holds time data.
    :type times: list
    :param enabled: Whether timing is enabled.
    :type enabled: bool
    :param *args: Other data to be stored besides time data, these args
                  will be joined to a string.
    """
    if not enabled:
        yield
    else:
        start = time.time()
        yield
        end = time.time()
        times.append((' '.join(args), start, end))


def get_function_name(func):
    if six.PY2:
        if hasattr(func, "im_class"):
            return "%s.%s" % (func.im_class, func.__name__)
        else:
            return "%s.%s" % (func.__module__, func.__name__)
    else:
        return "%s.%s" % (func.__module__, func.__qualname__)