# This code is part of Ansible, but is an independent component.
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# still belong to the author of the module, and may assign their own license
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# (c) 2016 Red Hat Inc.
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from ansible.module_utils.basic import AnsibleFallbackNotFound
from ansible.module_utils.six import iteritems


def to_list(val):
    if isinstance(val, (list, tuple, set)):
        return list(val)
    elif val is not None:
        return [val]
    else:
        return list()


class ComplexDict(object):
    """Transforms a dict to with an argument spec

    This class will take a dict and apply an Ansible argument spec to the
    values.  The resulting dict will contain all of the keys in the param
    with appropriate values set.

    Example::

        argument_spec = dict(
            command=dict(key=True),
            display=dict(default='text', choices=['text', 'json']),
            validate=dict(type='bool')
        )
        transform = ComplexDict(argument_spec, module)
        value = dict(command='foo')
        result = transform(value)
        print result
        {'command': 'foo', 'display': 'text', 'validate': None}

    Supported argument spec:
        * key - specifies how to map a single value to a dict
        * read_from - read and apply the argument_spec from the module
        * required - a value is required
        * type - type of value (uses AnsibleModule type checker)
        * fallback - implements fallback function
        * choices - set of valid options
        * default - default value

    """

    def __init__(self, attrs, module):
        self._attributes = attrs
        self._module = module
        self.attr_names = frozenset(self._attributes.keys())

        self._has_key = False
        for name, attr in iteritems(self._attributes):
            if attr.get('read_from'):
                spec = self._module.argument_spec.get(attr['read_from'])
                if not spec:
                    raise ValueError('argument_spec %s does not exist' % attr['read_from'])
                for key, value in iteritems(spec):
                    if key not in attr:
                        attr[key] = value

            if attr.get('key'):
                if self._has_key:
                    raise ValueError('only one key value can be specified')
                self_has_key = True
                attr['required'] = True

    def _dict(self, value):
        obj = {}
        for name, attr in iteritems(self._attributes):
            if attr.get('key'):
                obj[name] = value
            else:
                obj[name] = attr.get('default')
        return obj

    def __call__(self, value):
        if not isinstance(value, dict):
            value = self._dict(value)

        unknown = set(value).difference(self.attr_names)
        if unknown:
            raise ValueError('invalid keys: %s' % ','.join(unknown))

        for name, attr in iteritems(self._attributes):
            if not value.get(name):
                value[name] = attr.get('default')

            if attr.get('fallback') and not value.get(name):
                fallback = attr.get('fallback', (None,))
                fallback_strategy = fallback[0]
                fallback_args = []
                fallback_kwargs = {}
                if fallback_strategy is not None:
                    for item in fallback[1:]:
                        if isinstance(item, dict):
                            fallback_kwargs = item
                        else:
                            fallback_args = item
                    try:
                        value[name] = fallback_strategy(*fallback_args, **fallback_kwargs)
                    except AnsibleFallbackNotFound:
                        continue

            if attr.get('required') and value.get(name) is None:
                raise ValueError('missing required attribute %s' % name)

            if 'choices' in attr:
                if value[name] not in attr['choices']:
                    raise ValueError('%s must be one of %s, got %s' % (name, ', '.join(attr['choices']), value[name]))

            if value[name] is not None:
                value_type = attr.get('type', 'str')
                type_checker = self._module._CHECK_ARGUMENT_TYPES_DISPATCHER[value_type]
                type_checker(value[name])

        return value


class ComplexList(ComplexDict):
    """Extends ```ComplexDict``` to handle a  list of dicts """

    def __call__(self, values):
        if not isinstance(values, (list, tuple)):
            raise TypeError('value must be an ordered iterable')
        return [(super(ComplexList, self).__call__(v)) for v in values]