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#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

import inspect
import os

import jsonschema
import six

from rally.common import logging
from rally.common import validation

LOG = logging.getLogger(__name__)


@validation.configure(name="jsonschema")
class JsonSchemaValidator(validation.Validator):
    """JSON schema validator"""

    def validate(self, context, config, plugin_cls, plugin_cfg):
        try:
            jsonschema.validate(plugin_cfg, plugin_cls.CONFIG_SCHEMA)
        except jsonschema.ValidationError as err:
            self.fail(str(err))


@validation.configure(name="args-spec")
class ArgsValidator(validation.Validator):
    """Scenario arguments validator"""

    def validate(self, context, config, plugin_cls, plugin_cfg):
        scenario = plugin_cls
        name = scenario.get_name()
        platform = scenario.get_platform()
        scenario = scenario().run
        args, _varargs, varkwargs, defaults = inspect.getargspec(scenario)

        hint_msg = (" Use `rally plugin show --name %s --platform %s` "
                    "to display scenario description." % (name, platform))

        # scenario always accepts an instance of scenario cls as a first arg
        missed_args = args[1:]
        if defaults:
            # do not require args with default values
            missed_args = missed_args[:-len(defaults)]
        if "args" in config:
            missed_args = set(missed_args) - set(config["args"])
        if missed_args:
            msg = ("Argument(s) '%(args)s' should be specified in task config."
                   "%(hint)s" % {"args": "', '".join(missed_args),
                                 "hint": hint_msg})
            self.fail(msg)

        if varkwargs is None and "args" in config:
            redundant_args = set(config["args"]) - set(args[1:])
            if redundant_args:
                msg = ("Unexpected argument(s) found ['%(args)s'].%(hint)s" %
                       {"args": "', '".join(redundant_args),
                        "hint": hint_msg})
                self.fail(msg)


@validation.configure(name="required_params")
class RequiredParameterValidator(validation.Validator):
    """Scenario required parameter validator.

    This allows us to search required parameters in subdict of config.

    :param subdict: sub-dict of "config" to search. if
                    not defined - will search in "config"
    :param params: list of required parameters
    """

    def __init__(self, params=None, subdict=None):
        super(RequiredParameterValidator, self).__init__()
        self.subdict = subdict
        self.params = params

    def validate(self, context, config, plugin_cls, plugin_cfg):
        missing = []
        args = config.get("args", {})
        if self.subdict:
            args = args.get(self.subdict, {})
        for arg in self.params:
            if isinstance(arg, (tuple, list)):
                for case in arg:
                    if case in args:
                        break
                else:
                    arg = "'/'".join(arg)
                    missing.append("'%s' (at least one parameter should be "
                                   "specified)" % arg)
            else:
                if arg not in args:
                    missing.append("'%s'" % arg)

        if missing:
            msg = ("%s parameter(s) are not defined in "
                   "the input task file") % ", ".join(missing)
            self.fail(msg)


@validation.configure(name="number")
class NumberValidator(validation.Validator):
    """Checks that parameter is a number that pass specified condition.

    Ensure a parameter is within the range [minval, maxval]. This is a
    closed interval so the end points are included.

    :param param_name: Name of parameter to validate
    :param minval: Lower endpoint of valid interval
    :param maxval: Upper endpoint of valid interval
    :param nullable: Allow parameter not specified, or parameter=None
    :param integer_only: Only accept integers
    """

    def __init__(self, param_name, minval=None, maxval=None, nullable=False,
                 integer_only=False):
        self.param_name = param_name
        self.minval = minval
        self.maxval = maxval
        self.nullable = nullable
        self.integer_only = integer_only

    def validate(self, context, config, plugin_cls, plugin_cfg):

        value = config.get("args", {}).get(self.param_name)

        num_func = float
        if self.integer_only:
            # NOTE(boris-42): Force check that passed value is not float, this
            #   is important cause int(float_numb) won't raise exception
            if type(value) == float:
                return self.fail("%(name)s is %(val)s which hasn't int type"
                                 % {"name": self.param_name, "val": value})
            num_func = int

        # None may be valid if the scenario sets a sensible default.
        if self.nullable and value is None:
            return

        try:
            number = num_func(value)
            if self.minval is not None and number < self.minval:
                self.fail("%(name)s is %(val)s which is less than the minimum "
                          "(%(min)s)" % {"name": self.param_name,
                                         "val": number,
                                         "min": self.minval})
            if self.maxval is not None and number > self.maxval:
                self.fail("%(name)s is %(val)s which is greater than the "
                          "maximum (%(max)s)" % {"name": self.param_name,
                                                 "val": number,
                                                 "max": self.maxval})
        except (ValueError, TypeError):
            self.fail("%(name)s is %(val)s which is not a valid %(type)s" %
                      {"name": self.param_name, "val": value,
                       "type": num_func.__name__})


@validation.configure(name="enum")
class EnumValidator(validation.Validator):
    """Checks that parameter is in a list.

    Ensure a parameter has the right value. This value need to be defined
    in a list.

    :param param_name: Name of parameter to validate
    :param values: List of values accepted
    :param missed: Allow to accept optional parameter
    :param case_insensitive: Ignore case in enum values
    """

    def __init__(self, param_name, values, missed=False,
                 case_insensitive=False):
        self.param_name = param_name
        self.missed = missed
        self.case_insensitive = case_insensitive
        if self.case_insensitive:
            self.values = []
            for value in values:
                if isinstance(value, (six.text_type, six.string_types)):
                    value = value.lower()
                self.values.append(value)
        else:
            self.values = values

    def validate(self, context, config, plugin_cls, plugin_cfg):
        value = config.get("args", {}).get(self.param_name)
        if value:
            if self.case_insensitive:
                if isinstance(value, (six.text_type, six.string_types)):
                    value = value.lower()

            if value not in self.values:
                self.fail("%(name)s is %(val)s which is not a valid value "
                          "from %(list)s" % {"name": self.param_name,
                                             "val": value,
                                             "list": self.values})
        else:
            if not self.missed:
                self.fail("%s parameter is not defined in the task config file"
                          % self.param_name)


@validation.configure(name="restricted_parameters")
class RestrictedParametersValidator(validation.Validator):

    def __init__(self, param_names, subdict=None):
        """Validates that parameters is not set.

        :param param_names: parameter or parameters list to be validated.
        :param subdict: sub-dict of "config" to search for param_names. if
                        not defined - will search in "config"
        """
        super(RestrictedParametersValidator, self).__init__()
        if isinstance(param_names, (list, tuple)):
            self.params = param_names
        else:
            self.params = [param_names]
        self.subdict = subdict

    def validate(self, context, config, plugin_cls, plugin_cfg):
        restricted_params = []
        for param_name in self.params:
            args = config.get("args", {})
            a_dict, a_key = (args, self.subdict) if self.subdict else (
                config, "args")
            if param_name in a_dict.get(a_key, {}):
                restricted_params.append(param_name)
        if restricted_params:
            self.fail("You can't specify parameters '%s' in '%s'" % (
                ", ".join(restricted_params),
                self.subdict if self.subdict else "args"))


@validation.configure(name="required_contexts")
class RequiredContextsValidator(validation.Validator):

    def __init__(self, contexts, *args):
        """Validator checks if required contexts are specified.

        :param contexts: list of strings and tuples with context names that
                         should be specified. Tuple represent 'at least one
                         of the'.
        """
        super(RequiredContextsValidator, self).__init__()
        if isinstance(contexts, (list, tuple)):
            # services argument is a list, so it is a new way of validators
            #  usage, args in this case should not be provided
            self.contexts = contexts
            if args:
                LOG.warning("Positional argument is not what "
                            "'required_context' decorator expects. "
                            "Use `contexts` argument instead")
        else:
            # it is old way validator
            self.contexts = [contexts]
            self.contexts.extend(args)

    def validate(self, context, config, plugin_cls, plugin_cfg):
        missing_contexts = []
        input_context = config.get("contexts", {})

        for name in self.contexts:
            if isinstance(name, tuple):
                if not set(name) & set(input_context):
                    # formatted string like: 'foo or bar or baz'
                    formatted_names = "'%s'" % " or ".join(name)
                    missing_contexts.append(formatted_names)
            else:
                if name not in input_context:
                    missing_contexts.append(name)

        if missing_contexts:
            self.fail("The following context(s) are required but missing from "
                      "the input task file: %s" % ", ".join(missing_contexts))


@validation.configure(name="required_param_or_context")
class RequiredParamOrContextValidator(validation.Validator):

    def __init__(self, param_name, ctx_name):
        """Validator checks if required image is specified.

        :param param_name: name of parameter
        :param ctx_name: name of context
        """
        super(RequiredParamOrContextValidator, self).__init__()
        self.param_name = param_name
        self.ctx_name = ctx_name

    def validate(self, context, config, plugin_cls, plugin_cfg):
        msg = ("You should specify either scenario argument %s or"
               " use context %s." % (self.param_name, self.ctx_name))

        if self.ctx_name in config.get("contexts", {}):
            return
        if self.param_name in config.get("args", {}):
            return
        self.fail(msg)


@validation.configure(name="file_exists")
class FileExistsValidator(validation.Validator):

    def __init__(self, param_name, mode=os.R_OK, required=True):
        """Validator checks parameter is proper path to file with proper mode.

        Ensure a file exists and can be accessed with the specified mode.
        Note that path to file will be expanded before access checking.

        :param param_name: Name of parameter to validate
        :param mode: Access mode to test for. This should be one of:
            * os.F_OK (file exists)
            * os.R_OK (file is readable)
            * os.W_OK (file is writable)
            * os.X_OK (file is executable)

            If multiple modes are required they can be added, eg:
                mode=os.R_OK+os.W_OK
        :param required: Boolean indicating whether this argument is required.
        """
        super(FileExistsValidator, self).__init__()

        self.param_name = param_name
        self.mode = mode
        self.required = required

    def _file_access_ok(self, filename, mode, param_name, required=True):
        if not filename:
            if not required:
                return
            self.fail("Parameter %s required" % param_name)
        if not os.access(os.path.expanduser(filename), mode):
            self.fail("Could not open %(filename)s with mode %(mode)s for "
                      "parameter %(param_name)s" % {"filename": filename,
                                                    "mode": mode,
                                                    "param_name": param_name})

    def validate(self, context, config, plugin_cls, plugin_cfg):

        self._file_access_ok(config.get("args", {}).get(self.param_name),
                             self.mode, self.param_name, self.required)
