# Copyright (c) 2019 Cisco and/or its affiliates.
# 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.

"""Python API executor library.
"""

import binascii
import json

from pprint import pformat

from robot.api import logger

from resources.libraries.python.Constants import Constants
from resources.libraries.python.ssh import SSH, SSHTimeout
from resources.libraries.python.PapiHistory import PapiHistory


__all__ = ["PapiExecutor", "PapiResponse"]


class PapiResponse(object):
    """Class for metadata specifying the Papi reply, stdout, stderr and return
    code.
    """

    def __init__(self, papi_reply=None, stdout="", stderr="", requests=None):
        """Construct the Papi response by setting the values needed.

        TODO:
            Implement 'dump' analogue of verify_replies that would concatenate
            the values, so that call sites do not have to do that themselves.

        :param papi_reply: API reply from last executed PAPI command(s).
        :param stdout: stdout from last executed PAPI command(s).
        :param stderr: stderr from last executed PAPI command(s).
        :param requests: List of used PAPI requests. It is used while verifying
            replies. If None, expected replies must be provided for verify_reply
            and verify_replies methods.
        :type papi_reply: list or None
        :type stdout: str
        :type stderr: str
        :type requests: list
        """

        # API reply from last executed PAPI command(s).
        self.reply = papi_reply

        # stdout from last executed PAPI command(s).
        self.stdout = stdout

        # stderr from last executed PAPI command(s).
        self.stderr = stderr

        # List of used PAPI requests.
        self.requests = requests

        # List of expected PAPI replies. It is used while verifying replies.
        if self.requests:
            self.expected_replies = \
                ["{rqst}_reply".format(rqst=rqst) for rqst in self.requests]

    def __str__(self):
        """Return string with human readable description of the PapiResponse.

        :returns: Readable description.
        :rtype: str
        """
        return (
            "papi_reply={papi_reply},stdout={stdout},stderr={stderr},"
            "requests={requests}").format(
                papi_reply=self.reply, stdout=self.stdout, stderr=self.stderr,
                requests=self.requests)

    def __repr__(self):
        """Return string executable as Python constructor call.

        :returns: Executable constructor call.
        :rtype: str
        """
        return "PapiResponse({str})".format(str=str(self))

    def verify_reply(self, cmd_reply=None, idx=0,
                     err_msg="Failed to verify PAPI reply."):
        """Verify and return data from the PAPI response.

        Note: Use only with a simple request / reply command. In this case the
        PAPI reply includes 'retval' which is checked in this method.

        Do not use with 'dump' and 'vpp-stats' methods.

        Use if PAPI response includes only one command reply.

        Use it this way (preferred):

        with PapiExecutor(node) as papi_exec:
            data = papi_exec.add('show_version').get_replies().verify_reply()

        or if you must provide the expected reply (not recommended):

        with PapiExecutor(node) as papi_exec:
            data = papi_exec.add('show_version').get_replies().\
                verify_reply('show_version_reply')

        :param cmd_reply: PAPI reply. If None, list of 'requests' should have
            been provided to the __init__ method as pre-generated list of
            replies is used in this method in this case.
            The PapiExecutor._execute() method provides the requests
            automatically.
        :param idx: Index to PapiResponse.reply list.
        :param err_msg: The message used if the verification fails.
        :type cmd_reply: str
        :type idx: int
        :type err_msg: str or None
        :returns: Verified data from PAPI response.
        :rtype: dict
        :raises AssertionError: If the PAPI return value is not 0, so the reply
            is not valid.
        :raises KeyError, IndexError: If the reply does not have expected
            structure.
        """
        cmd_rpl = self.expected_replies[idx] if cmd_reply is None else cmd_reply

        data = self.reply[idx]['api_reply'][cmd_rpl]
        if data['retval'] != 0:
            raise AssertionError("{msg}\nidx={idx}, cmd_reply={reply}".
                                 format(msg=err_msg, idx=idx, reply=cmd_rpl))

        return data

    def verify_replies(self, cmd_replies=None,
                       err_msg="Failed to verify PAPI reply."):
        """Verify and return data from the PAPI response.

        Note: Use only with request / reply commands. In this case each
        PAPI reply includes 'retval' which is checked.

        Do not use with 'dump' and 'vpp-stats' methods.

        Use if PAPI response includes more than one command reply.

        Use it this way:

        with PapiExecutor(node) as papi_exec:
            papi_exec.add(cmd1, **args1).add(cmd2, **args2).add(cmd2, **args3).\
                get_replies(err_msg).verify_replies()

        or if you need the data from the PAPI response:

        with PapiExecutor(node) as papi_exec:
            data = papi_exec.add(cmd1, **args1).add(cmd2, **args2).\
                add(cmd2, **args3).get_replies(err_msg).verify_replies()

        or if you must provide the list of expected replies (not recommended):

        with PapiExecutor(node) as papi_exec:
            data = papi_exec.add(cmd1, **args1).add(cmd2, **args2).\
                add(cmd2, **args3).get_replies(err_msg).\
                verify_replies(cmd_replies=cmd_replies)

        :param cmd_replies: List of PAPI command replies. If None, list of
            'requests' should have been provided to the __init__ method as
            pre-generated list of replies is used in this method in this case.
            The PapiExecutor._execute() method provides the requests
            automatically.
        :param err_msg: The message used if the verification fails.
        :type cmd_replies: list of str or None
        :type err_msg: str
        :returns: List of verified data from PAPI response.
        :rtype list
        :raises AssertionError: If the PAPI response does not include at least
            one of specified command replies.
        """
        data = list()

        cmd_rpls = self.expected_replies if cmd_replies is None else cmd_replies

        if len(self.reply) != len(cmd_rpls):
            raise AssertionError(err_msg)
        for idx, cmd_reply in enumerate(cmd_rpls):
            data.append(self.verify_reply(cmd_reply, idx, err_msg))

        return data


class PapiExecutor(object):
    """Contains methods for executing VPP Python API commands on DUTs.

    Note: Use only with "with" statement, e.g.:

        with PapiExecutor(node) as papi_exec:
            papi_resp = papi_exec.add('show_version').get_replies(err_msg)

    This class processes three classes of VPP PAPI methods:
    1. simple request / reply: method='request',
    2. dump functions: method='dump',
    3. vpp-stats: method='stats'.

    The recommended ways of use are (examples):

    1. Simple request / reply

    a. One request with no arguments:

        with PapiExecutor(node) as papi_exec:
            data = papi_exec.add('show_version').get_replies().\
                verify_reply()

    b. Three requests with arguments, the second and the third ones are the same
       but with different arguments.

        with PapiExecutor(node) as papi_exec:
            data = papi_exec.add(cmd1, **args1).add(cmd2, **args2).\
                add(cmd2, **args3).get_replies(err_msg).verify_replies()

    2. Dump functions

        cmd = 'sw_interface_rx_placement_dump'
        with PapiExecutor(node) as papi_exec:
            papi_resp = papi_exec.add(cmd, sw_if_index=ifc['vpp_sw_index']).\
                get_dump(err_msg)

    3. vpp-stats

        path = ['^/if', '/err/ip4-input', '/sys/node/ip4-input']

        with PapiExecutor(node) as papi_exec:
            data = papi_exec.add(api_name='vpp-stats', path=path).get_stats()

        print('RX interface core 0, sw_if_index 0:\n{0}'.\
            format(data[0]['/if/rx'][0][0]))

        or

        path_1 = ['^/if', ]
        path_2 = ['^/if', '/err/ip4-input', '/sys/node/ip4-input']

        with PapiExecutor(node) as papi_exec:
            data = papi_exec.add('vpp-stats', path=path_1).\
                add('vpp-stats', path=path_2).get_stats()

        print('RX interface core 0, sw_if_index 0:\n{0}'.\
            format(data[1]['/if/rx'][0][0]))

        Note: In this case, when PapiExecutor method 'add' is used:
        - its parameter 'csit_papi_command' is used only to keep information
          that vpp-stats are requested. It is not further processed but it is
          included in the PAPI history this way:
          vpp-stats(path=['^/if', '/err/ip4-input', '/sys/node/ip4-input'])
          Always use csit_papi_command="vpp-stats" if the VPP PAPI method
          is "stats".
        - the second parameter must be 'path' as it is used by PapiExecutor
          method 'add'.
    """

    def __init__(self, node):
        """Initialization.

        :param node: Node to run command(s) on.
        :type node: dict
        """

        # Node to run command(s) on.
        self._node = node

        # The list of PAPI commands to be executed on the node.
        self._api_command_list = list()

        self._ssh = SSH()

    def __enter__(self):
        try:
            self._ssh.connect(self._node)
        except IOError:
            raise RuntimeError("Cannot open SSH connection to host {host} to "
                               "execute PAPI command(s)".
                               format(host=self._node["host"]))
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        self._ssh.disconnect(self._node)

    def add(self, csit_papi_command="vpp-stats", **kwargs):
        """Add next command to internal command list; return self.

        The argument name 'csit_papi_command' must be unique enough as it cannot
        be repeated in kwargs.

        :param csit_papi_command: VPP API command.
        :param kwargs: Optional key-value arguments.
        :type csit_papi_command: str
        :type kwargs: dict
        :returns: self, so that method chaining is possible.
        :rtype: PapiExecutor
        """
        PapiHistory.add_to_papi_history(self._node, csit_papi_command, **kwargs)
        self._api_command_list.append(dict(api_name=csit_papi_command,
                                           api_args=kwargs))
        return self

    def get_stats(self, err_msg="Failed to get statistics.", timeout=120):
        """Get VPP Stats from VPP Python API.

        :param err_msg: The message used if the PAPI command(s) execution fails.
        :param timeout: Timeout in seconds.
        :type err_msg: str
        :type timeout: int
        :returns: Requested VPP statistics.
        :rtype: list
        """

        paths = [cmd['api_args']['path'] for cmd in self._api_command_list]
        self._api_command_list = list()

        stdout, _ = self._execute_papi(
            paths, method='stats', err_msg=err_msg, timeout=timeout)

        return json.loads(stdout)

    def get_stats_reply(self, err_msg="Failed to get statistics.", timeout=120):
        """Get VPP Stats reply from VPP Python API.

        :param err_msg: The message used if the PAPI command(s) execution fails.
        :param timeout: Timeout in seconds.
        :type err_msg: str
        :type timeout: int
        :returns: Requested VPP statistics.
        :rtype: list
        """

        args = self._api_command_list[0]['api_args']
        self._api_command_list = list()

        stdout, _ = self._execute_papi(
            args, method='stats_request', err_msg=err_msg, timeout=timeout)

        return json.loads(stdout)

    def get_replies(self, err_msg="Failed to get replies.",
                    process_reply=True, ignore_errors=False, timeout=120):
        """Get reply/replies from VPP Python API.

        :param err_msg: The message used if the PAPI command(s) execution fails.
        :param process_reply: Process PAPI reply if True.
        :param ignore_errors: If true, the errors in the reply are ignored.
        :param timeout: Timeout in seconds.
        :type err_msg: str
        :type process_reply: bool
        :type ignore_errors: bool
        :type timeout: int
        :returns: Papi response including: papi reply, stdout, stderr and
            return code.
        :rtype: PapiResponse
        """
        return self._execute(
            method='request', process_reply=process_reply,
            ignore_errors=ignore_errors, err_msg=err_msg, timeout=timeout)

    def get_dump(self, err_msg="Failed to get dump.",
                 process_reply=True, ignore_errors=False, timeout=120):
        """Get dump from VPP Python API.

        :param err_msg: The message used if the PAPI command(s) execution fails.
        :param process_reply: Process PAPI reply if True.
        :param ignore_errors: If true, the errors in the reply are ignored.
        :param timeout: Timeout in seconds.
        :type err_msg: str
        :type process_reply: bool
        :type ignore_errors: bool
        :type timeout: int
        :returns: Papi response including: papi reply, stdout, stderr and
            return code.
        :rtype: PapiResponse
        """
        return self._execute(
            method='dump', process_reply=process_reply,
            ignore_errors=ignore_errors, err_msg=err_msg, timeout=timeout)

    @staticmethod
    def dump_and_log(node, cmds):
        """Dump and log requested information.

        :param node: DUT node.
        :param cmds: Dump commands to be executed.
        :type node: dict
        :type cmds: list
        """
        with PapiExecutor(node) as papi_exec:
            for cmd in cmds:
                dump = papi_exec.add(cmd).get_dump()
                logger.debug("{cmd}:\n{data}".format(
                    cmd=cmd, data=pformat(dump.reply[0]["api_reply"])))

    @staticmethod
    def run_cli_cmd(node, cmd, log=True):
        """Run a CLI command.

        :param node: Node to run command on.
        :param cmd: The CLI command to be run on the node.
        :param log: If True, the response is logged.
        :type node: dict
        :type cmd: str
        :type log: bool
        :returns: Verified data from PAPI response.
        :rtype: dict
        """

        cli = 'cli_inband'
        args = dict(cmd=cmd)
        err_msg = "Failed to run 'cli_inband {cmd}' PAPI command on host " \
                  "{host}".format(host=node['host'], cmd=cmd)

        with PapiExecutor(node) as papi_exec:
            data = papi_exec.add(cli, **args).get_replies(err_msg). \
                verify_reply(err_msg=err_msg)

        if log:
            logger.info("{cmd}:\n{data}".format(cmd=cmd, data=data["reply"]))

        return data

    def execute_should_pass(self, err_msg="Failed to execute PAPI command.",
                            process_reply=True, ignore_errors=False,
                            timeout=120):
        """Execute the PAPI commands and check the return code.
        Raise exception if the PAPI command(s) failed.

        IMPORTANT!
        Do not use this method in L1 keywords. Use:
        - get_replies()
        - get_dump()
        This method will be removed soon.

        :param err_msg: The message used if the PAPI command(s) execution fails.
        :param process_reply: Indicate whether or not to process PAPI reply.
        :param ignore_errors: If true, the errors in the reply are ignored.
        :param timeout: Timeout in seconds.
        :type err_msg: str
        :type process_reply: bool
        :type ignore_errors: bool
        :type timeout: int
        :returns: Papi response including: papi reply, stdout, stderr and
            return code.
        :rtype: PapiResponse
        :raises AssertionError: If PAPI command(s) execution failed.
        """
        # TODO: Migrate callers to get_replies and delete this method.
        return self.get_replies(
            process_reply=process_reply, ignore_errors=ignore_errors,
            err_msg=err_msg, timeout=timeout)

    @staticmethod
    def _process_api_data(api_d):
        """Process API data for smooth converting to JSON string.

        Apply binascii.hexlify() method for string values.

        :param api_d: List of APIs with their arguments.
        :type api_d: list
        :returns: List of APIs with arguments pre-processed for JSON.
        :rtype: list
        """

        def process_value(val):
            """Process value.

            :param val: Value to be processed.
            :type val: object
            :returns: Processed value.
            :rtype: dict or str or int
            """
            if isinstance(val, dict):
                val_dict = dict()
                for val_k, val_v in val.iteritems():
                    val_dict[str(val_k)] = process_value(val_v)
                return val_dict
            else:
                return binascii.hexlify(val) if isinstance(val, str) else val

        api_data_processed = list()
        for api in api_d:
            api_args_processed = dict()
            for a_k, a_v in api["api_args"].iteritems():
                api_args_processed[str(a_k)] = process_value(a_v)
            api_data_processed.append(dict(api_name=api["api_name"],
                                           api_args=api_args_processed))
        return api_data_processed

    @staticmethod
    def _revert_api_reply(api_r):
        """Process API reply / a part of API reply.

        Apply binascii.unhexlify() method for unicode values.

        TODO: Implement complex solution to process of replies.

        :param api_r: API reply.
        :type api_r: dict
        :returns: Processed API reply / a part of API reply.
        :rtype: dict
        """
        reply_dict = dict()
        reply_value = dict()
        for reply_key, reply_v in api_r.iteritems():
            for a_k, a_v in reply_v.iteritems():
                reply_value[a_k] = binascii.unhexlify(a_v) \
                    if isinstance(a_v, unicode) else a_v
            reply_dict[reply_key] = reply_value
        return reply_dict

    def _process_reply(self, api_reply):
        """Process API reply.

        :param api_reply: API reply.
        :type api_reply: dict or list of dict
        :returns: Processed API reply.
        :rtype: list or dict
        """
        if isinstance(api_reply, list):
            reverted_reply = [self._revert_api_reply(a_r) for a_r in api_reply]
        else:
            reverted_reply = self._revert_api_reply(api_reply)
        return reverted_reply

    def _execute_papi(self, api_data, method='request', err_msg="",
                      timeout=120):
        """Execute PAPI command(s) on remote node and store the result.

        :param api_data: List of APIs with their arguments.
        :param method: VPP Python API method. Supported methods are: 'request',
            'dump' and 'stats'.
        :param err_msg: The message used if the PAPI command(s) execution fails.
        :param timeout: Timeout in seconds.
        :type api_data: list
        :type method: str
        :type err_msg: str
        :type timeout: int
        :returns: Stdout and stderr.
        :rtype: 2-tuple of str
        :raises SSHTimeout: If PAPI command(s) execution has timed out.
        :raises RuntimeError: If PAPI executor failed due to another reason.
        :raises AssertionError: If PAPI command(s) execution has failed.
        """

        if not api_data:
            RuntimeError("No API data provided.")

        json_data = json.dumps(api_data) \
            if method in ("stats", "stats_request") \
            else json.dumps(self._process_api_data(api_data))

        cmd = "{fw_dir}/{papi_provider} --method {method} --data '{json}'".\
            format(fw_dir=Constants.REMOTE_FW_DIR,
                   papi_provider=Constants.RESOURCES_PAPI_PROVIDER,
                   method=method,
                   json=json_data)
        try:
            ret_code, stdout, stderr = self._ssh.exec_command_sudo(
                cmd=cmd, timeout=timeout, log_stdout_err=False)
        except SSHTimeout:
            logger.error("PAPI command(s) execution timeout on host {host}:"
                         "\n{apis}".format(host=self._node["host"],
                                           apis=api_data))
            raise
        except Exception:
            raise RuntimeError("PAPI command(s) execution on host {host} "
                               "failed: {apis}".format(host=self._node["host"],
                                                       apis=api_data))
        if ret_code != 0:
            raise AssertionError(err_msg)

        return stdout, stderr

    def _execute(self, method='request', process_reply=True,
                 ignore_errors=False, err_msg="", timeout=120):
        """Turn internal command list into proper data and execute; return
        PAPI response.

        This method also clears the internal command list.

        IMPORTANT!
        Do not use this method in L1 keywords. Use:
        - get_stats()
        - get_replies()
        - get_dump()

        :param method: VPP Python API method. Supported methods are: 'request',
            'dump' and 'stats'.
        :param process_reply: Process PAPI reply if True.
        :param ignore_errors: If true, the errors in the reply are ignored.
        :param err_msg: The message used if the PAPI command(s) execution fails.
        :param timeout: Timeout in seconds.
        :type method: str
        :type process_reply: bool
        :type ignore_errors: bool
        :type err_msg: str
        :type timeout: int
        :returns: Papi response including: papi reply, stdout, stderr and
            return code.
        :rtype: PapiResponse
        :raises KeyError: If the reply is not correct.
        """

        local_list = self._api_command_list

        # Clear first as execution may fail.
        self._api_command_list = list()

        stdout, stderr = self._execute_papi(
            local_list, method=method, err_msg=err_msg, timeout=timeout)
        papi_reply = list()
        if process_reply:
            try:
                json_data = json.loads(stdout)
            except ValueError:
                logger.error("An error occured while processing the PAPI "
                             "request:\n{rqst}".format(rqst=local_list))
                raise
            for data in json_data:
                try:
                    api_reply_processed = dict(
                        api_name=data["api_name"],
                        api_reply=self._process_reply(data["api_reply"]))
                except KeyError:
                    if ignore_errors:
                        continue
                    else:
                        raise
                papi_reply.append(api_reply_processed)

        # Log processed papi reply to be able to check API replies changes
        logger.debug("Processed PAPI reply: {reply}".format(reply=papi_reply))

        return PapiResponse(
            papi_reply=papi_reply, stdout=stdout, stderr=stderr,
            requests=[rqst["api_name"] for rqst in local_list])