#!/usr/bin/env python
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"""
=====
local
=====

Execution utilities
"""


import os
import sys
import tempfile
import shutil
import zmq
import time
import logging

from beat.backend.python.execution import AlgorithmExecutor
from beat.backend.python.execution import MessageHandler
from beat.backend.python.execution import LoopExecutor
from beat.backend.python.execution import LoopMessageHandler

from .base import BaseExecutor

logger = logging.getLogger(__name__)


class LocalExecutor(BaseExecutor):
    """LocalExecutor runs the code given an execution block information


    Parameters:

      prefix (str): Establishes the prefix of your installation.

      data (dict, str): The piece of data representing the block to be executed.
        It must validate against the schema defined for execution blocks. If a
        string is passed, it is supposed to be a fully qualified absolute path to
        a JSON file containing the block execution information.

      cache (:py:class:`str`, Optional): If your cache is not located under
        ``<prefix>/cache``, then specify a full path here. It will be used
        instead.

      dataformat_cache (:py:class:`dict`, Optional): A dictionary mapping
        dataformat names to loaded dataformats. This parameter is optional and,
        if passed, may greatly speed-up database loading times as dataformats
        that are already loaded may be re-used. If you use this parameter, you
        must guarantee that the cache is refreshed as appropriate in case the
        underlying dataformats change.

      database_cache (:py:class:`dict`, Optional): A dictionary mapping
        database names to loaded databases. This parameter is optional and, if
        passed, may greatly speed-up database loading times as databases that
        are already loaded may be re-used. If you use this parameter, you must
        guarantee that the cache is refreshed as appropriate in case the
        underlying databases change.

      algorithm_cache (:py:class:`dict`, Optional): A dictionary mapping
        algorithm names to loaded algorithms. This parameter is optional and,
        if passed, may greatly speed-up database loading times as algorithms
        that are already loaded may be re-used. If you use this parameter, you
        must guarantee that the cache is refreshed as appropriate in case the
        underlying algorithms change.

      library_cache (:py:class:`dict`, Optional): A dictionary mapping library
        names to loaded libraries. This parameter is optional and, if passed,
        may greatly speed-up library loading times as libraries that are
        already loaded may be re-used. If you use this parameter, you must
        guarantee that the cache is refreshed as appropriate in case the
        underlying libraries change.

      custom_root_folders (:py:class:`dict`, Optional): A dictionary where the
        keys are database identifiers (``<db_name>/<version>``) and the values
        are paths to the given database's files. These values will override the
        value found in the database's metadata.


    Attributes:

      cache (str): The path to the cache currently being used

      errors (list): A list containing errors found while loading this execution
        block.

      data (dict): The original data for this executor, as loaded by our JSON
        decoder.

      algorithm (.algorithm.Algorithm): An object representing the
        algorithm to be run.

      databases (dict): A dictionary in which keys are strings with database
        names and values are :py:class:`.database.Database`, representing the
        databases required for running this block. The dictionary may be empty
        in case all inputs are taken from the file cache.

      views (dict): A dictionary in which the keys are tuples pointing to the
        ``(<database-name>, <protocol>, <set>)`` and the value is a setup view
        for that particular combination of details. The dictionary may be empty
        in case all inputs are taken from the file cache.

      input_list (beat.backend.python.inputs.InputList): A list of inputs that
        will be served to the algorithm.

      output_list (beat.backend.python.outputs.OutputList): A list of outputs
        that the algorithm will produce.

      data_sources (list): A list with all data-sources created by our execution
        loader.

      data_sinks (list): A list with all data-sinks created by our execution
        loader. These are useful for clean-up actions in case of problems.

      custom_root_folders (dict): A dictionary where the keys are database
        identifiers (`<db_name>/<version>`) and the values are paths to the
        given database's files. These values will override the value found
        in the database's metadata.

    """

    def __init__(
        self,
        prefix,
        data,
        cache=None,
        dataformat_cache=None,
        database_cache=None,
        algorithm_cache=None,
        library_cache=None,
        custom_root_folders=None,
    ):

        super(LocalExecutor, self).__init__(
            prefix,
            data,
            cache=cache,
            dataformat_cache=dataformat_cache,
            database_cache=database_cache,
            algorithm_cache=algorithm_cache,
            library_cache=library_cache,
            custom_root_folders=custom_root_folders,
        )

        self.working_dir = None
        self.executor = None
        self.message_handler = None
        self.executor_socket = None

        self.loop_executor = None
        self.loop_message_handler = None
        self.loop_socket = None

        self.zmq_context = None

    def __cleanup(self, early=False):
        if self.loop_executor:
            if early:
                self.loop_socket.send_string("don")
                self.loop_socket.recv()  # ack

            self.loop_executor.wait()
            self.loop_executor.close()

        for handler in [self.message_handler, self.loop_message_handler]:
            if handler:
                handler.kill()
                handler.join()
                handler.destroy()

        for socket in [self.executor_socket, self.loop_socket]:
            if socket:
                socket.setsockopt(zmq.LINGER, 0)
                socket.close()

        if self.zmq_context is not None:
            self.zmq_context.destroy()

        if self.working_dir is not None:
            shutil.rmtree(self.working_dir)

    def process(
        self, virtual_memory_in_megabytes=0, max_cpu_percent=0, timeout_in_minutes=0
    ):
        """Executes the user algorithm code

        Parameters:

          virtual_memory_in_megabytes (:py:class:`int`, Optional): The amount
            of virtual memory (in Megabytes) available for the job. If set to
            zero, no limit will be applied.

          max_cpu_percent (:py:class:`int`, Optional): The maximum amount of
            CPU usage allowed in a system. This number must be an integer
            number between 0 and ``100*number_of_cores`` in your system. For
            instance, if your system has 2 cores, this number can go between 0
            and 200. If it is <= 0, then we don't track CPU usage.

          timeout_in_minutes (int): The number of minutes to wait for the user
            process to execute. After this amount of time, the user process is
            killed with ``signal.SIGKILL``. If set to zero, no timeout will be
            applied.

        Returns:

          dict: A dictionary which is JSON formattable containing the summary of
            this block execution.

        """

        def _create_result(status, error_message=""):
            return {
                "status": status,
                "statistics": {
                    "data": self.io_statistics,
                    "cpu": {
                        "user": 0.0,
                        "system": 0.0,
                        "total": 0.0,
                        "percent": 0.0,
                        "processors": 1,
                    },
                    "memory": {"rss": 0, "limit": 0, "percent": 0.0},
                },
                "stderr": "",
                "stdout": "",
                "system_error": "",
                "user_error": error_message,
                "timed_out": False,
            }

        def _process_exception(exception, prefix, contribution_kind):
            import traceback

            exc_type, exc_value, exc_traceback = sys.exc_info()
            tb = traceback.extract_tb(exc_traceback)

            contributions_prefix = os.path.join(prefix, contribution_kind) + os.sep

            for first_line, line in enumerate(tb):
                if line[0].startswith(contributions_prefix):
                    break

            if first_line == len(tb):
                first_line = 0

            s = "".join(traceback.format_list(tb[first_line:]))
            s = s.replace(contributions_prefix, "").strip()

            return "%s\n%s: %s" % (s, type(exception).__name__, exception)

        if not self.valid:
            raise RuntimeError(
                "execution information is bogus:\n  * %s" % "\n  * ".join(self.errors)
            )

        self.message_handler = MessageHandler("127.0.0.1")
        self.message_handler.start()

        self.zmq_context = zmq.Context()
        self.executor_socket = self.zmq_context.socket(zmq.PAIR)
        self.executor_socket.connect(self.message_handler.address)

        self.working_dir = tempfile.mkdtemp(prefix=__name__)
        working_prefix = os.path.join(self.working_dir, "prefix")

        self.dump_runner_configuration(self.working_dir)
        self.algorithm.export(working_prefix)

        if self.loop_algorithm:
            self.loop_algorithm.export(working_prefix)
            self.loop_message_handler = LoopMessageHandler("127.0.0.1")
            self.loop_socket = self.zmq_context.socket(zmq.PAIR)
            self.loop_socket.connect(self.loop_message_handler.address)

            self.loop_executor = LoopExecutor(
                self.loop_message_handler,
                self.working_dir,
                database_cache=self.databases,
                cache_root=self.cache,
            )

            try:
                retval = self.loop_executor.setup()
            except Exception as e:
                message = _process_exception(e, self.prefix, "algorithms")
                retval = False
            else:
                message = None

            if not retval:
                self.__cleanup()
                error = "Loop algorithm {} setup failed".format(self.algorithm.name)
                if message:
                    error += ": {}".format(message)
                raise RuntimeError(error)

            try:
                prepared = self.loop_executor.prepare()
            except Exception as e:
                message = _process_exception(e, self.prefix, "algorithms")
                prepared = False
            else:
                message = None

            if not prepared:
                self.__cleanup()
                error = "Loop algorithm {} prepare failed".format(self.algorithm.name)
                if message:
                    error += ": {}".format(message)
                raise RuntimeError(error)

            self.loop_executor.process()

        self.executor = AlgorithmExecutor(
            self.executor_socket,
            self.working_dir,
            database_cache=self.databases,
            cache_root=self.cache,
            loop_socket=self.loop_socket,
        )

        try:
            status = self.executor.setup()
        except Exception as e:
            message = _process_exception(e, self.prefix, "algorithms")
            status = 0
        else:
            message = None

        if not status:
            self.__cleanup(early=True)
            error = "Algorithm {} setup failed".format(self.algorithm.name)
            if message:
                error += ": {}".format(message)
            raise RuntimeError(error)

        try:
            prepared = self.executor.prepare()
        except Exception as e:
            message = _process_exception(e, self.prefix, "algorithms")
            prepared = 0
        else:
            message = None

        if not prepared:
            self.__cleanup(early=True)
            error = "Algorithm {} prepare failed".format(self.algorithm.name)
            if message:
                error += ": {}".format(message)
            raise RuntimeError(error)

        _start = time.time()

        try:
            processed = self.executor.process()
        except Exception as e:
            message = _process_exception(e, self.prefix, "algorithms")
            self.__cleanup()
            return _create_result(1, message)

        if not processed:
            self.__cleanup()
            raise RuntimeError(
                "Algorithm {} process failed".format(self.algorithm.name)
            )

        proc_time = time.time() - _start

        # some local information
        logger.debug("Total processing time was %.3f seconds", proc_time)

        self.__cleanup()

        return _create_result(0)
