#    Copyright 2013-2015 ARM Limited
#
# 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.
#

# pylint: disable=no-member

import logging
import os
import random
import subprocess
import uuid
from collections import Counter, defaultdict, OrderedDict
from contextlib import contextmanager
from copy import copy
from datetime import datetime
from itertools import izip_longest

import wa.framework.signal as signal
from wa.framework import instrumentation, pluginloader
from wa.framework.configuration.core import settings, Status
from wa.framework.exception import (WAError, ConfigError, TimeoutError,
                                    InstrumentError, TargetError,
                                    TargetNotRespondingError)
from wa.framework.output import init_job_output
from wa.framework.plugin import Artifact
from wa.framework.processor import ProcessorManager
from wa.framework.resource import ResourceResolver
from wa.framework.run import RunState
from wa.framework.target.info import TargetInfo
from wa.framework.target.manager import TargetManager
from wa.utils import log
from wa.utils.misc import (ensure_directory_exists as _d, merge_config_values,
                           get_traceback, format_duration)
from wa.utils.serializer import json


class ExecutionContext(object):

    @property
    def previous_job(self):
        if not self.job_queue:
            return None
        return self.job_queue[0]

    @property
    def next_job(self):
        if not self.completed_jobs:
            return None
        return self.completed_jobs[-1]

    @property
    def spec_changed(self):
        if self.previous_job is None and self.current_job is not None:  # Start of run
            return True
        if self.previous_job is not None and self.current_job is None:  # End of run
            return True
        return self.current_job.spec.id != self.previous_job.spec.id

    @property
    def spec_will_change(self):
        if self.current_job is None and self.next_job is not None:  # Start of run
            return True
        if self.current_job is not None and self.next_job is None:  # End of run
            return True
        return self.current_job.spec.id != self.next_job.spec.id

    @property
    def job_output(self):
        if self.current_job:
            return self.current_job.output

    @property
    def output(self):
        if self.current_job:
            return self.job_output
        return self.run_output

    @property
    def output_directory(self):
        return self.output.basepath

    def __init__(self, cm, tm, output):
        self.logger = logging.getLogger('context')
        self.cm = cm
        self.tm = tm
        self.run_output = output
        self.run_state = output.state
        self.target_info = self.tm.get_target_info()
        self.logger.debug('Loading resource discoverers')
        self.resolver = ResourceResolver(cm.plugin_cache)
        self.resolver.load()
        self.job_queue = None
        self.completed_jobs = None
        self.current_job = None
        self.successful_jobs = 0
        self.failed_jobs = 0

    def start_run(self):
        self.output.info.start_time = datetime.utcnow()
        self.output.write_info()
        self.job_queue = copy(self.cm.jobs)
        self.completed_jobs = []
        self.run_state.status = Status.STARTED
        self.output.status = Status.STARTED
        self.output.write_state()

    def end_run(self):
        if self.successful_jobs:
            if self.failed_jobs:
                status = Status.PARTIAL
            else:
                status = Status.OK
        else:
            status = Status.FAILED
        self.run_state.status = status
        self.output.status = status
        self.output.info.end_time = datetime.utcnow()
        self.output.info.duration = self.output.info.end_time -\
                                    self.output.info.start_time
        self.output.write_info()
        self.output.write_state()
        self.output.write_result()

    def start_job(self):
        if not self.job_queue:
            raise RuntimeError('No jobs to run')
        self.current_job = self.job_queue.pop(0)
        self.current_job.output = init_job_output(self.run_output, self.current_job)
        self.update_job_state(self.current_job)
        return self.current_job

    def end_job(self):
        if not self.current_job:
            raise RuntimeError('No jobs in progress')
        self.completed_jobs.append(self.current_job)
        self.update_job_state(self.current_job)
        self.output.write_result()
        self.current_job = None

    def move_failed(self, job):
        self.run_output.move_failed(job.output)

    def update_job_state(self, job):
        self.run_state.update_job(job)
        self.run_output.write_state()

    def skip_remaining_jobs(self):
        while self.job_queue:
            job = self.job_queue.pop(0)
            job.status = Status.SKIPPED
            self.run_state.update_job(job)
            self.completed_jobs.append(job)
        self.write_state()

    def write_state(self):
        self.run_output.write_state()

    def add_metric(self, name, value, units=None, lower_is_better=False,
                   classifiers=None):
        if self.current_job:
            classifiers = merge_config_values(self.current_job.classifiers,
                                              classifiers)
        self.output.add_metric(name, value, units, lower_is_better, classifiers)

    def add_artifact(self, name, path, kind, description=None, classifiers=None):
        self.output.add_artifact(name, path, kind, description, classifiers)

    def add_run_artifact(self, name, path, kind, description=None,
                         classifiers=None):
        self.run_output.add_artifact(name, path, kind, description, classifiers)

    def add_event(self, message):
        self.output.add_event(message)


class Executor(object):
    """
    The ``Executor``'s job is to set up the execution context and pass to a
    ``Runner`` along with a loaded run specification. Once the ``Runner`` has
    done its thing, the ``Executor`` performs some final reporint before
    returning.

    The initial context set up involves combining configuration from various
    sources, loading of requided workloads, loading and installation of
    instruments and result processors, etc. Static validation of the combined
    configuration is also performed.

    """
    # pylint: disable=R0915

    def __init__(self):
        self.logger = logging.getLogger('executor')
        self.error_logged = False
        self.warning_logged = False
        pluginloader = None
        self.device_manager = None
        self.device = None

    def execute(self, config_manager, output):
        """
        Execute the run specified by an agenda. Optionally, selectors may be
        used to only selecute a subset of the specified agenda.

        Params::

            :state: a ``ConfigManager`` containing processed configuraiton
            :output: an initialized ``RunOutput`` that will be used to
                     store the results.

        """
        signal.connect(self._error_signalled_callback, signal.ERROR_LOGGED)
        signal.connect(self._warning_signalled_callback, signal.WARNING_LOGGED)

        self.logger.info('Initializing run')
        self.logger.debug('Finalizing run configuration.')
        config = config_manager.finalize()
        output.write_config(config)

        self.logger.info('Connecting to target')
        target_manager = TargetManager(config.run_config.device,
                                       config.run_config.device_config)
        output.write_target_info(target_manager.get_target_info())

        self.logger.info('Initializing execution conetext')
        context = ExecutionContext(config_manager, target_manager, output)

        self.logger.info('Generating jobs')
        config_manager.generate_jobs(context)
        output.write_job_specs(config_manager.job_specs)
        output.write_state()

        self.logger.info('Installing instrumentation')
        for instrument in config_manager.get_instruments(target_manager.target):
            instrumentation.install(instrument)
        instrumentation.validate()

        self.logger.info('Installing result processors')
        pm = ProcessorManager()
        for proc in config_manager.get_processors():
            pm.install(proc)
        pm.validate()

        self.logger.info('Starting run')
        runner = Runner(context, pm)
        signal.send(signal.RUN_STARTED, self)
        runner.run()
        self.execute_postamble(context, output)
        signal.send(signal.RUN_COMPLETED, self)

    def execute_postamble(self, context, output):
        self.logger.info('Done.')
        duration = format_duration(output.info.duration)
        self.logger.info('Run duration: {}'.format(duration))
        num_ran = context.run_state.num_completed_jobs
        status_summary = 'Ran a total of {} iterations: '.format(num_ran)

        counter = context.run_state.get_status_counts()
        parts = []
        for status in reversed(Status.values):
            if status in counter:
                parts.append('{} {}'.format(counter[status], status))
        self.logger.info(status_summary + ', '.join(parts))

        self.logger.info('Results can be found in {}'.format(output.basepath))

        if self.error_logged:
            self.logger.warn('There were errors during execution.')
            self.logger.warn('Please see {}'.format(output.logfile))
        elif self.warning_logged:
            self.logger.warn('There were warnings during execution.')
            self.logger.warn('Please see {}'.format(output.logfile))

    def _error_signalled_callback(self):
        self.error_logged = True
        signal.disconnect(self._error_signalled_callback, signal.ERROR_LOGGED)

    def _warning_signalled_callback(self):
        self.warning_logged = True
        signal.disconnect(self._warning_signalled_callback, signal.WARNING_LOGGED)


class Runner(object):
    """
    
    """

    def __init__(self, context, pm):
        self.logger = logging.getLogger('runner')
        self.context = context
        self.pm = pm
        self.output = self.context.output
        self.config = self.context.cm

    def run(self):
        try:
            self.initialize_run()
            self.send(signal.RUN_INITIALIZED)

            while self.context.job_queue:
                try:
                    with signal.wrap('JOB_EXECUTION', self):
                        self.run_next_job(self.context)
                except KeyboardInterrupt:
                    self.context.skip_remaining_jobs()
        except Exception as e:
            self.context.add_event(e.message)
            if (not getattr(e, 'logged', None) and
                    not isinstance(e, KeyboardInterrupt)):
                log.log_error(e, self.logger)
                e.logged = True
            raise e
        finally:
            self.finalize_run()
            self.send(signal.RUN_FINALIZED)

    def initialize_run(self):
        self.logger.info('Initializing run')
        self.context.start_run()
        self.pm.initialize()
        log.indent()
        for job in self.context.job_queue:
            job.initialize(self.context)
        log.dedent()
        self.context.write_state()

    def finalize_run(self):
        self.logger.info('Finalizing run')
        self.context.end_run()
        self.pm.process_run_output(self.context)
        self.pm.export_run_output(self.context)
        self.pm.finalize()

    def run_next_job(self, context):
        job = context.start_job()
        self.logger.info('Running job {}'.format(job.id))

        try:
            log.indent()
            self.do_run_job(job, context)
            job.status = Status.OK
        except KeyboardInterrupt:
            job.status = Status.ABORTED
            raise
        except Exception as e:
            job.status = Status.FAILED
            context.add_event(e.message)
            if not getattr(e, 'logged', None):
                log.log_error(e, self.logger)
                e.logged = True
        finally:
            self.logger.info('Completing job {}'.format(job.id))
            self.send(signal.JOB_COMPLETED)
            context.end_job()

            log.dedent()
            self.check_job(job)

    def do_run_job(self, job, context):
        job.status = Status.RUNNING
        self.send(signal.JOB_STARTED)

        with signal.wrap('JOB_TARGET_CONFIG', self):
            job.configure_target(context)

        with signal.wrap('JOB_SETUP', self):
            job.setup(context)
        
        try:
            with signal.wrap('JOB_EXECUTION', self):
                job.run(context)

            try:
                with signal.wrap('JOB_OUTPUT_PROCESSED', self):
                    job.process_output(context)
                self.pm.process_job_output(context)
                self.pm.export_job_output(context)
            except Exception:
                job.status = Status.PARTIAL
                raise

        except KeyboardInterrupt:
            job.status = Status.ABORTED
            self.logger.info('Got CTRL-C. Aborting.')
            raise
        except Exception as e:
            job.status = Status.FAILED
            if not getattr(e, 'logged', None):
                log.log_error(e, self.logger)
                e.logged = True
            raise e
        finally:
            # If setup was successfully completed, teardown must
            # run even if the job failed
            with signal.wrap('JOB_TEARDOWN', self):
                job.teardown(context)

    def check_job(self, job):
        rc = self.context.cm.run_config
        if job.status in rc.retry_on_status:
            if job.retries < rc.max_retries:
                msg = 'Job {} iteration {} completed with status {}. retrying...'
                self.logger.error(msg.format(job.id, job.status, job.iteration))
                self.context.move_failed(job)
                job.retries += 1
                job.status = Status.PENDING
                self.context.job_queue.insert(0, job)
                self.context.write_state()
            else:
                msg = 'Job {} iteration {} completed with status {}. '\
                      'Max retries exceeded.'
                self.logger.error(msg.format(job.id, job.status, job.iteration))
                self.context.failed_jobs += 1
        else:  # status not in retry_on_status
            self.logger.info('Job completed with status {}'.format(job.status))
            self.context.successful_jobs += 1
        
    def send(self, s):
        signal.send(s, self, self.context)

    def __str__(self):
        return 'runner'