import json
import logging
import os
import platform
from datetime import datetime

import psutil
import requests

from lib.render_job import RenderJob
from utilities.render_worker import RenderWorkerFactory, RenderStatus

logger = logging.getLogger()

JSON_FILE = 'server_state.json'
#todo: move history to sqlite db


class RenderQueue:
    job_queue = []
    render_clients = []
    maximum_renderer_instances = {'Blender': 2, 'After Effects': 1, 'ffmpeg': 4}
    host_name = None
    port = 8080
    client_mode = False
    server_hostname = None

    last_saved_counts = {}

    def __init__(self):
        pass

    @classmethod
    def add_to_render_queue(cls, render_job, force_start=False, client=None):

        if not client or render_job.client == cls.host_name:
            logger.debug('Adding priority {} job to render queue: {}'.format(render_job.priority, render_job.render))
            render_job.client = cls.host_name
            cls.job_queue.append(render_job)
            if force_start:
                cls.start_job(render_job)
            else:
                cls.evaluate_queue()
        else:
            # todo: implement client rendering
            logger.warning('remote client rendering not implemented yet')

    @classmethod
    def running_jobs(cls):
        return cls.jobs_with_status(RenderStatus.RUNNING)

    @classmethod
    def pending_jobs(cls):
        pending_jobs = cls.jobs_with_status(RenderStatus.NOT_STARTED)
        pending_jobs.extend(cls.jobs_with_status(RenderStatus.SCHEDULED))
        return pending_jobs

    @classmethod
    def jobs_with_status(cls, status, priority_sorted=False, include_archived=True):
        found_jobs = [x for x in cls.job_queue if x.render_status() == status]
        if not include_archived:
            found_jobs = [x for x in found_jobs if not x.archived]
        if priority_sorted:
            found_jobs = sorted(found_jobs, key=lambda a: a.priority, reverse=False)
        return found_jobs

    @classmethod
    def job_with_id(cls, job_id):
        found_job = next((x for x in cls.job_queue if x.id == job_id), None)
        return found_job

    @classmethod
    def clear_history(cls):
        to_remove = [x for x in cls.job_queue if x.render_status() in [RenderStatus.CANCELLED,
                                                                       RenderStatus.COMPLETED, RenderStatus.ERROR]]
        for x in to_remove:
            x.archived = True
        cls.save_state()

    @classmethod
    def load_state(cls, json_path=None):
        """Load state history from JSON file"""

        input_path = json_path or JSON_FILE
        if os.path.exists(input_path):
            with open(input_path) as f:

                # load saved data
                saved_state = json.load(f)
                cls.render_clients = saved_state.get('clients', {})

                for job in saved_state.get('jobs', []):

                    # Identify renderer type and recreate Renderer object
                    job_render_object = RenderWorkerFactory.create_worker(job['renderer'], input_path=job['render']['input'], output_path=job['render']['output'])

                    # Load Renderer values
                    for key, val in job['render'].items():
                        if val and key in ['start_time', 'end_time']:  # convert date strings back into date objects
                            job_render_object.__dict__[key] = datetime.fromisoformat(val)
                        else:
                            job_render_object.__dict__[key] = val

                    job_render_object.status = RenderStatus[job['status'].upper()]
                    job.pop('render', None)

                    # Create RenderJob with re-created Renderer object
                    new_job = RenderJob(job_render_object, job['priority'], job['client'])
                    for key, val in job.items():
                        if key in ['date_created']:  # convert date strings back to datetime objects
                            new_job.__dict__[key] = datetime.fromisoformat(val)
                        else:
                            new_job.__dict__[key] = val
                    new_job.__delattr__('status')

                    # Handle older loaded jobs that were cancelled before closing
                    if new_job.render_status() == RenderStatus.RUNNING:
                        new_job.render.status = RenderStatus.CANCELLED

                    # finally add back to render queue
                    cls.job_queue.append(new_job)

                cls.last_saved_counts = cls.job_counts()

    @classmethod
    def save_state(cls, json_path=None):
        """Save state history to JSON file"""
        try:
            logger.debug("Saving Render History")
            output = {'timestamp': datetime.now().isoformat(),
                      'jobs': [json.loads(j.json()) for j in cls.job_queue],
                      'clients': cls.render_clients}
            output_path = json_path or JSON_FILE
            with open(output_path, 'w') as f:
                json.dump(output, f, indent=4)
            cls.last_saved_counts = cls.job_counts()
        except Exception as e:
            logger.error("Error saving state JSON: {}".format(e))

    @classmethod
    def evaluate_queue(cls):

        instances = cls.renderer_instances()

        not_started = cls.jobs_with_status(RenderStatus.NOT_STARTED, priority_sorted=True)
        if not_started:
            for job in not_started:
                renderer = job.render.renderer
                higher_priority_jobs = [x for x in cls.running_jobs() if x.priority < job.priority]
                max_renderers = renderer in instances.keys() and instances[
                    renderer] >= cls.maximum_renderer_instances.get(renderer, 1)

                if not max_renderers and not higher_priority_jobs:
                    cls.start_job(job)

        scheduled = cls.jobs_with_status(RenderStatus.SCHEDULED, priority_sorted=True)
        for job in scheduled:
            if job.scheduled_start <= datetime.now():
                cls.start_job(job)

        if cls.last_saved_counts != cls.job_counts():
            cls.save_state()

    @classmethod
    def start_job(cls, job):
        logger.info('Starting {}render: {} - Priority {}'.format('scheduled ' if job.scheduled_start else '', job.name,
                                                                  job.priority))
        job.render.start()

    @classmethod
    def cancel_job(cls, job):
        logger.info('Cancelling job ID: {}'.format(job.id))
        if job.render_status() in [RenderStatus.NOT_STARTED, RenderStatus.RUNNING, RenderStatus.ERROR]:
            job.render.stop()
            job.render.status = RenderStatus.CANCELLED
            return True
        return False

    @classmethod
    def renderer_instances(cls):
        from collections import Counter
        all_instances = [x.render.renderer for x in cls.running_jobs()]
        return Counter(all_instances)

    @classmethod
    def job_counts(cls):
        job_counts = {}
        for job_status in RenderStatus:
            job_counts[job_status.value] = len(cls.jobs_with_status(job_status))

        return job_counts

    @classmethod
    def status(cls):

        stats = {"timestamp": datetime.now().isoformat(),
                 "platform": platform.platform(),
                 "cpu_percent": psutil.cpu_percent(percpu=False),
                 "cpu_percent_per_cpu": psutil.cpu_percent(percpu=True),
                 "cpu_count": psutil.cpu_count(),
                 "memory_total": psutil.virtual_memory().total,
                 "memory_available": psutil.virtual_memory().available,
                 "memory_percent": psutil.virtual_memory().percent,
                 "job_counts": cls.job_counts(),
                 "host_name": cls.host_name
                 }

        return stats

    @classmethod
    def all_jobs(cls):
        all_jobs = [x for x in cls.job_queue if not x.archived]
        return all_jobs

    @classmethod
    def register_client(cls, hostname):

        #todo: check to make sure not adding ourselves

        success = False

        if hostname in cls.render_clients:
            logger.warning(f"Client '{hostname}' already registered")
            return success

        try:
            response = requests.get(f"http://{hostname}:8080/status", timeout=3)
            if response.ok:
                cls.render_clients.append(hostname)
                logger.info(f"Client '{hostname}' successfully registered")
                success = True
                cls.save_state()
        except requests.ConnectionError as e:
            logger.error(f"Cannot connect to client at hostname: {hostname}")
        return success

    @classmethod
    def unregister_client(cls, hostname):
        success = False
        if hostname in cls.render_clients and hostname != cls.host_name:
            cls.render_clients.remove(hostname)
            logger.info(f"Client '{hostname}' successfully unregistered")
            success = True
        return success

    @staticmethod
    def is_client_available(client_hostname, timeout=3):
        try:
            response = requests.get(f"http://{client_hostname}:8080/status", timeout=timeout)
            if response.ok:
                return True
        except requests.ConnectionError as e:
            pass
        return False