#!/usr/bin/env python3
import io
import logging
import os
import subprocess
import threading
import json
from datetime import datetime
from enum import Enum

from sqlalchemy import Column, Integer, String, DateTime, JSON, event
from sqlalchemy.ext.declarative import declarative_base

import psutil

logger = logging.getLogger()
Base = declarative_base()


class RenderStatus(Enum):
    NOT_STARTED = "not_started"
    RUNNING = "running"
    COMPLETED = "completed"
    CANCELLED = "cancelled"
    ERROR = "error"
    SCHEDULED = "scheduled"
    UNDEFINED = "undefined"


def string_to_status(string):
    for stat in RenderStatus:
        if stat.value == string:
            return stat
    return RenderStatus.ERROR


class BaseRenderWorker(Base):
    __tablename__ = 'render_workers'

    id = Column(Integer, primary_key=True)
    input_path = Column(String)
    output_path = Column(String)
    date_created = Column(DateTime)
    renderer = Column(String)
    renderer_version = Column(String)
    priority = Column(Integer)
    owner = Column(String)
    client = Column(String)
    name = Column(String)
    file_hash = Column(String)

    engine = None

    def __init__(self, input_path, output_path, priority=2, args=None, ignore_extensions=True, owner=None, client=None,
                 name=None):

        if not ignore_extensions:
            if not any(ext in input_path for ext in self.engine.supported_extensions):
                err_meg = f'Cannot find valid project with supported file extension for {self.engine.name()} renderer'
                logger.error(err_meg)
                raise ValueError(err_meg)
        if not self.engine:
            raise NotImplementedError("Engine not defined")

        # Essential Info
        self.input_path = input_path
        self.output_path = output_path
        self.args = args or {}
        self.date_created = datetime.now()
        self.renderer = self.engine.name()
        self.renderer_version = self.engine.version()
        self.priority = priority
        self.owner = owner
        self.client = client
        self.name = name

        # Frame Ranges
        self.total_frames = 0
        self.current_frame = 0

        # Logging
        self.log_path = None
        self.start_time = None
        self.end_time = None

        # History
        self.status = RenderStatus.NOT_STARTED
        self.warnings = []
        self.errors = []
        self.failed_attempts = 0
        self.maximum_attempts = 1

        # Threads and processes
        self.__thread = threading.Thread(target=self.run, args=())
        self.__thread.daemon = True
        self.__process = None
        self.is_finished = False
        self.last_output = None

    def validate(self):
        if not os.path.exists(self.input_path):
            raise FileNotFoundError(f"Cannot find input path: {self.input_path}")
        self.generate_subprocess()

    def generate_subprocess(self):
        # Convert raw args from string if available and catch conflicts
        generated_args = self.generate_worker_subprocess()
        generated_args_flags = [x for x in generated_args if x.startswith('-')]
        if len(generated_args_flags) != len(set(generated_args_flags)):
            msg = "Cannot generate subprocess - Multiple arg conflicts detected"
            logger.error(msg)
            logger.debug(f"Generated args for subprocess: {generated_args}")
            raise ValueError(msg)
        return generated_args

    def get_raw_args(self):
        raw_args_string = self.args.get('raw', None)
        raw_args = None
        if raw_args_string:
            import shlex
            raw_args = shlex.split(raw_args_string)
        return raw_args

    def generate_worker_subprocess(self):
        raise NotImplementedError("generate_worker_subprocess not implemented")

    def start(self):

        if not os.path.exists(self.input_path):
            self.status = RenderStatus.ERROR
            msg = 'Cannot find input path: {}'.format(self.input_path)
            logger.error(msg)
            self.errors.append(msg)
            return

        if not self.engine.renderer_path():
            self.status = RenderStatus.ERROR
            msg = 'Cannot find render engine path for {}'.format(self.engine.name())
            logger.error(msg)
            self.errors.append(msg)
            return

        self.status = RenderStatus.RUNNING
        logger.info(f'Starting {self.engine.name()} {self.engine.version()} Render for {self.input_path}')
        self.__thread.start()

    def run(self):

        # Setup logging
        try:
            if not self.log_path:
                log_dir = os.path.join(os.path.dirname(self.input_path), 'logs')
                if not os.path.exists(log_dir):
                    os.makedirs(log_dir)
                self.log_path = os.path.join(log_dir, os.path.basename(self.input_path)) + '.log'
            logger.info('Logs saved in {}'.format(self.log_path))
        except Exception as e:
            logger.error("Error setting up logging: {}".format(e))

        while self.failed_attempts < self.maximum_attempts and self.status is not RenderStatus.COMPLETED:

            if self.failed_attempts:
                logger.info(f'Attempt #{self.failed_attempts} failed. Starting attempt #{self.failed_attempts + 1}')

            # Start process and get updates
            subprocess_cmds = self.generate_subprocess()
            logger.debug("Renderer commands generated - {}".format(" ".join(subprocess_cmds)))
            self.__process = subprocess.Popen(subprocess_cmds, stdout=subprocess.PIPE, stderr=subprocess.STDOUT,
                                              universal_newlines=False)
            self.start_time = datetime.now()

            with open(self.log_path, "a") as f:

                f.write(f"{self.start_time.isoformat()} - Starting {self.engine.name()} {self.engine.version()} "
                        f"Render for {self.input_path}")
                f.write(f"Running command: {' '.join(subprocess_cmds)}\n")
                for c in io.TextIOWrapper(self.__process.stdout, encoding="utf-8"):  # or another encoding
                    f.write(c)
                    logger.debug(f"{self.engine.name()}Worker: {c.strip()}")
                    self.last_output = c.strip()
                    self._parse_stdout(c.strip())
                f.write('\n')

                # Check return codes
                return_code = self.__process.wait()
                self.end_time = datetime.now()
                # Return early if job was cancelled
                if self.status in [RenderStatus.CANCELLED, RenderStatus.ERROR]:
                    self.is_finished = True
                    return

                duration = self.end_time - self.start_time

                if return_code:
                    message = f"{self.engine.name()} render failed with return_code {return_code} after {duration}"
                    logger.error(message)
                    self.failed_attempts = self.failed_attempts + 1
                else:
                    message = f"{self.engine.name()} render completed successfully in {duration}"
                    logger.info(message)
                    self.status = RenderStatus.COMPLETED

                f.write(message)

        if self.failed_attempts >= self.maximum_attempts and self.status is not RenderStatus.CANCELLED:
            logger.error('{} Render of {} failed after {} attempts'.format(self.engine.name(), self.input_path,
                                                                           self.failed_attempts))
            self.status = RenderStatus.ERROR
            if not self.errors:
                self.errors = [self.last_output]
        self.is_finished = True
        self.post_processing()

    def post_processing(self):
        pass

    def is_running(self):
        if self.__thread:
            return self.__thread.is_alive()
        return False

    def log_error(self, error_line, halt_render=False):
        logger.error(error_line)
        self.errors.append(error_line)
        if halt_render:
            self.stop(is_error=True)

    def stop(self, is_error=False):
        if self.__process:
            try:
                if self.status in [RenderStatus.RUNNING, RenderStatus.NOT_STARTED, RenderStatus.SCHEDULED]:
                    if is_error:
                        err_message = self.errors[-1] if self.errors else 'Unknown error'
                        logger.error(f"Halting render due to error: {err_message}")
                        self.status = RenderStatus.ERROR
                    else:
                        self.status = RenderStatus.CANCELLED
                self.maximum_attempts = 0
                process = psutil.Process(self.__process.pid)
                for proc in process.children(recursive=True):
                    proc.kill()
                process.kill()
            except Exception as e:
                logger.debug(f"Error stopping the process: {e}")

    def percent_complete(self):
        return 0

    def _parse_stdout(self, line):
        raise NotImplementedError("_parse_stdout not implemented")

    def time_elapsed(self):

        from string import Template

        class DeltaTemplate(Template):
            delimiter = "%"

        def strfdelta(tdelta, fmt='%H:%M:%S'):
            d = {"D": tdelta.days}
            hours, rem = divmod(tdelta.seconds, 3600)
            minutes, seconds = divmod(rem, 60)
            d["H"] = '{:02d}'.format(hours)
            d["M"] = '{:02d}'.format(minutes)
            d["S"] = '{:02d}'.format(seconds)
            t = DeltaTemplate(fmt)
            return t.substitute(**d)

        # calculate elapsed time
        elapsed_time = None
        start_time = self.start_time
        end_time = self.end_time

        if start_time:
            if end_time:
                elapsed_time = end_time - start_time
            elif self.status == RenderStatus.RUNNING:
                elapsed_time = datetime.now() - start_time

        elapsed_time_string = strfdelta(elapsed_time) if elapsed_time else "Unknown"
        return elapsed_time_string

    def json(self):
        worker_data = self.__dict__.copy()
        worker_data['percent_complete'] = self.percent_complete()
        worker_data['time_elapsed'] = self.time_elapsed()
        worker_data['status'] = self.status.value
        keys_to_remove = ['thread', 'process']  # remove unwanted keys from dict
        for key in worker_data.keys():
            if key.startswith('_'):
                keys_to_remove.append(key)
        for key in keys_to_remove:
            worker_data.pop(key, None)

        # convert to json and back to auto-convert dates to iso format
        def date_serializer(o):
            if isinstance(o, datetime):
                return o.isoformat()

        json_convert = json.dumps(worker_data, default=date_serializer)
        worker_json = json.loads(json_convert)
        return worker_json


def timecode_to_frames(timecode, frame_rate):
    e = [int(x) for x in timecode.split(':')]
    seconds = (((e[0] * 60) + e[1] * 60) + e[2])
    frames = (seconds * frame_rate) + e[-1] + 1
    return frames