<?php
/**
 * FuzeWorks Async Library
 *
 * The FuzeWorks PHP FrameWork
 *
 * Copyright (C) 2013-2020 TechFuze
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * @author    TechFuze
 * @copyright Copyright (c) 2013 - 2020, TechFuze. (http://techfuze.net)
 * @license   https://opensource.org/licenses/MIT MIT License
 *
 * @link  http://techfuze.net/fuzeworks
 * @since Version 1.0.0
 *
 * @version Version 1.0.0
 */

namespace FuzeWorks\Async;
class Task
{

    /**
     * If a task is waiting to be executed, its status will be PENDING
     */
    const PENDING = 1;

    /**
     * If a task is currently in process, its status will be RUNNING
     */
    const RUNNING = 2;

    /**
     * If a task does not reach the goal it sets out to, its status should be set to FAILED.
     *
     * Not to be confused with Process::FAILED. Process::FAILED will be the Process status when a Process running a Task unexpectedly stops running.
     * This will set the Task to Task::PFAILED
     */
    const FAILED = 3;
    const PFAILED = 4;

    /**
     * If a task has reached its goal, its status should be set to SUCCESS
     */
    const SUCCESS = 5;

    /**
     * If a task is in process of its postHandler, its status will be POST
     */
    const POST = 6;

    /**
     * If a task has completed all its goals, its status will be COMPLETED
     */
    const COMPLETED = 7;

    /**
     * If a task has a timed based constraint, its status will be DELAYED
     *
     * Task is delayed by the time in $delayTime
     */
    const DELAYED = 8;

    /**
     * If a task has a constraint preventing it from running at any point, its status will be CANCELLED
     */
    const CANCELLED = 9;

    public static function getStatusType($statusId)
    {
        switch ($statusId) {
            case 1:
                return 'Task::PENDING';
            case 2:
                return 'Task::RUNNING';
            case 3:
                return 'Task::FAILED';
            case 4:
                return 'Task::PFAILED';
            case 5:
                return 'Task::SUCCESS';
            case 6:
                return 'Task::POST';
            case 7:
                return 'Task::COMPLETED';
            case 8:
                return 'Task::DELAYED';
            case 9:
                return 'Task::CANCELLED';
            default:
                return false;
        }
    }

    /**
     * @var string
     */
    protected $taskId;

    /**
     * @var int
     */
    protected $status = Task::PENDING;

    /**
     * @var array
     */
    protected $arguments;

    /**
     * @var Handler
     */
    protected $handler;

    /**
     * @var bool
     */
    protected $usePostHandler = false;

    /**
     * @var Constraint[]
     */
    protected $constraints = [];

    /**
     * When the status of this task is Task::DELAYED, this is the amount of time in seconds before it should be tried again.
     *
     * @var int Delay time in seconds
     */
    protected $delayTime = 0;

    /**
     * The output of the execution of this task
     *
     * @var string
     */
    protected $output;
    protected $postOutput;

    /**
     * The errors thrown by the execution of this task
     *
     * @var string
     */
    protected $errors;
    protected $postErrors;

    /**
     * Contains a key, value array with properties of this Task
     *
     * @var array
     */
    protected $attributes = [];

    /* -------- Some settings ------------ */

    protected $retryOnFail = false;
    protected $maxRetries = 2;
    protected $retryPFailures = true;
    protected $retryRFailures = true;
    protected $retryPostFailures = true;
    protected $retries = 0;
    protected $maxTime = 30;

    /**
     * Task constructor.
     *
     * Creates a Task object, which can be added to the TaskQueue.
     *
     * @param string $identifier    The unique identifier of this task. Make sure it is always unique!
     * @param Handler $handler      The Handler object which will run the Task in the Worker
     * @param bool $usePostHandler  Whether the postHandler on Handler should also be used
     * @param mixed $parameters,... The arguments provided to the method that shall handle this class
     * @throws TasksException
     */
    public function __construct(string $identifier, Handler $handler, bool $usePostHandler = false)
    {
        // Check if the provided Handler is serializable
        if (!$this->isSerializable($handler))
            throw new TasksException("Could not create Task. Provided Handler is not serializable.");

        $this->taskId = $identifier;
        $this->handler = $handler;
        $this->usePostHandler = $usePostHandler;
        if (func_num_args() > 3)
            $args = array_slice(func_get_args(), 3);
        else
            $args = [];

        foreach ($args as $arg)
            if (!$this->isSerializable($arg))
                throw new TasksException("Could not create Task. Provided arguments are not serializable.");

        $this->arguments = $args;

        // Init the handler
        $this->handler->init($this);
    }

    /**
     * Returns the unique ID of this task
     *
     * @return string
     */
    public function getId(): string
    {
        return $this->taskId;
    }

    /**
     * Gets the Handler that shall process this task
     *
     * @return Handler
     */
    public function getHandler(): Handler
    {
        return $this->handler;
    }

    /**
     * Whether the postHandler on the Handler should be invoked after processing the initial task.
     *
     * @return bool
     */
    public function getUsePostHandler(): bool
    {
        return $this->usePostHandler;
    }

    /**
     * Gets the arguments to be provided to the method of the class that shall process this task
     *
     * @return array
     */
    public function getArguments(): array
    {
        return $this->arguments;
    }

    /**
     * Add a constraint to this Task; in order to make the execution conditional.
     *
     * @param Constraint $constraint
     */
    public function addConstraint(Constraint $constraint)
    {
        $this->constraints[] = $constraint;
    }

    /**
     * Gets the constraints to this job.
     *
     * @return Constraint[]
     */
    public function getConstraints(): array
    {
        return $this->constraints;
    }

    /**
     * Gets the current status of this Task
     *
     * @return int
     */
    public function getStatus(): int
    {
        return $this->status;
    }

    /**
     * Sets the status of this Task.
     *
     * Must be one of the constants of this Task class
     *
     * @param int $status
     */
    public function setStatus(int $status)
    {
        $this->status = $status;
    }

    /**
     * Set the delay time to the Task
     *
     * @param int $delayTime
     */
    public function setDelayTime(int $delayTime)
    {
        $this->delayTime = $delayTime;
    }

    /**
     * Receive the delay time for this task
     *
     * @return int
     */
    public function getDelayTime(): int
    {
        return $this->delayTime;
    }

    /* ---------------------------------- Attributes setters and getters ------------------ */

    /**
     * Fetch an attribute of this task
     *
     * @param string $key
     * @return mixed
     */
    public function attribute(string $key)
    {
        if (!isset($this->attributes[$key]))
            return null;

        return $this->attributes[$key];
    }

    /**
     * Adds an attribute to this task.
     *
     * @param string $key
     * @param $value
     * @throws TasksException
     */
    public function addAttribute(string $key, $value)
    {
        if (!$this->isSerializable($value))
            throw new TasksException("Could not set Task '$this->taskId' attribute '$key'. Value not serializable.");

        $this->attributes[$key] = $value;
    }

    /**
     * Remove an attribute from a Task
     *
     * @param string $key
     * @throws TasksException
     */
    public function removeAttribute(string $key)
    {
        if (!isset($this->attributes[$key]))
            throw new TasksException("Could not remove Task '$this->taskId' attribute '$key'. Not found.");

        unset($this->attributes[$key]);
    }

    /* ---------------------------------- Output setters and getters ---------------------- */

    /**
     * Return the output of this task execution
     *
     * @return string|null
     */
    public function getOutput(): ?string
    {
        return $this->output;
    }

    public function getPostOutput(): ?string
    {
        return $this->postOutput;
    }

    /**
     * Return the errors of this task execution
     *
     * @return string|null
     */
    public function getErrors(): ?string
    {
        return $this->errors;
    }

    public function getPostErrors(): ?string
    {
        return $this->postErrors;
    }

    /**
     * @param string $output
     * @param string $errors
     * @todo Handle output from multiple attempts
     */
    public function setOutput(string $output, string $errors)
    {
        $this->output = $output;
        $this->errors = $errors;
    }

    /**
     * @param string $output
     * @param string $errors
     * @todo Handle output from multiple attempts
     */
    public function setPostOutput(string $output, string $errors)
    {
        $this->postOutput = $output;
        $this->postErrors = $errors;
    }

    /* ---------------------------------- Failure settings and criteria ------------------- */

    /**
     * Set whether this task should retry after a failure, and how many times
     *
     * @param bool $retryOnFail             Whether this task should be retried if failing
     * @param int $maxRetries               How many times the task should be retried
     * @param int $maxTime                  How long a task may run before it shall be forcefully shut down
     * @param bool $retryRegularFailures    Whether regular Task::FAILED should be retried
     * @param bool $retryProcessFailures    Whether process based Task::PFAILED should be retried
     * @param bool $retryPostFailures       Whether failures during the Task::POST phase should be retried.
     */
    public function setSettings(bool $retryOnFail, int $maxRetries = 2, int $maxTime = 30, bool $retryRegularFailures = true, bool $retryProcessFailures = true, bool $retryPostFailures = true)
    {
        $this->retryOnFail = $retryOnFail;
        $this->maxRetries = $maxRetries;
        $this->retryPFailures = $retryProcessFailures;
        $this->retryRFailures = $retryRegularFailures;
        $this->retryPostFailures = $retryPostFailures;
        $this->maxTime = $maxTime;
    }

    /**
     * Returns the failure retry settings
     *
     * @return array
     */
    public function getSettings(): array
    {
        return [
            'retryOnFail' => $this->retryOnFail,
            'maxRetries' => $this->maxRetries,
            'retryPFailures' => $this->retryPFailures,
            'retryRFailures' => $this->retryRFailures,
            'retryPostFailures' => $this->retryPostFailures,
            'maxTime' => $this->maxTime
        ];
    }

    /* ---------------------------------- Retries and attempts registers ------------------ */

    /**
     * Add a retry to the retry counter
     */
    public function addRetry()
    {
        $this->retries++;
    }

    /**
     * Reset the retry counter back to 0
     */
    public function resetRetries()
    {
        $this->retries = 0;
    }

    /**
     * Receive the amount of retries already attempted
     *
     * @return int
     */
    public function getRetries(): int
    {
        return $this->retries;
    }

    /* ---------------------------------- Runtime data getters and setters----------------- */

    protected $taskStartTime;
    protected $taskEndTime;
    protected $postStartTime;
    protected $postEndTime;

    public function startTaskTime()
    {
        $this->taskEndTime = null;
        $this->taskStartTime = time();
    }

    public function endTaskTime()
    {
        $this->taskEndTime = time();
    }

    public function getTaskTime(): ?int
    {
        if (is_null($this->taskStartTime))
            return null;

        if (is_null($this->taskEndTime))
            return time() - $this->taskStartTime;

        return $this->taskEndTime - $this->taskStartTime;
    }

    public function startPostTime()
    {
        $this->postEndTime = null;
        $this->postStartTime = time();
    }

    public function endPostTime()
    {
        $this->postEndTime = time();
    }

    public function getPostTime(): ?int
    {
        if (is_null($this->postStartTime))
            return null;

        if (is_null($this->postEndTime))
            return time() - $this->postStartTime;

        return $this->postEndTime - $this->postStartTime;
    }

    /**
     * Checks whether an object can be serialized
     *
     * @param $value
     * @return bool
     * @todo Improve so it is properly tested
     */
    private function isSerializable($value)
    {
        $return = true;
        $arr = array($value);

        array_walk_recursive($arr, function ($element) use (&$return) {
            if (is_object($element) && get_class($element) == 'Closure') {
                $return = false;
            }
        });

        return $return;
    }


}