<?php

/*
 * AVSDev UF Scheduler (https://avsdev.uk)
 *
 * @link      https://git.avsdev.uk/avsdev/sprinkle-scheduler
 * @license   https://git.avsdev.uk/avsdev/sprinkle-scheduler/blob/master/LICENSE.md (LGPL-3.0 License)
 */

namespace UserFrosting\Sprinkle\Scheduler\Scheduler;

use Illuminate\Support\Str;
use Psr\Container\ContainerInterface;
use UserFrosting\UniformResourceLocator\Resource as ResourceInstance;

/**
 * Scheduler Class.
 *
 * Finds all tasks class across sprinkles
 *
 * @author Craig Williams (https://avsdev.uk)
 */
class Scheduler
{
    /**
     * @var ContainerInterface
     */
    protected $ci;

    /**
     * @var string The resource locator scheme
     */
    protected $scheme = 'tasks://';

    /**
     * Class Constructor.
     *
     * @param ContainerInterface $ci
     */
    public function __construct(ContainerInterface $ci)
    {
        $this->ci = $ci;
    }

    /**
     * Loop all the available sprinkles and return a list of their tasks.
     *
     * @return array An array of all the task classes found for every sprinkle
     */
    public function getTasks()
    {
        $tasks = $this->ci->locator->listResources($this->scheme, false, false);

        return $this->loadTasks($tasks);
    }

    /**
     * Get a single task info.
     *
     * @param string $name The task name
     *
     * @throws \Exception If task not found
     *
     * @return array The details about a task file [name, class, sprinkle]
     */
    public function getTask($name)
    {
        // Get task resource
        $taskResource = $this->ci->locator->getResource($this->scheme . $name . '.php');

        // Make sure we found something
        if (!$taskResource) {
            throw new \Exception("Task $name not found");
        }

        // Return the task info
        return $this->getTaskDetails($taskResource);
    }

    /**
     * Return the class instance of a task.
     *
     * @param string $name The task name
     *
     * @throws \Exception If class doesn't exist or is not right interface
     *
     * @return TaskInterface The task class instance
     */
    public function getTaskClass($name)
    {
        // Try to get task info
        $task = $this->getTask($name);

        // Make sure class exist
        $classPath = $task['class'];
        if (!class_exists($classPath)) {
            throw new \Exception("Task class `$classPath` not found. Make sure the class has the correct namespace.");
        }

        // Create a new class instance
        $taskClass = new $classPath($this->ci);

        // Class must be an instance of `TaskerInterface`
        if (!$taskClass instanceof TaskInterface) {
            throw new \Exception('Task class must be an instance of `TaskerInterface`');
        }

        return $taskClass;
    }

    /**
     * Run a task class.
     *
     * @param TaskInterface $task The task to run
     */
    public function runTask(TaskInterface $task)
    {
        $task->run();
    }

    /**
     * Run a task based on it's name.
     *
     * @param string $taskName
     */
    public function run($taskName)
    {
        $task = $this->getTaskClass($taskName);
        $this->runTask($task);
    }

    /**
     * Return a list of tasks due to be run
     */
    public function dueTasks()
    {
        $tasks = $this->getTasks();

        return array_filter($tasks, function($task) {
            // Get the task's class
            $classPath = $task['class'];

            // Create a new class instance
            $taskClass = new $classPath($this->ci);

            // Class must be an instance of `TaskerInterface`
            if (!$taskClass instanceof TaskInterface) {
                throw new \Exception('Task class must be an instance of `TaskerInterface`');
            }

            return $taskClass->isDue();
        });
    }

    /**
     * Process tasks Resource into info.
     *
     * @param array $taskFiles List of tasks files
     *
     * @return array
     */
    protected function loadTasks(array $taskFiles)
    {
        $tasks = [];

        foreach ($taskFiles as $taskFile) {
            $tasks[] = $this->getTaskDetails($taskFile);
        }

        return $tasks;
    }

    /**
     * Return an array of task details including the class name and the sprinkle name.
     *
     * @param ResourceInstance $file The task file
     *
     * @return array The details about a task file [name, class, sprinkle]
     */
    protected function getTaskDetails(ResourceInstance $file)
    {
        /** @var \UserFrosting\System\Sprinkle\SprinkleManager */
        $sprinkleManager = $this->ci->sprinkleManager;

        // Format the sprinkle name for the namespace
        $sprinkleName = $file->getLocation()->getName();
        $sprinkleNS = $sprinkleManager->getSprinkleClassNamespace($sprinkleName);


        // Getting base path, name and class name
        $basePath = str_replace($file->getBasename(), '', $file->getBasePath());
        $name = $basePath . $file->getFilename();
        $className = str_replace('/', '\\', $basePath) . $file->getFilename();
        $classPath = "\\$sprinkleNS\\Scheduler\\Tasks\\$className";

        if (!class_exists($classPath)) {
            throw new \Exception("Task class `$className` not found. Make sure the class has the correct namespace.");
        }

        // Create a new class instance
        $taskClass = new $classPath($this->ci);

        // Class must be an instance of `TaskerInterface`
        if (!$taskClass instanceof TaskInterface) {
            throw new \Exception('Task class must be an instance of `TaskerInterface`');
        }

        $schedule = $taskClass->cronExpression();

        $nextRun = $taskClass->nextRunDate();

        // Build the class name and namespace
        return [
            'schedule' => $schedule,
            'sprinkle' => $sprinkleName,
            'name'     => $name,
            'class'    => $classPath,
            'instance' => $taskClass,
            'next_run' => $nextRun,
        ];
    }
}