<?php

namespace App\Message;

use Exception;

/**
* Handles messages and context
*
* @author Phil Burton <phil@pgburton.com>
*/
class Handler
{
    /**
     * The important set of injects for this handler
     *
     * @var string[]
     */
    protected $important = [];

    /**
     * Construct our handler
     *
     * @author Phil Burton <phil@pgburton.com>
     * @param string[] $important
     */
    public function __construct($important)
    {
        $this->important = $important;
        $this->initImportantValues();
    }

    /**
     * Set important values
     *
     * @author Phil Burton <phil@pgburton.com>
     * @param mixed[] $array
     */
    protected function initImportantValues()
    {
        foreach ($this->important as $name) {
            $this->addImportantValue($name, false);
        }
    }

    /**
     * Add an important value to our array
     *
     * @author Phil Burton <phil@pgburton.com>
     * @param string $name
     * @param mixed[] $value
     */
    protected function addImportantValue($name, $value)
    {
        if (in_array($name, $this->important)) {
            $this->$name = $value;
        }

        return $name;
    }

    /**
     * Get a single important value
     *
     * @author Phil Burton <phil@pgburton.com>
     * @param string $name
     * @return mixed
     */
    public function returnImportant($name)
    {
        if (!isset($this->$name)) {
            throw new Exception('The var ' . $name . ' is not set in this context');
        }

        return $this->$name;
    }

    protected function addImportantFromArray($array)
    {
        foreach ($array as $key => $value) {
            if (!isset($this->$key)) {
                throw new Exception('The var ' . $value . ' is not set in this context');
            }

            $this->$key = $value;
        }
    }

    /**
     * Return all importnat vars and values in array
     *
     * @author Phil Burton <phil@pgburton.com>
     * @return string[]
     */
    public function returnImportants()
    {
        return $this->important;
    }

    /**
     * Magic __get override to be able to get important values using ->myValue
     * which then runs $this->returnImportant('myValue')
     *
     * @author Phil Burton <phil@pgburton.com>
     * @param string $name
     * @param mixed[] $arguments
     * @return string
     */
    public function __get($name)
    {
        return $this->returnImporant(substr($name, 3));
    }

    /**
     * Allow for magic rendering
     * Call renderFooBar to render the FooBar message class
     *
     * @author Phil Burton <phil@pgburton.com>
     * @param string $name
     * @param mixed[] $arguments
     * @return string
     */
    public function __call($name, $arguments)
    {
        if (strpos($name, 'render') === 0) {
            return $this->doRender(substr($name, 6));
        }
    }

    /**
     * Render the opening message
     *
     * @author Phil Burton <phil@pgburton.com>
     * @return string
     */
    public function doRender($name)
    {
        $name = "App\\Message\\" . $name;
        if (!class_exists($name)) {
            throw new Exception('Could not find message class `' . $name . '`');
        }

        $messageObj = new $name($this);
        $message = $messageObj->renderMessage();

        $this->addImportantFromArray($messageObj->getImportantValues());
        return $message;
    }
}