<?php

namespace Creativeorange\Gravatar;

use Creativeorange\Gravatar\Exceptions\InvalidEmailException;
use Illuminate\Support\Arr;

/**
 * Class Gravatar
 * @package Creativeorange\Gravatar
 */
class Gravatar
{
	/**
	 * Gravatar base url
	 *
	 * @var string
	 */
	private $publicBaseUrl = 'https://www.gravatar.com/avatar/';

	/**
	 * Gravatar secure base url
	 *
	 * @var string
	 */
	private $secureBaseUrl = 'https://secure.gravatar.com/avatar/';

	/**
	 * Email address to check
	 *
	 * @var string
	 */
	private $email;

	/**
	 * @var array
	 */
	private $config;

	/**
	 * @var string
	 */
	private $fallback;

	/**
	 * Override the default image fallback set in the config.
	 * Can either be a public URL to an image or a valid themed image.
	 * For more info, visit http://en.gravatar.com/site/implement/images/#default-image
	 *
	 * @param string $fallback
	 * @return $this
	 */
	public function fallback($fallback)
	{
		if (
			filter_var($fallback, FILTER_VALIDATE_URL, FILTER_FLAG_PATH_REQUIRED)
			|| in_array($fallback, array('mm', 'identicon', 'monsterid', 'wavatar', 'retro', 'blank'))
		) {
			$this->fallback = $fallback;
		} else {
			$this->fallback = false;
		}

		return $this;
	}

	/**
	 * Check if Gravatar has an avatar for the given email address
	 *
	 * @param $email
	 * @return bool
	 * @throws InvalidEmailException
	 */
	public function exists($email)
	{
		$this->checkEmail($email);
		$this->email = $email;

		$this->setConfig(['fallback' => 404]);

		$headers = @get_headers($this->buildUrl());

		return (bool) strpos($headers[0], '200');
	}

	/**
	 * Get the gravatar url
	 *
	 * @param $email
	 * @param string $configGroup
	 * @return string
	 * @throws InvalidEmailException
	 */
	public function get($email, $configGroup = 'default')
	{
		$this->checkEmail($email);

		$this->setConfig($configGroup);
		$this->email = $email;

		return $this->buildUrl();
	}

	/**
	 * Helper function for setting the config based on either:
	 * 1. The name of a config group
	 * 2. A custom array
	 * 3. The default group in the config
	 *
	 * @param string|array|null $group
	 * @return $this
	 */
	private function setConfig($group = null)
	{
		if (
			is_string($group)
			&& $group != 'default'
		) {
			$this->config = Arr::dot(array_replace_recursive(config('gravatar.default'), config('gravatar.' . $group)));
		} elseif (is_array($group)) {
			$this->config = Arr::dot(array_replace_recursive(config('gravatar.default'), $group));
		} else {
			$this->config = Arr::dot(config('gravatar.default'));
		}

		return $this;
	}

	/**
	 * Helper function to retrieve config settings.
	 *
	 * @param $value
	 * @param null $default
	 * @return null
	 */
	protected function c($value, $default = null)
	{
		return array_key_exists($value, $this->config) ? $this->config[$value] : $default;
	}

	/**
	 * Helper function to md5 hash the email address
	 *
	 * @return string
	 */
	private function hashEmail()
	{
		return md5(strtolower(trim($this->email)));
	}

	/**
	 * @return string
	 */
	private function getExtension()
	{
		$v = $this->c('forceExtension');

		return $v ? '.' . $v : '';
	}

	/**
	 * @return string
	 */
	private function buildUrl()
	{
		$url  = $this->c('secure') === true ? $this->secureBaseUrl : $this->publicBaseUrl;
		$url .= $this->hashEmail();
		$url .= $this->getExtension();
		$url .= $this->getUrlParameters();

		return $url;
	}

	/**
	 * @return string
	 */
	private function getUrlParameters()
	{
		$build = array();

		foreach (get_class_methods($this) as $method) {
			if (substr($method, -strlen('Parameter')) !== 'Parameter') {
				continue;
			}

			if ($called = call_user_func(array($this, $method))) {
				$build = array_replace($build, $called);
			}
		}

		return '?' . http_build_query($build);
	}

	/**
	 * @return array|null
	 */
	private function sizeParameter()
	{
		if (
			!$this->c('size')
			|| !is_integer($this->c('size'))
		) {
			return null;
		}

		return array('s' => $this->c('size'));
	}

	/**
	 * @return array|null
	 */
	private function defaultParameter()
	{
		if (!$this->fallback) {
            $this->fallback = $this->c('fallback') ? $this->c('fallback') : null;
		}

		return array('d' => $this->fallback);
	}

	/**
	 * @return array|null
	 */
	private function ratingParameter()
	{
		$rating = $this->c('maximumRating');

		if (
			!$rating
			|| !in_array($rating, array('g', 'pg', 'r', 'x'))
		) {
			return null;
		}

		return array('r' => $rating);
	}

	/**
	 * @return array|null
	 */
	private function forceDefaultParameter()
	{
		if ($this->c('forceDefault') === true) {
			return array('forcedefault' => 'y');
		}

		return null;
	}

	/**
	 * Check if the provided email address is valid
	 *
	 * @param $email
	 * @throws InvalidEmailException
	 */
	private function checkEmail($email)
	{
		if (!filter_var($email, FILTER_VALIDATE_EMAIL))
			throw new InvalidEmailException('Please specify a valid email address');
	}
}
