<?php namespace CodeIgniter\Pager;

/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2016, British Columbia Institute of Technology
 *
 * 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.
 *
 * @package	CodeIgniter
 * @author	CodeIgniter Dev Team
 * @copyright	Copyright (c) 2014 - 2016, British Columbia Institute of Technology (http://bcit.ca/)
 * @license	http://opensource.org/licenses/MIT	MIT License
 * @link	http://codeigniter.com
 * @since	Version 3.0.0
 * @filesource
 */

use Config\Services;
use CodeIgniter\View\RendererInterface;

/**
 * Class Pager
 *
 * The Pager class provides semi-automatic and manual methods for creating
 * pagination links and reading the current url's query variable, "page"
 * to determine the current page. This class can support multiple
 * paginations on a single page.
 *
 * @package CodeIgniter\Pager
 */
class Pager implements PagerInterface
{
	/**
	 * The group data.
	 *
	 * @var array
	 */
	protected $groups = [];

	/**
	 * Our configuration instance.
	 *
	 * @var \Config\Pager
	 */
	protected $config;

	/**
	 * The view engine to render the links with.
	 *
	 * @var RendererInterface
	 */
	protected $view;

	//--------------------------------------------------------------------

	public function __construct($config, RendererInterface $view)
	{
		$this->config = $config;
		$this->view   = $view;
	}

	//--------------------------------------------------------------------

	/**
	 * Handles creating and displaying the
	 *
	 * @param string|null $group
	 * @param string      $template The output template alias to render.
	 *
	 * @return string
	 */
	public function links(string $group = 'default', string $template = 'default_full'): string
	{
		$this->ensureGroup($group);

		return $this->displayLinks($group, $template);
	}

	//--------------------------------------------------------------------

	/**
	 * Creates simple Next/Previous links, instead of full pagination.
	 *
	 * @param string $template
	 * @param string $group
	 *
	 * @return string
	 */
	public function simpleLinks(string $group = 'default', string $template = 'default_simple'): string
	{
		$this->ensureGroup($group);

		return $this->displayLinks($group, $template);
	}

	//--------------------------------------------------------------------

	/**
	 * Allows for a simple, manual, form of pagination where all of the data
	 * is provided by the user. The URL is the current URI.
	 *
	 * @param int    $page
	 * @param int    $perPage
	 * @param int    $total
	 * @param string $template The output template alias to render.
	 *
	 * @return string
	 */
	public function makeLinks(int $page, int $perPage, int $total, string $template = 'default_full'): string
	{
		$name = time();

		$this->store($name, $page, $perPage, $total);

		return $this->displayLinks($name, $template);
	}

	//--------------------------------------------------------------------

	/**
	 * Does the actual work of displaying the view file. Used internally
	 * by links(), simpleLinks(), and makeLinks().
	 *
	 * @param string $group
	 * @param string $template
	 *
	 * @return string
	 */
	protected function displayLinks(string $group, string $template)
	{
		$pager = new PagerRenderer($this->getDetails($group));

		if (! array_key_exists($template, $this->config->templates))
		{
			throw new \InvalidArgumentException($template.' is not a valid Pager template.');
		}

		return $this->view->setVar('pager', $pager)
						  ->render($this->config->templates[$template]);
	}

	//--------------------------------------------------------------------

	/**
	 * Stores a set of pagination data for later display. Most commonly used
	 * by the model to automate the process.
	 *
	 * @param string $group
	 * @param int    $page
	 * @param int    $perPage
	 * @param int    $total
	 *
	 * @return mixed
	 */
	public function store(string $group, int $page, int $perPage, int $total)
	{
		$this->ensureGroup($group);

		$this->groups[$group]['currentPage'] = $page;
		$this->groups[$group]['perPage']     = $perPage;
		$this->groups[$group]['total']       = $total;
		$this->groups[$group]['pageCount']   = ceil($total/$perPage);

		return $this;
	}

	//--------------------------------------------------------------------

	/**
	 * Sets the path that an aliased group of links will use.
	 *
	 * @param string $group
	 * @param string $path
	 *
	 * @return mixed
	 */
	public function setPath(string $path, string $group = 'default')
	{
		$this->ensureGroup($group);

		$this->groups[$group]['uri']->setPath($path);

		return $this;
	}

	//--------------------------------------------------------------------

	/**
	 * Returns the total number of pages.
	 *
	 * @param string|null $group
	 *
	 * @return int
	 */
	public function getPageCount(string $group = 'default'): int
	{
		$this->ensureGroup($group);

		return $this->groups[$group]['pageCount'];
	}

	//--------------------------------------------------------------------

	/**
	 * Returns the number of the current page of results.
	 *
	 * @param string|null $group
	 *
	 * @return int
	 */
	public function getCurrentPage(string $group = 'default'): int
	{
		$this->ensureGroup($group);

		return $this->groups[$group]['currentPage'];
	}

	//--------------------------------------------------------------------

	/**
	 * Tells whether this group of results has any more pages of results.
	 *
	 * @param string|null $group
	 *
	 * @return bool
	 */
	public function hasMore(string $group = 'default'): bool
	{
		$this->ensureGroup($group);

		return ($this->groups[$group]['currentPage']*$this->groups[$group]['perPage'])
			   < $this->groups[$group]['total'];
	}

	//--------------------------------------------------------------------

	/**
	 * Returns the last page, if we have a total that we can calculate with.
	 *
	 * @param string $group
	 *
	 * @return int|null
	 */
	public function getLastPage(string $group = 'default')
	{
		$this->ensureGroup($group);

		if (! is_numeric($this->groups[$group]['total']) || ! is_numeric($this->groups[$group]['perPage']))
		{
			return null;
		}

		return ceil($this->groups[$group]['total']/$this->groups[$group]['perPage']);
	}

	//--------------------------------------------------------------------

	/**
	 * Determines the first page # that should be shown.
	 *
	 * @param string $group
	 *
	 * @return int
	 */
	public function getFirstPage(string $group = 'default')
	{
		$this->ensureGroup($group);

		// @todo determine based on a 'surroundCount' value
		return 1;
	}

	//--------------------------------------------------------------------


	/**
	 * Returns the URI for a specific page for the specified group.
	 *
	 * @param int    $page
	 * @param string $group
	 * @param bool   $returnObject
	 *
	 * @return string
	 */
	public function getPageURI(int $page = null, string $group = 'default', $returnObject = false)
	{
		$this->ensureGroup($group);

		$uri = $this->groups[$group]['uri'];

		$uri->setQuery('page='.$page);

		return $returnObject === true
			? $uri
			: (string)$uri;
	}

	//--------------------------------------------------------------------

	/**
	 * Returns the full URI to the next page of results, or null.
	 *
	 * @param string $group
	 * @param bool   $returnObject
	 *
	 * @return string|null
	 */
	public function getNextPageURI(string $group = 'default', $returnObject = false)
	{
		$this->ensureGroup($group);

		$last = $this->getLastPage($group);
		$curr = $this->getCurrentPage($group);
		$page = null;

		if (! empty($last) && ! empty($curr) && $last == $curr)
		{
			return null;
		}

		if ($last > $curr)
		{
			$page = $curr+1;
		}

		return $this->getPageURI($page, $group, $returnObject);
	}

	//--------------------------------------------------------------------

	/**
	 * Returns the full URL to the previous page of results, or null.
	 *
	 * @param string $group
	 * @param bool   $returnObject
	 *
	 * @return string|null
	 */
	public function getPreviousPageURI(string $group = 'default', $returnObject = false)
	{
		$this->ensureGroup($group);

		$first = $this->getFirstPage($group);
		$curr  = $this->getCurrentPage($group);
		$page  = null;

		if (! empty($first) && ! empty($curr) && $first == $curr)
		{
			return null;
		}

		if ($first < $curr)
		{
			$page = $curr-1;
		}

		return $this->getPageURI($page, $group, $returnObject);
	}

	//--------------------------------------------------------------------

	/**
	 * Returns the number of results per page that should be shown.
	 *
	 * @param string $group
	 *
	 * @return int
	 */
	public function getPerPage(string $group = 'default'): int
	{
		$this->ensureGroup($group);

		return (int)$this->groups[$group]['perPage'];
	}

	//--------------------------------------------------------------------

	/**
	 * Returns an array with details about the results, including
	 * total, per_page, current_page, last_page, next_url, prev_url, from, to.
	 * Does not include the actual data. This data is suitable for adding
	 * a 'data' object to with the result set and converting to JSON.
	 *
	 * @param string $group
	 *
	 * @return array
	 */
	public function getDetails(string $group = 'default'): array
	{
		if (! array_key_exists($group, $this->groups))
		{
			throw new \InvalidArgumentException($group.' is not a valid Pagination group.');
		}

		$newGroup = $this->groups[$group];

		$newGroup['next']     = $this->getNextPageURI($group);
		$newGroup['previous'] = $this->getPreviousPageURI($group);

		return $newGroup;
	}

	//--------------------------------------------------------------------

	/**
	 * Ensures that an array exists for the group specified.
	 *
	 * @param string $group
	 */
	protected function ensureGroup(string $group)
	{
		if (array_key_exists($group, $this->groups))
		{
			return;
		}

		$this->groups[$group] = [
			'uri'         => clone Services::request()->uri,
			'hasMore'     => false,
			'total'       => null,
			'currentPage' => $_GET['page_'.$group] ?? $_GET['page'] ?? 1,
			'perPage'     => $this->config->perPage,
			'pageCount'   => 1,
		];
	}

	//--------------------------------------------------------------------

}
