<?php

/**
 * @link https://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license https://www.yiiframework.com/license/
 */

declare(strict_types=1);

namespace yii\bootstrap5;

use yii\base\InvalidConfigException;
use yii\data\Pagination;
use yii\helpers\ArrayHelper;

/**
 * LinkPager represents a Bootstrap 5 version of [[\yii\widgets\LinkPager]]. It displays a list of hyperlinks
 * that lead to different pages of target.
 *
 * LinkPager works with a [[\yii\widget\Pagination]] object which specifies the total number
 * of pages and the current page number.
 *
 * To apply LinkPager globally e.g. in all GridViews, set in configuration DI:
 *
 * ```php
 * 'container' => [
 *    'definitions' => [
 *       \yii\widgets\LinkPager::class => \yii\bootstrap5\LinkPager::class,
 *    ],
 * ],
 * ```
 *
 * @see https://getbootstrap.com/docs/5.1/components/pagination/
 * @author Simon Karlen <simi.albi@outlook.com>
 * @since 2.0.2
 *
 * @property-read array $pageRange
 */
class LinkPager extends Widget
{
    /**
     * @var Pagination the pagination object that this pager is associated with.
     * You must set this property in order to make LinkPager work.
     */
    public $pagination;
    /**
     * @var array HTML attributes for the pager container tag.
     * @see \yii\helpers\Html::renderTagAttributes() for details on how attributes are being rendered.
     */
    public $options = [];
    /**
     * @var array HTML attributes for the pager list tag.
     * @see \yii\helpers\Html::renderTagAttributes() for details on how attributes are being rendered.
     */
    public $listOptions = [
        'class' => ['pagination'],
    ];
    /**
     * @var array HTML attributes which will be applied to all link containers
     */
    public $linkContainerOptions = [
        'class' => ['page-item'],
    ];
    /**
     * @var array HTML attributes for the link in a pager container tag.
     * @see \yii\helpers\Html::renderTagAttributes() for details on how attributes are being rendered.
     */
    public $linkOptions = [
        'class' => ['page-link'],
    ];
    /**
     * @var string the CSS class for the each page button.
     */
    public $pageCssClass = 'page-item';
    /**
     * @var string the CSS class for the "first" page button.
     */
    public $firstPageCssClass = 'first';
    /**
     * @var string the CSS class for the "last" page button.
     */
    public $lastPageCssClass = 'last';
    /**
     * @var string the CSS class for the "previous" page button.
     */
    public $prevPageCssClass = 'prev';
    /**
     * @var string the CSS class for the "next" page button.
     */
    public $nextPageCssClass = 'next';
    /**
     * @var string the CSS class for the active (currently selected) page button.
     */
    public $activePageCssClass = 'active';
    /**
     * @var string the CSS class for the disabled page buttons.
     */
    public $disabledPageCssClass = 'disabled';
    /**
     * @var array the options for the disabled tag to be generated inside the disabled list element.
     * In order to customize the html tag, please use the tag key.
     *
     * ```php
     * $disabledListItemSubTagOptions = ['class' => 'disabled-link'];
     * ```
     */
    public $disabledListItemSubTagOptions = [];
    /**
     * @var int maximum number of page buttons that can be displayed. Defaults to 10.
     */
    public $maxButtonCount = 10;
    /**
     * @var string|bool the label for the "next" page button. Note that this will NOT be HTML-encoded.
     * If this property is false, the "next" page button will not be displayed.
     */
    public $nextPageLabel = '<span aria-hidden="true">&raquo;</span>';
    /**
     * @var string|bool the text label for the "previous" page button. Note that this will NOT be HTML-encoded.
     * If this property is false, the "previous" page button will not be displayed.
     */
    public $prevPageLabel = '<span aria-hidden="true">&laquo;</span>';
    /**
     * @var string|bool the text label for the "first" page button. Note that this will NOT be HTML-encoded.
     * If it's specified as true, page number will be used as label.
     * Default is false that means the "first" page button will not be displayed.
     */
    public $firstPageLabel = false;
    /**
     * @var string|bool the text label for the "last" page button. Note that this will NOT be HTML-encoded.
     * If it's specified as true, page number will be used as label.
     * Default is false that means the "last" page button will not be displayed.
     */
    public $lastPageLabel = false;
    /**
     * @var bool whether to register link tags in the HTML header for prev, next, first and last page.
     * Defaults to `false` to avoid conflicts when multiple pagers are used on one page.
     * @see https://www.w3.org/TR/html401/struct/links.html#h-12.1.2
     * @see registerLinkTags()
     */
    public $registerLinkTags = false;
    /**
     * @var bool Hide widget when only one page exist.
     */
    public $hideOnSinglePage = true;
    /**
     * @var bool whether to render current page button as disabled.
     */
    public $disableCurrentPageButton = false;


    /**
     * Initializes the pager.
     * @throws InvalidConfigException
     */
    public function init(): void
    {
        parent::init();

        if ($this->pagination === null) {
            throw new InvalidConfigException('The "pagination" property must be set.');
        }
    }

    /**
     * Executes the widget.
     * This overrides the parent implementation by displaying the generated page buttons.
     */
    public function run(): string
    {
        if ($this->registerLinkTags) {
            $this->registerLinkTags();
        }
        $options = $this->options;
        $tag = ArrayHelper::remove($options, 'tag', 'nav');
        $html = Html::beginTag($tag, $options);
        $html .= $this->renderPageButtons();
        $html .= Html::endTag($tag);

        return $html;
    }

    /**
     * Registers relational link tags in the html header for prev, next, first and last page.
     * These links are generated using [[\yii\data\Pagination::getLinks()]].
     * @see https://www.w3.org/TR/html401/struct/links.html#h-12.1.2
     */
    protected function registerLinkTags(): void
    {
        $view = $this->getView();
        foreach ($this->pagination->getLinks() as $rel => $href) {
            $view->registerLinkTag([
                'rel' => $rel,
                'href' => $href,
            ], $rel);
        }
    }

    /**
     * Renders the page buttons.
     * @return string the rendering result
     */
    protected function renderPageButtons(): string
    {
        $pageCount = $this->pagination->getPageCount();
        if ($pageCount < 2 && $this->hideOnSinglePage) {
            return '';
        }

        $buttons = [];
        $currentPage = $this->pagination->getPage();

        // first page
        $firstPageLabel = $this->firstPageLabel === true ? '1' : $this->firstPageLabel;
        if ($firstPageLabel !== false) {
            $buttons[] = $this->renderPageButton(
                $firstPageLabel,
                0,
                $this->firstPageCssClass,
                $currentPage <= 0,
                false,
            );
        }

        // prev page
        if ($this->prevPageLabel !== false) {
            if (($page = $currentPage - 1) < 0) {
                $page = 0;
            }
            $buttons[] = $this->renderPageButton(
                $this->prevPageLabel,
                $page,
                $this->prevPageCssClass,
                $currentPage <= 0,
                false,
            );
        }

        // internal pages
        list($beginPage, $endPage) = $this->getPageRange();
        for ($i = $beginPage; $i <= $endPage; ++$i) {
            $buttons[] = $this->renderPageButton(
                (string) ($i + 1),
                $i,
                '',
                $this->disableCurrentPageButton && $i === $currentPage,
                $i === $currentPage,
            );
        }

        // next page
        if ($this->nextPageLabel !== false) {
            if (($page = $currentPage + 1) >= $pageCount - 1) {
                $page = $pageCount - 1;
            }
            $buttons[] = $this->renderPageButton(
                $this->nextPageLabel,
                $page,
                $this->nextPageCssClass,
                $currentPage >= $pageCount - 1,
                false,
            );
        }

        // last page
        $lastPageLabel = $this->lastPageLabel === true ? $pageCount : $this->lastPageLabel;
        if ($lastPageLabel !== false) {
            $buttons[] = $this->renderPageButton(
                (string) $lastPageLabel,
                $pageCount - 1,
                $this->lastPageCssClass,
                $currentPage >= $pageCount - 1,
                false,
            );
        }

        $options = $this->listOptions;
        $tag = ArrayHelper::remove($options, 'tag', 'ul');

        return Html::tag($tag, implode("\n", $buttons), $options);
    }

    /**
     * Renders a page button.
     * You may override this method to customize the generation of page buttons.
     * @param string $label the text label for the button
     * @param int $page the page number
     * @param string $class the CSS class for the page button.
     * @param bool $disabled whether this page button is disabled
     * @param bool $active whether this page button is active
     * @return string the rendering result
     */
    protected function renderPageButton(string $label, int $page, string $class, bool $disabled, bool $active): string
    {
        $options = $this->linkContainerOptions;
        $linkWrapTag = ArrayHelper::remove($options, 'tag', 'li');
        Html::addCssClass($options, $class ?: $this->pageCssClass);

        $linkOptions = $this->linkOptions;
        $linkOptions['data']['page'] = $page;

        if ($active) {
            $options['aria'] = [
                'current' => 'page',
            ];
            Html::addCssClass($options, $this->activePageCssClass);
        }
        if ($disabled) {
            Html::addCssClass($options, $this->disabledPageCssClass);
            $disabledItemOptions = $this->disabledListItemSubTagOptions;
            $linkOptions = ArrayHelper::merge($linkOptions, $disabledItemOptions);
            $linkOptions['tabindex'] = '-1';
        }

        return Html::tag($linkWrapTag, Html::a($label, $this->pagination->createUrl($page), $linkOptions), $options);
    }

    /**
     * @return array the begin and end pages that need to be displayed.
     */
    protected function getPageRange(): array
    {
        $currentPage = $this->pagination->getPage();
        $pageCount = $this->pagination->getPageCount();

        $beginPageOffset = $this->maxButtonCount > 2 ? (int) ($this->maxButtonCount / 2) : 0;
        $beginPage = max(0, $currentPage - $beginPageOffset);

        if (($endPage = $beginPage + $this->maxButtonCount - 1) >= $pageCount) {
            $endPage = $pageCount - 1;
            $beginPage = max(0, $endPage - $this->maxButtonCount + 1);
        }

        return [$beginPage, $endPage];
    }
}
