<?php
/**
 * The Dashboard's "Conditional shortcode" card.
 *
 * @package Yangra\Conditional
 */

namespace Yangra\Conditional\Admin;

use Yangra\Conditional\Index\ContentIndex;
use Yangra\Conditional\Rules\RuleSummary;
use Yangra\Conditional\Shortcodes\SavedRules;

defined( 'ABSPATH' ) || exit;

/**
 * Lists the posts that use the conditional shortcode (any nesting level),
 * with how many shortcodes each has, from the content index (published and
 * private content only), newest first. Each user only sees posts they can edit.
 *
 * Also lists the saved rules that are on and have conditions, by name, with
 * how many shortcodes in those posts use each one. Saved rules are made with
 * Pro, but they keep working without it, so the list is Free code too.
 */
class ShortcodesCard {

	/**
	 * Items listed on the card itself.
	 */
	const CARD_ITEMS = 10;

	/**
	 * Items per page of the full list.
	 */
	const PER_PAGE = 20;

	/**
	 * Content index.
	 *
	 * @var ContentIndex
	 */
	private $index;

	/**
	 * Saved rules.
	 *
	 * @var SavedRules
	 */
	private $saved_rules;

	/**
	 * Rule summaries.
	 *
	 * @var RuleSummary
	 */
	private $summary;

	/**
	 * Constructor.
	 *
	 * @param ContentIndex $index       Content index.
	 * @param SavedRules   $saved_rules Saved rules.
	 * @param RuleSummary  $summary     Rule summaries.
	 */
	public function __construct( ContentIndex $index, SavedRules $saved_rules, RuleSummary $summary ) {
		$this->index       = $index;
		$this->saved_rules = $saved_rules;
		$this->summary     = $summary;
	}

	/**
	 * Whether the current user can see the card.
	 *
	 * @return bool
	 */
	public function can_view(): bool {
		return current_user_can( DashboardPage::CAPABILITY );
	}

	/**
	 * One page of the posts that use the shortcode, with counts, the card's
	 * saved rules and a link to the builder.
	 *
	 * @param int $page     Page number, from 1. Out-of-range pages are clamped.
	 * @param int $per_page Items per page.
	 * @return array{total: int, shortcodes: int, page: int, pages: int, items: array<int, array{key: string, title: string, type: string, shortcodes: int, editUrl: string}>, savedRules: array{total: int, page: int, pages: int, items: array<int, array{key: string, name: string, summary: string, shortcodes: int}>}, builderUrl: string}
	 */
	public function data( int $page = 1, int $per_page = self::CARD_ITEMS ): array {
		$all   = $this->all();
		$paged = $this->page( $all, $page, $per_page );

		$items = array();
		foreach ( $paged['items'] as $item ) {
			$items[] = array(
				'key'        => 'post-' . $item['id'],
				'title'      => '' !== $item['title'] ? $item['title'] : __( '(no title)', 'yangra-conditional' ),
				'type'       => $item['type'],
				'shortcodes' => $item['shortcodes'],
				'editUrl'    => $item['edit_url'],
			);
		}

		return array(
			'total'      => count( $all ),
			'shortcodes' => (int) array_sum( array_column( $all, 'shortcodes' ) ),
			'page'       => $paged['page'],
			'pages'      => $paged['pages'],
			'items'      => $items,
			'savedRules' => $this->saved_rules_data(),
			'builderUrl' => ShortcodeBuilderPage::url(),
		);
	}

	/**
	 * One page of the saved rules that are on and have conditions, by name,
	 * each with its rule summary and how many shortcodes use it.
	 *
	 * @param int $page     Page number, from 1. Out-of-range pages are clamped.
	 * @param int $per_page Items per page.
	 * @return array{total: int, page: int, pages: int, items: array<int, array{key: string, name: string, summary: string, shortcodes: int}>}
	 */
	public function saved_rules_data( int $page = 1, int $per_page = self::CARD_ITEMS ): array {
		$active = array();
		foreach ( $this->saved_rules->all() as $saved ) {
			foreach ( $saved['rule']['groups'] as $group ) {
				if ( $saved['rule']['enabled'] && array() !== $group['conditions'] ) {
					$active[] = $saved;
					break;
				}
			}
		}
		$paged = $this->page( $active, $page, $per_page );

		$uses  = array() !== $paged['items'] ? $this->saved_rule_uses() : array();
		$items = array();
		foreach ( $paged['items'] as $saved ) {
			$items[] = array(
				'key'        => 'rule-' . $saved['id'],
				'name'       => '' !== $saved['name'] ? $saved['name'] : __( '(no name)', 'yangra-conditional' ),
				'summary'    => $this->summary->summarize( $saved['rule'] ),
				'shortcodes' => $uses[ $saved['id'] ] ?? 0,
			);
		}

		return array(
			'total' => count( $active ),
			'page'  => $paged['page'],
			'pages' => $paged['pages'],
			'items' => $items,
		);
	}

	/**
	 * Every post the current user can edit that uses the shortcode, most
	 * recently changed first.
	 *
	 * @return array<int, array{id: int, title: string, type: string, shortcodes: int, edit_url: string, modified: int}>
	 */
	public function all(): array {
		$items = array();
		foreach ( $this->index->live_posts() as $post_id => $index ) {
			$count = (int) ( $index['shortcodes'] ?? 0 );
			if ( $count < 1 || ! current_user_can( 'edit_post', $post_id ) ) {
				continue;
			}

			$post = get_post( $post_id );
			if ( null === $post ) {
				continue;
			}

			$type    = get_post_type_object( $post->post_type );
			$items[] = array(
				'id'         => (int) $post_id,
				'title'      => trim( html_entity_decode( wp_strip_all_tags( $post->post_title ), ENT_QUOTES, 'UTF-8' ) ),
				'type'       => null !== $type ? (string) $type->labels->singular_name : $post->post_type,
				'shortcodes' => $count,
				'edit_url'   => (string) get_edit_post_link( $post_id, 'raw' ),
				'modified'   => (int) strtotime( $post->post_modified_gmt . ' UTC' ),
			);
		}

		usort(
			$items,
			static function ( array $a, array $b ): int {
				return array( $b['modified'], $a['id'] ) <=> array( $a['modified'], $b['id'] );
			}
		);

		return $items;
	}

	/**
	 * How many shortcodes use each saved rule, in shown content the current
	 * user can edit.
	 *
	 * @return array<string, int> Saved rule ID => shortcodes.
	 */
	private function saved_rule_uses(): array {
		$uses = array();
		foreach ( $this->index->live_posts() as $post_id => $index ) {
			$rules = isset( $index['rules'] ) && is_array( $index['rules'] ) ? $index['rules'] : array();
			if ( array() === $rules || ! current_user_can( 'edit_post', $post_id ) ) {
				continue;
			}

			foreach ( $rules as $id => $count ) {
				$uses[ (string) $id ] = ( $uses[ (string) $id ] ?? 0 ) + (int) $count;
			}
		}

		return $uses;
	}

	/**
	 * One page of a list.
	 *
	 * @template T
	 * @param array<int, T> $rows     The whole list.
	 * @param int           $page     Page number, from 1. Out-of-range pages are clamped.
	 * @param int           $per_page Items per page.
	 * @return array{page: int, pages: int, items: array<int, T>}
	 */
	private function page( array $rows, int $page, int $per_page ): array {
		$per_page = max( 1, $per_page );
		$pages    = (int) max( 1, ceil( count( $rows ) / $per_page ) );
		$page     = min( max( 1, $page ), $pages );

		return array(
			'page'  => $page,
			'pages' => $pages,
			'items' => array_slice( $rows, ( $page - 1 ) * $per_page, $per_page ),
		);
	}
}