<?php
/**
 * Notes and change history on stored entries.
 *
 * @package TFlexForms
 */

declare( strict_types = 1 );

namespace TFlexForms;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * One table holds both kinds of record: a note someone wrote (type note,
 * content is the text) and a change to the submitted values (type edit,
 * content is JSON field => {from, to}). Each records who and when.
 *
 * phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Custom table; results are request-specific.
 */
final class Entry_Notes {

	public const NOTE = 'note';
	public const EDIT = 'edit';

	/** Longest note kept, in characters. */
	public const MAX_LENGTH = 5000;

	/**
	 * Adds a note to an entry.
	 *
	 * @param int    $entry_id Entry ID.
	 * @param string $text     Note text (plain; tags are stripped, line breaks kept).
	 * @param int    $user_id  Author.
	 * @return int Note ID, or 0 when the text is empty or the insert failed.
	 */
	public static function add( int $entry_id, string $text, int $user_id ): int {
		$text = mb_substr( trim( sanitize_textarea_field( $text ) ), 0, self::MAX_LENGTH );
		if ( '' === $text || $entry_id <= 0 ) {
			return 0;
		}
		return self::insert( $entry_id, self::NOTE, $text, $user_id );
	}

	/**
	 * Records a change to an entry's values.
	 *
	 * @param int                                        $entry_id Entry ID.
	 * @param array<string,array{from:string,to:string}> $changes  Field name => old and new value.
	 * @param int                                        $user_id  Who changed it.
	 */
	public static function add_edit( int $entry_id, array $changes, int $user_id ): int {
		if ( array() === $changes ) {
			return 0;
		}
		return self::insert( $entry_id, self::EDIT, (string) wp_json_encode( $changes ), $user_id );
	}

	/**
	 * Inserts a row.
	 *
	 * @param int    $entry_id Entry ID.
	 * @param string $type     note|edit.
	 * @param string $content  Content.
	 * @param int    $user_id  User.
	 */
	private static function insert( int $entry_id, string $type, string $content, int $user_id ): int {
		global $wpdb;
		$ok = $wpdb->insert(
			Database::table( 'entry_notes' ),
			array(
				'entry_id'   => $entry_id,
				'user_id'    => max( 0, $user_id ),
				'type'       => $type,
				'content'    => $content,
				'created_at' => current_time( 'mysql', true ),
			),
			array( '%d', '%d', '%s', '%s', '%s' )
		);
		return false === $ok ? 0 : (int) $wpdb->insert_id;
	}

	/**
	 * An entry's notes or change records, oldest first.
	 *
	 * @param int    $entry_id Entry ID.
	 * @param string $type     note|edit.
	 * @return array<int,object> Rows with id, entry_id, user_id, type, created_at and
	 *                           content (string for notes; field => {from, to} array for edits).
	 */
	public static function for_entry( int $entry_id, string $type = self::NOTE ): array {
		global $wpdb;
		$rows = $wpdb->get_results( $wpdb->prepare( 'SELECT * FROM %i WHERE entry_id = %d AND type = %s ORDER BY id', Database::table( 'entry_notes' ), $entry_id, $type ) );
		$out  = array();
		foreach ( is_array( $rows ) ? $rows : array() as $row ) {
			if ( self::EDIT === $type ) {
				$row->content = self::changes( (string) $row->content );
			}
			$out[] = $row;
		}
		return $out;
	}

	/**
	 * Decodes a change record.
	 *
	 * @param string $json Stored JSON.
	 * @return array<string,array{from:string,to:string}>
	 */
	private static function changes( string $json ): array {
		$data = json_decode( $json, true );
		$out  = array();
		foreach ( is_array( $data ) ? $data : array() as $name => $change ) {
			if ( is_array( $change ) ) {
				$out[ (string) $name ] = array(
					'from' => (string) ( $change['from'] ?? '' ),
					'to'   => (string) ( $change['to'] ?? '' ),
				);
			}
		}
		return $out;
	}

	/**
	 * One note row, or null.
	 *
	 * @param int $note_id Note ID.
	 */
	public static function get( int $note_id ): ?object {
		global $wpdb;
		$row = $wpdb->get_row( $wpdb->prepare( 'SELECT * FROM %i WHERE id = %d', Database::table( 'entry_notes' ), $note_id ) );
		return is_object( $row ) ? $row : null;
	}

	/**
	 * Deletes a note. Change records are never deleted on their own; they go
	 * with the entry.
	 *
	 * @param int $note_id Note ID.
	 * @return bool Whether a note was deleted.
	 */
	public static function delete( int $note_id ): bool {
		global $wpdb;
		return (bool) $wpdb->delete(
			Database::table( 'entry_notes' ),
			array(
				'id'   => $note_id,
				'type' => self::NOTE,
			),
			array( '%d', '%s' )
		);
	}

	/**
	 * Deletes everything recorded for an entry (when the entry is deleted).
	 *
	 * @param int $entry_id Entry ID.
	 */
	public static function delete_for_entry( int $entry_id ): void {
		global $wpdb;
		$wpdb->delete( Database::table( 'entry_notes' ), array( 'entry_id' => $entry_id ), array( '%d' ) );
	}

	/**
	 * Whether the current user may delete a note: anyone who can edit entries
	 * may delete their own notes; deleting someone else's needs the
	 * delete_tflexforms_entries capability.
	 *
	 * @param object $note Note row.
	 */
	public static function current_user_can_delete( object $note ): bool {
		if ( self::NOTE !== $note->type || ! current_user_can( 'edit_tflexforms_entries' ) ) {
			return false;
		}
		return get_current_user_id() === (int) $note->user_id || current_user_can( 'delete_tflexforms_entries' );
	}
}