<?php
namespace Relay\Backups;

use Relay\Database\Db;
use Relay\Install\Schema;
use Relay\Support\RelayError;

/** Rows of {base_prefix}relay_backups. A row is an array; summary is decoded. */
final class BackupRepository
{
    public const BUILDING = 'building';
    public const UPLOADING = 'uploading';
    public const READY = 'ready';
    public const FAILED = 'failed';

    private Db $db;
    private string $table;

    public function __construct(Db $db)
    {
        $this->db = $db;
        $this->table = Schema::tables()['backups'];
    }

    public function create(array $fields): array
    {
        $now = gmdate('Y-m-d H:i:s');
        $row = array_merge([
            'id' => wp_generate_uuid4(),
            'label' => '',
            'origin' => 'local',
            'source_url' => '',
            'file' => '',
            'status' => self::BUILDING,
            'size' => 0,
            'summary' => [],
            'created_at' => $now,
            'added_at' => $now,
            'job_id' => null,
        ], $fields);
        $this->write($this->db->quietly(fn () => $this->db->wpdb()->insert($this->table, self::encode($row))));
        return $row;
    }

    public function find(string $id): ?array
    {
        $rows = $this->db->results($this->db->wpdb()->prepare('SELECT * FROM ' . Db::ident($this->table) . ' WHERE id = %s', $id), ARRAY_A);
        return $rows ? self::decode($rows[0]) : null;
    }

    public function update(string $id, array $fields): void
    {
        $this->write($this->db->quietly(fn () => $this->db->wpdb()->update($this->table, self::encode($fields), ['id' => $id])));
    }

    public function delete(string $id): void
    {
        $this->db->quietly(fn () => $this->db->wpdb()->delete($this->table, ['id' => $id]));
    }

    /** @return array[] ready backups, newest first */
    public function ready(): array
    {
        return $this->with_status(self::READY);
    }

    /** @return array[] rows with $status (added before $added_before when given), newest first */
    public function with_status(string $status, ?string $added_before = null): array
    {
        $wpdb = $this->db->wpdb();
        $where = $wpdb->prepare('status = %s', $status) . ($added_before !== null ? $wpdb->prepare(' AND added_at < %s', $added_before) : '');
        $rows = $this->db->results('SELECT * FROM ' . Db::ident($this->table) . " WHERE {$where} ORDER BY created_at DESC, added_at DESC", ARRAY_A);
        return array_map([self::class, 'decode'], $rows);
    }

    /** The shape the REST API and the UI use. */
    public static function to_api(array $row): array
    {
        return [
            'id' => $row['id'],
            'label' => $row['label'],
            'origin' => $row['origin'],
            'source_url' => $row['source_url'],
            'size' => (int) $row['size'],
            'created_at' => $row['created_at'],
            'added_at' => $row['added_at'],
            'summary' => $row['summary'],
        ];
    }

    private static function encode(array $row): array
    {
        if (array_key_exists('summary', $row)) {
            $row['summary'] = wp_json_encode($row['summary']);
        }
        return $row;
    }

    private static function decode(array $row): array
    {
        $row['size'] = (int) $row['size'];
        $row['summary'] = json_decode((string) $row['summary'], true) ?: [];
        return $row;
    }

    /** @param int|false $result */
    private function write($result): void
    {
        if ($result === false) {
            throw new RelayError(
                'db.query_failed',
                /* translators: %s: database error message */
                esc_html(sprintf(__('Database error: %s', 'siterelay'), $this->db->wpdb()->last_error)),
                esc_html__('SiteRelay could not save the backup record.', 'siterelay')
            );
        }
    }
}