<?php

class WPI_Config_Model
{
    private static function table()
    {
        global $wpdb;
        return $wpdb->prefix . 'wpi_configs';
    }

    public static function acquire_lock(string $key): bool
    {
        global $wpdb;

        $table = self::table();

        return (bool) $wpdb->query(
            $wpdb->prepare(
                "UPDATE {$table}
             SET config_value = 1
             WHERE config_key = %s AND config_value = 0",
                $key
            )
        );
    }


    /**
     * Check config exists
     */
    private static function exists(string $key): bool
    {
        global $wpdb;

        return (bool) $wpdb->get_var(
            $wpdb->prepare(
                "SELECT 1 FROM " . self::table() . " WHERE config_key = %s LIMIT 1",
                $key
            )
        );
    }

    /**
     * Insert or update config
     */
    public static function set_config(string $key, $value, string $description = null)
    {
        global $wpdb;

        $table = self::table();
        $now   = current_time('mysql');
        $data  = [
            'config_value' => wp_json_encode($value),
            'updated_at'   => $now,
        ];

        if ($description !== null) {
            $data['description'] = $description;
        }

        if (self::exists($key)) {

            // UPDATE only
            $wpdb->update(
                $table,
                $data,
                ['config_key' => $key],
                ['%s', '%s', '%s'],
                ['%s']
            );
        } else {

            // INSERT new
            $wpdb->insert(
                $table,
                array_merge($data, [
                    'config_key' => $key,
                    'created_at' => $now,
                ]),
                ['%s', '%s', '%s', '%s']
            );
        }
    }

    /**
     * Get config (auto json decode)
     */
    public static function get_config(string $key, $default = null)
    {
        global $wpdb;

        $value = $wpdb->get_var(
            $wpdb->prepare(
                "SELECT config_value FROM " . self::table() . " WHERE config_key = %s",
                $key
            )
        );

        return $value !== null ? json_decode($value, true) : $default;
    }

    public static function any_worker_running(): bool
    {
        global $wpdb;

        $table = self::table();

        $rows = $wpdb->get_results(
            "SELECT config_value 
         FROM {$table}
         WHERE config_key LIKE 'sync_status_%'"
        );

        if (empty($rows)) {
            // Không có worker nào
            return false;
        }

        foreach ($rows as $row) {
            $value = json_decode($row->config_value, true);

            if ((int) $value !== 1) {
                return false;
            }
        }

        return true;
    }

    public static function claim_next_page(): int
    {
        global $wpdb;

        $table = self::table();

        // Atomic increment
        $updated = $wpdb->query(
            "UPDATE {$table}
         SET config_value = config_value + 1
         WHERE config_key = 'current_page'"
        );

        if ($updated === false) {
            return 0;
        }

        // Lấy page vừa claim
        $page = (int) $wpdb->get_var(
            "SELECT config_value FROM {$table} WHERE config_key = 'current_page'"
        );

        return $page;
    }
}