type FieldIssue = { field: string; message: string };

function describeIssues(message: string, issues: FieldIssue[]) {
    const details = issues.slice(0, 3).map((issue) => `${issue.field}：${issue.message}`);
    return details.length ? `${message}（${details.join('；')}）` : message;
}

/** 只展示服务端错误信封的业务说明，避免把请求或授权信息带入错误提示。 */
export function requestError(body: unknown, status: number) {
    const error = body && typeof body === 'object' && 'error' in body
        ? body.error
        : null;
    const info = error && typeof error === 'object'
        ? error as { message?: unknown; details?: unknown }
        : null;
    const message = typeof info?.message === 'string'
        ? info.message
        : `请求失败（HTTP ${status}）`;
    const issues = Array.isArray(info?.details)
        ? info.details.filter((item): item is FieldIssue =>
            !!item && typeof item === 'object' &&
            typeof item.field === 'string' && typeof item.message === 'string')
        : [];
    return Object.assign(new Error(describeIssues(message, issues)), { status });
}

/** Chrome 消息只返回可序列化错误，交给内容脚本显示，避免后台未处理异常。 */
export function backgroundError(error: unknown) {
    return { error: { message: error instanceof Error ? error.message : '操作失败，请重试' } };
}

export function unwrapBackgroundResponse<T>(response: unknown): T {
    if (!response || typeof response !== 'object')
        throw new Error('插件后台未响应，请重载扩展并刷新商品页');
    if ('error' in response && response.error && typeof response.error === 'object') {
        const error = response.error as { message?: unknown };
        throw new Error(typeof error.message === 'string' ? error.message : '操作失败，请重试');
    }
    return response as T;
}