DiAL/src/server/helpers.ts

import type { ApiErrorResponse, CheckFailure, CheckResult, HealthResponse, RuntimeMode } from "../shared/api";
import type { StoredCheckResult } from "./checker/types";

export function createApiError(error: string, status: number): ApiErrorResponse {
  return { error, status };
}

export function createHeaders(mode: RuntimeMode, init: HeadersInit): Headers {
  const headers = new Headers(init);

  if (mode === "production") {
    headers.set("X-Content-Type-Options", "nosniff");
    headers.set("Referrer-Policy", "strict-origin-when-cross-origin");
  }

  return headers;
}

export function jsonResponse(
  body: unknown,
  options: { method?: string; mode: RuntimeMode; status?: number; headers?: HeadersInit },
): Response {
  const headers = createHeaders(options.mode, {
    "Content-Type": "application/json; charset=utf-8",
    ...options.headers,
  });
  const responseBody = options.method === "HEAD" ? null : JSON.stringify(body);

  return new Response(responseBody, {
    status: options.status,
    headers,
  });
}

export function methodNotAllowedResponse(allow: string[], mode: RuntimeMode): Response {
  return jsonResponse(createApiError("Method not allowed", 405), {
    mode,
    status: 405,
    headers: { Allow: allow.join(", ") },
  });
}

export function allowsGetHead(method: string): boolean {
  return method === "GET" || method === "HEAD";
}

export function formatDuration(ms: number): string {
  if (ms >= 60000 && ms % 60000 === 0) return `${ms / 60000}m`;
  if (ms >= 1000 && ms % 1000 === 0) return `${ms / 1000}s`;
  return `${ms}ms`;
}

export function mapCheckResult(row: StoredCheckResult): CheckResult {
  let failure: CheckFailure | null = null;
  if (row.failure) {
    try {
      failure = JSON.parse(row.failure) as CheckFailure;
    } catch {
      console.warn(`无法解析 failure 数据: target_id=${row.target_id}, timestamp=${row.timestamp}`);
      failure = null;
    }
  }

  return {
    timestamp: row.timestamp,
    matched: row.matched === 1,
    durationMs: row.duration_ms,
    statusDetail: row.status_detail,
    failure,
  };
}

export function createHealthResponse(): HealthResponse {
  return {
    ok: true,
    service: "dial-server",
    timestamp: new Date().toISOString(),
  };
}