/** Default timeouts (ms) for hybrid discovery. */
export const DEFAULT_BOOT_TIMEOUT_MS = 5_000;
export const DEFAULT_RETRY_TIMEOUT_MS = 5_000;
export const DEFAULT_RELOAD_TIMEOUT_MS = 30_000;

export interface CLIPProxyConfig {
  baseUrl: string;
  apiKey: string;
  /** Normalized URL to GET for model listing (includes `/models`). */
  modelsUrl: string;
  bootTimeoutMs: number;
  retryTimeoutMs: number;
  reloadTimeoutMs: number;
}

export type ConfigResult =
  | { ok: true; config: CLIPProxyConfig }
  | { ok: false; error: string };

/**
 * Parse a positive integer env value; invalid or non-positive → fallback.
 */
export function parseTimeoutMs(raw: string | undefined, fallback: number): number {
  if (raw === undefined || raw.trim() === '') return fallback;
  const n = Number(raw);
  if (!Number.isFinite(n) || n <= 0) return fallback;
  return Math.floor(n);
}

/**
 * Normalize user-supplied base URL for CLIProxyAPI.
 * - trim
 * - strip trailing slashes
 * - if already ends with `/models`, treat as models endpoint base (no double append later)
 * - does NOT invent a missing `/v1`
 */
export function normalizeBaseUrl(raw: string): string {
  let url = raw.trim();
  while (url.endsWith('/')) {
    url = url.slice(0, -1);
  }
  return url;
}

/** Build the models list endpoint from a normalized base URL. */
export function buildModelsUrl(normalizedBaseUrl: string): string {
  if (/\/models$/i.test(normalizedBaseUrl)) {
    return normalizedBaseUrl;
  }
  return `${normalizedBaseUrl}/models`;
}

/**
 * Read provider config from environment.
 * Required: CLIPROXY_BASE_URL, CLIPROXY_API_KEY.
 */
export function loadConfig(
  env: NodeJS.ProcessEnv = process.env,
): ConfigResult {
  const baseRaw = env.CLIPROXY_BASE_URL;
  const apiKey = env.CLIPROXY_API_KEY;

  if (!baseRaw?.trim() || !apiKey?.trim()) {
    return {
      ok: false,
      error:
        'CLIPROXY_BASE_URL 和 CLIPROXY_API_KEY 为必填环境变量。Provider 未注册。',
    };
  }

  const baseUrl = normalizeBaseUrl(baseRaw);
  return {
    ok: true,
    config: {
      baseUrl,
      apiKey: apiKey.trim(),
      modelsUrl: buildModelsUrl(baseUrl),
      bootTimeoutMs: parseTimeoutMs(env.CLIPROXY_BOOT_TIMEOUT_MS, DEFAULT_BOOT_TIMEOUT_MS),
      retryTimeoutMs: parseTimeoutMs(env.CLIPROXY_RETRY_TIMEOUT_MS, DEFAULT_RETRY_TIMEOUT_MS),
      reloadTimeoutMs: parseTimeoutMs(env.CLIPROXY_RELOAD_TIMEOUT_MS, DEFAULT_RELOAD_TIMEOUT_MS),
    },
  };
}