export const BACKEND_API_BASE_URLS = {
  production:    "https://jr-shikoku-backend-api-v1.haruk.in",
  experimental:  "https://jr-shikoku-backend-api-v1-beta.haruk.in",
} as const;

export const JR_DATA_SYSTEM_ENVS = {
  production_release: {
    label: "本番 / リリース",
    caption: "一般公開向け運用",
    baseUrl: "https://shikoku-railinfo.haruk.in",
    track: "production",
    uiVariant: "release",
    backendApiBaseUrl: BACKEND_API_BASE_URLS.production,
  },
  production_beta: {
    label: "本番 / ベータ",
    caption: "UI検証向け運用",
    baseUrl: "https://nightly.shikoku-railinfo.haruk.in",
    track: "production",
    uiVariant: "beta",
    backendApiBaseUrl: BACKEND_API_BASE_URLS.production,
  },
  experimental: {
    label: "実験 / 実験場",
    caption: "毎日リセットされる実験環境",
    baseUrl: "https://experimental.shikoku-railinfo.haruk.in",
    track: "experimental",
    uiVariant: "release",
    backendApiBaseUrl: BACKEND_API_BASE_URLS.experimental,
  },
} as const;

export type JrDataSystemEnvironmentKey = keyof typeof JR_DATA_SYSTEM_ENVS;

export const DEFAULT_JR_DATA_SYSTEM_ENV: JrDataSystemEnvironmentKey =
  "production_release";

export type JrDataSystemTrack = "production" | "experimental";
export type JrDataSystemUiVariant = "release" | "beta";

export const JR_DATA_SYSTEM_ENV_OPTIONS = (
  Object.entries(JR_DATA_SYSTEM_ENVS) as [
    JrDataSystemEnvironmentKey,
    (typeof JR_DATA_SYSTEM_ENVS)[JrDataSystemEnvironmentKey],
  ][]
).map(([key, value]) => ({
  key,
  ...value,
}));

export const normalizeJrDataSystemEnvironment = (
  value: unknown,
): JrDataSystemEnvironmentKey => {
  // Backward compatibility for legacy keys.
  if (value === "production") return "production_release";
  if (value === "chatgpt" || value === "claude") return "production_beta";

  if (typeof value === "string" && value in JR_DATA_SYSTEM_ENVS) {
    return value as JrDataSystemEnvironmentKey;
  }
  return DEFAULT_JR_DATA_SYSTEM_ENV;
};

export const resolveJrDataSystemEnvironment = (
  track: JrDataSystemTrack,
  uiVariant: JrDataSystemUiVariant,
): JrDataSystemEnvironmentKey => {
  if (track === "experimental") {
    return "experimental";
  }
  return uiVariant === "beta" ? "production_beta" : "production_release";
};

export const getJrDataSystemTrack = (
  environment: unknown,
): JrDataSystemTrack => {
  const envKey = normalizeJrDataSystemEnvironment(environment);
  return JR_DATA_SYSTEM_ENVS[envKey].track;
};

export const getJrDataSystemUiVariant = (
  environment: unknown,
): JrDataSystemUiVariant => {
  const envKey = normalizeJrDataSystemEnvironment(environment);
  return JR_DATA_SYSTEM_ENVS[envKey].uiVariant;
};

export const getBackendApiBaseUrl = (environment: unknown): string => {
  const envKey = normalizeJrDataSystemEnvironment(environment);
  return JR_DATA_SYSTEM_ENVS[envKey].backendApiBaseUrl;
};

export const rewriteBackendApiUrl = (url: string, environment: unknown): string => {
  if (typeof url !== "string" || url.length === 0) return url;
  const target = getBackendApiBaseUrl(environment);
  for (const base of Object.values(BACKEND_API_BASE_URLS)) {
    if (url.startsWith(base)) {
      return url.replace(base, target);
    }
  }
  return url;
};

export const rewriteJrDataSystemUrl = (
  uri: string,
  environment: unknown,
): string => {
  if (typeof uri !== "string" || uri.length === 0) {
    return uri;
  }

  const envKey = normalizeJrDataSystemEnvironment(environment);
  const targetBaseUrl = JR_DATA_SYSTEM_ENVS[envKey].baseUrl;

  const knownBaseUrls = [
    "https://jr-shikoku-data-system.pages.dev",
    JR_DATA_SYSTEM_ENVS.production_release.baseUrl,
    JR_DATA_SYSTEM_ENVS.production_beta.baseUrl,
    JR_DATA_SYSTEM_ENVS.experimental.baseUrl,
  ];

  for (const baseUrl of knownBaseUrls) {
    if (uri.startsWith(baseUrl)) {
      return uri.replace(baseUrl, targetBaseUrl);
    }
  }

  return uri;
};