import axios, { InternalAxiosRequestConfig } from 'axios';
import { getApiBaseUrl } from '../config';
import { triggerSessionExpired, isUserSyncEndpoint, isTenantEndpoint } from './sessionExpiration';
import { isUserSyncedInBrowser, isActivationPending, syncUserAccount } from './userSyncService';

export const BASE_API_URL = getApiBaseUrl();

const MUTATION_EPOCH_STORAGE_KEY = 'pfm_mutation_epoch';

let activeMutationEpoch: number = (() => {
  if (typeof window !== 'undefined') {
    try {
      const stored = sessionStorage.getItem(MUTATION_EPOCH_STORAGE_KEY);
      if (stored) {
        const parsed = Number(stored);
        if (!isNaN(parsed) && parsed > 0) return parsed;
      }
    } catch {}
  }
  return Date.now();
})();

export function getMutationEpoch(): number {
  return activeMutationEpoch;
}

export function bumpMutationEpoch(): number {
  activeMutationEpoch = Date.now();
  if (typeof window !== 'undefined') {
    try {
      sessionStorage.setItem(MUTATION_EPOCH_STORAGE_KEY, String(activeMutationEpoch));
    } catch {}
  }
  return activeMutationEpoch;
}

export const apiClient = axios.create({
  baseURL: BASE_API_URL,
  headers: {
    'Content-Type': 'application/json; version=1',
    Accept: 'application/json; version=1',
    'Cache-Control': 'no-cache, no-store, must-revalidate',
    Pragma: 'no-cache',
  },
  timeout: 15000,
});

apiClient.interceptors.request.use(
  async (config: InternalAxiosRequestConfig) => {
    config.baseURL = getApiBaseUrl();
    const token = localStorage.getItem('pfm_access_token');
    if (token && config.headers) {
      config.headers.Authorization = `Bearer ${token}`;
    }

    const isLifecycleRequest = isUserSyncEndpoint(config.url) || isTenantEndpoint(config.url);
    const isExternal =
      config.url?.startsWith('http://') ||
      config.url?.startsWith('https://') ||
      config.url?.includes('amazonaws.com') ||
      config.url?.includes('garage');

    // Always attach freshness timestamp and mutation epoch to internal GET requests
    // to guarantee zero stale data, bypass browser HTTP caches, and prevent stale OutputCache hits
    if (config.method?.toUpperCase() === 'GET' && !isExternal) {
      if (config.params instanceof URLSearchParams) {
        config.params.set('_t', String(Date.now()));
        config.params.set('_v', String(getMutationEpoch()));
      } else {
        config.params = config.params || {};
        config.params._t = Date.now();
        config.params._v = getMutationEpoch();
      }
    }

    if (token && !isLifecycleRequest) {
      if (isActivationPending()) {
        return Promise.reject(new Error('User account is pending administrator activation'));
      }

      const storedSub = localStorage.getItem('pfm_user_sub') || '';
      if (!isUserSyncedInBrowser(storedSub, token)) {
        const syncRes = await syncUserAccount(storedSub, token);
        if (!syncRes.success) {
          return Promise.reject(new Error(syncRes.errorMessage || 'User account sync pending activation'));
        }
      }
    }

    return config;
  },
  (error) => Promise.reject(error)
);

apiClient.interceptors.response.use(
  (response) => {
    const method = response.config?.method?.toLowerCase();
    if (method && ['post', 'put', 'patch', 'delete'].includes(method)) {
      bumpMutationEpoch();
    }
    return response;
  },
  (error) => {
    if (error?.response?.status === 401) {
      const requestUrl = error.config?.url;
      const isLifecycleEndpoint = isUserSyncEndpoint(requestUrl) || isTenantEndpoint(requestUrl);

      if (!isLifecycleEndpoint) {
        const detailMsg =
          error?.response?.data?.detail ||
          error?.response?.data?.message ||
          'Authentication session expired or security token invalidated (HTTP 401).';

        triggerSessionExpired(detailMsg, requestUrl);
      } else {
        if (typeof window !== 'undefined') {
          localStorage.removeItem('pfm_access_token');
          localStorage.removeItem('pfm_access_user');
          localStorage.removeItem('pfm_user_sync_record');
          localStorage.removeItem('pfm_user_pending_activation');
          localStorage.removeItem('pfm_user_pending_activation_reason');
        }
      }
    }
    return Promise.reject(error);
  }
);