const API_BASE = (import.meta.env.VITE_LISGLOSIPS_API_BASE || '/api/v2').replace(/\/$/, '');
const ACCESS_TOKEN_KEY = 'lisglosips.accessToken';

export function getAccessToken() {
  return window.localStorage.getItem(ACCESS_TOKEN_KEY);
}

export function setAccessToken(token) {
  if (token) {
    window.localStorage.setItem(ACCESS_TOKEN_KEY, token);
  } else {
    window.localStorage.removeItem(ACCESS_TOKEN_KEY);
  }
}

export class ApiError extends Error {
  constructor(message, { status, code } = {}) {
    super(message);
    this.name = 'ApiError';
    this.status = status;
    this.code = code;
  }
}

const DEFAULT_TIMEOUT_MS = 10_000;

async function fetchWithTimeout(path, options = {}) {
  const { timeoutMs = DEFAULT_TIMEOUT_MS, signal: externalSignal, ...fetchOptions } = options;
  const controller = new AbortController();
  const abortFromExternal = () => controller.abort(externalSignal?.reason);
  if (externalSignal) {
    if (externalSignal.aborted) {
      abortFromExternal();
    } else {
      externalSignal.addEventListener('abort', abortFromExternal, { once: true });
    }
  }
  const timeout = window.setTimeout(() => controller.abort('REQUEST_TIMEOUT'), timeoutMs);
  try {
    return await fetch(`${API_BASE}${path}`, {
      ...fetchOptions,
      signal: controller.signal,
    });
  } catch (error) {
    if (controller.signal.aborted && !externalSignal?.aborted) {
      throw new ApiError('请求超过 10 秒未响应，请稍后重试。', { status: 408, code: 'REQUEST_TIMEOUT' });
    }
    throw error;
  } finally {
    window.clearTimeout(timeout);
    externalSignal?.removeEventListener('abort', abortFromExternal);
  }
}

async function request(path, options = {}) {
  const token = window.localStorage.getItem(ACCESS_TOKEN_KEY);
  const headers = new Headers(options.headers || {});
  headers.set('Accept', 'application/json');
  if (options.body && !headers.has('Content-Type')) {
    headers.set('Content-Type', 'application/json');
  }
  if (token) {
    headers.set('Authorization', `Bearer ${token}`);
  }

  const response = await fetchWithTimeout(path, {
    ...options,
    headers,
    credentials: 'include',
  });
  const contentType = response.headers.get('content-type') || '';
  const payload = contentType.includes('application/json') ? await response.json() : await response.text();

  if (!response.ok) {
    throw new ApiError(errorMessage(payload, response.status), {
      status: response.status,
      code: typeof payload === 'object' && payload ? payload.code : undefined,
    });
  }

  return payload;
}

async function requestBlob(path, options = {}) {
  const token = window.localStorage.getItem(ACCESS_TOKEN_KEY);
  const headers = new Headers(options.headers || {});
  if (token) {
    headers.set('Authorization', `Bearer ${token}`);
  }

  const response = await fetchWithTimeout(path, {
    ...options,
    headers,
    credentials: 'include',
  });

  if (!response.ok) {
    const contentType = response.headers.get('content-type') || '';
    const payload = contentType.includes('application/json') ? await response.json() : await response.text();
    throw new ApiError(errorMessage(payload, response.status), {
      status: response.status,
      code: typeof payload === 'object' && payload ? payload.code : undefined,
    });
  }

  return response.blob();
}

function errorMessage(payload, status) {
  if (payload && typeof payload === 'object') {
    return payload.message || payload.error || `API request failed with HTTP ${status}.`;
  }
  return payload || `API request failed with HTTP ${status}.`;
}

function jsonBody(value) {
  return JSON.stringify(value);
}

function idempotencyKey(scope) {
  const random = crypto.randomUUID ? crypto.randomUUID() : `${Date.now()}-${Math.random().toString(16).slice(2)}`;
  return `${scope}:${random}`;
}

function queryString(params = {}) {
  const entries = Object.entries(params).filter(([, value]) => value !== undefined && value !== null && value !== '' && value !== 'all');
  return entries.length ? `?${new URLSearchParams(Object.fromEntries(entries))}` : '';
}

export const api = {
  captcha: () => request('/auth/captcha'),
  login: async (body) => {
    const response = await request('/auth/login', { method: 'POST', body: jsonBody(body) });
    setAccessToken(response.accessToken);
    return response;
  },
  refresh: async () => {
    const response = await request('/auth/refresh', { method: 'POST' });
    setAccessToken(response.accessToken);
    return response;
  },
  logout: async () => {
    try {
      await request('/auth/logout', { method: 'POST' });
    } finally {
      setAccessToken('');
    }
  },
  dashboardSummary: (options) => request('/dashboard/summary', options),
  dashboardTrends: (params = { hours: 24, bucketMinutes: 60 }, options) => request(`/dashboard/trends?${new URLSearchParams(params)}`, options),
  dashboardOverview: (params = { hours: 24, bucketMinutes: 60 }, options) => request(`/dashboard/overview?${new URLSearchParams(params)}`, options),
  activeCalls: (options) => request('/active-calls', options),
  hangupActiveCall: (id) => request(`/active-calls/${encodeURIComponent(id)}/hangup`, { method: 'POST' }),
  cdrs: (params = {}) => request(`/cdrs${queryString({ take: 25, ...params })}`),
  cdrDetail: (id) => request(`/cdrs/${encodeURIComponent(id)}`),
  recordings: (params = {}) => request(`/recordings${queryString({ status: 'READY', limit: 50, ...params })}`),
  recordingDetail: (id) => request(`/recordings/${encodeURIComponent(id)}`),
  recordingPlayback: (id) => requestBlob(`/recordings/${encodeURIComponent(id)}/play`),
  saveRecordingReview: (id, body) => request(`/recordings/${encodeURIComponent(id)}/review`, { method: 'PUT', body: jsonBody(body) }),
  qualityRules: () => request('/quality/rules'),
  createQualityRule: (body) => request('/quality/rules', { method: 'POST', body: jsonBody(body) }),
  updateQualityRule: (id, body) => request(`/quality/rules/${encodeURIComponent(id)}`, { method: 'PATCH', body: jsonBody(body) }),
  enableQualityRule: (id) => request(`/quality/rules/${encodeURIComponent(id)}/enable`, { method: 'POST' }),
  disableQualityRule: (id) => request(`/quality/rules/${encodeURIComponent(id)}/disable`, { method: 'POST' }),
  deleteQualityRule: (id) => request(`/quality/rules/${encodeURIComponent(id)}`, { method: 'DELETE' }),
  customers: (options) => request('/customers', options),
  createCustomer: (body) => request('/customers', { method: 'POST', body: jsonBody(body) }),
  updateCustomer: (id, body) => request(`/customers/${encodeURIComponent(id)}`, { method: 'PATCH', body: jsonBody(body) }),
  enableCustomer: (id) => request(`/customers/${encodeURIComponent(id)}/enable`, { method: 'POST' }),
  disableCustomer: (id) => request(`/customers/${encodeURIComponent(id)}/disable`, { method: 'POST' }),
  deleteCustomer: (id) => request(`/customers/${encodeURIComponent(id)}`, { method: 'DELETE' }),
  rechargeCustomer: (id, body) =>
    request(`/customers/${encodeURIComponent(id)}/recharges`, {
      method: 'POST',
      body: jsonBody({ ...body, idempotencyKey: idempotencyKey('customer-recharge') }),
    }),
  vendors: (options) => request('/vendors', options),
  createVendor: (body) => request('/vendors', { method: 'POST', body: jsonBody(body) }),
  updateVendor: (id, body) => request(`/vendors/${encodeURIComponent(id)}`, { method: 'PATCH', body: jsonBody(body) }),
  deleteVendor: (id) => request(`/vendors/${encodeURIComponent(id)}`, { method: 'DELETE' }),
  rechargeVendor: (id, body) =>
    request(`/vendors/${encodeURIComponent(id)}/recharges`, {
      method: 'POST',
      body: jsonBody({ ...body, idempotencyKey: idempotencyKey('vendor-recharge') }),
    }),
  customerGateways: (options) => request('/customer-gateways', options),
  createCustomerGateway: (body) => request('/customer-gateways', { method: 'POST', body: jsonBody(body) }),
  updateCustomerGateway: (id, body) => request(`/customer-gateways/${encodeURIComponent(id)}`, { method: 'PATCH', body: jsonBody(body) }),
  enableCustomerGateway: (id) => request(`/customer-gateways/${encodeURIComponent(id)}/enable`, { method: 'POST' }),
  disableCustomerGateway: (id) => request(`/customer-gateways/${encodeURIComponent(id)}/disable`, { method: 'POST' }),
  deleteCustomerGateway: (id) => request(`/customer-gateways/${encodeURIComponent(id)}`, { method: 'DELETE' }),
  vendorGateways: (options) => request('/vendor-gateways', options),
  createVendorGateway: (body) => request('/vendor-gateways', { method: 'POST', body: jsonBody(body) }),
  updateVendorGateway: (id, body) => request(`/vendor-gateways/${encodeURIComponent(id)}`, { method: 'PATCH', body: jsonBody(body) }),
  enableVendorGateway: (id) => request(`/vendor-gateways/${encodeURIComponent(id)}/enable`, { method: 'POST' }),
  disableVendorGateway: (id) => request(`/vendor-gateways/${encodeURIComponent(id)}/disable`, { method: 'POST' }),
  deleteVendorGateway: (id) => request(`/vendor-gateways/${encodeURIComponent(id)}`, { method: 'DELETE' }),
  landingLineGroups: (options) => request('/landing-line-groups', options),
  deleteLandingLineGroup: (id) => request(`/landing-line-groups/${encodeURIComponent(id)}`, { method: 'DELETE' }),
  recharges: (options) => request('/recharges?take=100', options),
  users: (options) => request('/users', options),
  deleteUser: (id) => request(`/users/${encodeURIComponent(id)}`, { method: 'DELETE' }),
  roles: (options) => request('/roles', options),
  deleteRole: (id) => request(`/roles/${encodeURIComponent(id)}`, { method: 'DELETE' }),
  auditLogs: (params = {}, options) => request(`/audit-logs${queryString({ take: 100, ...params })}`, options),
  businessPrefixes: (params = {}) => request(`/business-prefixes${queryString(params)}`),
  createBusinessPrefix: (body) => request('/business-prefixes', { method: 'POST', body: jsonBody(body) }),
  updateBusinessPrefix: (id, body) => request(`/business-prefixes/${encodeURIComponent(id)}`, { method: 'PATCH', body: jsonBody(body) }),
  enableBusinessPrefix: (id) => request(`/business-prefixes/${encodeURIComponent(id)}/enable`, { method: 'POST' }),
  disableBusinessPrefix: (id) => request(`/business-prefixes/${encodeURIComponent(id)}/disable`, { method: 'POST' }),
  deleteBusinessPrefix: (id) => request(`/business-prefixes/${encodeURIComponent(id)}`, { method: 'DELETE' }),
  numberLibraryCities: (params = {}) => request(`/number-library/cities${queryString({ take: 25, ...params })}`),
  importNumberLibraryCities: (items) => request('/number-library/cities/import', { method: 'POST', body: jsonBody({ items }) }),
  numberLibraryPhoneSegments: (params = {}) => request(`/number-library/phone-segments${queryString({ take: 25, ...params })}`),
  importNumberLibraryPhoneSegments: (items) => request('/number-library/phone-segments/import', { method: 'POST', body: jsonBody({ items }) }),
  numberLibraryAreaCodes: (params = {}) => request(`/number-library/area-codes${queryString({ take: 25, ...params })}`),
  importNumberLibraryAreaCodes: (items) => request('/number-library/area-codes/import', { method: 'POST', body: jsonBody({ items }) }),
  numberLibraryCarrierPrefixRules: (params = {}) => request(`/number-library/carrier-prefix-rules${queryString({ take: 25, ...params })}`),
  importNumberLibraryCarrierPrefixRules: (items) => request('/number-library/carrier-prefix-rules/import', { method: 'POST', body: jsonBody({ items }) }),
};

export function explainApiError(error) {
  if (error instanceof ApiError && error.code === 'AUTH_CAPTCHA_INVALID') {
    return '验证码错误或已过期，请重新输入。';
  }
  if (error instanceof ApiError && error.code === 'AUTH_INVALID_CREDENTIALS') {
    return '用户名、密码或验证码不正确。';
  }
  if (error instanceof ApiError && error.code === 'CUSTOMER_HAS_GATEWAYS') {
    return '该客户仍有关联客户网关，不能删除。';
  }
  if (error instanceof ApiError && error.code === 'VENDOR_HAS_GATEWAYS') {
    return '该供应商仍有关联落地网关，不能删除。';
  }
  if (error instanceof ApiError && error.code === 'LINE_GROUP_IN_USE') {
    return '该落地线路组仍被客户网关使用，不能删除。';
  }
  if (error instanceof ApiError && error.code === 'VENDOR_GATEWAY_IN_LINE_GROUP') {
    return '该落地网关仍被落地线路组引用，不能删除。';
  }
  if (error instanceof ApiError && error.code === 'ROLE_HAS_USERS') {
    return '该角色仍有关联用户，不能删除。';
  }
  if (error instanceof ApiError && error.code === 'BUILT_IN_ROLE_PROTECTED') {
    return '系统内置角色受保护，不能删除或修改关键权限。';
  }
  if (error instanceof ApiError && error.code === 'BUSINESS_PREFIX_IN_USE') {
    return '该业务前缀仍被客户网关使用，不能删除。';
  }
  if (error instanceof ApiError && error.code === 'BUSINESS_PREFIX_INVALID') {
    return '业务前缀只能包含 1-32 位英文或数字。';
  }
  if (error instanceof ApiError && (error.status === 401 || error.status === 403)) {
    return '登录状态已失效，请重新登录。';
  }
  if (error instanceof ApiError && error.status === 429) {
    return '登录尝试过于频繁，请稍后再试。';
  }
  return error instanceof Error ? error.message : '请求失败，请稍后重试。';
}