const API_BASE_STORAGE_KEY = 'x-financial-api-base-url'

function normalizeApiBaseUrl(value) {
  return String(value || '/api/v1').replace(/\/$/, '')
}

function readStoredApiBaseUrl() {
  if (typeof window === 'undefined') {
    return ''
  }

  return window.localStorage.getItem(API_BASE_STORAGE_KEY) || ''
}

let runtimeApiBaseUrl = normalizeApiBaseUrl(readStoredApiBaseUrl() || import.meta.env.VITE_API_BASE_URL || '/api/v1')

export function setRuntimeApiBaseUrl(value) {
  runtimeApiBaseUrl = normalizeApiBaseUrl(value)

  if (typeof window !== 'undefined') {
    window.localStorage.setItem(API_BASE_STORAGE_KEY, runtimeApiBaseUrl)
  }
}

export function getRuntimeApiBaseUrl() {
  return runtimeApiBaseUrl
}

function buildUrl(path) {
  if (!path.startsWith('/')) {
    return `${runtimeApiBaseUrl}/${path}`
  }

  return `${runtimeApiBaseUrl}${path}`
}

export async function apiRequest(path, options = {}) {
  let response

  try {
    response = await fetch(buildUrl(path), {
      headers: {
        'Content-Type': 'application/json',
        ...(options.headers || {})
      },
      ...options
    })
  } catch {
    throw new Error('无法连接后端员工服务，请确认 FastAPI 已启动。')
  }

  let payload = null

  try {
    payload = await response.json()
  } catch {
    payload = null
  }

  if (!response.ok) {
    throw new Error(payload?.detail || '接口请求失败，请稍后重试。')
  }

  return payload
}