/**
 * API 请求组合式函数
 * 提供统一的错误处理和加载状态管理
 */
import { ref } from 'vue'

export function useApi() {
  const loading = ref(false)
  const error = ref(null)

  /**
   * 执行 API 请求
   * @param {Function} apiFn - API 函数
   * @param {Object} options - 配置选项
   * @returns {Promise<Object>} 响应数据
   */
  const request = async (apiFn, options = {}) => {
    const { showLoading = true, errorMessage = '请求失败' } = options
    
    loading.value = true
    error.value = null
    
    try {
      const response = await apiFn()
      
      if (response.success) {
        return response.data
      } else {
        throw new Error(response.message || errorMessage)
      }
    } catch (err) {
      error.value = err.message || errorMessage
      throw err
    } finally {
      loading.value = false
    }
  }

  /**
   * 重置状态
   */
  const reset = () => {
    loading.value = false
    error.value = null
  }

  return {
    loading,
    error,
    request,
    reset
  }
}

/**
 * 分页组合式函数
 */
export function usePagination(initialPage = 1, initialPageSize = 20) {
  const page = ref(initialPage)
  const pageSize = ref(initialPageSize)
  const total = ref(0)

  const totalPages = () => Math.ceil(total.value / pageSize.value)

  const nextPage = () => {
    if (page.value < totalPages()) {
      page.value++
    }
  }

  const prevPage = () => {
    if (page.value > 1) {
      page.value--
    }
  }

  const goToPage = (p) => {
    if (p >= 1 && p <= totalPages()) {
      page.value = p
    }
  }

  const resetPagination = () => {
    page.value = initialPage
    total.value = 0
  }

  return {
    page,
    pageSize,
    total,
    totalPages,
    nextPage,
    prevPage,
    goToPage,
    resetPagination
  }
}

/**
 * 表单组合式函数
 */
export function useForm(initialData = {}) {
  const formData = ref({ ...initialData })
  const errors = ref({})
  const submitting = ref(false)

  const updateField = (field, value) => {
    formData.value[field] = value
    // 清除字段错误
    if (errors.value[field]) {
      delete errors.value[field]
    }
  }

  const setFieldError = (field, message) => {
    errors.value[field] = message
  }

  const setErrors = (errorObj) => {
    errors.value = errorObj
  }

  const clearErrors = () => {
    errors.value = {}
  }

  const resetForm = (newData = {}) => {
    formData.value = { ...initialData, ...newData }
    errors.value = {}
  }

  const validate = (rules) => {
    const newErrors = {}
    
    for (const [field, rule] of Object.entries(rules)) {
      const value = formData.value[field]
      
      if (rule.required && !value) {
        newErrors[field] = rule.message || `${field}不能为空`
      }
      
      if (rule.minLength && value && value.length < rule.minLength) {
        newErrors[field] = rule.message || `${field}长度不能少于${rule.minLength}位`
      }
      
      if (rule.maxLength && value && value.length > rule.maxLength) {
        newErrors[field] = rule.message || `${field}长度不能超过${rule.maxLength}位`
      }
      
      if (rule.pattern && value && !rule.pattern.test(value)) {
        newErrors[field] = rule.message || `${field}格式不正确`
      }
    }
    
    setErrors(newErrors)
    return Object.keys(newErrors).length === 0
  }

  return {
    formData,
    errors,
    submitting,
    updateField,
    setFieldError,
    setErrors,
    clearErrors,
    resetForm,
    validate
  }
}