import { createUseFetch } from '#imports'
import type { NitroFetchRequest } from 'nitropack/types'
import type { $Fetch } from 'ofetch'
import type { NuxtApp } from '#app'

/** 与 `R.success` / `R.error` 返回结构对齐 */
export type ApiResponse<T = unknown> = {
    code: number
    message: string
    data: T
}


/** 从 Nitro 推断的响应体上剥离一层 `ApiResponse`，得到 `data` 字段类型 */
export type UnwrapApiResponse<T> = T extends ApiResponse<infer D> ? D : T

export function unwrapApiBody<T>(payload: ApiResponse<T>): T {
    if (payload.code !== 0) {
        throw new Error(payload.message)
    }
    return payload.data
}


export const request = $fetch.create({
  credentials: 'include',
})

interface AsyncDataRequestContext {
  cause: 'initial' | 'refresh:manual' | 'refresh:hook' | 'watch'
}

function ssrFriendlyCache<DataT>(key: string, nuxtApp: NuxtApp, ctx: AsyncDataRequestContext): DataT | undefined {
  // SSR 首次水合用 payload 缓存（零闪烁），refresh 时跳过缓存走真实请求
  if (ctx.cause === 'initial') {
    return nuxtApp.payload.data[key] as DataT | undefined
  }
  return undefined
}

const httpFetchDefaults = {
  retry: 0,
  $fetch: import.meta.server ? undefined : request,
  transform: unwrapApiBody,
  getCachedData: ssrFriendlyCache,
}

export const _useHttpFetch = createUseFetch(httpFetchDefaults)
export const _useLazyHttpFetch = createUseFetch({
  ...httpFetchDefaults,
  lazy: true,
})