import type { NitroFetchOptions, NitroFetchRequest } from 'nitropack'
import { FetchError } from 'ofetch'

/**
 * 封装 HTTP 请求
 * @param url 请求的路径
 * @param options 请求选项
 * @returns 返回请求结果
 *
 * @throws {FetchError} 请求失败时抛出错误
 */
export const http = async <T>(
  url: string,
  options?: NitroFetchOptions<NitroFetchRequest>,
) => {
  const loginState = useLoginState()

  const runtimeConfig = useRuntimeConfig()
  const baseURL = runtimeConfig.public.baseURL as string

  try {
    const data = await $fetch<T>(url, {
      baseURL,
      headers: {
        'Content-Type': 'application/json',
        'Authorization': `Bearer ${loginState.token}`,
      },
      ...options,
    })

    return data
  }
  catch (err: unknown) {
    if (err instanceof FetchError) {
      throw err
    }
    else {
      throw new FetchError('请求失败')
    }
  }
}

export const http_stream = async <ReqT>(
  endpoint: string,
  params: ReqT,
  events: {
    onStart?: (id: string, created_at?: number) => void
    onTextChunk?: (message: string) => void
    onComplete?: (id: string | null, finished_at?: number) => void
  }) => {
  const { onStart, onTextChunk, onComplete } = events

  const loginState = useLoginState()

  const runtimeConfig = useRuntimeConfig()
  const baseURL = runtimeConfig.public.baseURL as string

  const response = await fetch(new URL(endpoint, baseURL), {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'Accept': 'text/event-stream',
      'Authorization': `Bearer ${loginState.token}`,
    },
    body: JSON.stringify(params),
  })

  if (!response) {
    throw new Error('Network response was not ok')
  }

  const reader = response.body?.getReader()
  const decoder = new TextDecoder('utf-8')
  let buffer = ''

  while (true) {
    const { done, value } = await reader?.read() || {}
    if (done) break

    buffer += decoder.decode(value, { stream: true })

    const parts = buffer.split('\n\n')
    buffer = parts.pop()!

    for (const part of parts) {
      if (!part.trim().startsWith('data:')) continue
      const payload = part.replace(/^data:\s*/, '').trim()

      try {
        const obj = JSON.parse(payload)
        if (obj?.event && obj.event === 'workflow_started') {
          onStart?.(obj?.data?.id || null, obj?.data?.created_at || 0)
        }
        if (obj?.event && obj.event === 'workflow_finished') {
          onComplete?.(obj?.data?.id || null, obj?.data?.finished_at || 0)
          return
        }
        if (obj?.event && obj.event === 'text_chunk') {
          let text_chunk = obj.data?.text as string
          if (text_chunk) {
            if (text_chunk.startsWith('<') && text_chunk.endsWith('>')) {
              const endTag = text_chunk.match(/<\/[^>]*>/)
              if (endTag) {
                text_chunk = text_chunk.replace(endTag[0], '\n' + endTag[0])
              }
            }
            onTextChunk?.(text_chunk)
          }
        }
      } catch {
        // ignore
      }
    }
  }
  onComplete?.(null)
}