import { useState } from 'react'
import { getServerAddress } from '@junwon/config'
interface UseServerResponse {
  generatePage: (
    pageSpec: string,
    outputFormat: 'html' | 'react'
  ) => AsyncGenerator<string, void, unknown>
  error: Error | null
}

const createServer = () => {
  const serverAddress = getServerAddress()

  let lastRequestTime = 0

  const streamResponse = async function* (
    endpoint: string,
    pageSpec: string,
    outputFormat: 'html' | 'react'
  ): AsyncGenerator<string, void, unknown> {
    try {
      const now = Date.now()
      const timeSinceLastRequest = now - lastRequestTime

      if (timeSinceLastRequest < 1000) {
        throw new Error('Rate Limit Exceeded: Wait 1 second.')
      }

      lastRequestTime = now

      const response = await fetch(`${serverAddress}/${endpoint}`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ page_spec: pageSpec, output_format: outputFormat }),
      })

      if (!response.ok) {
        throw new Error(`HTTP error! status: ${response.status}`)
      }

      const reader = response.body?.getReader()
      if (!reader) throw new Error('No reader available')

      const decoder = new TextDecoder()

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

          const chunk = decoder.decode(value, { stream: true })
          if (chunk) yield chunk
        }
      } finally {
        reader.releaseLock()
      }
    } catch (err) {
      throw err instanceof Error ? err : new Error('Error')
    }
  }

  return {
    generatePage: (pageSpec: string, outputFormat: 'html' | 'react') =>
      streamResponse('generate_page', pageSpec, outputFormat),
    error: null,
  }
}

let server: UseServerResponse | null = null

export function useServer(): UseServerResponse {
  const [serverInstance] = useState(() => {
    if (!server) {
      server = createServer()
    }
    return server
  })

  return serverInstance
}