import { useEffect, useState } from 'react'
import Constants from 'expo-constants'

/**
 * 기능 #11 — Ollama AI 자동 분류 훅 (온프레미스 sLLM, 외부 API 미사용)
 * 제목 입력 시 debounce 후 Ollama /api/generate 호출 →
 * { category, priority } JSON 파싱하여 입력 필드 자동 제안.
 */

const OLLAMA_HOST: string =
  Constants.expoConfig?.extra?.ollamaUrl ?? 'http://localhost:11434'
const OLLAMA_MODEL: string =
  Constants.expoConfig?.extra?.ollamaModel ?? 'llama3'

const CATEGORIES = ['DEPLOY', 'RESTART', 'LOG', 'INQUIRY', 'OTHER']
const PRIORITIES = ['CRITICAL', 'HIGH', 'MEDIUM', 'LOW']

export interface AIClassifyResult {
  category: string
  priority: string
  loading: boolean
  error: boolean
}

function extractJson(text: string): { category?: string; priority?: string } | null {
  try {
    const match = text.match(/\{[\s\S]*\}/)
    if (!match) return null
    return JSON.parse(match[0])
  } catch { return null }
}

export function useAIClassify(title: string): AIClassifyResult {
  const [category, setCategory] = useState('')
  const [priority, setPriority] = useState('')
  const [loading,  setLoading]  = useState(false)
  const [error,    setError]    = useState(false)

  useEffect(() => {
    const trimmed = title.trim()
    if (trimmed.length < 4) {
      setCategory(''); setPriority(''); setLoading(false); setError(false)
      return
    }

    let alive = true
    setLoading(true); setError(false)
    const controller = new AbortController()

    const timer = setTimeout(async () => {
      const prompt =
        `다음 SR 제목의 카테고리와 우선순위를 JSON으로만 답하라. ` +
        `category 는 [${CATEGORIES.join(', ')}] 중 하나, ` +
        `priority 는 [${PRIORITIES.join(', ')}] 중 하나. ` +
        `제목: "${trimmed}"`

      try {
        const res = await fetch(`${OLLAMA_HOST}/api/generate`, {
          method: 'POST',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({ model: OLLAMA_MODEL, prompt, stream: false, format: 'json' }),
          signal: controller.signal,
        })
        const data = await res.json()
        const parsed = extractJson(data?.response ?? '')
        if (!alive) return
        if (parsed) {
          const cat = (parsed.category ?? '').toUpperCase()
          const pri = (parsed.priority ?? '').toUpperCase()
          setCategory(CATEGORIES.includes(cat) ? cat : '')
          setPriority(PRIORITIES.includes(pri) ? pri : '')
        } else {
          setError(true)
        }
      } catch {
        if (alive) setError(true)
      } finally {
        if (alive) setLoading(false)
      }
    }, 700)

    return () => { alive = false; clearTimeout(timer); controller.abort() }
  }, [title])

  return { category, priority, loading, error }
}