/**
 * RAG (Retrieval-Augmented Generation) composable
 */

import { computed, type ComputedRef, type Ref, ref, reactive } from 'vue'
import { useComplianceStore } from '../plugin'
import type {
  SearchResponse,
  AssistantResponse,
  ChatMessage,
  LegalDocument,
} from '@breakpilot/compliance-sdk-types'

export interface UseRAGReturn {
  // Search
  search: (query: string, regulationCodes?: string[]) => Promise<SearchResponse>
  searchResults: Ref<SearchResponse | null>

  // Chat
  ask: (question: string, context?: string) => Promise<AssistantResponse>
  chatHistory: Ref<ChatMessage[]>
  clearChat: () => void
  isTyping: Ref<boolean>

  // Documents
  documents: ComputedRef<LegalDocument[]>
  availableRegulations: ComputedRef<string[]>

  // Loading state
  isLoading: Ref<boolean>
  error: Ref<Error | null>
}

export function useRAG(): UseRAGReturn {
  const store = useComplianceStore()
  const { state, rag } = store

  const isLoading = ref(false)
  const isTyping = ref(false)
  const error = ref<Error | null>(null)
  const searchResults = ref<SearchResponse | null>(null)
  const chatHistory = ref<ChatMessage[]>([])

  // Search
  const search = async (query: string, regulationCodes?: string[]): Promise<SearchResponse> => {
    isLoading.value = true
    error.value = null

    try {
      const results = await rag.search(query, regulationCodes)
      searchResults.value = results
      return results
    } catch (err) {
      error.value = err instanceof Error ? err : new Error(String(err))
      throw err
    } finally {
      isLoading.value = false
    }
  }

  // Chat
  const ask = async (question: string, context?: string): Promise<AssistantResponse> => {
    isLoading.value = true
    isTyping.value = true
    error.value = null

    // Add user message to history
    chatHistory.value.push({
      id: `msg_${Date.now()}`,
      role: 'user',
      content: question,
      timestamp: new Date().toISOString(),
    })

    try {
      const response = await rag.ask(question, context)

      // Add assistant response to history
      chatHistory.value.push({
        id: `msg_${Date.now()}`,
        role: 'assistant',
        content: response.answer,
        timestamp: new Date().toISOString(),
        citations: response.citations,
      })

      return response
    } catch (err) {
      error.value = err instanceof Error ? err : new Error(String(err))

      // Add error message to history
      chatHistory.value.push({
        id: `msg_${Date.now()}`,
        role: 'assistant',
        content: 'Es ist ein Fehler aufgetreten. Bitte versuchen Sie es erneut.',
        timestamp: new Date().toISOString(),
      })

      throw err
    } finally {
      isLoading.value = false
      isTyping.value = false
    }
  }

  const clearChat = (): void => {
    chatHistory.value = []
    rag.clearHistory()
  }

  // Documents
  const documents = computed(() => state.legalDocuments)

  const availableRegulations = computed(() => {
    const codes = new Set<string>()
    state.legalDocuments.forEach(doc => {
      if (doc.regulationCode) {
        codes.add(doc.regulationCode)
      }
    })
    return Array.from(codes).sort()
  })

  return {
    search,
    searchResults,
    ask,
    chatHistory,
    clearChat,
    isTyping,
    documents,
    availableRegulations,
    isLoading,
    error,
  }
}