import { writable } from 'svelte/store'
import { backendService, type StoredDocument } from '../utils/backendService'

// Interface for reference documents stored in backend
export interface ReferenceDocument extends StoredDocument {
  // Inherits: id, name, category, fileType, uploadDate, size
}

// Interface for current RFP (metadata only, not stored in backend)
export interface CurrentRFPDocument {
  id: string
  name: string
  size: number
  uploadDate: string
  pageCount?: number
  quality?: string
  keyTopics?: string[]
  wordCount?: number
  fileType?: string
  // RFP specific metadata
  rfpName?: string
  bidNumber?: string
  // Note: No content field - this is metadata only
}

export interface Question {
  id: string
  text: string
  selected: boolean
  priority: 'high' | 'medium' | 'low'
  source?: string
}

export interface RFPAnswer {
  id: string
  question: string
  previousAnswer?: string
  aiGeneratedAnswer?: string
  finalAnswer?: string
  source?: string
  pageNumber?: number
  isFinalized: boolean
  isFormatted?: boolean
  hasAdditionalInfo?: boolean
  additionalInfo?: string
  citations: string[]
}

export interface RFPData {
  currentRFP: CurrentRFPDocument | null  // Changed from previousRFPs array
  newQuestions: File | null
  questions: string[]
  answers: RFPAnswer[]
  extractedData: any[]
}

export interface AppState {
  currentStep: number
  isLoading: boolean
  error: string | null
}

// App state stores
// LocalStorage keys
const STORAGE_KEYS = {
  CURRENT_STEP: 'rfp_current_step',
  CURRENT_RFP: 'rfp_current_rfp',  // Changed from PREVIOUS_RFPS
  QUESTIONS: 'rfp_questions',
  ANSWERS: 'rfp_answers',
  RFP_DATA: 'rfp_data'
}

// Load data from localStorage
function loadFromStorage<T>(key: string, defaultValue: T): T {
  if (typeof window === 'undefined') return defaultValue
  try {
    const stored = localStorage.getItem(key)
    return stored ? JSON.parse(stored) : defaultValue
  } catch (error) {
    console.warn(`Failed to load ${key} from localStorage:`, error)
    return defaultValue
  }
}

// Save data to localStorage
function saveToStorage<T>(key: string, value: T): void {
  if (typeof window === 'undefined') return
  try {
    localStorage.setItem(key, JSON.stringify(value))
  } catch (error) {
    console.warn(`Failed to save ${key} to localStorage:`, error)
  }
}

export const currentStep = writable<number>(loadFromStorage(STORAGE_KEYS.CURRENT_STEP, 1))
export const isLoading = writable<boolean>(false)
export const error = writable<string | null>(null)

// Store for reference documents (managed by backend)
export const referenceDocuments = writable<ReferenceDocument[]>([])

// Store for current RFP (metadata only, localStorage)
export const currentRfp = writable<CurrentRFPDocument | null>(loadFromStorage(STORAGE_KEYS.CURRENT_RFP, null))

// Other stores with localStorage persistence
export const questions = writable<Question[]>(loadFromStorage(STORAGE_KEYS.QUESTIONS, []))
export const answers = writable<RFPAnswer[]>(loadFromStorage(STORAGE_KEYS.ANSWERS, []))

// Legacy RFP data store (updated structure)
export const rfpData = writable<RFPData>(loadFromStorage(STORAGE_KEYS.RFP_DATA, {
  currentRFP: null,
  newQuestions: null,
  questions: [],
  answers: [],
  extractedData: []
}))

// Subscribe to store changes and save to localStorage
currentStep.subscribe(value => saveToStorage(STORAGE_KEYS.CURRENT_STEP, value))
currentRfp.subscribe(value => saveToStorage(STORAGE_KEYS.CURRENT_RFP, value))
questions.subscribe(value => saveToStorage(STORAGE_KEYS.QUESTIONS, value))
answers.subscribe(value => saveToStorage(STORAGE_KEYS.ANSWERS, value))
rfpData.subscribe(value => saveToStorage(STORAGE_KEYS.RFP_DATA, value))

// Helper functions
export function nextStep() {
  currentStep.update(step => Math.min(step + 1, 5))
}

export function prevStep() {
  currentStep.update(step => Math.max(step - 1, 1))
}

export function resetApp() {
  currentStep.set(1)
  isLoading.set(false)
  error.set(null)
  referenceDocuments.set([])
  currentRfp.set(null)
  questions.set([])
  answers.set([])
  rfpData.set({
    currentRFP: null,
    newQuestions: null,
    questions: [],
    answers: [],
    extractedData: []
  })
  
  // Clear localStorage
  if (typeof window !== 'undefined') {
    Object.values(STORAGE_KEYS).forEach(key => {
      localStorage.removeItem(key)
    })
  }
}

// Function to clear current RFP (keeping reference documents in backend)
export function clearCurrentRfp() {
  currentRfp.set(null)
  if (typeof window !== 'undefined') {
    localStorage.removeItem(STORAGE_KEYS.CURRENT_RFP)
  }
}

// Backend service functions
export async function loadReferenceDocuments() {
  try {
    isLoading.set(true)
    error.set(null)
    
    // Check backend health first
    const isHealthy = await backendService.healthCheck()
    if (!isHealthy) {
      throw new Error('Backend server is not responding')
    }
    
    const documents = await backendService.getPreviousRFPs()
    referenceDocuments.set(documents)
    
    console.log(`✅ Loaded ${documents.length} reference documents from backend`)
  } catch (err) {
    const errorMessage = err instanceof Error ? err.message : 'Failed to load reference documents'
    error.set(errorMessage)
    console.warn('❌ Failed to load reference documents:', errorMessage)
    
    // Set empty array if backend fails
    referenceDocuments.set([])
  } finally {
    isLoading.set(false)
  }
}

export async function uploadReferenceDocument(file: File, category: string) {
  try {
    isLoading.set(true)
    const document = await backendService.uploadPreviousRFP(file, category)
    
    // Add to current list
    referenceDocuments.update(docs => [...docs, document])
    
    return document
  } catch (err) {
    error.set(err instanceof Error ? err.message : 'Failed to upload document')
    throw err
  } finally {
    isLoading.set(false)
  }
}

export async function deleteReferenceDocument(id: string) {
  try {
    isLoading.set(true)
    await backendService.deleteDocument(id)
    
    // Remove from current list
    referenceDocuments.update(docs => docs.filter(doc => doc.id !== id))
  } catch (err) {
    error.set(err instanceof Error ? err.message : 'Failed to delete document')
    throw err
  } finally {
    isLoading.set(false)
  }
}

export async function getDocumentContent(id: string) {
  try {
    return await backendService.getDocumentContent(id)
  } catch (err) {
    error.set(err instanceof Error ? err.message : 'Failed to get document content')
    throw err
  }
}