'use client'

import { useState, useRef, useEffect } from 'react'
import { useTheme } from '@/lib/ThemeContext'
import { useLanguage } from '@/lib/LanguageContext'
import { useActivity } from '@/lib/ActivityContext'
import type { UploadedFile } from '@/components/QRCodeUpload'

import type {
  VocabularyEntry, ExtraColumn, Session, StoredDocument, OcrPrompts,
  TabId, WorksheetType, WorksheetFormat, IpaMode, SyllableMode,
  VocabWorksheetHook,
} from './types'
import {
  getApiBase, DOCUMENTS_KEY, OCR_PROMPTS_KEY, SESSION_ID_KEY,
  defaultOcrPrompts, formatFileSize,
} from './constants'
import { startSessionFlow, resumeSessionFlow } from './useSessionHandlers'
import { processSinglePage, reprocessPagesFlow } from './usePageProcessing'

export function useVocabWorksheet(): VocabWorksheetHook {
  const { isDark } = useTheme()
  const { t } = useLanguage()
  const { startActivity, completeActivity } = useActivity()
  const [mounted, setMounted] = useState(false)

  // Tab state
  const [activeTab, setActiveTab] = useState<TabId>('upload')

  // Session state
  const [session, setSession] = useState<Session | null>(null)
  const [sessionName, setSessionName] = useState('')
  const [isCreatingSession, setIsCreatingSession] = useState(false)
  const [error, setError] = useState<string | null>(null)
  const [extractionStatus, setExtractionStatus] = useState<string>('')

  // Existing sessions
  const [existingSessions, setExistingSessions] = useState<Session[]>([])
  const [isLoadingSessions, setIsLoadingSessions] = useState(true)

  // Documents
  const [storedDocuments, setStoredDocuments] = useState<StoredDocument[]>([])
  const [selectedDocumentId, setSelectedDocumentId] = useState<string | null>(null)

  // Direct file
  const [directFile, setDirectFile] = useState<File | null>(null)
  const [directFilePreview, setDirectFilePreview] = useState<string | null>(null)
  const [showFullPreview, setShowFullPreview] = useState(false)
  const directFileInputRef = useRef<HTMLInputElement>(null)

  // PDF pages
  const [pdfPageCount, setPdfPageCount] = useState<number>(0)
  const [selectedPages, setSelectedPages] = useState<number[]>([])
  const [pagesThumbnails, setPagesThumbnails] = useState<string[]>([])
  const [isLoadingThumbnails, setIsLoadingThumbnails] = useState(false)
  const [excludedPages, setExcludedPages] = useState<number[]>([])

  // Extra columns
  const [pageExtraColumns, setPageExtraColumns] = useState<Record<number, ExtraColumn[]>>({})

  // Upload
  const [uploadedImage, setUploadedImage] = useState<string | null>(null)
  const [isExtracting, setIsExtracting] = useState(false)
  const fileInputRef = useRef<HTMLInputElement>(null)

  // Vocabulary
  const [vocabulary, setVocabulary] = useState<VocabularyEntry[]>([])

  // Worksheet
  const [selectedTypes, setSelectedTypes] = useState<WorksheetType[]>(['en_to_de'])
  const [worksheetTitle, setWorksheetTitle] = useState('')
  const [includeSolutions, setIncludeSolutions] = useState(true)
  const [lineHeight, setLineHeight] = useState('normal')
  const [selectedFormat, setSelectedFormat] = useState<WorksheetFormat>('standard')
  const [ipaMode, setIpaMode] = useState<IpaMode>('none')
  const [syllableMode, setSyllableMode] = useState<SyllableMode>('none')

  // Export
  const [worksheetId, setWorksheetId] = useState<string | null>(null)
  const [isGenerating, setIsGenerating] = useState(false)

  // Processing
  const [processingErrors, setProcessingErrors] = useState<string[]>([])
  const [successfulPages, setSuccessfulPages] = useState<number[]>([])
  const [failedPages, setFailedPages] = useState<number[]>([])
  const [currentlyProcessingPage, setCurrentlyProcessingPage] = useState<number | null>(null)
  const [processingQueue, setProcessingQueue] = useState<number[]>([])

  // OCR Settings
  const [ocrPrompts, setOcrPrompts] = useState<OcrPrompts>(defaultOcrPrompts)
  const [showSettings, setShowSettings] = useState(false)
  const [ocrEnhance, setOcrEnhance] = useState(true)
  const [ocrMaxCols, setOcrMaxCols] = useState(3)
  const [ocrMinConf, setOcrMinConf] = useState(0)

  // QR
  const [showQRModal, setShowQRModal] = useState(false)
  const [uploadSessionId, setUploadSessionId] = useState('')
  const [mobileUploadedFiles, setMobileUploadedFiles] = useState<UploadedFile[]>([])
  const [selectedMobileFile, setSelectedMobileFile] = useState<UploadedFile | null>(null)

  // OCR Comparison
  const [showOcrComparison, setShowOcrComparison] = useState(false)
  const [ocrComparePageIndex, setOcrComparePageIndex] = useState<number | null>(null)
  const [ocrCompareResult, setOcrCompareResult] = useState<any>(null)
  const [isComparingOcr, setIsComparingOcr] = useState(false)
  const [ocrCompareError, setOcrCompareError] = useState<string | null>(null)

  // --- Effects ---
  useEffect(() => {
    setMounted(true)
    let sid = localStorage.getItem(SESSION_ID_KEY)
    if (!sid) { sid = `vocab-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`; localStorage.setItem(SESSION_ID_KEY, sid) }
    setUploadSessionId(sid)
  }, [])

  useEffect(() => {
    if (!mounted) return
    const stored = localStorage.getItem(OCR_PROMPTS_KEY)
    if (stored) { try { setOcrPrompts({ ...defaultOcrPrompts, ...JSON.parse(stored) }) } catch {} }
  }, [mounted])

  useEffect(() => {
    if (!mounted) return
    const stored = localStorage.getItem(DOCUMENTS_KEY)
    if (stored) {
      try { setStoredDocuments(JSON.parse(stored).filter((d: StoredDocument) => d.type?.startsWith('image/') || d.type === 'application/pdf')) } catch {}
    }
  }, [mounted])

  useEffect(() => {
    if (!mounted) return
    ;(async () => {
      try {
        const res = await fetch(`${getApiBase()}/api/v1/vocab/sessions`)
        if (res.ok) setExistingSessions(await res.json())
      } catch {} finally { setIsLoadingSessions(false) }
    })()
  }, [mounted])

  // --- Glassmorphism styles ---
  const glassCard = isDark ? 'backdrop-blur-xl bg-white/10 border border-white/20' : 'backdrop-blur-xl bg-white/70 border border-black/10'
  const glassInput = isDark ? 'bg-white/10 border-white/20 text-white placeholder-white/40 focus:border-purple-400' : 'bg-white/50 border-black/10 text-slate-900 placeholder-slate-400 focus:border-purple-500'

  // --- Handlers ---
  const saveOcrPrompts = (prompts: OcrPrompts) => { setOcrPrompts(prompts); localStorage.setItem(OCR_PROMPTS_KEY, JSON.stringify(prompts)) }

  const handleDirectFileSelect = (e: React.ChangeEvent<HTMLInputElement>) => {
    const file = e.target.files?.[0]; if (!file) return
    setDirectFile(file); setSelectedDocumentId(null); setSelectedMobileFile(null)
    if (file.type.startsWith('image/')) {
      const reader = new FileReader(); reader.onload = (ev) => setDirectFilePreview(ev.target?.result as string); reader.readAsDataURL(file)
    } else if (file.type === 'application/pdf') { setDirectFilePreview(URL.createObjectURL(file)) }
    else { setDirectFilePreview(null) }
  }

  const startSession = async () => {
    if (!sessionName.trim()) { setError('Bitte geben Sie einen Namen fuer die Session ein.'); return }
    if (!selectedDocumentId && !directFile && !selectedMobileFile) { setError('Bitte waehlen Sie ein Dokument aus oder laden Sie eine Datei hoch.'); return }
    setIsCreatingSession(true)
    try {
      await startSessionFlow({
        sessionName, selectedDocumentId, directFile, selectedMobileFile, storedDocuments,
        ocrPrompts, startActivity, setSession, setWorksheetTitle, setExtractionStatus,
        setPdfPageCount, setSelectedPages, setPagesThumbnails, setIsLoadingThumbnails,
        setVocabulary, setActiveTab, setError,
      })
    } catch (error) {
      setError(error instanceof Error ? error.message : 'Ein Fehler ist aufgetreten')
      setExtractionStatus(''); setSession(null)
    } finally { setIsCreatingSession(false) }
  }

  const processSelectedPages = async () => {
    if (!session || selectedPages.length === 0) return
    const pagesToProcess = [...selectedPages].sort((a, b) => a - b)
    setIsExtracting(true); setProcessingErrors([]); setSuccessfulPages([]); setFailedPages([])
    setProcessingQueue(pagesToProcess); setVocabulary([]); setActiveTab('vocabulary')

    const errors: string[] = []; const successful: number[] = []; const failed: number[] = []

    for (let i = 0; i < pagesToProcess.length; i++) {
      const pageIndex = pagesToProcess[i]
      setCurrentlyProcessingPage(pageIndex + 1)
      setExtractionStatus(`Verarbeite Seite ${pageIndex + 1} von ${pagesToProcess.length}... (kann 30-60 Sekunden dauern)`)
      const result = await processSinglePage(session.id, pageIndex, ipaMode, syllableMode, ocrPrompts, ocrEnhance, ocrMaxCols, ocrMinConf)
      if (result.success) {
        successful.push(pageIndex + 1); setSuccessfulPages([...successful]); setVocabulary(prev => [...prev, ...result.vocabulary])
        const qi = result.scanQuality ? ` | Qualitaet: ${result.scanQuality.quality_pct}%${result.scanQuality.is_degraded ? ' (degradiert!)' : ''}` : ''
        setExtractionStatus(`Seite ${pageIndex + 1} fertig: ${result.vocabulary.length} Vokabeln gefunden${qi}`)
      } else {
        failed.push(pageIndex + 1); setFailedPages([...failed])
        if (result.error) { errors.push(result.error); setProcessingErrors([...errors]) }
        setExtractionStatus(`Seite ${pageIndex + 1} fehlgeschlagen`)
      }
      await new Promise(r => setTimeout(r, 500))
    }

    setCurrentlyProcessingPage(null); setProcessingQueue([]); setIsExtracting(false)

    if (successful.length === pagesToProcess.length) setExtractionStatus(`Fertig! Alle ${successful.length} Seiten verarbeitet.`)
    else if (successful.length > 0) setExtractionStatus(`${successful.length} von ${pagesToProcess.length} Seiten verarbeitet. ${failed.length} fehlgeschlagen.`)
    else setExtractionStatus(`Alle Seiten fehlgeschlagen.`)

    // Reload thumbnails for processed pages
    if (successful.length > 0 && session) {
      const API_BASE = getApiBase(); const updatedThumbs = [...pagesThumbnails]
      for (const pageNum of successful) {
        const idx = pageNum - 1
        try {
          const res = await fetch(`${API_BASE}/api/v1/vocab/sessions/${session.id}/pdf-thumbnail/${idx}?hires=true&t=${Date.now()}`)
          if (res.ok) { if (updatedThumbs[idx]) URL.revokeObjectURL(updatedThumbs[idx]); updatedThumbs[idx] = URL.createObjectURL(await res.blob()) }
        } catch {}
      }
      setPagesThumbnails(updatedThumbs)
    }
    setSession(prev => prev ? { ...prev, status: 'extracted' } : null)
  }

  const togglePageSelection = (i: number) => { setSelectedPages(p => p.includes(i) ? p.filter(x => x !== i) : [...p, i].sort((a, b) => a - b)) }
  const selectAllPages = () => setSelectedPages(Array.from({ length: pdfPageCount }, (_, i) => i).filter(p => !excludedPages.includes(p)))
  const selectNoPages = () => setSelectedPages([])
  const excludePage = (i: number, e: React.MouseEvent) => { e.stopPropagation(); setExcludedPages(p => [...p, i]); setSelectedPages(p => p.filter(x => x !== i)) }
  const restoreExcludedPages = () => setExcludedPages([])

  const runOcrComparison = async (pageIndex: number) => {
    if (!session) return
    setOcrComparePageIndex(pageIndex); setShowOcrComparison(true); setIsComparingOcr(true); setOcrCompareError(null); setOcrCompareResult(null)
    try {
      const res = await fetch(`${getApiBase()}/api/v1/vocab/sessions/${session.id}/compare-ocr/${pageIndex}`, { method: 'POST' })
      if (!res.ok) throw new Error(`HTTP ${res.status}`)
      setOcrCompareResult(await res.json())
    } catch (e) { setOcrCompareError(e instanceof Error ? e.message : 'Vergleich fehlgeschlagen') }
    finally { setIsComparingOcr(false) }
  }

  const updateVocabularyEntry = (id: string, field: string, value: string) => {
    setVocabulary(prev => prev.map(v => {
      if (v.id !== id) return v
      if (field === 'english' || field === 'german' || field === 'example_sentence' || field === 'word_type') return { ...v, [field]: value }
      return { ...v, extras: { ...(v.extras || {}), [field]: value } }
    }))
  }

  const addExtraColumn = (sourcePage: number) => {
    const label = prompt('Spaltenname:'); if (!label || !label.trim()) return
    const key = `extra_${Date.now()}`
    setPageExtraColumns(prev => ({ ...prev, [sourcePage]: [...(prev[sourcePage] || []), { key, label: label.trim() }] }))
  }

  const removeExtraColumn = (sourcePage: number, key: string) => {
    setPageExtraColumns(prev => ({ ...prev, [sourcePage]: (prev[sourcePage] || []).filter(c => c.key !== key) }))
    setVocabulary(prev => prev.map(v => { if (!v.extras || !(key in v.extras)) return v; const { [key]: _, ...rest } = v.extras; return { ...v, extras: rest } }))
  }

  const getExtraColumnsForPage = (sourcePage: number): ExtraColumn[] => [...(pageExtraColumns[0] || []), ...(pageExtraColumns[sourcePage] || [])]

  const getAllExtraColumns = (): ExtraColumn[] => {
    const seen = new Set<string>(); const result: ExtraColumn[] = []
    for (const cols of Object.values(pageExtraColumns)) for (const col of cols) { if (!seen.has(col.key)) { seen.add(col.key); result.push(col) } }
    return result
  }

  const deleteVocabularyEntry = (id: string) => setVocabulary(prev => prev.filter(v => v.id !== id))
  const toggleVocabularySelection = (id: string) => setVocabulary(prev => prev.map(v => v.id === id ? { ...v, selected: !v.selected } : v))
  const toggleAllSelection = () => { const all = vocabulary.every(v => v.selected); setVocabulary(prev => prev.map(v => ({ ...v, selected: !all }))) }

  const addVocabularyEntry = (atIndex?: number) => {
    const ne: VocabularyEntry = { id: `new-${Date.now()}`, english: '', german: '', example_sentence: '', selected: true }
    setVocabulary(prev => { if (atIndex === undefined) return [...prev, ne]; const nl = [...prev]; nl.splice(atIndex, 0, ne); return nl })
  }

  const saveVocabulary = async () => {
    if (!session) return
    try { await fetch(`${getApiBase()}/api/v1/vocab/sessions/${session.id}/vocabulary`, { method: 'PUT', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ vocabulary }) }) }
    catch (e) { console.error('Failed to save vocabulary:', e) }
  }

  const generateWorksheet = async () => {
    if (!session) return; if (selectedFormat === 'standard' && selectedTypes.length === 0) return
    setIsGenerating(true)
    try {
      await saveVocabulary()
      const API_BASE = getApiBase()
      const endpoint = selectedFormat === 'nru' ? 'generate-nru' : 'generate'
      const body = selectedFormat === 'nru'
        ? { title: worksheetTitle || session.name, include_solutions: includeSolutions }
        : { worksheet_types: selectedTypes, title: worksheetTitle || session.name, include_solutions: includeSolutions, line_height: lineHeight }
      const res = await fetch(`${API_BASE}/api/v1/vocab/sessions/${session.id}/${endpoint}`, {
        method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify(body),
      })
      if (res.ok) { const data = await res.json(); setWorksheetId(data.worksheet_id || data.id); setActiveTab('export'); completeActivity({ vocabCount: vocabulary.length }) }
    } catch (e) { console.error('Failed to generate worksheet:', e) }
    finally { setIsGenerating(false) }
  }

  const downloadPDF = (type: 'worksheet' | 'solution') => {
    if (!worksheetId) return
    window.open(`${getApiBase()}/api/v1/vocab/worksheets/${worksheetId}/${type === 'worksheet' ? 'pdf' : 'solution'}`, '_blank')
  }

  const toggleWorksheetType = (type: WorksheetType) => setSelectedTypes(prev => prev.includes(type) ? prev.filter(t => t !== type) : [...prev, type])

  const resumeSession = async (existingSession: Session) => {
    setError(null); setExtractionStatus('Session wird geladen...')
    try { await resumeSessionFlow(existingSession, setSession, setWorksheetTitle, setVocabulary, setActiveTab, setExtractionStatus) }
    catch (e) { setError(e instanceof Error ? e.message : 'Fehler beim Laden der Session'); setExtractionStatus('') }
  }

  const resetSession = async () => {
    setSession(null); setSessionName(''); setVocabulary([]); setUploadedImage(null); setWorksheetId(null)
    setSelectedDocumentId(null); setDirectFile(null); setDirectFilePreview(null); setShowFullPreview(false)
    setPdfPageCount(0); setSelectedPages([]); setPagesThumbnails([]); setExcludedPages([])
    setActiveTab('upload'); setError(null); setExtractionStatus('')
    try { const res = await fetch(`${getApiBase()}/api/v1/vocab/sessions`); if (res.ok) setExistingSessions(await res.json()) } catch {}
  }

  const deleteSession = async (sessionId: string, e: React.MouseEvent) => {
    e.stopPropagation()
    if (!confirm('Session wirklich loeschen? Diese Aktion kann nicht rueckgaengig gemacht werden.')) return
    try { const res = await fetch(`${getApiBase()}/api/v1/vocab/sessions/${sessionId}`, { method: 'DELETE' }); if (res.ok) setExistingSessions(prev => prev.filter(s => s.id !== sessionId)) } catch {}
  }

  const reprocessPages = (ipa: IpaMode, syllable: SyllableMode) => {
    if (!session) return
    let pages: number[]
    if (successfulPages.length > 0) pages = successfulPages.map(p => p - 1)
    else if (vocabulary.length > 0) pages = [...new Set(vocabulary.map(v => (v.source_page || 1) - 1))].sort((a, b) => a - b)
    else if (selectedPages.length > 0) pages = [...selectedPages]
    else pages = [0]
    if (pages.length === 0) return

    setIsExtracting(true); setExtractionStatus('Verarbeite mit neuen Einstellungen...')
    ;(async () => {
      const { vocabulary: allVocab, qualityInfo } = await reprocessPagesFlow(
        session.id, pages, ipa, syllable, ocrPrompts, ocrEnhance, ocrMaxCols, ocrMinConf, setExtractionStatus
      )
      setVocabulary(allVocab); setIsExtracting(false)
      setExtractionStatus(`${allVocab.length} Vokabeln mit neuen Einstellungen${qualityInfo}`)
    })()
  }

  return {
    mounted, isDark, glassCard, glassInput,
    activeTab, setActiveTab,
    session, sessionName, setSessionName, isCreatingSession, error, setError, extractionStatus,
    existingSessions, isLoadingSessions,
    storedDocuments, selectedDocumentId, setSelectedDocumentId,
    directFile, setDirectFile, directFilePreview, showFullPreview, setShowFullPreview, directFileInputRef,
    pdfPageCount, selectedPages, pagesThumbnails, isLoadingThumbnails, excludedPages,
    pageExtraColumns,
    uploadedImage, isExtracting,
    vocabulary,
    selectedTypes, worksheetTitle, setWorksheetTitle,
    includeSolutions, setIncludeSolutions, lineHeight, setLineHeight,
    selectedFormat, setSelectedFormat, ipaMode, setIpaMode, syllableMode, setSyllableMode,
    worksheetId, isGenerating,
    processingErrors, successfulPages, failedPages, currentlyProcessingPage,
    ocrPrompts, showSettings, setShowSettings,
    showQRModal, setShowQRModal, uploadSessionId,
    mobileUploadedFiles, selectedMobileFile, setSelectedMobileFile, setMobileUploadedFiles,
    showOcrComparison, setShowOcrComparison,
    ocrComparePageIndex, ocrCompareResult, isComparingOcr, ocrCompareError,
    handleDirectFileSelect, startSession, processSelectedPages,
    togglePageSelection, selectAllPages, selectNoPages, excludePage, restoreExcludedPages,
    runOcrComparison,
    updateVocabularyEntry, addExtraColumn, removeExtraColumn,
    getExtraColumnsForPage, getAllExtraColumns,
    deleteVocabularyEntry, toggleVocabularySelection, toggleAllSelection, addVocabularyEntry,
    saveVocabulary, generateWorksheet, downloadPDF, toggleWorksheetType,
    resumeSession, resetSession, deleteSession,
    saveOcrPrompts, formatFileSize, reprocessPages,
  }
}