'use client'

import { useState, useEffect, useCallback } from 'react'
import { API_PROXY, DSFA_API_PROXY } from '../rag-data'
import type {
  TabId,
  RegulationCategory,
  CollectionStatus,
  SearchResult,
  DsfaSource,
  DsfaCorpusStatus,
  CustomDocument,
  PipelineState,
  PipelineCheckpoint,
} from '../types'

export function useRAGPage() {
  const [activeTab, setActiveTab] = useState<TabId>('overview')
  const [collectionStatus, setCollectionStatus] = useState<CollectionStatus | null>(null)
  const [loading, setLoading] = useState(true)
  const [searchQuery, setSearchQuery] = useState('')
  const [searchResults, setSearchResults] = useState<SearchResult[]>([])
  const [searching, setSearching] = useState(false)
  const [selectedRegulations, setSelectedRegulations] = useState<string[]>([])
  const [ingestionRunning, setIngestionRunning] = useState(false)
  const [ingestionLog, setIngestionLog] = useState<string[]>([])
  const [pipelineState, setPipelineState] = useState<PipelineState | null>(null)
  const [pipelineLoading, setPipelineLoading] = useState(false)
  const [pipelineStarting, setPipelineStarting] = useState(false)
  const [expandedRegulation, setExpandedRegulation] = useState<string | null>(null)
  const [autoRefresh, setAutoRefresh] = useState(true)
  const [elapsedTime, setElapsedTime] = useState<string>('')
  const [expandedDocTypes, setExpandedDocTypes] = useState<string[]>(['eu_regulation', 'eu_directive'])
  const [expandedMatrixDoc, setExpandedMatrixDoc] = useState<string | null>(null)

  // DSFA corpus state
  const [dsfaSources, setDsfaSources] = useState<DsfaSource[]>([])
  const [dsfaStatus, setDsfaStatus] = useState<DsfaCorpusStatus | null>(null)
  const [dsfaLoading, setDsfaLoading] = useState(false)
  const [regulationCategory, setRegulationCategory] = useState<RegulationCategory>('regulations')
  const [expandedDsfaSource, setExpandedDsfaSource] = useState<string | null>(null)

  // Data tab state
  const [customDocuments, setCustomDocuments] = useState<CustomDocument[]>([])
  const [uploadFile, setUploadFile] = useState<File | null>(null)
  const [uploadTitle, setUploadTitle] = useState('')
  const [uploadCode, setUploadCode] = useState('')
  const [uploading, setUploading] = useState(false)
  const [linkUrl, setLinkUrl] = useState('')
  const [linkTitle, setLinkTitle] = useState('')
  const [linkCode, setLinkCode] = useState('')
  const [addingLink, setAddingLink] = useState(false)

  const fetchStatus = useCallback(async () => {
    setLoading(true)
    try {
      const res = await fetch(`${API_PROXY}?action=status`)
      if (res.ok) {
        const data = await res.json()
        setCollectionStatus(data)
      }
    } catch (error) {
      console.error('Failed to fetch status:', error)
    } finally {
      setLoading(false)
    }
  }, [])

  const fetchPipeline = useCallback(async () => {
    setPipelineLoading(true)
    try {
      const res = await fetch(`${API_PROXY}?action=pipeline-checkpoints`)
      if (res.ok) {
        const data = await res.json()
        setPipelineState(data)
      }
    } catch (error) {
      console.error('Failed to fetch pipeline:', error)
    } finally {
      setPipelineLoading(false)
    }
  }, [])

  const fetchDsfaStatus = useCallback(async () => {
    setDsfaLoading(true)
    try {
      const [statusRes, sourcesRes] = await Promise.all([
        fetch(`${DSFA_API_PROXY}?action=status`),
        fetch(`${DSFA_API_PROXY}?action=sources`),
      ])
      if (statusRes.ok) {
        const data = await statusRes.json()
        setDsfaStatus(data)
      }
      if (sourcesRes.ok) {
        const data = await sourcesRes.json()
        setDsfaSources(data.sources || data || [])
      }
    } catch (error) {
      console.error('Failed to fetch DSFA status:', error)
    } finally {
      setDsfaLoading(false)
    }
  }, [])

  const fetchCustomDocuments = useCallback(async () => {
    try {
      const res = await fetch(`${API_PROXY}?action=custom-documents`)
      if (res.ok) {
        const data = await res.json()
        setCustomDocuments(data.documents || [])
      }
    } catch (error) {
      console.error('Failed to fetch custom documents:', error)
    }
  }, [])

  const handleUpload = async () => {
    if (!uploadFile || !uploadTitle || !uploadCode) return

    setUploading(true)
    try {
      const formData = new FormData()
      formData.append('file', uploadFile)
      formData.append('title', uploadTitle)
      formData.append('code', uploadCode)
      formData.append('document_type', 'custom')

      const res = await fetch(`${API_PROXY}?action=upload`, {
        method: 'POST',
        body: formData,
      })

      if (res.ok) {
        setUploadFile(null)
        setUploadTitle('')
        setUploadCode('')
        fetchCustomDocuments()
        fetchStatus()
      }
    } catch (error) {
      console.error('Upload failed:', error)
    } finally {
      setUploading(false)
    }
  }

  const handleAddLink = async () => {
    if (!linkUrl || !linkTitle || !linkCode) return

    setAddingLink(true)
    try {
      const res = await fetch(`${API_PROXY}?action=add-link`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
          url: linkUrl,
          title: linkTitle,
          code: linkCode,
          document_type: 'custom',
        }),
      })

      if (res.ok) {
        setLinkUrl('')
        setLinkTitle('')
        setLinkCode('')
        fetchCustomDocuments()
      }
    } catch (error) {
      console.error('Add link failed:', error)
    } finally {
      setAddingLink(false)
    }
  }

  const handleDeleteDocument = async (docId: string) => {
    try {
      const res = await fetch(`${API_PROXY}?action=delete-document&docId=${docId}`, {
        method: 'DELETE',
      })
      if (res.ok) {
        fetchCustomDocuments()
        fetchStatus()
      }
    } catch (error) {
      console.error('Delete failed:', error)
    }
  }

  const handleStartPipeline = async (skipIngestion: boolean = false) => {
    setPipelineStarting(true)
    try {
      const res = await fetch(`${API_PROXY}?action=start-pipeline`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
          force_reindex: false,
          skip_ingestion: skipIngestion,
        }),
      })

      if (res.ok) {
        setTimeout(() => {
          fetchPipeline()
          setPipelineStarting(false)
        }, 2000)
      } else {
        setPipelineStarting(false)
      }
    } catch (error) {
      console.error('Failed to start pipeline:', error)
      setPipelineStarting(false)
    }
  }

  const handleSearch = async () => {
    if (!searchQuery.trim()) return

    setSearching(true)
    try {
      const params = new URLSearchParams({
        action: 'search',
        query: searchQuery,
        top_k: '5',
      })
      if (selectedRegulations.length > 0) {
        params.append('regulations', selectedRegulations.join(','))
      }

      const res = await fetch(`${API_PROXY}?${params}`)
      if (res.ok) {
        const data = await res.json()
        setSearchResults(data.results || [])
      }
    } catch (error) {
      console.error('Search failed:', error)
    } finally {
      setSearching(false)
    }
  }

  const triggerIngestion = async () => {
    setIngestionRunning(true)
    setIngestionLog(['Starte Re-Ingestion aller 19 Regulierungen...'])

    try {
      const res = await fetch(`${API_PROXY}?action=ingest`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ force: true }),
      })

      if (res.ok) {
        const data = await res.json()
        setIngestionLog((prev) => [...prev, 'Ingestion gestartet. Job-ID: ' + (data.job_id || 'N/A')])
        const checkStatus = setInterval(async () => {
          try {
            const statusRes = await fetch(`${API_PROXY}?action=ingestion-status`)
            if (statusRes.ok) {
              const statusData = await statusRes.json()
              if (statusData.completed) {
                clearInterval(checkStatus)
                setIngestionRunning(false)
                setIngestionLog((prev) => [...prev, 'Ingestion abgeschlossen!'])
                fetchStatus()
              } else if (statusData.current_regulation) {
                setIngestionLog((prev) => [
                  ...prev,
                  `Verarbeite: ${statusData.current_regulation} (${statusData.processed}/${statusData.total})`,
                ])
              }
            }
          } catch {
            // Ignore polling errors
          }
        }, 5000)
      } else {
        setIngestionLog((prev) => [...prev, 'Fehler: ' + res.statusText])
        setIngestionRunning(false)
      }
    } catch (error) {
      setIngestionLog((prev) => [...prev, 'Fehler: ' + String(error)])
      setIngestionRunning(false)
    }
  }

  const getRegulationChunks = (code: string): number => {
    return collectionStatus?.regulations?.[code] || 0
  }

  const getTotalChunks = (): number => {
    return collectionStatus?.totalPoints || 0
  }

  // Initial data fetch
  useEffect(() => {
    fetchStatus()
    fetchDsfaStatus()
  }, [fetchStatus, fetchDsfaStatus])

  // Fetch pipeline when tab changes
  useEffect(() => {
    if (activeTab === 'pipeline') {
      fetchPipeline()
    }
  }, [activeTab, fetchPipeline])

  // Fetch custom documents when data tab is active
  useEffect(() => {
    if (activeTab === 'data') {
      fetchCustomDocuments()
    }
  }, [activeTab, fetchCustomDocuments])

  // Auto-refresh pipeline status when running
  useEffect(() => {
    if (activeTab !== 'pipeline' || !autoRefresh) return

    const isRunning = pipelineState?.status === 'running'

    if (isRunning) {
      const interval = setInterval(() => {
        fetchPipeline()
        fetchStatus()
      }, 5000)

      return () => clearInterval(interval)
    }
  }, [activeTab, autoRefresh, pipelineState?.status, fetchPipeline, fetchStatus])

  // Update elapsed time
  useEffect(() => {
    if (!pipelineState?.started_at || pipelineState?.status !== 'running') {
      setElapsedTime('')
      return
    }

    const updateElapsed = () => {
      const start = new Date(pipelineState.started_at!).getTime()
      const now = Date.now()
      const diff = Math.floor((now - start) / 1000)

      const hours = Math.floor(diff / 3600)
      const minutes = Math.floor((diff % 3600) / 60)
      const seconds = diff % 60

      if (hours > 0) {
        setElapsedTime(`${hours}h ${minutes}m ${seconds}s`)
      } else if (minutes > 0) {
        setElapsedTime(`${minutes}m ${seconds}s`)
      } else {
        setElapsedTime(`${seconds}s`)
      }
    }

    updateElapsed()
    const interval = setInterval(updateElapsed, 1000)
    return () => clearInterval(interval)
  }, [pipelineState?.started_at, pipelineState?.status])

  return {
    // Tab state
    activeTab,
    setActiveTab,

    // Collection status
    collectionStatus,
    loading,
    fetchStatus,

    // Search
    searchQuery,
    setSearchQuery,
    searchResults,
    searching,
    selectedRegulations,
    setSelectedRegulations,
    handleSearch,

    // Ingestion
    ingestionRunning,
    ingestionLog,
    triggerIngestion,

    // Pipeline
    pipelineState,
    pipelineLoading,
    pipelineStarting,
    autoRefresh,
    setAutoRefresh,
    elapsedTime,
    fetchPipeline,
    handleStartPipeline,

    // Regulation expansion
    expandedRegulation,
    setExpandedRegulation,
    expandedDocTypes,
    setExpandedDocTypes,
    expandedMatrixDoc,
    setExpandedMatrixDoc,

    // DSFA
    dsfaSources,
    dsfaStatus,
    dsfaLoading,
    regulationCategory,
    setRegulationCategory,
    expandedDsfaSource,
    setExpandedDsfaSource,
    fetchDsfaStatus,

    // Data tab
    customDocuments,
    uploadFile,
    setUploadFile,
    uploadTitle,
    setUploadTitle,
    uploadCode,
    setUploadCode,
    uploading,
    handleUpload,
    linkUrl,
    setLinkUrl,
    linkTitle,
    setLinkTitle,
    linkCode,
    setLinkCode,
    addingLink,
    handleAddLink,
    handleDeleteDocument,
    fetchCustomDocuments,

    // Helpers
    getRegulationChunks,
    getTotalChunks,
  }
}

export type UseRAGPageReturn = ReturnType<typeof useRAGPage>