'use client'

import { useCallback, useEffect, useState } from 'react'
import {
  ConsentRecord,
  ConsentStatus,
  ConsentType,
  HistoryAction,
  PAGE_SIZE,
} from '../_types'

interface GlobalStats {
  total: number
  active: number
  revoked: number
}

export function useConsents() {
  const [records, setRecords] = useState<ConsentRecord[]>([])
  const [isLoading, setIsLoading] = useState(true)
  const [currentPage, setCurrentPage] = useState(1)
  const [totalRecords, setTotalRecords] = useState(0)
  const [globalStats, setGlobalStats] = useState<GlobalStats>({ total: 0, active: 0, revoked: 0 })

  const loadConsents = useCallback(async (page: number) => {
    setIsLoading(true)
    try {
      const offset = (page - 1) * PAGE_SIZE
      const listResponse = await fetch(
        `/api/sdk/v1/einwilligungen/consent?limit=${PAGE_SIZE}&offset=${offset}`
      )
      if (listResponse.ok) {
        const listData = await listResponse.json()
        setTotalRecords(listData.total ?? 0)
        if (listData.consents?.length > 0) {
          const mapped: ConsentRecord[] = listData.consents.map((c: {
            id: string
            user_id: string
            data_point_id: string
            granted: boolean
            granted_at: string
            revoked_at?: string
            consent_version?: string
            source?: string
            ip_address?: string
            user_agent?: string
            history?: Array<{
              id: string
              action: string
              created_at: string
              consent_version?: string
              ip_address?: string
              user_agent?: string
              source?: string
            }>
          }) => ({
            id: c.id,
            identifier: c.user_id,
            email: c.user_id,
            consentType: (c.data_point_id as ConsentType) || 'privacy',
            status: (c.revoked_at ? 'withdrawn' : 'granted') as ConsentStatus,
            currentVersion: c.consent_version || '1.0',
            grantedAt: c.granted_at ? new Date(c.granted_at) : null,
            withdrawnAt: c.revoked_at ? new Date(c.revoked_at) : null,
            source: c.source ?? null,
            ipAddress: c.ip_address ?? '',
            userAgent: c.user_agent ?? '',
            history: (c.history ?? []).map(h => ({
              id: h.id,
              action: h.action as HistoryAction,
              timestamp: new Date(h.created_at),
              version: h.consent_version || '1.0',
              ipAddress: h.ip_address ?? '',
              userAgent: h.user_agent ?? '',
              source: h.source ?? '',
            })),
          }))
          setRecords(mapped)
        } else {
          setRecords([])
        }
      }
    } catch {
      // Backend nicht erreichbar, leere Liste anzeigen
    } finally {
      setIsLoading(false)
    }
  }, [])

  const loadStats = useCallback(async () => {
    try {
      const res = await fetch('/api/sdk/v1/einwilligungen/consent?stats=true')
      if (res.ok) {
        const data = await res.json()
        const s = data.statistics
        if (s) {
          setGlobalStats({
            total: s.total_consents ?? 0,
            active: s.active_consents ?? 0,
            revoked: s.revoked_consents ?? 0,
          })
          setTotalRecords(s.total_consents ?? 0)
        }
      }
    } catch {
      // Statistiken nicht erreichbar — lokale Werte behalten
    }
  }, [])

  useEffect(() => {
    loadStats()
  }, [loadStats])

  useEffect(() => { loadConsents(currentPage) }, [currentPage, loadConsents])

  const handleRevoke = useCallback(async (recordId: string) => {
    try {
      const response = await fetch('/api/sdk/v1/einwilligungen/consent', {
        method: 'PUT',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ consentId: recordId, action: 'revoke' }),
      })
      if (response.ok) {
        const now = new Date()
        setRecords(prev => prev.map(r => {
          if (r.id === recordId) {
            return {
              ...r,
              status: 'withdrawn' as ConsentStatus,
              withdrawnAt: now,
              history: [
                ...r.history,
                {
                  id: `h-${recordId}-${r.history.length + 1}`,
                  action: 'withdrawn' as HistoryAction,
                  timestamp: now,
                  version: r.currentVersion,
                  ipAddress: 'Admin-Portal',
                  userAgent: 'Admin Action',
                  source: 'Manueller Widerruf durch Admin',
                  notes: 'Widerruf über Admin-Portal durchgeführt',
                },
              ],
            }
          }
          return r
        }))
        loadStats()
      }
    } catch {
      // Fallback: update local state even if API call fails
      const now = new Date()
      setRecords(prev => prev.map(r => {
        if (r.id === recordId) {
          return { ...r, status: 'withdrawn' as ConsentStatus, withdrawnAt: now }
        }
        return r
      }))
    }
  }, [loadStats])

  return {
    records,
    isLoading,
    currentPage,
    setCurrentPage,
    totalRecords,
    globalStats,
    handleRevoke,
  }
}