'use client'

import { createContext, useContext, useState, useEffect, useRef, useCallback } from 'react'
import { useSession } from 'next-auth/react'
import { getLocalStorageAiConsent, setLocalStorageAiConsent, removeLocalStorageAiConsent } from '@/lib/consent/ai-consent-client'
import { updateAISettings } from '@/app/actions/ai-settings'
import { AiConsentModal } from './ai-consent-modal'
import { toast } from 'sonner'
import { useLanguage } from '@/lib/i18n'

interface AiConsentContextType {
  hasAiConsent: boolean
  requestAiConsent: () => Promise<boolean>
  revokeConsent: () => Promise<void>
}

const AiConsentContext = createContext<AiConsentContextType | undefined>(undefined)

interface AiConsentProviderProps {
  children: React.ReactNode
  initialPersistentConsent?: boolean
}

export function AiConsentProvider({ children, initialPersistentConsent = false }: AiConsentProviderProps) {
  const { data: session, update: updateSession } = useSession()
  const { t } = useLanguage()

  const [persistentConsent, setPersistentConsent] = useState(false)
  const [sessionConsent, setSessionConsent] = useState(false)
  const [modalOpen, setModalOpen] = useState(false)
  const [hydrated, setHydrated] = useState(false)

  const pendingResolveRef = useRef<((value: boolean) => void) | null>(null)

  useEffect(() => {
    const local = getLocalStorageAiConsent()
    if (local || initialPersistentConsent) {
      setPersistentConsent(true)
      if (initialPersistentConsent && !local) {
        setLocalStorageAiConsent(true)
      }
    }
    setHydrated(true)
  }, [initialPersistentConsent])

  useEffect(() => {
    if (session?.aiSessionConsent === true) {
      setSessionConsent(true)
    } else if (session?.aiSessionConsent === false) {
      setSessionConsent(false)
    }
  }, [session?.aiSessionConsent])

  const hasAiConsent =
    hydrated &&
    (persistentConsent || sessionConsent || session?.aiSessionConsent === true)

  const requestAiConsent = useCallback((): Promise<boolean> => {
    if (hasAiConsent) {
      return Promise.resolve(true)
    }

    setModalOpen(true)
    return new Promise<boolean>((resolve) => {
      pendingResolveRef.current = resolve
    })
  }, [hasAiConsent])

  const handleConfirm = async (remember: boolean) => {
    setModalOpen(false)

    const grantConsentLocally = async () => {
      if (remember) {
        setLocalStorageAiConsent(true)
        setPersistentConsent(true)
        await updateAISettings({ aiProcessingConsent: true })
      } else {
        await updateSession({ aiSessionConsent: true })
        setSessionConsent(true)
      }
    }

    try {
      const res = await fetch('/api/user/ai-consent', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ consent: true, remember }),
      })

      if (res.ok) {
        const data = await res.json().catch(() => ({}))
        if (data?.auditLogged === false) {
          console.warn('[AiConsentProvider] Consent saved without audit trail')
        }

        if (remember) {
          setLocalStorageAiConsent(true)
          setPersistentConsent(true)
          try {
            await updateAISettings({ aiProcessingConsent: true })
          } catch (e) {
            console.error('[AiConsentProvider] Failed to sync consent to DB:', e)
          }
        } else {
          await updateSession({ aiSessionConsent: true })
          setSessionConsent(true)
        }
      } else {
        try {
          await grantConsentLocally()
        } catch (fallbackError) {
          console.error('[AiConsentProvider] Consent fallback failed:', fallbackError)
          toast.error(t('consent.ai.auditFailed') || 'Impossible d’enregistrer votre consentement. Réessayez.')
          pendingResolveRef.current?.(false)
          pendingResolveRef.current = null
          return
        }
      }

      pendingResolveRef.current?.(true)
      pendingResolveRef.current = null
    } catch (e) {
      console.error('[AiConsentProvider] Failed to log consent audit:', e)
      try {
        await grantConsentLocally()
        pendingResolveRef.current?.(true)
      } catch (fallbackError) {
        console.error('[AiConsentProvider] Consent fallback failed:', fallbackError)
        toast.error(t('consent.ai.auditFailed') || 'Impossible d’enregistrer votre consentement. Réessayez.')
        pendingResolveRef.current?.(false)
      }
      pendingResolveRef.current = null
    }
  }

  const handleClose = () => {
    setModalOpen(false)
    toast.warning(t('consent.ai.aborted') || 'Traitement IA annulé (consentement refusé).')

    pendingResolveRef.current?.(false)
    pendingResolveRef.current = null
  }

  const revokeConsent = async () => {
    removeLocalStorageAiConsent()
    setPersistentConsent(false)
    setSessionConsent(false)

    try {
      await fetch('/api/user/ai-consent', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ consent: false, remember: true }),
      })
    } catch (e) {
      console.error('[AiConsentProvider] Failed to log revocation:', e)
    }

    try {
      await updateSession({ aiSessionConsent: false })
    } catch (e) {
      console.error('[AiConsentProvider] Failed to clear session consent:', e)
    }

    if (session?.user) {
      try {
        await updateAISettings({ aiProcessingConsent: false })
      } catch (e) {
        console.error('[AiConsentProvider] Failed to sync revocation to DB:', e)
      }
    }

    toast.success(t('consent.ai.revokedToast') || 'Consentement IA révoqué avec succès.')
  }

  return (
    <AiConsentContext.Provider
      value={{
        hasAiConsent,
        requestAiConsent,
        revokeConsent,
      }}
    >
      {children}
      <AiConsentModal
        open={modalOpen}
        onClose={handleClose}
        onConfirm={handleConfirm}
      />
    </AiConsentContext.Provider>
  )
}

export function useAiConsent() {
  const context = useContext(AiConsentContext)
  if (context === undefined) {
    throw new Error('useAiConsent must be used within an AiConsentProvider')
  }
  return context
}