import { useState, useCallback, useEffect, useRef } from 'react'
import { useInstanceStore } from '../store/instanceStore'
import { contactApi, type BackendContact } from '../services/chatApiService'

const PAGE_SIZE = 50

export function usePhonebookLogic() {
  const instanceStore = useInstanceStore()

  // ── Data ──────────────────────────────────────────────────────────────────
  const [contacts, setContacts] = useState<BackendContact[]>([])
  const [total, setTotal] = useState(0)
  const [stats, setStats] = useState({ total: 0, blocked: 0, flagged: 0, active: 0 })
  const [loading, setLoading] = useState(false)

  // ── Filters ───────────────────────────────────────────────────────────────
  const [search, setSearch] = useState('')
  const [blockedFilter, setBlockedFilter] = useState<'all' | 'blocked' | 'active'>('all')
  const [offset, setOffset] = useState(0)

  // ── Edit modal ────────────────────────────────────────────────────────────
  const [editingContact, setEditingContact] = useState<BackendContact | null>(null)
  const [editName, setEditName] = useState('')
  const [editSaving, setEditSaving] = useState(false)

  // ── Toast ─────────────────────────────────────────────────────────────────
  const [toast, setToast] = useState<{ message: string; type: 'success' | 'error' } | null>(null)

  const showToast = useCallback((message: string, type: 'success' | 'error') => {
    setToast({ message, type })
    setTimeout(() => setToast(null), 3000)
  }, [])

  // ── Derived ───────────────────────────────────────────────────────────────
  const activeInstanceId = instanceStore.activeInstanceId

  const searchDebounceRef = useRef<ReturnType<typeof setTimeout>>()

  // ── Load contacts ─────────────────────────────────────────────────────────
  const load = useCallback(async (newOffset = 0) => {
    setLoading(true)
    try {
      const params: Parameters<typeof contactApi.list>[0] = {
        instanceId: activeInstanceId ?? undefined,
        limit: PAGE_SIZE,
        offset: newOffset,
      }
      if (search.trim()) params.search = search.trim()
      if (blockedFilter === 'blocked') params.blocked = true
      if (blockedFilter === 'active') params.blocked = false

      const [data, statsData] = await Promise.all([
        contactApi.list(params),
        contactApi.stats(activeInstanceId ?? undefined),
      ])
      setContacts(data.contacts)
      setTotal(data.total)
      setStats(statsData)
      setOffset(newOffset)
    } catch {
      showToast('Erro ao carregar contatos.', 'error')
    } finally {
      setLoading(false)
    }
  }, [activeInstanceId, search, blockedFilter, showToast])

  // Initial load + instance change
  useEffect(() => {
    instanceStore.loadInstances()
  }, [])

  useEffect(() => {
    load(0)
  }, [activeInstanceId, blockedFilter])

  // Debounce search
  useEffect(() => {
    clearTimeout(searchDebounceRef.current)
    searchDebounceRef.current = setTimeout(() => load(0), 350)
    return () => clearTimeout(searchDebounceRef.current)
  }, [search])

  // ── Pagination ────────────────────────────────────────────────────────────
  const goToPage = useCallback((page: number) => {
    load(page * PAGE_SIZE)
  }, [load])

  const currentPage = Math.floor(offset / PAGE_SIZE)
  const totalPages  = Math.ceil(total / PAGE_SIZE)

  // ── Block/unblock ─────────────────────────────────────────────────────────
  const handleToggleBlock = useCallback(async (contact: BackendContact) => {
    try {
      const updated = await contactApi.update(contact.id, { isBlocked: !contact.isBlocked })
      setContacts((prev) => prev.map((c) => c.id === updated.id ? updated : c))
      showToast(updated.isBlocked ? 'Contato bloqueado.' : 'Contato desbloqueado.', 'success')
    } catch {
      showToast('Erro ao alterar bloqueio.', 'error')
    }
  }, [showToast])

  // ── Delete ────────────────────────────────────────────────────────────────
  const handleDelete = useCallback(async (id: string) => {
    try {
      await contactApi.delete(id)
      setContacts((prev) => prev.filter((c) => c.id !== id))
      setTotal((t) => t - 1)
      showToast('Contato removido.', 'success')
    } catch {
      showToast('Erro ao remover contato.', 'error')
    }
  }, [showToast])

  // ── Edit ──────────────────────────────────────────────────────────────────
  const openEdit = useCallback((contact: BackendContact) => {
    setEditingContact(contact)
    setEditName(contact.name ?? '')
  }, [])

  const closeEdit = useCallback(() => {
    setEditingContact(null)
    setEditName('')
  }, [])

  const saveEdit = useCallback(async () => {
    if (!editingContact) return
    setEditSaving(true)
    try {
      const updated = await contactApi.update(editingContact.id, { name: editName.trim() || undefined })
      setContacts((prev) => prev.map((c) => c.id === updated.id ? updated : c))
      showToast('Contato atualizado.', 'success')
      closeEdit()
    } catch {
      showToast('Erro ao salvar contato.', 'error')
    } finally {
      setEditSaving(false)
    }
  }, [editingContact, editName, showToast, closeEdit])

  // ── Display name helper ───────────────────────────────────────────────────
  function displayName(c: BackendContact & { displayName?: string }): string {
    if (c.displayName || c.name || c.verifiedName || c.notify) {
      return c.displayName || c.name || c.verifiedName || c.notify || ''
    }
    if (c.phone) return `+${c.phone}`
    // @lid — identificador interno do WhatsApp: exibe como +número
    if (c.jid.endsWith('@lid')) {
      const id = c.jid.split('@')[0]
      return `+${id}`
    }
    return c.jid.split('@')[0]
  }

  return {
    // instances
    instances: instanceStore.instances,
    activeInstanceId,
    selectInstance: instanceStore.setActiveInstance.bind(instanceStore),

    // data
    contacts,
    total,
    stats,
    loading,

    // filters
    search, setSearch,
    blockedFilter, setBlockedFilter,

    // pagination
    currentPage, totalPages, goToPage,

    // actions
    handleToggleBlock,
    handleDelete,
    refresh: () => load(0),

    // edit modal
    editingContact,
    editName, setEditName,
    editSaving,
    openEdit, closeEdit, saveEdit,

    // feedback
    toast,
    displayName,
  }
}