import { useState, useMemo } from 'react'
import { useQuery } from '@tanstack/react-query'
import {
  Search,
  Wifi,
  WifiOff,
  HelpCircle,
  Pencil,
  Plus,
  Trash2,
  AlertTriangle,
  ChevronLeft,
  ChevronRight,
  Server,
  Radio,
  ShieldCheck,
} from 'lucide-react'
import { fetchPrinters } from '../services/printerService'
import type { Printer } from '../types/printer'

const PAGE_SIZE = 20

type SortField = 'name' | 'printer_type' | 'manufacturer' | 'model'
type SortDir = 'asc' | 'desc'

type ConnStatus = 'online' | 'offline' | 'unknown'

export default function PrintersPage() {
  const [search, setSearch] = useState('')
  const [statusFilter, setStatusFilter] = useState<ConnStatus | ''>('')
  const [typeFilter, setTypeFilter] = useState('')
  const [sortBy, setSortBy] = useState<SortField>('name')
  const [sortDir, setSortDir] = useState<SortDir>('asc')
  const [page, setPage] = useState(0)
  const [deleteId, setDeleteId] = useState<number | null>(null)

  const {
    data: printers,
    isLoading,
    error,
    refetch,
  } = useQuery({
    queryKey: ['printers'],
    queryFn: fetchPrinters,
  })

  // Derive connection status from backend is_active for now
  // TODO: replace with real status endpoint / SSE when available
  const printersWithStatus = useMemo(() => {
    return (printers ?? []).map((p) => {
      const status: ConnStatus = p.is_active ? 'online' : 'offline'
      return { ...p, connection_status: status }
    })
  }, [printers])

  // Client-side filter + sort
  const filtered = useMemo(() => {
    let list = [...printersWithStatus]

    if (search.trim()) {
      const q = search.toLowerCase()
      list = list.filter(
        (p) =>
          p.name.toLowerCase().includes(q) ||
          (p.manufacturer?.toLowerCase().includes(q) ?? false) ||
          (p.model?.toLowerCase().includes(q) ?? false)
      )
    }

    if (statusFilter) {
      list = list.filter((p) => p.connection_status === statusFilter)
    }

    if (typeFilter) {
      list = list.filter((p) => p.printer_type?.name === typeFilter)
    }

    list.sort((a, b) => {
      const dir = sortDir === 'asc' ? 1 : -1
      switch (sortBy) {
        case 'name':
          return a.name.localeCompare(b.name) * dir
        case 'printer_type':
          return (a.printer_type?.name ?? '').localeCompare(b.printer_type?.name ?? '') * dir
        case 'manufacturer':
          return (a.manufacturer ?? '').localeCompare(b.manufacturer ?? '') * dir
        case 'model':
          return (a.model ?? '').localeCompare(b.model ?? '') * dir
        default:
          return 0
      }
    })

    return list
  }, [printersWithStatus, search, statusFilter, typeFilter, sortBy, sortDir])

  const total = filtered.length
  const totalPages = Math.max(1, Math.ceil(total / PAGE_SIZE))
  const pageItems = filtered.slice(page * PAGE_SIZE, (page + 1) * PAGE_SIZE)

  const uniqueTypes = useMemo(() => {
    const s = new Set<string>()
    ;(printers ?? []).forEach((p) => {
      if (p.printer_type?.name) s.add(p.printer_type.name)
    })
    return Array.from(s).sort()
  }, [printers])

  const handleSort = (field: SortField) => {
    if (sortBy === field) {
      setSortDir((prev) => (prev === 'asc' ? 'desc' : 'asc'))
    } else {
      setSortBy(field)
      setSortDir('asc')
    }
    setPage(0)
  }

  const handleDelete = async (_id: number) => {
    // await deletePrinter(id)
    setDeleteId(null)
    refetch()
  }

  const SortIndicator = ({ field }: { field: SortField }) => {
    if (sortBy !== field) return <span className="text-slate-600 ml-1">↕</span>
    return <span className="text-emerald-400 ml-1">{sortDir === 'asc' ? '↑' : '↓'}</span>
  }

  const StatusBadge = ({ status }: { status: ConnStatus }) => {
    if (status === 'online') {
      return (
        <span className="inline-flex items-center gap-1.5 rounded-full bg-emerald-900/30 border border-emerald-700 px-2.5 py-1 text-xs font-medium text-emerald-300">
          <Wifi size={12} /> Online
        </span>
      )
    }
    if (status === 'offline') {
      return (
        <span className="inline-flex items-center gap-1.5 rounded-full bg-red-900/30 border border-red-700 px-2.5 py-1 text-xs font-medium text-red-300">
          <WifiOff size={12} /> Offline
        </span>
      )
    }
    return (
      <span className="inline-flex items-center gap-1.5 rounded-full bg-slate-700/50 border border-slate-600 px-2.5 py-1 text-xs font-medium text-slate-400">
        <HelpCircle size={12} /> Unknown
      </span>
    )
  }

  return (
    <div className="space-y-4">
      {/* Header */}
      <div className="flex flex-col sm:flex-row sm:items-center sm:justify-between gap-3">
        <div>
          <h2 className="text-xl font-bold text-slate-100">Printers</h2>
          <p className="text-sm text-slate-400">{total} printer(s)</p>
        </div>
        <button className="inline-flex items-center gap-2 rounded-lg bg-emerald-600 px-4 py-2 text-sm font-semibold text-white hover:bg-emerald-500 active:bg-emerald-700 transition-colors">
          <Plus size={16} /> Add Printer
        </button>
      </div>

      {/* Filters */}
      <div className="flex flex-col lg:flex-row gap-3">
        {/* Search */}
        <div className="relative flex-1">
          <Search size={16} className="absolute left-3 top-1/2 -translate-y-1/2 text-slate-400" />
          <input
            type="text"
            placeholder="Search by name, manufacturer, or model…"
            value={search}
            onChange={(e) => {
              setSearch(e.target.value)
              setPage(0)
            }}
            className="w-full rounded-lg bg-slate-800 border border-slate-700 pl-9 pr-3 py-2 text-sm text-slate-100 placeholder-slate-500 focus:outline-none focus:ring-2 focus:ring-emerald-500 focus:border-emerald-500"
          />
        </div>

        {/* Status filter */}
        <select
          value={statusFilter}
          onChange={(e) => {
            setStatusFilter(e.target.value as ConnStatus | '')
            setPage(0)
          }}
          className="rounded-lg bg-slate-800 border border-slate-700 px-3 py-2 text-sm text-slate-100 focus:outline-none focus:ring-2 focus:ring-emerald-500"
        >
          <option value="">All Status</option>
          <option value="online">Online</option>
          <option value="offline">Offline</option>
          <option value="unknown">Unknown</option>
        </select>

        {/* Type filter */}
        <select
          value={typeFilter}
          onChange={(e) => {
            setTypeFilter(e.target.value)
            setPage(0)
          }}
          className="rounded-lg bg-slate-800 border border-slate-700 px-3 py-2 text-sm text-slate-100 focus:outline-none focus:ring-2 focus:ring-emerald-500"
        >
          <option value="">All Types</option>
          {uniqueTypes.map((t) => (
            <option key={t} value={t}>
              {t}
            </option>
          ))}
        </select>
      </div>

      {/* Loading / Error */}
      {isLoading && <div className="text-center py-12 text-slate-400">Loading printers…</div>}
      {error && (
        <div className="text-center py-12 text-red-400">
          Failed to load printers.
          <button onClick={() => refetch()} className="ml-2 underline hover:text-red-300">
            Retry
          </button>
        </div>
      )}

      {/* Desktop Table */}
      {!isLoading && !error && (
        <>
          <div className="hidden md:block overflow-x-auto rounded-lg border border-slate-700">
            <table className="w-full text-sm">
              <thead className="bg-slate-800 text-slate-300">
                <tr>
                  <th
                    className="px-4 py-3 text-left font-semibold cursor-pointer select-none hover:text-slate-100"
                    onClick={() => handleSort('name')}
                  >
                    Name <SortIndicator field="name" />
                  </th>
                  <th
                    className="px-4 py-3 text-left font-semibold cursor-pointer select-none hover:text-slate-100"
                    onClick={() => handleSort('printer_type')}
                  >
                    Type <SortIndicator field="printer_type" />
                  </th>
                  <th
                    className="px-4 py-3 text-left font-semibold cursor-pointer select-none hover:text-slate-100"
                    onClick={() => handleSort('manufacturer')}
                  >
                    Manufacturer <SortIndicator field="manufacturer" />
                  </th>
                  <th
                    className="px-4 py-3 text-left font-semibold cursor-pointer select-none hover:text-slate-100"
                    onClick={() => handleSort('model')}
                  >
                    Model <SortIndicator field="model" />
                  </th>
                  <th className="px-4 py-3 text-left font-semibold">Connection</th>
                  <th className="px-4 py-3 text-left font-semibold">Moonraker</th>
                  <th className="px-4 py-3 text-left font-semibold">MQTT</th>
                  <th className="px-4 py-3 text-right font-semibold">Actions</th>
                </tr>
              </thead>
              <tbody className="divide-y divide-slate-700">
                {pageItems.length === 0 && (
                  <tr>
                    <td colSpan={8} className="px-4 py-8 text-center text-slate-500">
                      No printers found.
                    </td>
                  </tr>
                )}
                {pageItems.map((p: Printer & { connection_status: ConnStatus }) => (
                  <tr key={p.id} className="bg-slate-800/50 hover:bg-slate-700/50 transition-colors">
                    <td className="px-4 py-3 font-medium text-slate-100">{p.name}</td>
                    <td className="px-4 py-3 text-slate-300">
                      <span className="inline-flex items-center gap-1.5 rounded-md bg-slate-700/50 px-2 py-0.5 text-xs">
                        {p.printer_type?.name ?? '—'}
                      </span>
                    </td>
                    <td className="px-4 py-3 text-slate-300">{p.manufacturer ?? '—'}</td>
                    <td className="px-4 py-3 text-slate-300">{p.model ?? '—'}</td>
                    <td className="px-4 py-3">
                      <StatusBadge status={p.connection_status} />
                    </td>
                    <td className="px-4 py-3 text-slate-300">
                      {p.moonraker_url ? (
                        <span className="inline-flex items-center gap-1.5 text-xs text-blue-300">
                          <Server size={12} />
                          <a
                            href={p.moonraker_url}
                            target="_blank"
                            rel="noopener noreferrer"
                            className="hover:underline truncate max-w-[160px] inline-block"
                            title={p.moonraker_url}
                          >
                            {p.moonraker_url}
                          </a>
                        </span>
                      ) : (
                        <span className="text-slate-500 text-xs">—</span>
                      )}
                    </td>
                    <td className="px-4 py-3">
                      {p.mqtt_broker_host ? (
                        <span className="inline-flex items-center gap-1 text-xs text-slate-300">
                          <Radio size={12} className="text-emerald-400" />
                          {p.mqtt_topic_prefix ? `${p.mqtt_topic_prefix} @ ` : ''}
                          {p.mqtt_broker_host}
                          {p.mqtt_tls_enabled && (
                            <span title="TLS enabled">
                              <ShieldCheck size={12} className="text-emerald-400" />
                            </span>
                          )}
                        </span>
                      ) : (
                        <span className="text-slate-500 text-xs">—</span>
                      )}
                    </td>
                    <td className="px-4 py-3 text-right">
                      <div className="flex items-center justify-end gap-2">
                        <button
                          className="p-1.5 rounded hover:bg-slate-600 text-slate-400 hover:text-blue-400 transition-colors"
                          title="Edit"
                        >
                          <Pencil size={14} />
                        </button>
                        <button
                          onClick={() => setDeleteId(p.id)}
                          className="p-1.5 rounded hover:bg-slate-600 text-slate-400 hover:text-red-400 transition-colors"
                          title="Delete"
                        >
                          <Trash2 size={14} />
                        </button>
                      </div>
                    </td>
                  </tr>
                ))}
              </tbody>
            </table>
          </div>

          {/* Mobile Cards */}
          <div className="md:hidden space-y-3">
            {pageItems.length === 0 && (
              <div className="text-center py-12 text-slate-500">No printers found.</div>
            )}
            {pageItems.map((p: Printer & { connection_status: ConnStatus }) => (
              <div
                key={p.id}
                className="rounded-lg border border-slate-700 bg-slate-800 p-4 space-y-3"
              >
                <div className="flex items-start justify-between">
                  <div>
                    <div className="font-semibold text-slate-100">{p.name}</div>
                    <div className="text-xs text-slate-400 mt-0.5">
                      {p.printer_type?.name ?? '—'} · {p.manufacturer ?? '—'} {p.model ?? ''}
                    </div>
                  </div>
                  <StatusBadge status={p.connection_status} />
                </div>

                {/* Moonraker */}
                {p.moonraker_url && (
                  <div className="flex items-center gap-2 text-sm text-slate-300">
                    <Server size={14} className="text-blue-400 shrink-0" />
                    <a
                      href={p.moonraker_url}
                      target="_blank"
                      rel="noopener noreferrer"
                      className="text-blue-300 hover:underline truncate"
                    >
                      {p.moonraker_url}
                    </a>
                  </div>
                )}

                {/* MQTT */}
                {p.mqtt_broker_host && (
                  <div className="flex items-center gap-2 text-sm text-slate-300">
                    <Radio size={14} className="text-emerald-400 shrink-0" />
                    <span className="truncate">
                      {p.mqtt_topic_prefix ? `${p.mqtt_topic_prefix} @ ` : ''}
                      {p.mqtt_broker_host}
                      {p.mqtt_tls_enabled && (
                        <span title="TLS enabled">
                          <ShieldCheck size={14} className="text-emerald-400 inline ml-1" />
                        </span>
                      )}
                    </span>
                  </div>
                )}

                {/* Actions */}
                <div className="flex items-center justify-end gap-2 pt-1">
                  <button className="flex items-center gap-1 rounded-md bg-slate-700 px-3 py-1.5 text-xs font-medium text-slate-200 hover:bg-slate-600">
                    <Pencil size={12} /> Edit
                  </button>
                  <button
                    onClick={() => setDeleteId(p.id)}
                    className="flex items-center gap-1 rounded-md bg-red-900/30 border border-red-700 px-3 py-1.5 text-xs font-medium text-red-300 hover:bg-red-900/50"
                  >
                    <Trash2 size={12} /> Delete
                  </button>
                </div>
              </div>
            ))}
          </div>

          {/* Pagination */}
          <div className="flex items-center justify-between pt-2">
            <span className="text-sm text-slate-400">
              Showing {page * PAGE_SIZE + 1}–{Math.min((page + 1) * PAGE_SIZE, total)} of {total}
            </span>
            <div className="flex items-center gap-2">
              <button
                onClick={() => setPage((p) => Math.max(0, p - 1))}
                disabled={page === 0}
                className="p-2 rounded-lg bg-slate-800 border border-slate-700 text-slate-300 hover:bg-slate-700 disabled:opacity-40 disabled:cursor-not-allowed transition-colors"
              >
                <ChevronLeft size={16} />
              </button>
              <span className="text-sm text-slate-300 tabular-nums">
                {page + 1} / {totalPages}
              </span>
              <button
                onClick={() => setPage((p) => Math.min(totalPages - 1, p + 1))}
                disabled={page >= totalPages - 1}
                className="p-2 rounded-lg bg-slate-800 border border-slate-700 text-slate-300 hover:bg-slate-700 disabled:opacity-40 disabled:cursor-not-allowed transition-colors"
              >
                <ChevronRight size={16} />
              </button>
            </div>
          </div>
        </>
      )}

      {/* Delete confirmation modal */}
      {deleteId !== null && (
        <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/60 backdrop-blur-sm p-4">
          <div className="w-full max-w-sm rounded-xl bg-slate-800 border border-slate-700 p-6 shadow-2xl space-y-4">
            <div className="flex items-center gap-3">
              <div className="flex h-10 w-10 items-center justify-center rounded-full bg-red-900/30">
                <AlertTriangle size={20} className="text-red-400" />
              </div>
              <div>
                <h3 className="text-lg font-semibold text-slate-100">Delete Printer?</h3>
                <p className="text-sm text-slate-400">This action cannot be undone.</p>
              </div>
            </div>
            <div className="flex justify-end gap-3">
              <button
                onClick={() => setDeleteId(null)}
                className="rounded-lg bg-slate-700 px-4 py-2 text-sm font-medium text-slate-200 hover:bg-slate-600 transition-colors"
              >
                Cancel
              </button>
              <button
                onClick={() => handleDelete(deleteId)}
                className="rounded-lg bg-red-600 px-4 py-2 text-sm font-medium text-white hover:bg-red-500 transition-colors"
              >
                Delete
              </button>
            </div>
          </div>
        </div>
      )}
    </div>
  )
}