import { useState, useMemo } from 'react'
import { useQuery } from '@tanstack/react-query'
import { Search, Filter, ChevronLeft, ChevronRight, Loader2 } from 'lucide-react'
import { fetchPrintJobs } from '../services/printJobService'
import type { PrintJob, PrintJobFilter, PrintJobStatus } from '../types/printJob'

const PAGE_SIZE = 20

type SortField = 'name' | 'started_at' | 'duration_seconds' | 'filament_grams_used' | 'cost_usd'
type SortDir = 'asc' | 'desc'

// ── Status helpers ────────────────────────────────────────────────────────────

const STATUS_CONFIG: Record<PrintJobStatus, { label: string; badge: string; icon: string }> = {
  pending:   { label: 'Pending',   badge: 'bg-slate-700 text-slate-300 border-slate-600',       icon: '⏳' },
  printing:  { label: 'Printing',  badge: 'bg-blue-900/40 text-blue-300 border-blue-700',       icon: '🖨️' },
  completed: { label: 'Completed', badge: 'bg-emerald-900/30 text-emerald-300 border-emerald-700', icon: '✅' },
  failed:    { label: 'Failed',    badge: 'bg-red-900/40 text-red-300 border-red-700',          icon: '❌' },
}

function StatusBadge({ status }: { status: PrintJobStatus }) {
  const cfg = STATUS_CONFIG[status] ?? STATUS_CONFIG.pending
  return (
    <span className={`inline-flex items-center gap-1 rounded-full border px-2 py-0.5 text-xs font-medium ${cfg.badge}`}>
      <span className="text-xs">{cfg.icon}</span> {cfg.label}
    </span>
  )
}

// ── Duration formatter ────────────────────────────────────────────────────────

function formatDuration(totalSeconds?: number): string {
  if (totalSeconds == null || totalSeconds <= 0) return '—'
  const h = Math.floor(totalSeconds / 3600)
  const m = Math.floor((totalSeconds % 3600) / 60)
  const s = totalSeconds % 60
  if (h > 0) return `${h}h ${m}m`
  if (m > 0) return `${m}m ${s}s`
  return `${s}s`
}

function formatDateTime(iso: string): string {
  const d = new Date(iso)
  return d.toLocaleString(undefined, {
    month: 'short', day: 'numeric',
    hour: 'numeric', minute: '2-digit',
  })
}

// ── Component ─────────────────────────────────────────────────────────────────

export default function PrintJobsPage() {
  const [search, setSearch] = useState('')
  const [statusFilter, setStatusFilter] = useState<PrintJobStatus | ''>('')
  const [printerFilter, setPrinterFilter] = useState('')
  const [sortBy, setSortBy] = useState<SortField>('started_at')
  const [sortDir, setSortDir] = useState<SortDir>('desc')
  const [page, setPage] = useState(0)

  const filter: PrintJobFilter = useMemo(() => ({
    status: statusFilter || undefined,
    printer: printerFilter || undefined,
    sort_by: sortBy,
    sort_dir: sortDir,
    limit: PAGE_SIZE,
    offset: page * PAGE_SIZE,
  }), [statusFilter, printerFilter, sortBy, sortDir, page])

  const { data, isLoading, error, refetch } = useQuery({
    queryKey: ['printJobs', filter],
    queryFn: () => fetchPrintJobs(filter),
  })

  const total = data?.total ?? 0
  const totalPages = Math.max(1, Math.ceil(total / PAGE_SIZE))

  // Client-side search (name + printer name)
  const filtered = useMemo(() => {
    const jobList = data?.data ?? []
    if (!search.trim()) return jobList
    const q = search.toLowerCase()
    return jobList.filter(
      (j: PrintJob) =>
        j.name.toLowerCase().includes(q) ||
        j.printer_name.toLowerCase().includes(q)
    )
  }, [data?.data, search])

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

  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>
  }

  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">Print Jobs</h2>
          <p className="text-sm text-slate-400">{total} job(s) total</p>
        </div>
      </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 job or printer name…"
            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 PrintJobStatus | ''); 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 Statuses</option>
          <option value="pending">Pending</option>
          <option value="printing">Printing</option>
          <option value="completed">Completed</option>
          <option value="failed">Failed</option>
        </select>

        {/* Printer filter */}
        <input
          type="text"
          placeholder="Filter by printer…"
          value={printerFilter}
          onChange={e => { setPrinterFilter(e.target.value); setPage(0) }}
          className="rounded-lg bg-slate-800 border border-slate-700 px-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 min-w-[160px]"
        />

        {/* Filter indicator */}
        {(statusFilter || printerFilter) && (
          <span className="inline-flex items-center gap-1 rounded-lg bg-emerald-900/30 border border-emerald-700 px-3 py-2 text-xs text-emerald-300">
            <Filter size={14} />
            {[statusFilter && `Status: ${statusFilter}`, printerFilter && `Printer: ${printerFilter}`].filter(Boolean).join(' · ')}
          </span>
        )}
      </div>

      {/* Loading / Error */}
      {isLoading && (
        <div className="flex items-center justify-center py-12 gap-2 text-slate-400">
          <Loader2 size={18} className="animate-spin" /> Loading print jobs…
        </div>
      )}
      {error && (
        <div className="text-center py-12 text-red-400">
          Failed to load print jobs.
          <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')}>
                    Job <SortIndicator field="name" />
                  </th>
                  <th className="px-4 py-3 text-left font-semibold">Printer</th>
                  <th className="px-4 py-3 text-left font-semibold">Status</th>
                  <th className="px-4 py-3 text-left font-semibold cursor-pointer select-none hover:text-slate-100" onClick={() => handleSort('started_at')}>
                    Started <SortIndicator field="started_at" />
                  </th>
                  <th className="px-4 py-3 text-right font-semibold cursor-pointer select-none hover:text-slate-100" onClick={() => handleSort('duration_seconds')}>
                    Duration <SortIndicator field="duration_seconds" />
                  </th>
                  <th className="px-4 py-3 text-right font-semibold cursor-pointer select-none hover:text-slate-100" onClick={() => handleSort('filament_grams_used')}>
                    Filament <SortIndicator field="filament_grams_used" />
                  </th>
                  <th className="px-4 py-3 text-right font-semibold cursor-pointer select-none hover:text-slate-100" onClick={() => handleSort('cost_usd')}>
                    Cost <SortIndicator field="cost_usd" />
                  </th>
                </tr>
              </thead>
              <tbody className="divide-y divide-slate-700">
                {filtered.length === 0 && (
                  <tr>
                    <td colSpan={7} className="px-4 py-8 text-center text-slate-500">No print jobs found.</td>
                  </tr>
                )}
                {filtered.map((job: PrintJob) => (
                  <tr key={job.id} className="bg-slate-800/50 hover:bg-slate-700/50 transition-colors">
                    <td className="px-4 py-3 font-medium text-slate-100">{job.name}</td>
                    <td className="px-4 py-3 text-slate-300">{job.printer_name}</td>
                    <td className="px-4 py-3"><StatusBadge status={job.status} /></td>
                    <td className="px-4 py-3 text-slate-300">{formatDateTime(job.started_at)}</td>
                    <td className="px-4 py-3 text-right tabular-nums text-slate-300">{formatDuration(job.duration_seconds)}</td>
                    <td className="px-4 py-3 text-right tabular-nums text-slate-300">{job.filament_grams_used != null ? `${job.filament_grams_used.toLocaleString()} g` : '—'}</td>
                    <td className="px-4 py-3 text-right tabular-nums text-slate-300">{job.cost_usd != null ? `$${job.cost_usd.toFixed(2)}` : '—'}</td>
                  </tr>
                ))}
              </tbody>
            </table>
          </div>

          {/* Mobile Cards */}
          <div className="md:hidden space-y-3">
            {filtered.length === 0 && (
              <div className="text-center py-12 text-slate-500">No print jobs found.</div>
            )}
            {filtered.map((job: PrintJob) => (
              <div key={job.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">{job.name}</div>
                    <div className="text-xs text-slate-400 mt-0.5">{job.printer_name}</div>
                  </div>
                  <StatusBadge status={job.status} />
                </div>

                <div className="grid grid-cols-2 gap-2 text-sm">
                  <div>
                    <span className="text-slate-500 text-xs">Started</span>
                    <div className="text-slate-300">{formatDateTime(job.started_at)}</div>
                  </div>
                  <div>
                    <span className="text-slate-500 text-xs">Duration</span>
                    <div className="text-slate-300 tabular-nums">{formatDuration(job.duration_seconds)}</div>
                  </div>
                  <div>
                    <span className="text-slate-500 text-xs">Filament</span>
                    <div className="text-slate-300 tabular-nums">{job.filament_grams_used != null ? `${job.filament_grams_used.toLocaleString()} g` : '—'}</div>
                  </div>
                  <div>
                    <span className="text-slate-500 text-xs">Cost</span>
                    <div className="text-slate-300 tabular-nums">{job.cost_usd != null ? `$${job.cost_usd.toFixed(2)}` : '—'}</div>
                  </div>
                </div>
              </div>
            ))}
          </div>

          {/* Pagination */}
          <div className="flex items-center justify-between pt-2">
            <span className="text-sm text-slate-400">
              Showing {total === 0 ? 0 : 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>
        </>
      )}
    </div>
  )
}