'use client'

import { useEffect, useState } from 'react'
import {
  listDeliveryEvents,
  confirmDelivery,
  rejectDelivery,
  DeliveryEvent,
} from '@/lib/api/agent'
import { Card, CardContent } from '@/components/ui/Card'
import { Badge } from '@/components/ui/Badge'
import { Button } from '@/components/ui/Button'
import { Skeleton } from '@/components/ui/Skeleton'
import { Input } from '@/components/ui/Input'
import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/Select'
import { PackageCheck, Truck, CheckCircle, XCircle, AlertTriangle } from 'lucide-react'

export default function ReceivingPage() {
  const [events, setEvents] = useState<DeliveryEvent[]>([])
  const [loading, setLoading] = useState(true)
  const [confirmingId, setConfirmingId] = useState<string | null>(null)
  const [receiveQty, setReceiveQty] = useState<Record<string, number>>({})
  const [receiveNotes, setReceiveNotes] = useState<Record<string, string>>({})
  const [processingId, setProcessingId] = useState<string | null>(null)
  const [error, setError] = useState<string | null>(null)
  const [success, setSuccess] = useState<string | null>(null)
  const [filter, setFilter] = useState('dispatched')

  const load = async () => {
    try {
      const res = await listDeliveryEvents({ status: filter, limit: 50 })
      if (res.success) setEvents(res.data.events)
    } finally {
      setLoading(false)
    }
  }

  useEffect(() => {
    setLoading(true)
    load()
    const interval = setInterval(load, 15000)
    return () => clearInterval(interval)
  }, [filter])

  const handleConfirm = async (eventId: string) => {
    const qty = receiveQty[eventId]
    if (!qty || qty <= 0) {
      setError('Enter a valid quantity')
      return
    }
    setProcessingId(eventId)
    setError(null)
    try {
      const res = await confirmDelivery(eventId, {
        received_quantity: qty,
        notes: receiveNotes[eventId] || undefined,
      })
      if (res.success) {
        setSuccess(`Delivery confirmed: ${qty} units received`)
        setConfirmingId(null)
        setReceiveQty(prev => { const n = { ...prev }; delete n[eventId]; return n })
        setReceiveNotes(prev => { const n = { ...prev }; delete n[eventId]; return n })
        await load()
        setTimeout(() => setSuccess(null), 4000)
      } else {
        setError(res.message || 'Failed to confirm delivery')
      }
    } catch {
      setError('Network error')
    } finally {
      setProcessingId(null)
    }
  }

  const handleReject = async (eventId: string) => {
    const reason = receiveNotes[eventId]
    setProcessingId(eventId)
    setError(null)
    try {
      const res = await rejectDelivery(eventId, reason)
      if (res.success) {
        setSuccess('Delivery rejected')
        setConfirmingId(null)
        await load()
        setTimeout(() => setSuccess(null), 4000)
      } else {
        setError(res.message || 'Failed to reject delivery')
      }
    } catch {
      setError('Network error')
    } finally {
      setProcessingId(null)
    }
  }

  if (loading) {
    return (
      <div className="space-y-6">
        <Skeleton className="h-8 w-48" />
        <Skeleton className="h-10 w-full" />
        {Array.from({ length: 3 }).map((_, i) => <Skeleton key={i} className="h-32 rounded-xl" />)}
      </div>
    )
  }

  const filterOptions = [
    { value: 'dispatched', label: 'Dispatched (Ready to Receive)' },
    { value: 'expected', label: 'Expected' },
    { value: 'confirmed', label: 'Already Received' },
    { value: '', label: 'All Events' },
  ]

  return (
    <div className="space-y-6">
      <div>
        <h1 className="text-2xl font-bold text-gray-900 dark:text-white">Receive Stock</h1>
        <p className="text-gray-500 dark:text-gray-400">Confirm physical receipt of goods from suppliers</p>
      </div>

      {/* Status bar */}
      {error && (
        <div className="flex items-center gap-2 rounded-lg bg-red-50 border border-red-200 p-3 text-sm text-red-700 dark:bg-red-900/20 dark:border-red-800 dark:text-red-400">
          <AlertTriangle className="h-4 w-4 flex-shrink-0" />
          {error}
        </div>
      )}
      {success && (
        <div className="flex items-center gap-2 rounded-lg bg-emerald-50 border border-emerald-200 p-3 text-sm text-emerald-700 dark:bg-emerald-900/20 dark:border-emerald-800 dark:text-emerald-400">
          <CheckCircle className="h-4 w-4 flex-shrink-0" />
          {success}
        </div>
      )}

      {/* Filter */}
      <div className="flex items-center gap-3">
        <label className="text-sm font-medium text-gray-500">Filter:</label>
        <Select value={filter} onValueChange={setFilter}>
          <SelectTrigger className="w-64">
            <SelectValue placeholder="Filter events" />
          </SelectTrigger>
          <SelectContent>
            <SelectItem value="dispatched">Dispatched (Ready to Receive)</SelectItem>
            <SelectItem value="expected">Expected</SelectItem>
            <SelectItem value="confirmed">Already Received</SelectItem>
          </SelectContent>
        </Select>
      </div>

      {/* Delivery events list */}
      {events.length === 0 ? (
        <Card>
          <CardContent className="p-12 text-center">
            <PackageCheck className="mx-auto h-12 w-12 text-gray-300 dark:text-gray-600 mb-4" />
            <p className="text-lg font-medium text-gray-500 dark:text-gray-400">No delivery events</p>
            <p className="text-sm text-gray-400 dark:text-gray-500 mt-1">
              {filter === 'dispatched' ? 'No dispatched deliveries pending receipt' : 'No events match the filter'}
            </p>
          </CardContent>
        </Card>
      ) : (
        <div className="space-y-4">
          {events.map(event => (
            <Card key={event.id} className={confirmingId === event.id ? 'border-blue-300 dark:border-blue-700' : ''}>
              <CardContent className="p-5">
                <div className="flex flex-col sm:flex-row sm:items-center sm:justify-between gap-4">
                  <div className="flex-1 min-w-0">
                    <div className="flex items-center gap-3 mb-2">
                      <Truck className="h-5 w-5 text-gray-400" />
                      <span className="font-mono text-sm font-semibold text-gray-900 dark:text-white">
                        {event.id.slice(0, 8)}
                      </span>
                      <Badge variant={
                        event.status === 'dispatched' ? 'info' :
                        event.status === 'confirmed' ? 'success' :
                        'default'
                      }>{event.status}</Badge>
                    </div>
                    <div className="text-sm text-gray-500 dark:text-gray-400 space-y-1">
                      <p>Supplier: {event.supplier_name || event.supplier_id.slice(0, 12)}</p>
                      {event.expected_delivery_at && (
                        <p>Expected: {new Date(event.expected_delivery_at).toLocaleDateString()}</p>
                      )}
                      {event.notes && <p className="italic">Notes: {event.notes}</p>}
                    </div>
                  </div>

                  <div className="flex items-center gap-2 flex-shrink-0">
                    {event.status === 'dispatched' && confirmingId !== event.id && (
                      <>
                        <Button
                          size="sm"
                          onClick={() => {
                            setConfirmingId(event.id)
                            setError(null)
                          }}
                          className="bg-emerald-600 hover:bg-emerald-700 text-white"
                        >
                          <PackageCheck className="h-3.5 w-3.5 mr-1" />
                          Receive
                        </Button>
                        <Button
                          size="sm"
                          variant="outline"
                          onClick={() => {
                            setConfirmingId(event.id)
                            setError(null)
                          }}
                          className="text-red-600 border-red-200 hover:bg-red-50 dark:border-red-800 dark:hover:bg-red-900/20"
                        >
                          <XCircle className="h-3.5 w-3.5 mr-1" />
                          Reject
                        </Button>
                      </>
                    )}

                    {/* Inline receive form */}
                    {confirmingId === event.id && (
                      <div className="flex flex-col sm:flex-row gap-2 p-3 bg-gray-50 dark:bg-gray-800 rounded-lg border border-gray-200 dark:border-gray-700">
                        <Input
                          type="number"
                          min="1"
                          placeholder="Qty"
                          value={receiveQty[event.id] ?? ''}
                          onChange={(e) => setReceiveQty(prev => ({ ...prev, [event.id]: parseInt(e.target.value) || 0 }))}
                          className="w-24"
                        />
                        <Input
                          placeholder="Notes (optional)"
                          value={receiveNotes[event.id] ?? ''}
                          onChange={(e) => setReceiveNotes(prev => ({ ...prev, [event.id]: e.target.value }))}
                          className="w-48"
                        />
                        <div className="flex gap-2">
                          <Button
                            size="sm"
                            onClick={() => handleConfirm(event.id)}
                            disabled={processingId === event.id || !receiveQty[event.id]}
                            className="bg-emerald-600 hover:bg-emerald-700 text-white"
                          >
                            {processingId === event.id ? 'Confirming...' : 'Confirm'}
                          </Button>
                          <Button
                            size="sm"
                            variant="outline"
                            onClick={() => handleReject(event.id)}
                            disabled={processingId === event.id}
                            className="text-red-600"
                          >
                            Reject
                          </Button>
                          <Button
                            size="sm"
                            variant="ghost"
                            onClick={() => { setConfirmingId(null); setError(null) }}
                          >
                            Cancel
                          </Button>
                        </div>
                      </div>
                    )}

                    {event.status !== 'dispatched' && (
                      <span className="text-sm text-gray-400">—</span>
                    )}
                  </div>
                </div>
              </CardContent>
            </Card>
          ))}
        </div>
      )}
    </div>
  )
}