/**
 * Edit Booking Page (before payment)
 *
 * Lets the owner adjust cargo details (volume, weight, pallets, notes) and manage
 * documents of a booking that is still awaiting payment (PENDING_PAYMENT), then
 * continue to the payment page. Carrier, route and price derive from the selected
 * rate and are shown read-only.
 */

'use client';

import { useState, useEffect, useRef } from 'react';
import { useRouter, useParams } from 'next/navigation';
import {
  ArrowLeft,
  Loader2,
  AlertTriangle,
  Save,
  CreditCard,
  FileText,
  Trash2,
  Upload,
  Package,
} from 'lucide-react';
import { getCsvBooking, updateCsvBookingDetails } from '@/lib/api/bookings';
import { upload, del } from '@/lib/api/client';

interface BookingDoc {
  id?: string;
  type: string;
  fileName: string;
  url: string;
}

interface BookingData {
  id: string;
  bookingNumber?: string;
  carrierName: string;
  origin: string;
  destination: string;
  volumeCBM: number;
  weightKG: number;
  palletCount: number;
  containerType: string;
  status: string;
  notes?: string;
  documents: BookingDoc[];
}

export default function EditBookingPage() {
  const router = useRouter();
  const params = useParams();
  const bookingId = params.id as string;

  const [booking, setBooking] = useState<BookingData | null>(null);
  const [loading, setLoading] = useState(true);
  const [saving, setSaving] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [success, setSuccess] = useState<string | null>(null);

  const [volumeCBM, setVolumeCBM] = useState('');
  const [weightKG, setWeightKG] = useState('');
  const [palletCount, setPalletCount] = useState('');
  const [notes, setNotes] = useState('');

  const [uploadingDocs, setUploadingDocs] = useState(false);
  const [deletingDocId, setDeletingDocId] = useState<string | null>(null);
  const fileInputRef = useRef<HTMLInputElement>(null);

  const applyBooking = (data: BookingData) => {
    setBooking(data);
    setVolumeCBM(String(data.volumeCBM ?? ''));
    setWeightKG(String(data.weightKG ?? ''));
    setPalletCount(String(data.palletCount ?? ''));
    setNotes(data.notes ?? '');
  };

  const loadBooking = async () => {
    try {
      const data = (await getCsvBooking(bookingId)) as any as BookingData;
      if (data.status !== 'PENDING_PAYMENT') {
        // Only bookings awaiting payment can be edited.
        router.replace('/dashboard/bookings');
        return;
      }
      applyBooking(data);
    } catch (err) {
      setError('Impossible de charger la réservation');
    } finally {
      setLoading(false);
    }
  };

  useEffect(() => {
    if (bookingId) loadBooking();
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [bookingId]);

  const persistDetails = async (): Promise<boolean> => {
    setError(null);
    const vol = parseFloat(volumeCBM);
    const wgt = parseFloat(weightKG);
    const plt = parseInt(palletCount, 10);

    if (!Number.isFinite(vol) || vol <= 0) {
      setError('Le volume doit être un nombre positif.');
      return false;
    }
    if (!Number.isFinite(wgt) || wgt <= 0) {
      setError('Le poids doit être un nombre positif.');
      return false;
    }
    if (!Number.isFinite(plt) || plt < 0) {
      setError('Le nombre de palettes est invalide.');
      return false;
    }

    const updated = (await updateCsvBookingDetails(bookingId, {
      volumeCBM: vol,
      weightKG: wgt,
      palletCount: plt,
      notes: notes.trim() || undefined,
    })) as any as BookingData;
    applyBooking(updated);
    return true;
  };

  const handleSave = async () => {
    setSaving(true);
    setSuccess(null);
    try {
      const ok = await persistDetails();
      if (ok) setSuccess('Modifications enregistrées.');
    } catch (err) {
      setError(err instanceof Error ? err.message : "Erreur lors de l'enregistrement");
    } finally {
      setSaving(false);
    }
  };

  const handleContinueToPayment = async () => {
    setSaving(true);
    setSuccess(null);
    try {
      const ok = await persistDetails();
      if (ok) router.push(`/dashboard/booking/${bookingId}/pay`);
    } catch (err) {
      setError(err instanceof Error ? err.message : "Erreur lors de l'enregistrement");
    } finally {
      setSaving(false);
    }
  };

  const handleAddDocuments = async (files: FileList | null) => {
    if (!files || files.length === 0) return;
    setUploadingDocs(true);
    setError(null);
    try {
      const formData = new FormData();
      Array.from(files).forEach(file => formData.append('documents', file));
      await upload(`/api/v1/csv-bookings/${bookingId}/documents`, formData);
      await loadBooking();
    } catch (err) {
      setError(err instanceof Error ? err.message : "Erreur lors de l'ajout des documents");
    } finally {
      setUploadingDocs(false);
      if (fileInputRef.current) fileInputRef.current.value = '';
    }
  };

  const handleDeleteDocument = async (docId?: string) => {
    if (!docId) return;
    if (!confirm('Supprimer ce document ?')) return;
    setDeletingDocId(docId);
    setError(null);
    try {
      await del(`/api/v1/csv-bookings/${bookingId}/documents/${docId}`);
      await loadBooking();
    } catch (err) {
      setError(err instanceof Error ? err.message : 'Erreur lors de la suppression du document');
    } finally {
      setDeletingDocId(null);
    }
  };

  if (loading) {
    return (
      <div className="min-h-screen flex items-center justify-center bg-gradient-to-br from-slate-50 to-blue-50">
        <div className="flex items-center space-x-3">
          <Loader2 className="h-6 w-6 animate-spin text-blue-600" />
          <span className="text-gray-600">Chargement...</span>
        </div>
      </div>
    );
  }

  if (!booking) {
    return (
      <div className="min-h-screen flex items-center justify-center bg-gradient-to-br from-slate-50 to-blue-50">
        <div className="bg-white rounded-xl shadow-md p-8 max-w-md">
          <AlertTriangle className="h-12 w-12 text-red-500 mx-auto mb-4" />
          <p className="text-center text-gray-700">{error || 'Réservation introuvable'}</p>
          <button
            onClick={() => router.push('/dashboard/bookings')}
            className="mt-4 w-full px-4 py-2 bg-blue-600 text-white rounded-lg hover:bg-blue-700"
          >
            Retour aux réservations
          </button>
        </div>
      </div>
    );
  }

  return (
    <div className="min-h-screen bg-gradient-to-br from-slate-50 to-blue-50 py-10 px-4">
      <div className="max-w-4xl mx-auto">
        <button
          onClick={() => router.back()}
          className="mb-6 flex items-center text-blue-600 hover:text-blue-800 font-medium"
        >
          <ArrowLeft className="h-4 w-4 mr-2" />
          Retour
        </button>

        <h1 className="text-2xl font-bold text-gray-900 mb-1">Modifier la réservation</h1>
        <p className="text-gray-500 mb-8">
          Corrigez les informations de votre réservation avant de procéder au paiement.
        </p>

        {error && (
          <div className="mb-6 bg-red-50 border border-red-200 rounded-lg p-4 flex items-start space-x-3">
            <AlertTriangle className="h-5 w-5 text-red-500 flex-shrink-0 mt-0.5" />
            <p className="text-red-700 text-sm">{error}</p>
          </div>
        )}
        {success && (
          <div className="mb-6 bg-green-50 border border-green-200 rounded-lg p-4">
            <p className="text-green-700 text-sm">{success}</p>
          </div>
        )}

        {/* Read-only rate summary */}
        <div className="bg-white rounded-xl border border-gray-200 p-5 mb-6">
          <h2 className="text-sm font-semibold text-gray-500 uppercase tracking-wide mb-3">
            Réservation
          </h2>
          <div className="grid grid-cols-2 md:grid-cols-4 gap-4 text-sm">
            <div>
              <p className="text-gray-500">Transporteur</p>
              <p className="font-semibold text-gray-900">{booking.carrierName}</p>
            </div>
            <div>
              <p className="text-gray-500">Trajet</p>
              <p className="font-semibold text-gray-900">
                {booking.origin} → {booking.destination}
              </p>
            </div>
            <div>
              <p className="text-gray-500">Type</p>
              <p className="font-semibold text-gray-900">{booking.containerType}</p>
            </div>
            {booking.bookingNumber && (
              <div>
                <p className="text-gray-500">Numéro</p>
                <p className="font-semibold text-gray-900">{booking.bookingNumber}</p>
              </div>
            )}
          </div>
          <p className="text-xs text-gray-400 mt-3">
            Le transporteur, le trajet et le prix proviennent du tarif sélectionné et ne sont pas
            modifiables ici.
          </p>
        </div>

        {/* Editable cargo details */}
        <div className="bg-white rounded-xl border border-gray-200 p-5 mb-6 space-y-4">
          <h2 className="text-sm font-semibold text-gray-500 uppercase tracking-wide flex items-center gap-2">
            <Package className="h-4 w-4" />
            Caractéristiques de la marchandise
          </h2>
          <div className="grid grid-cols-1 md:grid-cols-3 gap-4">
            <div>
              <label className="block text-sm font-medium text-gray-700 mb-1">Volume (CBM)</label>
              <input
                type="number"
                min="0"
                step="0.01"
                value={volumeCBM}
                onChange={e => setVolumeCBM(e.target.value)}
                className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:outline-none focus:ring-2 focus:ring-blue-500"
              />
            </div>
            <div>
              <label className="block text-sm font-medium text-gray-700 mb-1">Poids (kg)</label>
              <input
                type="number"
                min="0"
                step="0.01"
                value={weightKG}
                onChange={e => setWeightKG(e.target.value)}
                className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:outline-none focus:ring-2 focus:ring-blue-500"
              />
            </div>
            <div>
              <label className="block text-sm font-medium text-gray-700 mb-1">Palettes</label>
              <input
                type="number"
                min="0"
                step="1"
                value={palletCount}
                onChange={e => setPalletCount(e.target.value)}
                className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:outline-none focus:ring-2 focus:ring-blue-500"
              />
            </div>
          </div>
          <div>
            <label className="block text-sm font-medium text-gray-700 mb-1">Notes</label>
            <textarea
              rows={3}
              value={notes}
              onChange={e => setNotes(e.target.value)}
              placeholder="Instructions particulières..."
              className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:outline-none focus:ring-2 focus:ring-blue-500 resize-none"
            />
          </div>
        </div>

        {/* Documents */}
        <div className="bg-white rounded-xl border border-gray-200 p-5 mb-6">
          <div className="flex items-center justify-between mb-3">
            <h2 className="text-sm font-semibold text-gray-500 uppercase tracking-wide flex items-center gap-2">
              <FileText className="h-4 w-4" />
              Documents
            </h2>
            <button
              type="button"
              onClick={() => fileInputRef.current?.click()}
              disabled={uploadingDocs}
              className="inline-flex items-center gap-2 px-3 py-1.5 text-sm font-medium text-blue-700 bg-blue-50 hover:bg-blue-100 rounded-lg transition-colors disabled:opacity-50"
            >
              {uploadingDocs ? (
                <Loader2 className="h-4 w-4 animate-spin" />
              ) : (
                <Upload className="h-4 w-4" />
              )}
              Ajouter
            </button>
            <input
              ref={fileInputRef}
              type="file"
              multiple
              className="hidden"
              onChange={e => handleAddDocuments(e.target.files)}
            />
          </div>
          {booking.documents.length === 0 ? (
            <p className="text-sm text-gray-400">Aucun document.</p>
          ) : (
            <ul className="divide-y divide-gray-100">
              {booking.documents.map((doc, idx) => (
                <li
                  key={doc.id || `${doc.fileName}-${idx}`}
                  className="flex items-center justify-between py-2.5"
                >
                  <div className="flex items-center gap-3 min-w-0">
                    <FileText className="h-4 w-4 text-gray-400 flex-shrink-0" />
                    <span className="text-sm text-gray-800 truncate">{doc.fileName}</span>
                  </div>
                  {doc.id && (
                    <button
                      type="button"
                      onClick={() => handleDeleteDocument(doc.id)}
                      disabled={deletingDocId === doc.id}
                      className="p-1.5 text-gray-400 hover:text-red-600 transition-colors disabled:opacity-50"
                      title="Supprimer"
                    >
                      {deletingDocId === doc.id ? (
                        <Loader2 className="h-4 w-4 animate-spin" />
                      ) : (
                        <Trash2 className="h-4 w-4" />
                      )}
                    </button>
                  )}
                </li>
              ))}
            </ul>
          )}
        </div>

        {/* Actions */}
        <div className="flex flex-col sm:flex-row gap-3">
          <button
            onClick={handleSave}
            disabled={saving}
            className="flex-1 py-3 bg-white border border-gray-300 text-gray-800 rounded-lg font-semibold hover:bg-gray-50 disabled:opacity-50 flex items-center justify-center gap-2 transition-colors"
          >
            {saving ? <Loader2 className="h-5 w-5 animate-spin" /> : <Save className="h-5 w-5" />}
            Enregistrer les modifications
          </button>
          <button
            onClick={handleContinueToPayment}
            disabled={saving}
            className="flex-1 py-3 bg-blue-600 text-white rounded-lg font-semibold hover:bg-blue-700 disabled:opacity-50 flex items-center justify-center gap-2 transition-colors"
          >
            {saving ? (
              <Loader2 className="h-5 w-5 animate-spin" />
            ) : (
              <CreditCard className="h-5 w-5" />
            )}
            Continuer vers le paiement
          </button>
        </div>
      </div>
    </div>
  );
}