"use client";

import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import { api } from "@/lib/api";
import type { Appointment, Case } from "@/lib/types";
import { format, parseISO } from "date-fns";
import { X } from "lucide-react";
import { toast } from "sonner";
import { useEffect, useState } from "react";

const APPOINTMENT_TYPES = [
  { value: "hearing", label: "Verhandlung" },
  { value: "meeting", label: "Besprechung" },
  { value: "consultation", label: "Beratung" },
  { value: "deadline_hearing", label: "Fristanhorung" },
  { value: "other", label: "Sonstiges" },
];

interface AppointmentModalProps {
  open: boolean;
  onClose: () => void;
  appointment?: Appointment | null;
}

function toLocalDatetime(iso: string): string {
  const d = parseISO(iso);
  return format(d, "yyyy-MM-dd'T'HH:mm");
}

export function AppointmentModal({ open, onClose, appointment }: AppointmentModalProps) {
  const queryClient = useQueryClient();
  const isEdit = !!appointment;

  const [title, setTitle] = useState("");
  const [description, setDescription] = useState("");
  const [startAt, setStartAt] = useState("");
  const [endAt, setEndAt] = useState("");
  const [location, setLocation] = useState("");
  const [appointmentType, setAppointmentType] = useState("");
  const [caseId, setCaseId] = useState("");

  const { data: cases } = useQuery({
    queryKey: ["cases"],
    queryFn: () => api.get<{ cases: Case[]; total: number }>("/cases"),
  });

  useEffect(() => {
    if (appointment) {
      setTitle(appointment.title);
      setDescription(appointment.description ?? "");
      setStartAt(toLocalDatetime(appointment.start_at));
      setEndAt(appointment.end_at ? toLocalDatetime(appointment.end_at) : "");
      setLocation(appointment.location ?? "");
      setAppointmentType(appointment.appointment_type ?? "");
      setCaseId(appointment.case_id ?? "");
    } else {
      setTitle("");
      setDescription("");
      setStartAt("");
      setEndAt("");
      setLocation("");
      setAppointmentType("");
      setCaseId("");
    }
  }, [appointment]);

  const createMutation = useMutation({
    mutationFn: (body: Record<string, unknown>) =>
      api.post<Appointment>("/appointments", body),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ["appointments"] });
      queryClient.invalidateQueries({ queryKey: ["dashboard"] });
      toast.success("Termin erstellt");
      onClose();
    },
    onError: () => toast.error("Fehler beim Erstellen des Termins"),
  });

  const updateMutation = useMutation({
    mutationFn: (body: Record<string, unknown>) =>
      api.put<Appointment>(`/appointments/${appointment!.id}`, body),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ["appointments"] });
      queryClient.invalidateQueries({ queryKey: ["dashboard"] });
      toast.success("Termin aktualisiert");
      onClose();
    },
    onError: () => toast.error("Fehler beim Aktualisieren des Termins"),
  });

  const deleteMutation = useMutation({
    mutationFn: () => api.delete(`/appointments/${appointment!.id}`),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ["appointments"] });
      queryClient.invalidateQueries({ queryKey: ["dashboard"] });
      toast.success("Termin geloscht");
      onClose();
    },
    onError: () => toast.error("Fehler beim Loschen des Termins"),
  });

  function handleSubmit(e: React.FormEvent) {
    e.preventDefault();
    if (!title.trim() || !startAt) return;

    const body: Record<string, unknown> = {
      title: title.trim(),
      start_at: new Date(startAt).toISOString(),
    };
    if (description.trim()) body.description = description.trim();
    if (endAt) body.end_at = new Date(endAt).toISOString();
    if (location.trim()) body.location = location.trim();
    if (appointmentType) body.appointment_type = appointmentType;
    if (caseId) body.case_id = caseId;

    if (isEdit) {
      updateMutation.mutate(body);
    } else {
      createMutation.mutate(body);
    }
  }

  const isPending = createMutation.isPending || updateMutation.isPending;

  if (!open) return null;

  return (
    <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/30">
      <div className="w-full max-w-lg rounded-lg border border-neutral-200 bg-white shadow-lg">
        <div className="flex items-center justify-between border-b border-neutral-200 px-5 py-3">
          <h2 className="text-sm font-semibold text-neutral-900">
            {isEdit ? "Termin bearbeiten" : "Neuer Termin"}
          </h2>
          <button
            onClick={onClose}
            className="rounded-md p-1 text-neutral-400 hover:bg-neutral-100 hover:text-neutral-600"
          >
            <X className="h-4 w-4" />
          </button>
        </div>

        <form onSubmit={handleSubmit} className="space-y-4 p-5">
          <div>
            <label className="mb-1 block text-xs font-medium text-neutral-600">
              Titel *
            </label>
            <input
              type="text"
              value={title}
              onChange={(e) => setTitle(e.target.value)}
              required
              className="w-full rounded-md border border-neutral-200 px-3 py-1.5 text-sm outline-none focus:border-neutral-400 focus:ring-1 focus:ring-neutral-400"
              placeholder="z.B. Mundliche Verhandlung"
            />
          </div>

          <div className="grid grid-cols-2 gap-3">
            <div>
              <label className="mb-1 block text-xs font-medium text-neutral-600">
                Beginn *
              </label>
              <input
                type="datetime-local"
                value={startAt}
                onChange={(e) => setStartAt(e.target.value)}
                required
                className="w-full rounded-md border border-neutral-200 px-3 py-1.5 text-sm outline-none focus:border-neutral-400 focus:ring-1 focus:ring-neutral-400"
              />
            </div>
            <div>
              <label className="mb-1 block text-xs font-medium text-neutral-600">
                Ende
              </label>
              <input
                type="datetime-local"
                value={endAt}
                onChange={(e) => setEndAt(e.target.value)}
                className="w-full rounded-md border border-neutral-200 px-3 py-1.5 text-sm outline-none focus:border-neutral-400 focus:ring-1 focus:ring-neutral-400"
              />
            </div>
          </div>

          <div className="grid grid-cols-2 gap-3">
            <div>
              <label className="mb-1 block text-xs font-medium text-neutral-600">
                Typ
              </label>
              <select
                value={appointmentType}
                onChange={(e) => setAppointmentType(e.target.value)}
                className="w-full rounded-md border border-neutral-200 px-3 py-1.5 text-sm outline-none focus:border-neutral-400"
              >
                <option value="">Kein Typ</option>
                {APPOINTMENT_TYPES.map((t) => (
                  <option key={t.value} value={t.value}>
                    {t.label}
                  </option>
                ))}
              </select>
            </div>
            <div>
              <label className="mb-1 block text-xs font-medium text-neutral-600">
                Akte
              </label>
              <select
                value={caseId}
                onChange={(e) => setCaseId(e.target.value)}
                className="w-full rounded-md border border-neutral-200 px-3 py-1.5 text-sm outline-none focus:border-neutral-400"
              >
                <option value="">Keine Akte</option>
                {cases?.cases?.map((c) => (
                  <option key={c.id} value={c.id}>
                    {c.case_number} — {c.title}
                  </option>
                ))}
              </select>
            </div>
          </div>

          <div>
            <label className="mb-1 block text-xs font-medium text-neutral-600">
              Ort
            </label>
            <input
              type="text"
              value={location}
              onChange={(e) => setLocation(e.target.value)}
              className="w-full rounded-md border border-neutral-200 px-3 py-1.5 text-sm outline-none focus:border-neutral-400 focus:ring-1 focus:ring-neutral-400"
              placeholder="z.B. UPC Munchen, Saal 3"
            />
          </div>

          <div>
            <label className="mb-1 block text-xs font-medium text-neutral-600">
              Beschreibung
            </label>
            <textarea
              value={description}
              onChange={(e) => setDescription(e.target.value)}
              rows={3}
              className="w-full rounded-md border border-neutral-200 px-3 py-1.5 text-sm outline-none focus:border-neutral-400 focus:ring-1 focus:ring-neutral-400"
              placeholder="Optionale Notizen zum Termin"
            />
          </div>

          <div className="flex items-center justify-between pt-2">
            <div>
              {isEdit && (
                <button
                  type="button"
                  onClick={() => deleteMutation.mutate()}
                  disabled={deleteMutation.isPending}
                  className="rounded-md px-3 py-1.5 text-sm text-red-600 hover:bg-red-50"
                >
                  Loschen
                </button>
              )}
            </div>
            <div className="flex items-center gap-2">
              <button
                type="button"
                onClick={onClose}
                className="rounded-md border border-neutral-200 bg-white px-3 py-1.5 text-sm text-neutral-700 hover:bg-neutral-50"
              >
                Abbrechen
              </button>
              <button
                type="submit"
                disabled={isPending || !title.trim() || !startAt}
                className="rounded-md bg-neutral-900 px-3 py-1.5 text-sm font-medium text-white hover:bg-neutral-800 disabled:opacity-50"
              >
                {isPending ? "Speichern..." : isEdit ? "Aktualisieren" : "Erstellen"}
              </button>
            </div>
          </div>
        </form>
      </div>
    </div>
  );
}