"use client";

import { useState, useEffect } from "react";
import { Calendar } from "@/components/ui/calendar";
import { Button } from "@/components/ui/button";
import { Input } from "@/components/ui/input";
import { Label } from "@/components/ui/label";
import { useLanguage } from "@/contexts/LanguageContext";
import { useAuth } from "@/contexts/AuthContext";
import { listServices, formatDuration, ApiService } from "@/lib/api/services";
import { getAvailableSlots, createBooking, TimeSlotApi } from "@/lib/api/bookings";
import { ApiError } from "@/lib/api";
import { Check, Clock, CalendarDays } from "lucide-react";
import { toast } from "sonner";

function toDateStr(d: Date): string {
  return d.toISOString().slice(0, 10);
}

export default function Booking() {
  const { t, locale } = useLanguage();
  const { user } = useAuth();

  const [services, setServices] = useState<ApiService[]>([]);
  const [servicesLoading, setServicesLoading] = useState(true);
  const [selectedService, setSelectedService] = useState<ApiService | null>(null);
  const [selectedDate, setSelectedDate] = useState<Date | undefined>();
  const [slots, setSlots] = useState<TimeSlotApi[]>([]);
  const [slotsLoading, setSlotsLoading] = useState(false);
  const [selectedSlot, setSelectedSlot] = useState<TimeSlotApi | null>(null);
  const [name, setName] = useState(user?.full_name ?? "");
  const [email, setEmail] = useState(user?.email ?? "");
  const [phone, setPhone] = useState(user?.phone ?? "");
  const [submitting, setSubmitting] = useState(false);
  const [confirmed, setConfirmed] = useState(false);

  useEffect(() => {
    listServices()
      .then(setServices)
      .catch((e) => { console.error("[reservation] listServices failed:", e); setServices([]); })
      .finally(() => setServicesLoading(false));
  }, []);

  useEffect(() => {
    if (user) {
      setName(user.full_name ?? "");
      setEmail(user.email ?? "");
      setPhone(user.phone ?? "");
    }
  }, [user]);

  useEffect(() => {
    if (!selectedDate) return;
    setSlotsLoading(true);
    setSelectedSlot(null);
    const dateStr = toDateStr(selectedDate);
    getAvailableSlots(dateStr, dateStr)
      .then(setSlots)
      .catch((e) => { console.error("[reservation] getAvailableSlots failed:", e); setSlots([]); })
      .finally(() => setSlotsLoading(false));
  }, [selectedDate]);

  const step = !selectedService ? 1 : !selectedDate ? 2 : !selectedSlot ? 3 : 4;

  const handleConfirm = async () => {
    if (!selectedSlot || !selectedService) return;
    setSubmitting(true);
    try {
      await createBooking({
        slot_id: selectedSlot.id,
        service_note: selectedService.name,
        ...(user ? {} : { guest_name: name, guest_email: email, guest_phone: phone }),
      });
      setConfirmed(true);
      toast.success(t("booking.success"));
    } catch (err) {
      const msg = err instanceof ApiError ? err.message : t("booking.error");
      toast.error(msg);
    } finally {
      setSubmitting(false);
    }
  };

  if (confirmed) {
    return (
      <div className="min-h-screen flex items-center justify-center py-12 px-4">
        <div className="text-center max-w-md">
          <div className="h-16 w-16 rounded-full bg-primary/10 flex items-center justify-center mx-auto mb-6">
            <Check className="h-8 w-8 text-primary" />
          </div>
          <h2 className="font-serif text-3xl mb-3">{t("booking.confirmed_title")}</h2>
          <p className="text-muted-foreground mb-2">
            {selectedService?.name} — {selectedDate?.toLocaleDateString(locale)} {t("booking.confirmed_at")} {selectedSlot?.start_time.slice(0, 5)}
          </p>
          <p className="text-sm text-muted-foreground">
            {t("booking.confirmed_desc")}
          </p>
        </div>
      </div>
    );
  }

  return (
    <div className="min-h-screen py-8 lg:py-16">
      <div className="container mx-auto px-4 lg:px-8 max-w-4xl">
        <div className="text-center mb-12">
          <CalendarDays className="h-10 w-10 mx-auto mb-4 text-primary" />
          <h1 className="font-serif text-3xl lg:text-5xl mb-3">{t("booking.title")}</h1>
          <p className="text-muted-foreground">{t("booking.subtitle")}</p>
        </div>

        <div className="flex justify-center gap-2 mb-10">
          {[1, 2, 3, 4].map((s) => (
            <div
              key={s}
              className={`h-1.5 w-12 rounded-full transition-colors ${
                s <= step ? "bg-primary" : "bg-muted"
              }`}
            />
          ))}
        </div>

        {/* Step 1: Service */}
        <div className="mb-10">
          <h2 className="font-serif text-xl mb-4">{t("booking.select_service")}</h2>
          {servicesLoading ? (
            <div className="grid grid-cols-1 md:grid-cols-2 gap-3">
              {Array.from({ length: 4 }).map((_, i) => (
                <div key={i} className="h-24 bg-muted animate-pulse rounded-lg" />
              ))}
            </div>
          ) : services.length === 0 ? (
            <p className="text-sm text-muted-foreground">{t("booking.no_services")}</p>
          ) : (
            <div className="grid grid-cols-1 md:grid-cols-2 gap-3">
              {services.map((service) => (
                <button
                  key={service.id}
                  onClick={() => setSelectedService(service)}
                  className={`text-left p-4 rounded-lg border-2 transition-all cursor-pointer ${
                    selectedService?.id === service.id
                      ? "border-primary"
                      : "border-border hover:border-primary/40"
                  }`}
                >
                  <div className="flex justify-between items-start">
                    <div>
                      <h3 className="font-medium text-sm">{service.name}</h3>
                      <p className="text-xs text-muted-foreground mt-1">{service.description}</p>
                      <div className="flex items-center gap-1 mt-2 text-xs text-muted-foreground">
                        <Clock className="h-3 w-3" />
                        {formatDuration(service.duration_minutes)}
                      </div>
                    </div>
                    <span className="text-sm font-semibold">
                      {service.price === 0 ? t("booking.free") : `${service.price} €`}
                    </span>
                  </div>
                  {selectedService?.id === service.id && (
                    <Check className="h-4 w-4 text-primary mt-2" />
                  )}
                </button>
              ))}
            </div>
          )}
        </div>

        {/* Step 2: Date */}
        {selectedService && (
          <div className="mb-10">
            <h2 className="font-serif text-xl mb-4">{t("booking.select_date")}</h2>
            <div className="flex justify-center">
              <Calendar
                mode="single"
                selected={selectedDate}
                onSelect={setSelectedDate}
                disabled={(date) => date < new Date() || date.getDay() === 0}
                className="rounded-lg border border-border p-4"
              />
            </div>
          </div>
        )}

        {/* Step 3: Time slot */}
        {selectedDate && (
          <div className="mb-10">
            <h2 className="font-serif text-xl mb-4">{t("booking.select_time")}</h2>
            {slotsLoading ? (
              <div className="grid grid-cols-4 md:grid-cols-7 gap-2">
                {Array.from({ length: 7 }).map((_, i) => (
                  <div key={i} className="h-10 bg-muted animate-pulse rounded-md" />
                ))}
              </div>
            ) : slots.length === 0 ? (
              <p className="text-sm text-muted-foreground">{t("booking.no_slots")}</p>
            ) : (
              <div className="grid grid-cols-4 md:grid-cols-7 gap-2">
                {slots.map((slot) => (
                  <button
                    key={slot.id}
                    onClick={() => setSelectedSlot(slot)}
                    className={`py-2 px-3 rounded-md text-sm transition-colors cursor-pointer ${
                      selectedSlot?.id === slot.id
                        ? "bg-primary text-primary-foreground"
                        : "bg-muted text-foreground hover:bg-accent"
                    }`}
                  >
                    {slot.start_time.slice(0, 5)}
                  </button>
                ))}
              </div>
            )}
          </div>
        )}

        {/* Step 4: Contact */}
        {selectedSlot && (
          <div className="max-w-md mx-auto space-y-4">
            <h2 className="font-serif text-xl mb-4 text-center">{t("booking.confirm")}</h2>
            {!user && (
              <>
                <div>
                  <Label htmlFor="name">{t("auth.name")}</Label>
                  <Input
                    id="name"
                    value={name}
                    onChange={(e) => setName(e.target.value)}
                    className="mt-1"
                    required
                  />
                </div>
                <div>
                  <Label htmlFor="email">{t("auth.email")}</Label>
                  <Input
                    id="email"
                    type="email"
                    value={email}
                    onChange={(e) => setEmail(e.target.value)}
                    className="mt-1"
                    required
                  />
                </div>
              </>
            )}
            {user && (
              <div className="p-3 bg-muted rounded-lg text-sm">
                <p className="font-medium">{user.full_name}</p>
                <p className="text-muted-foreground">{user.email}</p>
              </div>
            )}
            <div>
              <Label htmlFor="phone">{t("booking.phone")}</Label>
              <Input
                id="phone"
                type="tel"
                value={phone}
                onChange={(e) => setPhone(e.target.value)}
                className="mt-1"
              />
            </div>
            <Button
              className="w-full"
              size="lg"
              onClick={handleConfirm}
              disabled={submitting || (!user && (!name || !email))}
            >
              {submitting ? t("booking.submitting") : t("booking.confirm")}
            </Button>
          </div>
        )}
      </div>
    </div>
  );
}