"use client";

import { useState, useEffect } from "react";
import { useRouter, useSearchParams } from "next/navigation";
import { Apartment } from "@/src/config/apartments";
import { addDays } from "@/src/lib/date";
import { Calendar, Users } from "lucide-react";

interface BookingFormProps {
  apartment: Apartment;
  locale: string;
  /** Initial value (probed server-side for "tomorrow") — kept up to date
   * client-side via /api/min-stay whenever the guest changes the check-in
   * date, since the effective minimum stay can vary by season/rate. */
  minStayNights: number;
}

export function BookingForm({ apartment, locale, minStayNights: initialMinStayNights }: BookingFormProps) {
  const router = useRouter();
  const searchParams = useSearchParams();
  const [start, setStart] = useState(searchParams.get("checkin") || "");
  const [end, setEnd] = useState(searchParams.get("checkout") || "");
  const [guestName, setGuestName] = useState("");
  const [guestEmail, setGuestEmail] = useState("");
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState("");
  const [attemptedSubmit, setAttemptedSubmit] = useState(false);
  const [minStayNights, setMinStayNights] = useState(initialMinStayNights);
  const [minStayLoading, setMinStayLoading] = useState(false);
  const [price, setPrice] = useState<{
    nights: number;
    basePricePerNight: number;
    totalAfterDiscount: number;
    depositAmount: number;
    discountPercent: number;
    minStayValid: boolean;
    available: boolean;
  } | null>(null);

  const t = (key: string) => {
    const translations: Record<string, Record<string, string>> = {
      de: {
        checkIn: "Anreise",
        checkOut: "Abreise",
        guests: "Gäste",
        name: "Name",
        email: "E-Mail",
        calculate: "Preis berechnen",
        bookNow: "Jetzt anzahlungspflichtig buchen",
        minStay: "Mindestaufenthalt",
        nights: "Nächte",
        discount: "Ersparnis ggü. Kurzzeitpreis (bereits enthalten)",
        total: "Gesamt",
        deposit: "Anzahlung",
        unavailable: "Nicht verfügbar",
        loading: "Wird geladen...",
        needsCalculation: "Bitte zuerst den Preis berechnen.",
        needsNameAndEmail: "Bitte Name und E-Mail-Adresse eingeben, um fortzufahren.",
        needsName: "Bitte Namen eingeben, um fortzufahren.",
        needsEmail: "Bitte E-Mail-Adresse eingeben, um fortzufahren.",
      },
      en: {
        checkIn: "Check-in",
        checkOut: "Check-out",
        guests: "Guests",
        name: "Name",
        email: "Email",
        calculate: "Calculate price",
        bookNow: "Book with deposit",
        minStay: "Minimum stay",
        nights: "nights",
        discount: "Savings vs. short-term rate (already included)",
        total: "Total",
        deposit: "Deposit",
        unavailable: "Not available",
        loading: "Loading...",
        needsCalculation: "Please calculate the price first.",
        needsNameAndEmail: "Please enter your name and email address to continue.",
        needsName: "Please enter your name to continue.",
        needsEmail: "Please enter your email address to continue.",
      },
    };
    return translations[locale]?.[key] || key;
  };

  // Re-fetch the real, effective minimum stay whenever the check-in date
  // changes — Beds24's active rate (which can override the room's base
  // minimum) may require a different length of stay depending on the season.
  useEffect(() => {
    if (!start) return;
    let cancelled = false;
    setMinStayLoading(true);

    fetch(`/api/min-stay?apartmentSlug=${apartment.slug}&arrival=${start}`)
      .then((res) => res.json())
      .then((data) => {
        if (!cancelled && typeof data.minStayNights === "number") {
          setMinStayNights(data.minStayNights);
          setEnd((currentEnd) =>
            currentEnd && currentEnd < addDays(start, data.minStayNights) ? "" : currentEnd
          );
        }
      })
      .catch(() => {
        /* keep previous value on error */
      })
      .finally(() => {
        if (!cancelled) setMinStayLoading(false);
      });

    return () => {
      cancelled = true;
    };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [start, apartment.slug]);

  async function calculatePrice() {
    if (!start || !end) return;
    setLoading(true);
    setError("");

    try {
      const res = await fetch(
        `/api/availability?apartmentSlug=${apartment.slug}&start=${start}&end=${end}`
      );
      const data = await res.json();

      if (!res.ok) {
        throw new Error(data.error || "Failed to calculate price");
      }

      setPrice(data.price);
    } catch (err) {
      setError(err instanceof Error ? err.message : "Unknown error");
      setPrice(null);
    } finally {
      setLoading(false);
    }
  }

  async function handleBooking() {
    if (!price || !guestName || !guestEmail) {
      setAttemptedSubmit(true);
      return;
    }
    setAttemptedSubmit(false);
    setLoading(true);
    setError("");

    try {
      const res = await fetch("/api/checkout-session", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({
          apartmentSlug: apartment.slug,
          start,
          end,
          guestName,
          guestEmail,
        }),
      });

      const data = await res.json();

      if (!res.ok) {
        throw new Error(data.error || "Failed to create checkout session");
      }

      if (data.url) {
        router.push(data.url);
      } else {
        throw new Error("No checkout URL returned");
      }
    } catch (err) {
      setError(err instanceof Error ? err.message : "Unknown error");
    } finally {
      setLoading(false);
    }
  }

  return (
    <div className="bg-white rounded-2xl p-6 border border-brand-grey-soft shadow-sm">
      <h3 className="text-xl font-bold mb-1">
        {locale === "de" ? "Buchungsanfrage" : "Booking request"}
      </h3>
      <p className="text-sm text-brand-grey mb-4">
        {t("minStay")}:{" "}
        <span className="font-semibold text-brand-grey-dark">
          {minStayLoading
            ? locale === "de"
              ? "wird geprüft..."
              : "checking..."
            : `${minStayNights} ${t("nights")}`}
        </span>
      </p>

      <div className="grid grid-cols-2 gap-4 mb-4">
        <div>
          <label className="block text-sm font-medium text-brand-grey-dark mb-1">
            {t("checkIn")}
          </label>
          <div className="relative">
            <Calendar className="absolute left-3 top-3 w-4 h-4 text-brand-grey-light" />
            <input
              type="date"
              lang={locale === "de" ? "de-DE" : "en-US"}
              value={start}
              onChange={(e) => {
                setStart(e.target.value);
                // The checkout date's validity (and the min-stay value shown
                // below) is re-checked by the useEffect above once we know
                // the real minimum stay for this new check-in date.
                setPrice(null);
              }}
              className="w-full pl-9 pr-3 py-2 rounded-lg border border-brand-grey-soft focus:border-brand-green focus:ring-1 focus:ring-brand-green outline-none"
            />
          </div>
          <p className="text-xs text-brand-grey-light mt-1">
            {start
              ? new Intl.DateTimeFormat(locale === "de" ? "de-DE" : "en-US", {
                  dateStyle: "medium",
                }).format(new Date(`${start}T00:00:00`))
              : locale === "de"
              ? "Format: TT.MM.JJJJ"
              : "Format: MM/DD/YYYY"}
          </p>
        </div>
        <div>
          <label className="block text-sm font-medium text-brand-grey-dark mb-1">
            {t("checkOut")}
          </label>
          <div className="relative">
            <Calendar className="absolute left-3 top-3 w-4 h-4 text-brand-grey-light" />
            <input
              type="date"
              lang={locale === "de" ? "de-DE" : "en-US"}
              value={end}
              min={start ? addDays(start, minStayNights) : undefined}
              onChange={(e) => {
                setEnd(e.target.value);
                setPrice(null);
              }}
              className="w-full pl-9 pr-3 py-2 rounded-lg border border-brand-grey-soft focus:border-brand-green focus:ring-1 focus:ring-brand-green outline-none"
            />
          </div>
          <p className="text-xs text-brand-grey-light mt-1">
            {end
              ? new Intl.DateTimeFormat(locale === "de" ? "de-DE" : "en-US", {
                  dateStyle: "medium",
                }).format(new Date(`${end}T00:00:00`))
              : locale === "de"
              ? "Format: TT.MM.JJJJ"
              : "Format: MM/DD/YYYY"}
          </p>
        </div>
      </div>

      <div className="mb-4">
        <label className="block text-sm font-medium text-brand-grey-dark mb-1">
          {t("guests")}
        </label>
        <div className="relative">
          <Users className="absolute left-3 top-3 w-4 h-4 text-brand-grey-light" />
          <input
            type="number"
            min={1}
            max={apartment.maxGuests}
            defaultValue={1}
            className="w-full pl-9 pr-3 py-2 rounded-lg border border-brand-grey-soft focus:border-brand-green focus:ring-1 focus:ring-brand-green outline-none"
          />
        </div>
      </div>

      <div className="mb-4">
        <label className="block text-sm font-medium text-brand-grey-dark mb-1">
          {t("name")}
        </label>
        <input
          type="text"
          value={guestName}
          onChange={(e) => {
            setGuestName(e.target.value);
            if (e.target.value) setAttemptedSubmit(false);
          }}
          className={`w-full px-3 py-2 rounded-lg border focus:ring-1 outline-none ${
            attemptedSubmit && !guestName
              ? "border-red-400 focus:border-red-500 focus:ring-red-400"
              : "border-brand-grey-soft focus:border-brand-green focus:ring-brand-green"
          }`}
        />
      </div>

      <div className="mb-4">
        <label className="block text-sm font-medium text-brand-grey-dark mb-1">
          {t("email")}
        </label>
        <input
          type="email"
          value={guestEmail}
          onChange={(e) => {
            setGuestEmail(e.target.value);
            if (e.target.value) setAttemptedSubmit(false);
          }}
          className={`w-full px-3 py-2 rounded-lg border focus:ring-1 outline-none ${
            attemptedSubmit && !guestEmail
              ? "border-red-400 focus:border-red-500 focus:ring-red-400"
              : "border-brand-grey-soft focus:border-brand-green focus:ring-brand-green"
          }`}
        />
      </div>

      <button
        onClick={calculatePrice}
        disabled={!start || !end || loading}
        className={`w-full mb-4 text-white font-semibold py-3 rounded-full transition-colors disabled:opacity-50 ${
          attemptedSubmit && !price
            ? "bg-red-500 hover:bg-red-600 ring-2 ring-red-300"
            : "bg-brand-grey hover:bg-brand-grey-dark"
        }`}
      >
        {loading ? t("loading") : t("calculate")}
      </button>

      {price && (
        <div className="bg-brand-grey-soft rounded-xl p-4 mb-4">
          <div className="flex justify-between mb-2">
            <span className="text-brand-grey">
              {price.nights} {t("nights")}
            </span>
            <span className="font-medium">
              {new Intl.NumberFormat("de-DE", {
                style: "currency",
                currency: "EUR",
              }).format(price.totalAfterDiscount)}
            </span>
          </div>
          {price.discountPercent > 0 && (
            <div className="flex justify-between mb-2 text-brand-green">
              <span>{t("discount")}</span>
              <span>{price.discountPercent}%</span>
            </div>
          )}
          <div className="flex justify-between text-lg font-bold text-brand-grey-dark">
            <span>{t("deposit")}</span>
            <span>
              {new Intl.NumberFormat("de-DE", {
                style: "currency",
                currency: "EUR",
              }).format(price.depositAmount)}
            </span>
          </div>
        </div>
      )}

      {error && (
        <div className="bg-red-50 text-red-600 rounded-lg p-3 mb-4 text-sm">
          {error}
        </div>
      )}

      <button
        onClick={handleBooking}
        disabled={loading}
        className={`w-full font-semibold py-3 rounded-full transition-colors disabled:opacity-50 ${
          price && guestName && guestEmail
            ? "bg-brand-green text-white hover:bg-brand-green-dark"
            : "bg-brand-grey-soft text-brand-grey-dark hover:bg-brand-grey-soft/70"
        }`}
      >
        {loading ? t("loading") : t("bookNow")}
      </button>

      {!loading && (!price || !guestName || !guestEmail) && (
        <p
          className={`text-lg font-semibold rounded-lg px-4 py-3 mt-3 text-center ${
            attemptedSubmit
              ? "bg-red-50 text-red-600 border-2 border-red-300"
              : "bg-brand-green/10 text-brand-green-dark"
          }`}
        >
          {!price
            ? t("needsCalculation")
            : !guestName && !guestEmail
            ? t("needsNameAndEmail")
            : !guestName
            ? t("needsName")
            : t("needsEmail")}
        </p>
      )}
    </div>
  );
}