"use client";

import { useState, useTransition } from "react";
import Link from "next/link";
import { useRouter } from "next/navigation";
import { submitCheckout } from "@/lib/api/checkout";
import { Button } from "@/components/ui/button";
import type { Address, Cart, DeliveryType, PaymentMethod } from "@/types/api";

const PAYMENT_LABELS_FA: Record<PaymentMethod, string> = {
  wallet: "کیف پول وینوفای",
  online: "درگاه بانکی",
  cash_on_delivery: "پرداخت در محل",
};

export function CheckoutForm({ cart, addresses }: { cart: Cart; addresses: Address[] }) {
  const router = useRouter();
  const [addressUuid, setAddressUuid] = useState(addresses.find((a) => a.is_default)?.uuid ?? addresses[0]?.uuid ?? "");
  const [deliveryType, setDeliveryType] = useState<DeliveryType>("express");
  const [scheduledAt, setScheduledAt] = useState("");
  const [paymentMethod, setPaymentMethod] = useState<PaymentMethod>("cash_on_delivery");
  const [notes, setNotes] = useState("");
  const [error, setError] = useState<string | null>(null);
  const [isPending, startTransition] = useTransition();

  function handleSubmit(e: React.FormEvent) {
    e.preventDefault();
    setError(null);

    if (!addressUuid) {
      setError("لطفاً یک آدرس انتخاب کنید.");
      return;
    }
    if (deliveryType === "scheduled" && !scheduledAt) {
      setError("لطفاً زمان ارسال را مشخص کنید.");
      return;
    }

    startTransition(async () => {
      const result = await submitCheckout({
        address_uuid: addressUuid,
        delivery_type: deliveryType,
        scheduled_at: deliveryType === "scheduled" ? new Date(scheduledAt).toISOString() : null,
        payment_method: paymentMethod,
        notes,
      });
      if (result.ok) {
        router.push(`/order-groups/${result.data.uuid}`);
      } else {
        setError(result.message);
      }
    });
  }

  if (addresses.length === 0) {
    return (
      <div className="flex flex-col items-center gap-3 rounded-2xl border border-border p-6 text-center">
        <p className="text-sm text-muted-foreground">برای ثبت سفارش ابتدا یک آدرس اضافه کنید.</p>
        <Link href="/addresses">
          <Button>افزودن آدرس</Button>
        </Link>
      </div>
    );
  }

  return (
    <form onSubmit={handleSubmit} className="flex flex-col gap-5">
      <section className="flex flex-col gap-2">
        <h2 className="text-sm font-semibold text-muted-foreground">آدرس تحویل</h2>
        {addresses.map((address) => (
          <label
            key={address.uuid}
            className={`flex cursor-pointer items-start gap-3 rounded-2xl border p-3 text-sm ${addressUuid === address.uuid ? "border-primary" : "border-border"}`}
          >
            <input
              type="radio"
              name="address"
              checked={addressUuid === address.uuid}
              onChange={() => setAddressUuid(address.uuid)}
              className="mt-1"
            />
            <span>
              <span className="block font-medium">{address.title || address.full_address}</span>
              <span className="block text-muted-foreground">{address.full_address}</span>
            </span>
          </label>
        ))}
        <Link href="/addresses" className="text-xs text-primary underline underline-offset-4">
          مدیریت آدرس‌ها
        </Link>
      </section>

      <section className="flex flex-col gap-2">
        <h2 className="text-sm font-semibold text-muted-foreground">زمان ارسال</h2>
        <div className="flex gap-2">
          <button
            type="button"
            onClick={() => setDeliveryType("express")}
            className={`flex-1 rounded-xl border px-3 py-2 text-sm ${deliveryType === "express" ? "border-primary bg-primary/10" : "border-border"}`}
          >
            ارسال فوری
          </button>
          <button
            type="button"
            onClick={() => setDeliveryType("scheduled")}
            className={`flex-1 rounded-xl border px-3 py-2 text-sm ${deliveryType === "scheduled" ? "border-primary bg-primary/10" : "border-border"}`}
          >
            زمان‌بندی شده
          </button>
        </div>
        {deliveryType === "scheduled" && (
          <input
            type="datetime-local"
            value={scheduledAt}
            onChange={(e) => setScheduledAt(e.target.value)}
            className="h-11 rounded-xl border border-border bg-background px-3 text-sm"
          />
        )}
      </section>

      <section className="flex flex-col gap-2">
        <h2 className="text-sm font-semibold text-muted-foreground">روش پرداخت</h2>
        <div className="flex flex-col gap-2">
          {(Object.keys(PAYMENT_LABELS_FA) as PaymentMethod[]).map((method) => (
            <label
              key={method}
              className={`flex cursor-pointer items-center gap-3 rounded-2xl border p-3 text-sm ${paymentMethod === method ? "border-primary" : "border-border"}`}
            >
              <input type="radio" name="payment" checked={paymentMethod === method} onChange={() => setPaymentMethod(method)} />
              {PAYMENT_LABELS_FA[method]}
            </label>
          ))}
        </div>
      </section>

      <section className="flex flex-col gap-2">
        <h2 className="text-sm font-semibold text-muted-foreground">توضیحات (اختیاری)</h2>
        <textarea
          value={notes}
          onChange={(e) => setNotes(e.target.value)}
          rows={2}
          className="rounded-xl border border-border bg-background px-3 py-2 text-sm"
        />
      </section>

      {error && <p className="rounded-lg bg-destructive/10 px-3 py-2 text-sm text-destructive">{error}</p>}

      <div className="flex items-center justify-between rounded-2xl border border-border p-4 font-semibold">
        <span>مبلغ قابل پرداخت</span>
        <span>{cart.grand_total.toLocaleString("fa-IR")} تومان</span>
      </div>

      <Button type="submit" size="lg" disabled={isPending}>
        {isPending ? "در حال ثبت سفارش..." : "ثبت نهایی سفارش"}
      </Button>
    </form>
  );
}