"use client";

import { useState, useTransition, type FormEvent } from "react";
import { CustomerChips } from "./CustomerChips";
import { ItemTable } from "./ItemTable";
import { SummaryPanel } from "./SummaryPanel";
import type {
  OrderItemData,
  OrderWithDetails,
  OrderStatus,
  FormState,
} from "@/lib/types";

interface OrderFormProps {
  mode: "create" | "edit";
  initialData?: OrderWithDetails;
  serverAction: (
    prevState: FormState | undefined,
    formData: FormData,
  ) => Promise<FormState>;
  disabled?: boolean;
}

export function OrderForm({
  mode,
  initialData,
  serverAction,
  disabled = false,
}: OrderFormProps) {
  const isClosed = initialData?.status === "closed";
  const isDisabled = disabled || isClosed;

  const [title, setTitle] = useState(initialData?.title ?? "");
  const [status, setStatus] = useState<OrderStatus>(
    initialData?.status ?? "pending",
  );
  const [notes, setNotes] = useState(initialData?.notes ?? "");
  const [customers, setCustomers] = useState<{ id: string; name: string }[]>(
    initialData?.customers.map((c) => ({
      id: c.customer.id,
      name: c.customer.name,
    })) ?? [],
  );
  const [items, setItems] = useState<OrderItemData[]>(
    initialData?.items ?? [],
  );
  const [customerInput, setCustomerInput] = useState("");
  const [actionMessage, setActionMessage] = useState<string | null>(null);
  const [actionSuccess, setActionSuccess] = useState(false);
  const [isPending, startTransition] = useTransition();

  function handleAddCustomer() {
    const name = customerInput.trim();
    if (!name) return;
    if (customers.some((c) => c.name.toLowerCase() === name.toLowerCase()))
      return;
    setCustomers((prev) => [...prev, { id: crypto.randomUUID(), name }]);
    setCustomerInput("");
  }

  function handleRemoveCustomer(id: string) {
    setCustomers((prev) => prev.filter((c) => c.id !== id));
    setItems((prev) =>
      prev.map((item) =>
        item.customerId === id
          ? { ...item, customerId: null, customerName: null }
          : item,
      ),
    );
  }

  function handleSubmit(e: FormEvent<HTMLFormElement>) {
    e.preventDefault();
    const formData = new FormData(e.currentTarget);
    formData.set("title", title);
    formData.set("status", status);
    formData.set("notes", notes);
    formData.set(
      "customers",
      JSON.stringify(customers.map((c) => ({ id: c.id, name: c.name }))),
    );
    formData.set(
      "items",
      JSON.stringify(
        items.map((i) => ({
          id: i.id,
          customerId: i.customerId,
          itemName: i.itemName,
          initPrice: i.initPrice,
          myPrice: i.myPrice,
          taxRatio: i.taxRatio,
          quantity: i.quantity,
        })),
      ),
    );

    startTransition(async () => {
      const result = await serverAction(undefined, formData);
      if (result?.message) {
        setActionMessage(result.message);
        setActionSuccess(result.success ?? false);
      }
    });
  }

  const inputClass =
    "border-2 border-border rounded-xl px-3 py-2 text-sm bg-bg text-fg focus:outline-none focus:border-accent disabled:opacity-50 disabled:cursor-not-allowed";
  const labelClass = "text-sm font-medium text-fg mb-1";
  const submitClass =
    "bg-accent text-accent-on font-bold px-6 py-3 rounded-xl border-b-4 border-accent-active hover:bg-accent-hover active:translate-y-0.5 active:border-b-0 transition-all disabled:opacity-50 disabled:cursor-not-allowed";

  return (
    <form onSubmit={handleSubmit} className="w-full max-w-[1080px] mx-auto">
      {/* Closed order lock banner */}
      {isClosed && (
        <div className="mb-6 p-4 rounded-xl border-2 border-border bg-surface text-fg font-medium">
          This order is closed and read-only. Editing is disabled.
        </div>
      )}

      <div className="grid grid-cols-1 lg:grid-cols-3 gap-6">
        {/* Main content — left 2/3 on desktop */}
        <div className="lg:col-span-2 flex flex-col gap-6">
          {/* Title + Status row */}
          <div className="flex flex-col sm:flex-row gap-4">
            <div className="flex-1 flex flex-col">
              <label htmlFor="order-title" className={labelClass}>
                Order Title
              </label>
              <input
                id="order-title"
                type="text"
                value={title}
                onChange={(e) => setTitle(e.target.value)}
                placeholder="Order title"
                className={inputClass}
                disabled={isDisabled}
              />
            </div>
            <div className="flex flex-col sm:w-48">
              <label htmlFor="order-status" className={labelClass}>
                Status
              </label>
              <select
                id="order-status"
                value={status}
                onChange={(e) => setStatus(e.target.value as OrderStatus)}
                className={inputClass}
                disabled={isDisabled}
              >
                <option value="pending">Pending</option>
                <option value="purchased">Purchased</option>
                <option value="delivered">Delivered</option>
                <option value="closed">Closed</option>
              </select>
            </div>
          </div>

          {/* Customer section */}
          <div className="flex flex-col gap-3">
            <label className={labelClass}>Customers</label>
            <div className="flex flex-col sm:flex-row gap-2">
              <input
                type="text"
                value={customerInput}
                onChange={(e) => setCustomerInput(e.target.value)}
                onKeyDown={(e) => {
                  if (e.key === "Enter") {
                    e.preventDefault();
                    handleAddCustomer();
                  }
                }}
                placeholder="Customer name"
                className={`flex-1 ${inputClass}`}
                disabled={isDisabled}
              />
              <button
                type="button"
                onClick={handleAddCustomer}
                disabled={isDisabled}
                className={submitClass}
              >
                Add Customer
              </button>
            </div>
            <CustomerChips
              customers={customers}
              onRemove={handleRemoveCustomer}
              disabled={isDisabled}
            />
          </div>

          {/* Items section */}
          <div className="flex flex-col gap-3">
            <label className={labelClass}>Items ({items.length})</label>
            <ItemTable
              items={items}
              customers={customers}
              onItemsChange={setItems}
              disabled={isDisabled}
            />
          </div>

          {/* Notes */}
          <div className="flex flex-col">
            <label htmlFor="order-notes" className={labelClass}>
              Notes
            </label>
            <textarea
              id="order-notes"
              value={notes}
              onChange={(e) => setNotes(e.target.value)}
              placeholder="Order notes"
              rows={4}
              className={`${inputClass} resize-y`}
              disabled={isDisabled}
            />
          </div>

          {/* Submit button */}
          <div>
            <button
              type="submit"
              disabled={isDisabled || isPending}
              className={submitClass}
            >
              {isPending
                ? "Saving..."
                : mode === "create"
                  ? "Create Order"
                  : "Save Order"}
            </button>
          </div>

          {/* Error/success message */}
          {actionMessage && (
            <p
              aria-live="polite"
              className={`text-sm font-medium ${actionSuccess ? "text-success" : "text-danger"}`}
            >
              {actionMessage}
            </p>
          )}
        </div>

        {/* Sidebar — right 1/3 on desktop, below on mobile */}
        <div className="lg:col-span-1">
          <SummaryPanel
            items={items}
            status={status}
            customerCount={customers.length}
          />
        </div>
      </div>
    </form>
  );
}