"use client";

import { useState } from "react";
import type { OrderItemData } from "@/lib/types";

// 6 color presets for customer grouping
const CUSTOMER_COLORS = [
  { border: "border-l-blue-500", bg: "bg-blue-50", text: "text-blue-800" },
  { border: "border-l-emerald-500", bg: "bg-emerald-50", text: "text-emerald-800" },
  { border: "border-l-violet-500", bg: "bg-violet-50", text: "text-violet-800" },
  { border: "border-l-orange-500", bg: "bg-orange-50", text: "text-orange-800" },
  { border: "border-l-teal-500", bg: "bg-teal-50", text: "text-teal-800" },
  { border: "border-l-pink-500", bg: "bg-pink-50", text: "text-pink-800" },
];

function getColor(index: number) {
  return CUSTOMER_COLORS[index % CUSTOMER_COLORS.length];
}

// Build a color map from customer list
function buildColorMap(customers: { id: string; name: string }[]) {
  const map: Record<string, number> = {};
  customers.forEach((c, i) => {
    map[c.id] = i;
  });
  return map;
}

// Group items by customerId
function groupItems(items: OrderItemData[]) {
  const groups: Record<string, OrderItemData[]> = {};
  const ungrouped: OrderItemData[] = [];

  for (const item of items) {
    if (item.customerId) {
      if (!groups[item.customerId]) groups[item.customerId] = [];
      groups[item.customerId].push(item);
    } else {
      ungrouped.push(item);
    }
  }

  return { groups, ungrouped };
}

// Inline edit form for an item
function ItemEditForm({
  item,
  customers,
  onSave,
  onCancel,
}: {
  item: OrderItemData;
  customers: { id: string; name: string }[];
  onSave: (item: OrderItemData) => void;
  onCancel: () => void;
}) {
  const [form, setForm] = useState({ ...item });

  function update(field: string, value: string | number) {
    const next = { ...form, [field]: value };
    // Recompute prices
    next.netPrice = (next.initPrice + next.initPrice * next.taxRatio) * next.quantity;
    next.myNetPrice = (next.myPrice + next.myPrice * next.taxRatio) * next.quantity;
    next.finalPrice = next.netPrice;
    setForm(next);
  }

  const inputClass = "border-2 border-border rounded-lg px-2 py-1.5 text-sm bg-bg text-fg focus:outline-none focus:border-accent w-full";
  const labelClass = "text-xs text-muted font-medium mb-0.5 block";

  return (
    <div className="bg-surface border-2 border-border rounded-xl p-4 mt-2">
      <div className="grid grid-cols-2 sm:grid-cols-4 gap-3">
        <div>
          <label className={labelClass}>Customer</label>
          <select
            value={form.customerId ?? ""}
            onChange={(e) => update("customerId", e.target.value)}
            className={inputClass}
          >
            <option value="">None</option>
            {customers.map((c) => (
              <option key={c.id} value={c.id}>{c.name}</option>
            ))}
          </select>
        </div>
        <div>
          <label className={labelClass}>Item Name</label>
          <input type="text" value={form.itemName} onChange={(e) => update("itemName", e.target.value)} className={inputClass} />
        </div>
        <div>
          <label className={labelClass}>Init Price</label>
          <input type="number" step="0.01" min="0" value={form.initPrice} onChange={(e) => update("initPrice", parseFloat(e.target.value) || 0)} className={inputClass} />
        </div>
        <div>
          <label className={labelClass}>My Price</label>
          <input type="number" step="0.01" min="0" value={form.myPrice} onChange={(e) => update("myPrice", parseFloat(e.target.value) || 0)} className={inputClass} />
        </div>
        <div>
          <label className={labelClass}>Tax Ratio</label>
          <input type="number" step="0.01" min="0" value={form.taxRatio} onChange={(e) => update("taxRatio", parseFloat(e.target.value) || 0)} className={inputClass} />
        </div>
        <div>
          <label className={labelClass}>Quantity</label>
          <input type="number" min="1" value={form.quantity} onChange={(e) => update("quantity", parseInt(e.target.value) || 1)} className={inputClass} />
        </div>
      </div>
      <div className="flex gap-2 mt-3">
        <button type="button" onClick={() => onSave(form)} className="bg-accent text-accent-on px-4 py-1.5 rounded-lg text-sm font-bold hover:bg-accent-hover cursor-pointer">
          Save
        </button>
        <button type="button" onClick={onCancel} className="bg-surface border-2 border-border px-4 py-1.5 rounded-lg text-sm font-medium text-muted hover:text-fg cursor-pointer">
          Cancel
        </button>
      </div>
    </div>
  );
}

// Add item form
function AddItemForm({
  customers,
  onAdd,
  disabled,
}: {
  customers: { id: string; name: string }[];
  onAdd: (item: OrderItemData) => void;
  disabled: boolean;
}) {
  const [form, setForm] = useState({
    customerId: customers[0]?.id ?? "",
    itemName: "",
    initPrice: 0,
    myPrice: 0,
    taxRatio: 0.16,
    quantity: 1,
  });

  function update(field: string, value: string | number) {
    setForm((prev) => ({ ...prev, [field]: value }));
  }

  function handleAdd() {
    if (!form.itemName.trim()) return;
    const netPrice = (form.initPrice + form.initPrice * form.taxRatio) * form.quantity;
    const myNetPrice = (form.myPrice + form.myPrice * form.taxRatio) * form.quantity;
    onAdd({
      id: crypto.randomUUID(),
      orderId: "",
      customerId: form.customerId || null,
      customerName: customers.find((c) => c.id === form.customerId)?.name ?? null,
      itemName: form.itemName,
      initPrice: form.initPrice,
      myPrice: form.myPrice,
      taxRatio: form.taxRatio,
      quantity: form.quantity,
      netPrice,
      myNetPrice,
      finalPrice: netPrice,
    });
    setForm({ customerId: customers[0]?.id ?? "", itemName: "", initPrice: 0, myPrice: 0, taxRatio: 0.16, quantity: 1 });
  }

  const inputClass = "border-2 border-border rounded-lg px-2 py-1.5 text-sm bg-bg text-fg focus:outline-none focus:border-accent w-full";
  const labelClass = "text-xs text-muted font-medium mb-0.5 block";

  return (
    <div className="bg-surface border-2 border-border rounded-xl p-4">
      <h4 className="text-sm font-bold text-fg mb-3">Add New Item</h4>
      <div className="grid grid-cols-2 sm:grid-cols-3 lg:grid-cols-6 gap-3">
        <div>
          <label className={labelClass}>Customer</label>
          <select value={form.customerId} onChange={(e) => update("customerId", e.target.value)} className={inputClass} disabled={disabled}>
            <option value="">None</option>
            {customers.map((c) => (
              <option key={c.id} value={c.id}>{c.name}</option>
            ))}
          </select>
        </div>
        <div>
          <label className={labelClass}>Item Name</label>
          <input type="text" value={form.itemName} onChange={(e) => update("itemName", e.target.value)} placeholder="Product name" className={inputClass} disabled={disabled} />
        </div>
        <div>
          <label className={labelClass}>Init Price</label>
          <input type="number" step="0.01" min="0" value={form.initPrice} onChange={(e) => update("initPrice", parseFloat(e.target.value) || 0)} className={inputClass} disabled={disabled} />
        </div>
        <div>
          <label className={labelClass}>My Price</label>
          <input type="number" step="0.01" min="0" value={form.myPrice} onChange={(e) => update("myPrice", parseFloat(e.target.value) || 0)} className={inputClass} disabled={disabled} />
        </div>
        <div>
          <label className={labelClass}>Tax / Qty</label>
          <div className="flex gap-1">
            <input type="number" step="0.01" min="0" value={form.taxRatio} onChange={(e) => update("taxRatio", parseFloat(e.target.value) || 0)} className={inputClass} disabled={disabled} />
            <input type="number" min="1" value={form.quantity} onChange={(e) => update("quantity", parseInt(e.target.value) || 1)} className={inputClass} disabled={disabled} />
          </div>
        </div>
        <div className="flex items-end">
          <button type="button" onClick={handleAdd} disabled={disabled || !form.itemName.trim()} className="bg-accent text-accent-on px-4 py-1.5 rounded-lg text-sm font-bold hover:bg-accent-hover disabled:opacity-50 cursor-pointer w-full">
            + Add
          </button>
        </div>
      </div>
    </div>
  );
}

// Main ItemTable component
export function ItemTable({
  items,
  customers,
  onItemsChange,
  disabled = false,
}: {
  items: OrderItemData[];
  customers: { id: string; name: string }[];
  onItemsChange: (items: OrderItemData[]) => void;
  disabled?: boolean;
}) {
  const [editingId, setEditingId] = useState<string | null>(null);
  const colorMap = buildColorMap(customers);
  const { groups, ungrouped } = groupItems(items);

  function handleAdd(newItem: OrderItemData) {
    onItemsChange([...items, newItem]);
  }

  function handleRemove(id: string) {
    onItemsChange(items.filter((i) => i.id !== id));
    if (editingId === id) setEditingId(null);
  }

  function handleEditSave(updated: OrderItemData) {
    onItemsChange(items.map((i) => (i.id === updated.id ? updated : i)));
    setEditingId(null);
  }

  // Get customer name by id
  function getCustomerName(id: string) {
    return customers.find((c) => c.id === id)?.name ?? "Unknown";
  }

  // Render a single item row (desktop table row)
  function TableRow({ item, colorIndex }: { item: OrderItemData; colorIndex: number | null }) {
    const color = colorIndex !== null ? getColor(colorIndex) : null;
    const isEditing = editingId === item.id;

    return (
      <>
        <tr className={`border-b border-border/50 hover:bg-surface/30 transition-colors ${color ? `border-l-4 ${color.border} ${color.bg}` : ""}`}>
          <td className="px-3 py-2 text-sm font-medium text-fg">{item.itemName || "—"}</td>
          <td className="px-3 py-2 text-sm font-mono text-right">${item.initPrice.toFixed(2)}</td>
          <td className="px-3 py-2 text-sm font-mono text-right">${item.myPrice.toFixed(2)}</td>
          <td className="px-3 py-2 text-sm font-mono text-center">{item.quantity}</td>
          <td className="px-3 py-2 text-sm font-mono text-right font-medium">${item.netPrice.toFixed(2)}</td>
          <td className="px-3 py-2 text-sm font-mono text-right font-bold">${item.finalPrice.toFixed(2)}</td>
          <td className="px-3 py-2 text-right">
            {!disabled && (
              <div className="flex gap-1 justify-end">
                <button type="button" onClick={() => setEditingId(isEditing ? null : item.id)} className="text-xs text-accent hover:text-accent-hover font-medium px-2 py-1 rounded cursor-pointer">
                  {isEditing ? "Cancel" : "Edit"}
                </button>
                <button type="button" onClick={() => handleRemove(item.id)} className="text-xs text-danger hover:text-red-700 font-medium px-2 py-1 rounded cursor-pointer">
                  Remove
                </button>
              </div>
            )}
          </td>
        </tr>
        {isEditing && (
          <tr>
            <td colSpan={7} className="px-3 py-0">
              <ItemEditForm item={item} customers={customers} onSave={handleEditSave} onCancel={() => setEditingId(null)} />
            </td>
          </tr>
        )}
      </>
    );
  }

  // Render a single item card (mobile)
  function MobileCard({ item, colorIndex }: { item: OrderItemData; colorIndex: number | null }) {
    const color = colorIndex !== null ? getColor(colorIndex) : null;
    const isEditing = editingId === item.id;

    return (
      <div className={`border-2 border-border rounded-xl overflow-hidden ${color ? `border-l-4 ${color.border}` : ""}`}>
        <div className={`p-3 ${color?.bg ?? "bg-white"}`}>
          <div className="flex items-start justify-between gap-2">
            <div className="flex-1 min-w-0">
              <p className="text-sm font-bold text-fg truncate">{item.itemName || "—"}</p>
              {colorIndex !== null && (
                <p className={`text-xs font-medium ${color?.text ?? "text-muted"}`}>
                  {getCustomerName(item.customerId!)}
                </p>
              )}
            </div>
            <p className="text-sm font-bold font-mono text-fg whitespace-nowrap">${item.finalPrice.toFixed(2)}</p>
          </div>
          <div className="grid grid-cols-3 gap-2 mt-2 text-xs">
            <div>
              <span className="text-muted">Init: </span>
              <span className="font-mono">${item.initPrice.toFixed(2)}</span>
            </div>
            <div>
              <span className="text-muted">My: </span>
              <span className="font-mono">${item.myPrice.toFixed(2)}</span>
            </div>
            <div>
              <span className="text-muted">Qty: </span>
              <span className="font-mono">{item.quantity}</span>
            </div>
          </div>
          {!disabled && (
            <div className="flex gap-2 mt-2">
              <button type="button" onClick={() => setEditingId(isEditing ? null : item.id)} className="text-xs text-accent hover:text-accent-hover font-medium cursor-pointer">
                {isEditing ? "Cancel" : "Edit"}
              </button>
              <button type="button" onClick={() => handleRemove(item.id)} className="text-xs text-danger hover:text-red-700 font-medium cursor-pointer">
                Remove
              </button>
            </div>
          )}
        </div>
        {isEditing && (
          <div className="p-3 border-t border-border">
            <ItemEditForm item={item} customers={customers} onSave={handleEditSave} onCancel={() => setEditingId(null)} />
          </div>
        )}
      </div>
    );
  }

  // Render items for a customer group
  function CustomerGroup({ customerId, groupItems: gi }: { customerId: string; groupItems: OrderItemData[] }) {
    const colorIndex = colorMap[customerId] ?? 0;
    const color = getColor(colorIndex);
    const name = getCustomerName(customerId);

    return (
      <div className="mb-4">
        <div className={`flex items-center gap-2 px-3 py-1.5 rounded-t-lg ${color.bg} border-l-4 ${color.border}`}>
          <span className={`text-sm font-bold ${color.text}`}>{name}</span>
          <span className="text-xs text-muted">({gi.length} item{gi.length !== 1 ? "s" : ""})</span>
        </div>
        {/* Desktop table */}
        <div className="hidden sm:block border-x border-b border-border rounded-b-lg overflow-hidden">
          <table className="w-full">
            <thead>
              <tr className="bg-surface/50">
                <th className="text-left px-3 py-1.5 text-xs font-medium text-muted">Item</th>
                <th className="text-right px-3 py-1.5 text-xs font-medium text-muted">Init Price</th>
                <th className="text-right px-3 py-1.5 text-xs font-medium text-muted">My Price</th>
                <th className="text-center px-3 py-1.5 text-xs font-medium text-muted">Qty</th>
                <th className="text-right px-3 py-1.5 text-xs font-medium text-muted">Net</th>
                <th className="text-right px-3 py-1.5 text-xs font-medium text-muted">Final</th>
                <th className="text-right px-3 py-1.5 text-xs font-medium text-muted">Actions</th>
              </tr>
            </thead>
            <tbody>
              {gi.map((item) => <TableRow key={item.id} item={item} colorIndex={colorIndex} />)}
            </tbody>
          </table>
        </div>
        {/* Mobile cards */}
        <div className="sm:hidden flex flex-col gap-2 mt-1">
          {gi.map((item) => <MobileCard key={item.id} item={item} colorIndex={colorIndex} />)}
        </div>
      </div>
    );
  }

  return (
    <div className="flex flex-col gap-4">
      {/* Add item form */}
      {!disabled && (
        <AddItemForm customers={customers} onAdd={handleAdd} disabled={disabled} />
      )}

      {/* Items grouped by customer */}
      {items.length === 0 ? (
        <div className="text-center py-8 text-muted text-sm border-2 border-dashed border-border rounded-xl">
          No items yet. Add one above.
        </div>
      ) : (
        <>
          {/* Customer groups */}
          {Object.entries(groups).map(([customerId, gi]) => (
            <CustomerGroup key={customerId} customerId={customerId} groupItems={gi} />
          ))}

          {/* Ungrouped items */}
          {ungrouped.length > 0 && (
            <div className="mb-4">
              <div className="flex items-center gap-2 px-3 py-1.5 rounded-t-lg bg-gray-50 border-l-4 border-l-gray-400">
                <span className="text-sm font-bold text-gray-700">Unassigned</span>
                <span className="text-xs text-muted">({ungrouped.length} item{ungrouped.length !== 1 ? "s" : ""})</span>
              </div>
              <div className="hidden sm:block border-x border-b border-border rounded-b-lg overflow-hidden">
                <table className="w-full">
                  <thead>
                    <tr className="bg-surface/50">
                      <th className="text-left px-3 py-1.5 text-xs font-medium text-muted">Item</th>
                      <th className="text-right px-3 py-1.5 text-xs font-medium text-muted">Init Price</th>
                      <th className="text-right px-3 py-1.5 text-xs font-medium text-muted">My Price</th>
                      <th className="text-center px-3 py-1.5 text-xs font-medium text-muted">Qty</th>
                      <th className="text-right px-3 py-1.5 text-xs font-medium text-muted">Net</th>
                      <th className="text-right px-3 py-1.5 text-xs font-medium text-muted">Final</th>
                      <th className="text-right px-3 py-1.5 text-xs font-medium text-muted">Actions</th>
                    </tr>
                  </thead>
                  <tbody>
                    {ungrouped.map((item) => <TableRow key={item.id} item={item} colorIndex={null} />)}
                  </tbody>
                </table>
              </div>
              <div className="sm:hidden flex flex-col gap-2 mt-1">
                {ungrouped.map((item) => <MobileCard key={item.id} item={item} colorIndex={null} />)}
              </div>
            </div>
          )}
        </>
      )}
    </div>
  );
}