import { useState, type PointerEvent, type ReactNode } from "react";
import type { FurnitureType } from "../types";

const CLICK_THRESHOLD_PX = 5;

interface Props {
  remaining: Record<FurnitureType, number>;
  onStartDrag: (type: FurnitureType, clientX: number, clientY: number) => void;
  onOpenMenu: (type: FurnitureType) => void;
  panel: ReactNode; // when set, replaces the tiles (type settings menu)
}

const tile: React.CSSProperties = {
  width: "100%",
  height: 84,
  boxSizing: "border-box",
  background: "#fff",
  border: "1px solid #cfcfcf",
  borderRadius: 8,
  display: "flex",
  flexDirection: "column",
  alignItems: "center",
  justifyContent: "center",
  gap: 6,
  cursor: "grab",
  userSelect: "none",
  touchAction: "none",
  font: "12px system-ui, sans-serif",
  color: "#444",
};

export function ChairIcon({ size = 36 }: { size?: number }) {
  return (
    <svg width={size} height={size} viewBox="0 0 36 36">
      <rect x="4" y="4" width="28" height="28" rx="3" fill="#8fb4d9" stroke="#3b3b3b" strokeWidth="1.5" />
      <rect x="4" y="4" width="28" height="8" rx="3" fill="#4a6f96" />
    </svg>
  );
}

export function TableIcon({ size = 36 }: { size?: number }) {
  return (
    <svg width={size} height={size} viewBox="0 0 36 36">
      <rect x="2" y="9" width="32" height="18" rx="3" fill="#d9b382" stroke="#3b3b3b" strokeWidth="1.5" />
    </svg>
  );
}

const MIN_W = 152;
const MAX_W = 600;

interface TileProps {
  type: FurnitureType;
  remaining: number;
  onStartDrag: Props["onStartDrag"];
  onOpenMenu: Props["onOpenMenu"];
}

/** Press + move > threshold = drag a new item out. Press + release without moving = open menu. */
function Tile({ type, remaining, onStartDrag, onOpenMenu }: TileProps) {
  const empty = remaining <= 0;

  const onPointerDown = (e: PointerEvent<HTMLDivElement>) => {
    e.preventDefault();
    const { clientX: x0, clientY: y0 } = e;
    let dragging = false;
    const move = (ev: globalThis.PointerEvent) => {
      if (dragging || empty) return;
      if (Math.hypot(ev.clientX - x0, ev.clientY - y0) >= CLICK_THRESHOLD_PX) {
        dragging = true;
        cleanup();
        onStartDrag(type, ev.clientX, ev.clientY);
      }
    };
    const up = (ev: globalThis.PointerEvent) => {
      cleanup();
      // Out-of-stock tiles can't be dragged, so any release over the tile counts as a click.
      if (Math.hypot(ev.clientX - x0, ev.clientY - y0) < CLICK_THRESHOLD_PX || empty) {
        onOpenMenu(type);
      }
    };
    const cleanup = () => {
      window.removeEventListener("pointermove", move);
      window.removeEventListener("pointerup", up);
    };
    window.addEventListener("pointermove", move);
    window.addEventListener("pointerup", up);
  };

  return (
    <div
      role="button"
      aria-label={`${type} (${remaining} remaining)`}
      style={{ ...tile, position: "relative", opacity: empty ? 0.45 : 1, filter: empty ? "grayscale(1)" : undefined, cursor: empty ? "pointer" : "grab" }}
      onPointerDown={onPointerDown}
    >
      <span
        style={{
          position: "absolute",
          top: 6,
          right: 6,
          minWidth: 20,
          height: 20,
          padding: "0 6px",
          boxSizing: "border-box",
          borderRadius: 10,
          background: empty ? "#888" : "#2b2b2b",
          color: "#fff",
          font: "600 11px/20px system-ui, sans-serif",
          textAlign: "center",
        }}
      >
        {remaining}
      </span>
      {type === "chair" ? <ChairIcon /> : <TableIcon />}
      {type === "chair" ? "Chair" : "Table"}
    </div>
  );
}

export function Palette({ remaining, onStartDrag, onOpenMenu, panel }: Props) {
  const [width, setWidth] = useState(264);

  const startResize = (e: PointerEvent) => {
    e.preventDefault();
    const startX = e.clientX;
    const startW = width;
    const move = (ev: globalThis.PointerEvent) =>
      setWidth(Math.min(MAX_W, Math.max(MIN_W, startW + ev.clientX - startX)));
    const up = () => {
      window.removeEventListener("pointermove", move);
      window.removeEventListener("pointerup", up);
    };
    window.addEventListener("pointermove", move);
    window.addEventListener("pointerup", up);
  };

  return (
    <aside
      style={{
        position: "relative",
        width,
        boxSizing: "border-box",
        flexShrink: 0,
        padding: 16,
        display: "grid",
        gridTemplateColumns: "repeat(auto-fill, minmax(84px, 1fr))",
        alignContent: "start",
        gap: 12,
        borderRight: "1px solid #d4d4d4",
        background: "#ececec",
      }}
    >
      {panel ?? (["chair", "table"] as const).map((type) => (
        <Tile key={type} type={type} remaining={remaining[type]} onStartDrag={onStartDrag} onOpenMenu={onOpenMenu} />
      ))}
      <div
        onPointerDown={startResize}
        style={{ position: "absolute", top: 0, right: -3, width: 6, height: "100%", cursor: "col-resize", touchAction: "none" }}
      />
    </aside>
  );
}