import React, { useRef, useState } from 'react';

import type {
  AppPlayer,
  SceneGrid,
  ScenePlayerTokensSessionState,
} from '../../../shared/types';
import { DEFAULT_NPC_TOKEN_SESSION_SCALE } from '../../../shared/types/appPlayers';
import { sceneGridTokenFitFactor } from '../../../shared/types/sceneGrid';
import { usePlayerImageUrl } from './usePlayerImageUrl';

import { PlayerTokenView } from './PlayerTokenView';
import { useLiveDragBroadcast } from './useLiveDragBroadcast';
import styles from './SceneNpcTokensOverlay.module.css';

type Viewport = { x: number; y: number; w: number; h: number };

function PlayerSprite({
  player,
  nx,
  ny,
  sizeN,
  viewport,
  editable,
  displayScale,
  gridFit,
  onMove,
  snapNorm,
}: {
  player: AppPlayer;
  nx: number;
  ny: number;
  sizeN: number;
  viewport: Viewport;
  editable: boolean;
  displayScale: number;
  gridFit: number;
  onMove?: (playerId: string, nx: number, ny: number) => void;
  snapNorm?: (nx: number, ny: number) => { nx: number; ny: number };
}) {
  const imageUrl = usePlayerImageUrl(player.id);
  const [localPos, setLocalPos] = useState<{ nx: number; ny: number } | null>(null);
  const dragRef = useRef<{
    pointerId: number;
    startNx: number;
    startNy: number;
    pointerNx: number;
    pointerNy: number;
    lastNx: number;
    lastNy: number;
  } | null>(null);
  const { schedule, flush } = useLiveDragBroadcast(onMove, String(player.id));
  const pos = localPos ?? { nx, ny };
  const minDim = Math.min(viewport.w, viewport.h);
  const sizePx = Math.max(16, sizeN * gridFit * displayScale * minDim);

  const point = (e: React.PointerEvent) => {
    const host = e.currentTarget.parentElement;
    const rect = host?.getBoundingClientRect();
    return {
      x: Math.max(0, Math.min(1, (e.clientX - ((rect?.left ?? 0) + viewport.x)) / Math.max(1, viewport.w))),
      y: Math.max(0, Math.min(1, (e.clientY - ((rect?.top ?? 0) + viewport.y)) / Math.max(1, viewport.h))),
    };
  };

  const end = (e: React.PointerEvent<HTMLDivElement>) => {
    const drag = dragRef.current;
    if (drag?.pointerId !== e.pointerId) return;
    dragRef.current = null;
    flush(drag.lastNx, drag.lastNy);
    setLocalPos(null);
  };

  return (
    <div
      className={[styles.token, editable ? styles.editable : ''].filter(Boolean).join(' ')}
      data-testid={`session-player-token-${player.id}`}
      style={{
        left: viewport.x + pos.nx * viewport.w,
        top: viewport.y + pos.ny * viewport.h,
        width: sizePx,
        height: sizePx,
      }}
      onPointerDown={
        editable && onMove !== undefined
          ? (e) => {
              if (e.button !== 0) return;
              e.preventDefault();
              e.stopPropagation();
              const p = point(e);
              dragRef.current = {
                pointerId: e.pointerId,
                startNx: pos.nx,
                startNy: pos.ny,
                pointerNx: p.x,
                pointerNy: p.y,
                lastNx: pos.nx,
                lastNy: pos.ny,
              };
              e.currentTarget.setPointerCapture(e.pointerId);
            }
          : undefined
      }
      onPointerMove={
        editable && onMove
          ? (e) => {
              const drag = dragRef.current;
              if (drag?.pointerId !== e.pointerId) return;
              const p = point(e);
              const rawNx = Math.max(0, Math.min(1, drag.startNx + p.x - drag.pointerNx));
              const rawNy = Math.max(0, Math.min(1, drag.startNy + p.y - drag.pointerNy));
              const snapped = snapNorm ? snapNorm(rawNx, rawNy) : { nx: rawNx, ny: rawNy };
              drag.lastNx = snapped.nx;
              drag.lastNy = snapped.ny;
              setLocalPos({ nx: drag.lastNx, ny: drag.lastNy });
              schedule(drag.lastNx, drag.lastNy);
            }
          : undefined
      }
      onPointerUp={end}
      onPointerCancel={end}
    >
      <PlayerTokenView
        name={player.name}
        imageUrl={imageUrl}
        ringColor={player.ringColor}
        imageOffset={player.imageOffset}
        imageScale={player.imageScale}
        sizePx={sizePx}
      />
    </div>
  );
}

export function ScenePlayerTokensOverlay({
  library,
  session,
  displayScale = DEFAULT_NPC_TOKEN_SESSION_SCALE,
  viewport,
  grid = null,
  editable = false,
  onMove,
  snapNorm,
}: {
  library: readonly AppPlayer[];
  session: ScenePlayerTokensSessionState | null;
  /** Общий масштаб с НПС-токенами. */
  displayScale?: number;
  viewport: Viewport | null;
  grid?: SceneGrid | null;
  editable?: boolean;
  onMove?: (playerId: string, nx: number, ny: number) => void;
  snapNorm?: (nx: number, ny: number) => { nx: number; ny: number };
}) {
  if (!viewport || !session?.visible) return null;
  const byId = new Map(library.map((p) => [String(p.id), p]));
  const gridFit = sceneGridTokenFitFactor(grid);
  return (
    <div className={styles.layer}>
      {session.selectedPlayerIds.map((playerId) => {
        const player = byId.get(playerId);
        const placement = session.byPlayerId[playerId];
        if (!player || !placement) return null;
        return (
          <PlayerSprite
            key={playerId}
            player={player}
            nx={placement.nx}
            ny={placement.ny}
            sizeN={placement.sizeN}
            viewport={viewport}
            editable={editable}
            displayScale={displayScale}
            gridFit={gridFit}
            {...(onMove ? { onMove } : {})}
            {...(snapNorm ? { snapNorm } : {})}
          />
        );
      })}
    </div>
  );
}