import type { GameStore } from '../game/GameStore';
import { GameWorld } from './GameWorld';
import { PixelPerfectWorld } from './PixelPerfectWorld';
import { NODE_CLICK_RADIUS } from './entities/NodesView';
import { rabbitClickRadius } from './entities/RabbitsView';

/** Must mirror the @media rule in index.css that rotates #root into landscape on a portrait
 * touchscreen — when that rule is active, the browser paints everything rotated 90°, so a raw
 * PointerEvent's clientX/clientY (and the container's getBoundingClientRect()) report the
 * physical, unrotated screen and have to be converted back to the game's own logical space. See
 * toLocalPoint. (container.clientWidth/clientHeight, used for sizing, are unaffected by the
 * rotation transform — only paint-space values like clientX/Y and getBoundingClientRect() are.) */
const ROTATE_QUERY = '(orientation: portrait) and (pointer: coarse)';

type Target = { kind: 'node'; id: string } | { kind: 'rabbit'; id: string };

/** Owns the pixel-perfect canvas for the game world (see GameWorld/PixelPerfectWorld) and all
 * pointer input for it — the canvas-rendering replacement for GameMap.tsx's map div. The HUD
 * around it stays plain DOM (see src/app). */
export class GameCanvas {
  private readonly world = new PixelPerfectWorld();
  private gameWorld: GameWorld | null = null;
  private store: GameStore | null = null;
  private container: HTMLElement | null = null;
  private isRotated = false;
  private readonly mql = window.matchMedia(ROTATE_QUERY);

  /** Mounts the canvas into `container`, sizes the world to the container's current (already-
   * logical, rotation-unaffected) box, and starts the game. Mirrors GameMap.tsx's mount effect. */
  async mount(container: HTMLElement, store: GameStore): Promise<void> {
    this.container = container;
    this.store = store;
    this.isRotated = this.mql.matches;
    this.mql.addEventListener('change', this.handleOrientationChange);

    // The game simulates and draws a virtual screen smaller than the container's real pixels —
    // sprites render at native 1:1 (see textures.ts), and gameplay distances (constants.ts/
    // rabbits.ts/upgrades.ts) are tuned for this smaller scale. A graphics-layer-only concern:
    // PixelPerfectWorld's own k upscales the virtual screen back to fill the real container,
    // however large it actually is — the game/ layer never reads clientWidth itself.
    const width = Math.round(container.clientWidth / 3);
    const height = Math.round(container.clientHeight / 3);
    if (width <= 0 || height <= 0)
      return;

    await this.world.mount(container, width, height);
    this.world.app.canvas.style.touchAction = 'none';

    this.gameWorld = new GameWorld();
    this.gameWorld.setWorldSize(width, height);
    this.world.content.addChild(this.gameWorld.container);

    store.initialize(width, height);
    store.start();

    container.addEventListener('pointerdown', this.handlePointerDown);
    container.addEventListener('pointermove', this.handlePointerMove);
    container.addEventListener('pointerup', this.handlePointerMove);
    container.addEventListener('pointercancel', this.handlePointerCancel);
    window.addEventListener('blur', store.release);
    window.addEventListener('beforeunload', store.save);

    this.world.app.ticker.add(this.tick);
  }

  /** Tears down the canvas and every listener — mirrors GameMap.tsx's unmount cleanup. */
  destroy(): void {
    this.mql.removeEventListener('change', this.handleOrientationChange);
    this.world.app.ticker.remove(this.tick);

    if (this.container) {
      this.container.removeEventListener('pointerdown', this.handlePointerDown);
      this.container.removeEventListener('pointermove', this.handlePointerMove);
      this.container.removeEventListener('pointerup', this.handlePointerMove);
      this.container.removeEventListener('pointercancel', this.handlePointerCancel);
    }
    if (this.store) {
      this.store.stop();
      window.removeEventListener('blur', this.store.release);
      window.removeEventListener('beforeunload', this.store.save);
    }

    this.world.destroy();
    this.gameWorld = null;
    this.store = null;
    this.container = null;
  }

  private readonly handleOrientationChange = (e: MediaQueryListEvent) => {
    this.isRotated = e.matches;
  };

  private readonly tick = () => {
    if (!this.gameWorld || !this.store)
      return;
    this.gameWorld.update(this.store, this.world.app.ticker.deltaMS / 1000);
    // Bake this frame's world at its fixed logical resolution — see PixelPerfectWorld's doc
    // comment for why this, rather than drawing world content directly to the screen, is what
    // keeps it shimmer-free and free of the uneven-pixel-size artifacts a fractional device pixel
    // ratio would otherwise cause.
    this.world.render();
  };

  /** Converts a pointer event's physical screen position into the map's own logical (world) (x,
   * y) — first undoing the portrait-rotation transform (see ROTATE_QUERY), then the world-sprite's
   * own scale/letterbox offset (see PixelPerfectWorld.screenToWorld). */
  private toLocalPoint(clientX: number, clientY: number, rect: DOMRect): { x: number; y: number } {
    const physicalX = clientX - rect.left;
    const physicalY = clientY - rect.top;
    const [screenX, screenY] = this.isRotated ? [physicalY, rect.width - physicalX] : [physicalX, physicalY];
    return this.world.screenToWorld(screenX, screenY);
  }

  /** Finds the node or rabbit (if any) under the given logical point, by distance to its center —
   * the canvas-rendering equivalent of GameMap.tsx's elementFromPoint hit-test. Among overlapping
   * candidates, picks whichever has the largest y (drawn frontmost — see the zIndex depth-sort in
   * the entity views). */
  private targetAt(x: number, y: number): Target | null {
    const store = this.store!;
    let best: (Target & { y: number }) | null = null;

    for (const node of store.nodes) {
      if (Math.hypot(node.x - x, node.y - y) <= NODE_CLICK_RADIUS[node.kind] && (!best || node.y > best.y))
        best = { kind: 'node', id: node.id, y: node.y };
    }

    const radius = rabbitClickRadius(store);
    for (const rabbit of store.rabbits) {
      if (Math.hypot(rabbit.x - x, rabbit.y - y) <= radius && (!best || rabbit.y > best.y))
        best = { kind: 'rabbit', id: rabbit.id, y: rabbit.y };
    }

    return best;
  }

  /** The character's action is purely a function of the current pointer state — shared by
   * pointerdown/move/up so panning the cursor across a node mid-drag starts/stops chopping it, and
   * releasing the button stops it. Mirrors GameMap.tsx's followPointer. */
  private readonly handlePointerMove = (e: PointerEvent) => {
    const store = this.store;
    if (!store)
      return;

    if ((e.buttons & 1) === 0) {
      store.release();
      return;
    }

    const rect = (e.currentTarget as HTMLElement).getBoundingClientRect();
    const { x, y } = this.toLocalPoint(e.clientX, e.clientY, rect);
    const target = this.targetAt(x, y);
    if (target) {
      if (target.kind === 'node')
        store.holdNode(target.id);
      else
        store.holdRabbit(target.id);
      return;
    }

    // A rabbit can jump out from under an otherwise-still cursor on its own — keep chasing it
    // until the player points at something else or releases the button (see GameStore).
    if (store.heldRabbitId)
      return;

    store.moveTo(x, y);
  };

  private readonly handlePointerDown = (e: PointerEvent) => {
    (e.currentTarget as HTMLElement).setPointerCapture(e.pointerId);
    this.handlePointerMove(e);
  };

  private readonly handlePointerCancel = () => {
    this.store?.release();
  };
}