// systems/InputSystem.js
import { clearSelection, setActiveUnit } from './ControlMode.js';

export class InputSystem {
  constructor(scene) {
    this.scene = scene;
    this.selectionStart = null;

    // 初始化键盘
    const kb = scene.input.keyboard;
    this.keys = {
      up: [kb.addKey(Phaser.Input.Keyboard.KeyCodes.W), kb.addKey(Phaser.Input.Keyboard.KeyCodes.UP)],
      down: [kb.addKey(Phaser.Input.Keyboard.KeyCodes.S), kb.addKey(Phaser.Input.Keyboard.KeyCodes.DOWN)],
      left: [kb.addKey(Phaser.Input.Keyboard.KeyCodes.A), kb.addKey(Phaser.Input.Keyboard.KeyCodes.LEFT)],
      right: [kb.addKey(Phaser.Input.Keyboard.KeyCodes.D), kb.addKey(Phaser.Input.Keyboard.KeyCodes.RIGHT)]
    };

    // 鼠标/触摸事件
    scene.input.on('pointerdown', this.onPointerDown, this);
    scene.input.on('pointerup', this.onPointerUp, this);
  }

  isKeyDown(keyGroup) {
    return keyGroup.some(key => key.isDown);
  }

  update() {
    // 键盘相对移动（仅当有激活单位）
    const dir = { x: 0, y: 0 };
    if (this.isKeyDown(this.keys.left)) dir.x -= 1;
    if (this.isKeyDown(this.keys.right)) dir.x += 1;
    if (this.isKeyDown(this.keys.up)) dir.y -= 1;
    if (this.isKeyDown(this.keys.down)) dir.y += 1;

    if (dir.x !== 0 || dir.y !== 0) {
      this.scene.events.emit('move-relative', dir);
    }
  }

  onPointerDown(pointer) {
    if (pointer.leftButtonDown()) {
      const worldX = pointer.worldX;
      const worldY = pointer.worldY;

      // 检查是否点中某个单位
      let clickedUnit = null;
      this.scene.unitGroup.getChildren().forEach(unit => {
        const bounds = unit.getBounds();
        if (worldX >= bounds.x && worldX <= bounds.right &&
            worldY >= bounds.y && worldY <= bounds.bottom) {
          clickedUnit = unit;
        }
      });

      if (clickedUnit) {
        // 切换控制目标
        this.scene.events.emit('select-unit', clickedUnit);
      } else {
        // 开始框选或移动指令
        this.selectionStart = { x: pointer.x, y: pointer.y };
        this.scene.events.emit('selection-start', this.selectionStart);
      }
    }
  }

  onPointerUp(pointer) {
    if (this.selectionStart) {
      const rect = new Phaser.Geom.Rectangle(
        Math.min(this.selectionStart.x, pointer.x),
        Math.min(this.selectionStart.y, pointer.y),
        Math.abs(pointer.x - this.selectionStart.x),
        Math.abs(pointer.y - this.selectionStart.y)
      );

      // 如果框太小，视为“点击地面移动”
      if (rect.width < 10 && rect.height < 10) {
        this.scene.events.emit('move-to-point', pointer.worldX, pointer.worldY);
      } else {
        // 否则执行框选
        this.scene.events.emit('selection-end', rect);
      }

      this.selectionStart = null;
    }
  }
}