/*
 * @Description: 使用键盘控制地图漫游
 * @Version: 1.0
 * @Author: Julian
 * @Date: 2022-04-07 16:04:07
 * @LastEditors: Julian
 * @LastEditTime: 2022-04-07 18:40:40
 */


/**
 * @description: 使用键盘控制地图漫游初始化
 * @param {*} _viewer
 * @return {*}
 */
function keyboardMapRoamingInit(_viewer) {
  // 添加键盘监听事件
  document.addEventListener('keydown', keyDown.bind(_viewer), false);
  document.addEventListener('keyup', keyUp.bind(_viewer), false);

  // 为每一帧添加监听事件
  _viewer && _viewer.clock.onTick.addEventListener(function () {
    keyboardMapRoamingRender(_viewer);
  });
}

// 定义事件组
let flags = {
  // 相机位置
  moveForward: false,
  moveBackward: false,
  moveLeft: false,
  moveRight: false,
  moveUp: false,
  moveDown: false,
  // 相机姿态
  lookUp: false,
  lookDown: false,
  lookLeft: false,
  lookRight: false,
  twistLeft: false,
  twistRight: false,
  // 缩放
  zoomIn: false,
  zoomOut: false
}


// 相机位置：W：向前；S：向后；D：向右；A：向左；Q：升高；E：降低；
// 相机姿态：↑：抬头；↓：低头；←：左转；→：右转；0：顺时针；.：逆时针
// 缩放：+：放大，-：缩小；

/**
 * @description: 根据键盘输入字符返回事件信息
 * @param {*} key
 * @return {*}
 */
function getFlagFromKeyboard(key) {
  switch (key) {
    // 按字符的Unicode编码
    // 相机位置
    case 87:
      return 'moveForward';
    case 83:
      return 'moveBackward';
    case 68:
      return 'moveRight';
    case 65:
      return 'moveLeft';
    case 81:
      return 'moveUp';
    case 69:
      return 'moveDown';
    // 相机姿态
    case 38:
      return 'lookUp';
    case 40:
      return 'lookDown';
    case 37:
      return 'lookLeft';
    case 39:
      return 'lookRight';
    case 96:
      return 'twistLeft';
    case 110:
      return 'twistRight';
    // 缩放
    case 107:
      return 'zoomIn';
    case 109:
      return 'zoomOut';
    default:
      return undefined;
  }
}

/**
 * @description: 键盘按下
 * @param {*} event
 * @return {*}
 */
function keyDown(event) {
  let _viewer = this
  // 判断是否有输入框聚焦
  function isInputFocused() {
    const activeElement = document.activeElement;
    return (activeElement.tagName.toLowerCase() === 'input' && activeElement.type !== 'checkbox') ||
      activeElement.tagName.toLowerCase() === 'textarea' ||
      activeElement.getAttribute('role') === 'textarea';
  }

  if (isInputFocused()) {
    // console.log('页面上有输入框已经获取焦点');
  } else if (_viewer.trackedEntity) {
    // console.log('视角跟随中');
  } else if (_viewer._firstPersonView) {
    // console.log('第一人称视角中');
  } else if (_viewer._disableKeyboardEvent) {
    // console.log('禁用键盘事件');
  } else if (event.ctrlKey && event.altKey) {
    if (event.key === 'v' || event.key === 'V') {
      let camera = _viewer.camera
      _viewer._CAMERA_SHORTCUT_VIEW = {
        orientation: { heading: camera.heading, pitch: camera.pitch, roll: camera.roll },
        position: { x: camera.position.x, y: camera.position.y, z: camera.position.z }
      }
      localStorage.setItem('CAMERA_SHORTCUT_VIEW', JSON.stringify(_viewer._CAMERA_SHORTCUT_VIEW))
    }
    if (event.key === 'f' || event.key === 'F') {
      let CAMERA_SHORTCUT_VIEW = localStorage.getItem('CAMERA_SHORTCUT_VIEW')
      _viewer._CAMERA_SHORTCUT_VIEW = JSON.parse(CAMERA_SHORTCUT_VIEW)
      if (_viewer._CAMERA_SHORTCUT_VIEW && _viewer._CAMERA_SHORTCUT_VIEW.position && _viewer._CAMERA_SHORTCUT_VIEW.orientation) {
        _viewer.camera.flyTo({
          destination: _viewer._CAMERA_SHORTCUT_VIEW.position,
          orientation: _viewer._CAMERA_SHORTCUT_VIEW.orientation
        })
      }
    }
  } else {
    // console.log('页面上没有输入框获取焦点');
    let flagName = getFlagFromKeyboard(event.keyCode);
    if (typeof flagName !== 'undefined') {
      flags[flagName] = true;
    }
  }
}

/**
 * @description: 键盘弹起
 * @param {*} event
 * @return {*}
 */
function keyUp(event) {
  let flagName = getFlagFromKeyboard(event.keyCode);
  if (typeof flagName !== 'undefined') {
    flags[flagName] = false;
  }
}


/**
 * @description: 根据事件调整相机
 * @param {*} _viewer
 * @return {*}
 */
function keyboardMapRoamingRender(_viewer) {
  if(!_viewer.scene.screenSpaceCameraController.enableTilt) {
    return
  }
  let camera = _viewer.camera;
  let ellipsoid = _viewer.scene.globe.ellipsoid;
  let cameraHeight = ellipsoid.cartesianToCartographic(camera.position).height;

  // 根据相机高度设置移动距离，比默认距离移动效果更好
  let moveRate = cameraHeight / 20.0;
  let rotationRate = moveRate / 500000 / Cesium.Math.toDegrees(camera.pitch);

  if (flags.moveForward) {
    // camera.moveForward(moveRate);
    camera.rotate(camera.right, -rotationRate);
  }
  if (flags.moveBackward) {
    // camera.moveBackward(moveRate);
    camera.rotate(camera.right, rotationRate);
  }
  if (flags.moveLeft) {
    // camera.moveLeft(moveRate);
    camera.rotate(camera.up, -rotationRate);
  }
  if (flags.moveRight) {
    // camera.moveRight(moveRate);
    camera.rotate(camera.up, rotationRate);
  }
  if (flags.moveUp) {
    camera.moveUp(moveRate);
  }
  if (flags.moveDown) {
    camera.moveDown(moveRate);
  }
  if (flags.lookUp) {
    camera.lookUp();
  }
  if (flags.lookDown) {
    camera.lookDown();
  }
  if (flags.lookLeft) {
    camera.lookLeft();
  }
  if (flags.lookRight) {
    camera.lookRight();
  }
  if (flags.twistLeft) {
    camera.twistLeft();
  }
  if (flags.twistRight) {
    camera.twistRight();
  }
  // 根据相机高度设置缩放参数
  if (flags.zoomIn) {
    let height = cameraHeight / 2
    if (height < 1) {
      height = 0
    }
    camera.zoomIn(height);
  }
  if (flags.zoomOut) {
    let height = cameraHeight / 2
    if ((cameraHeight + cameraHeight) >= 50000000) {
      height = 50000000 - cameraHeight
    }
    camera.zoomOut(height);
  }
}

export { keyboardMapRoamingInit }