/**
 * 轮播触屏脚本
 */
// 轮播容器ID
var containerId = '#swiperContainer';
// 移动阈值
var moveThreshold = 0.3;
// 轮播方向
var DIRECTION = {
  // 水平
  HOR: 'horizontal',
  // 垂直
  VER: 'vertical',
};

function updateMoveInfo(state, event) {
  var touchPoint = event.touches[0];
  state.moveX = touchPoint.clientX - state.startX;
  state.moveY = touchPoint.clientY - state.startY;
}

function moveContainer(state, reset) {
  if (state.direction === DIRECTION.HOR) {
    var offset = reset ? state.offsetX : state.offsetX + state.moveX;
    // console.log(DIRECTION.HOR, state.moveX);
    if (offset > 0) {
      offset = Math.min(state.width * moveThreshold, offset);
    } else {
      offset = Math.max(-state.width * (state.total - (1 - moveThreshold)), offset);
    }
    setOffset(state, offset, 0, !reset);
  } else {
    var offset = reset ? state.offsetY : state.offsetY + state.moveY;
    // console.log(DIRECTION.VER, state.moveY);
    if (offset > 0) {
      offset = Math.min(state.height * moveThreshold, offset);
    } else {
      offset = Math.max(-state.height * (state.total - (1 - moveThreshold)), offset);
    }
    setOffset(state, 0, offset, !reset);
  }
}

function setOffset(state, offsetX, offsetY, disAni) {
  var transform = 'translate3d(' + (offsetX || 0) + 'px, ' + (offsetY || 0) + 'px, 0)';
  var styles = {
    // '-webkit-transform': transform,
    transform: transform,
  };
  if (disAni) {
    styles['transition'] = 'none';
  }
  state.container.setStyle(styles);
}

function initContainer(ownerInstance) {
  var state = ownerInstance.getState();
  state.container = state.container || ownerInstance.selectComponent(containerId);
}

function startDrag(event, ownerInstance) {
  initContainer(ownerInstance);
  var state = ownerInstance.getState();
  var touchPoint = event.touches[0];
  state.moveX = 0;
  state.moveY = 0;
  state.startX = touchPoint.clientX;
  state.startY = touchPoint.clientY;
  ownerInstance.callMethod('pause');
}

function onDrag(event, ownerInstance) {
  var state = ownerInstance.getState();
  state.dragging = true;
  updateMoveInfo(state, event);
  moveContainer(state);
}

function endDrag(event, ownerInstance) {
  var state = ownerInstance.getState();
  state.dragging = false;
  ownerInstance.callMethod('replay');
  var pageDir = '';
  if (state.direction === DIRECTION.HOR) {
    pageDir = getPageDir(state.moveX, state.width);
  } else {
    pageDir = getPageDir(state.moveY, state.height);
  }
  if (pageDir) {
    ownerInstance.callMethod(pageDir, { source: 'touch' });
    return;
  }
  // 重置
  moveContainer(state, true);
}
/**
 * 返回分页操作的方向
 * @param move 移动距离
 * @param size 容器尺寸
 * @returns
 */
function getPageDir(move, size) {
  if (move > 0) {
    // 右滑超过阈值
    if (move > size * moveThreshold) {
      return 'prev';
    }
  } else {
    // 左滑超过阈值
    if (-move > size * moveThreshold) {
      return 'next';
    }
  }
}

function changeOffsetByDirection(direction, newVal, ownerInstance) {
  initContainer(ownerInstance);
  var state = ownerInstance.getState();
  if (state.direction !== direction) return;
  var needInit = !state.inited && state.currentInited;
  if (direction === DIRECTION.HOR) {
    setOffset(state, state.offsetX, 0, needInit);
  } else {
    setOffset(state, 0, state.offsetY, needInit);
  }

  if (needInit) {
    state.inited = true;
    ownerInstance.callMethod('inited');
  }
}

function changeOffsetX(newVal, oldVal, ownerInstance) {
  var state = ownerInstance.getState();
  state.offsetX = newVal;
  changeOffsetByDirection(DIRECTION.HOR, newVal, ownerInstance);
}

function changeOffsetY(newVal, oldVal, ownerInstance) {
  var state = ownerInstance.getState();
  state.offsetY = newVal;
  changeOffsetByDirection(DIRECTION.VER, newVal, ownerInstance);
}
function changeWidth(newVal, oldVal, ownerInstance) {
  var state = ownerInstance.getState();
  state.width = newVal;
}

function changeHeight(newVal, oldVal, ownerInstance) {
  var state = ownerInstance.getState();
  state.height = newVal;
}

function changeDirection(newVal, oldVal, ownerInstance) {
  var state = ownerInstance.getState();
  state.direction = newVal;
  if (oldVal && newVal !== oldVal) {
    state.inited = false;
    changeOffsetByDirection(newVal, state.offsetY, ownerInstance);
  }
}

function changeTotal(newVal, oldVal, ownerInstance) {
  var state = ownerInstance.getState();
  state.total = newVal;
}

function changeCurrentInited(newVal, oldVal, ownerInstance) {
  var state = ownerInstance.getState();
  state.currentInited = newVal;
}

module.exports = {
  startDrag: startDrag,
  onDrag: onDrag,
  endDrag: endDrag,
  changeOffsetX: changeOffsetX,
  changeOffsetY: changeOffsetY,
  changeWidth: changeWidth,
  changeHeight: changeHeight,
  changeDirection: changeDirection,
  changeTotal: changeTotal,
  changeCurrentInited: changeCurrentInited,
};