var touchStart

function handleTouchStart(event) {
    touchStart = event.changedTouches[0].clientX
}

function handleTouchEnd(event, ownerInstance) {
    var touchEndX = event.changedTouches[0].clientX
    var distance = touchEndX - touchStart

    // -1：后退；0：不动；1：前进
    var direction = 0
    // 向左滑，前进
    if (distance < 0 && distance < -70) {
        direction = 1
    }

    // 向右滑，后退
    if (distance > 0 && distance > 70) {
        direction = -1
    }

    if (direction !== 0) {
        ownerInstance.callMethod('handleTouchmove', {direction: direction})
    }
    touchStart = 0
}

module.exports = {
    handleTouchStart: handleTouchStart,
    handleTouchEnd: handleTouchEnd
}