<template>
 <section class="page" v-if="option" 
 :style="{background: option.background,color: option.color||'#fff'}" 
 :class="{'page-before': option.index < currentPage,
 'page-after': option.index > currentPage,
 'page-current': option.index === currentPage}">
 <div :class="{'all-center': option.isCenter}">
 <slot></slot>
 </div>
 </section>
 <section class="page" v-else>頁面正在渲染中。。</section>
</template>

<template>
 <nav class="controller">
 <button v-if="option.arrowsType" class="prev-btn" :class="{moving:option.arrowsType === 'animate'}" @click="changePage(prevIndex)"></button>
 <ul v-if="option.navbar">
 <li v-for="index in pageNum" @click="changePage(index)" :class="{current:option.highlight && index === currentPage}" :key="'controller-'+index" :data-index="index" class="controller-item"></li>
 </ul>
 <button v-if="option.arrowsType" class="next-btn" :class="{moving:option.arrowsType === 'animate'}" @click="changePage(nextIndex)"></button>
 </nav>
</template>

<script>
export default {
 name: 'page-controller',
 props: {
 pageNum: Number,
 currentPage: Number,
 option: {
 type: Object,
 default: {
 arrowsType: 'animate',
 navbar: true,
 highlight: true,
 loop: true //是否開啟滾動循環
 }
 }
 },
 methods: {
 changePage (index) {
 this.$emit('changePage', index);
 }
 },
 computed: {
 nextIndex () {
 if (this.currentPage === this.pageNum) {
 if(this.option.loop){
 return 1
 }else{
 return this.pageNum
 }
 } else {
 return this.currentPage + 1;
 }
 },
 prevIndex () {
 if (this.currentPage === 1) {
 if(this.option.loop){
 return this.pageNum
 }else{
 return 1
 }
 } else {
 return this.currentPage - 1;
 }
 }
 },
 created () {
 if (this.option.navbar === undefined) {
 this.option.navbar = true;
 }
 },
 mounted () {
 let _this = this;
 let timer = null;
 let start = 0;
 // 滾輪處理
 function scrollHandler (direction) {
 // 防止重復觸發滾動事件
 if (timer != null) {
 return;
 }
 if (direction === 'down') {
 _this.changePage(_this.nextIndex);
 } else {
 _this.changePage(_this.prevIndex);
 }
 timer = setTimeout(function() {
 clearTimeout(timer);
 timer = null;
 }, 300);
 }
 // if (Object.hasOwnProperty.call(window,'onmousewheel')) {
 if (Object.hasOwnProperty.call(window,'onmousewheel')) {
 // 監聽滾輪事件
 window.addEventListener('mousewheel',function (event) { // IE/Opera/Chrome
 let direction = event.wheelDelta > 0 ? 'up':'down';
 scrollHandler(direction);
 },false);
 } else {
 window.addEventListener('DOMMouseScroll',function (event) { // Firefox
 let direction = event.detail > 0 ? 'up':'down';
 scrollHandler(direction);
 },false);
 }
 // 移動端觸摸事件處理
 window.addEventListener('touchstart', function (event) {
 start = event.touches[0].clientY;
 })
 window.addEventListener('touchmove', function (event) {
 event.preventDefault();
 })
 window.addEventListener('touchend', function (event) {
 let spacing = event.changedTouches[0].clientY - start;
 let direction; 
 if (spacing > 50) {
 direction = 'up';
 scrollHandler(direction);
 } else if (spacing < -50) {
 direction = 'down';
 scrollHandler(direction);
 }
 })
 }
}
</script>

<style scoped>
.controller {
 position: fixed;
 right: 20px;
 top: 50%;
 z-index: 99;
}
.controller ul {
 transform: translate3d(0,-50%,0);
 list-style: none;
 margin: 0;
 padding: 0;
}
.controller-item {
 cursor: pointer;
 width: 20px;
 height: 20px;
 border-radius: 50%;
 margin-top: 10px;
 background-color: rgba(255, 255, 255, 0.3);
 transition: background-color 0.3s ease 0s;
}
.controller-item:hover {
 background-color: rgba(255, 255, 255, 0.7);
}
.controller-item.current {
 background-color: rgba(255, 255, 255, 1);
}
.prev-btn,.next-btn {
 cursor: pointer;
 display: block;
 text-align: center;
 width: 20px;
 height: 20px;
 position: fixed;
 left: 50%;
 margin-left: -10px;
 border: 4px solid #fff;
 background-color: transparent;
 outline: none;
}
.prev-btn {
 top: 80px;
 transform: rotate(-45deg);
 border-bottom-color: transparent;
 border-left-color: transparent;
}
.next-btn {
 bottom: 80px;
 transform: rotate(45deg);
 border-top-color: transparent;
 border-left-color: transparent;
}
.prev-btn.moving {
 animation: prev-up-down 0.7s linear 0s infinite;
}
.next-btn.moving {
 animation: next-up-down 0.7s linear 0s infinite;
}
@keyframes next-up-down {
 0% {
 transform: translate3d(0,0,0) rotate(45deg);
 }
 25% {
 transform: translate3d(0,6px,0) rotate(45deg);
 }
 50% {
 transform: translate3d(0,0,0) rotate(45deg);
 }
 75% {
 transform: translate3d(0,-6px,0) rotate(45deg);
 }
 100% {
 transform: translate3d(0,0,0) rotate(45deg);
 }
}
@keyframes prev-up-down {
 0% {
 transform: translate3d(0,0,0) rotate(-45deg);
 }
 25% {
 transform: translate3d(0,-6px,0) rotate(-45deg);
 }
 50% {
 transform: translate3d(0,0,0) rotate(-45deg);
 }
 75% {
 transform: translate3d(0,6px,0) rotate(-45deg);
 }
 100% {
 transform: translate3d(0,0,0) rotate(-45deg);
 }
}
</style>