<template>
	<div class="side-nav" @mouseenter="isFade = false" :class="{ 'is-fade': isFade }" :style="navStyle">
		<ul>
			<li class="nav-item" v-for="(item, key) in data.filter(a => !a.hidden)" :key="key">
				<a v-if="!item.path && !item.href" @click="expandMenu">{{item.name}}</a>
				<a v-if="item.href" :href="item.href" target="_blank">{{item.name}}</a>
				<router-link v-if="item.path" active-class="active" :to="base + item.path" exact v-text="item.title || item.name"></router-link>
				<ul class="pure-menu-list sub-nav" v-if="item.children">
					<li class="nav-item" v-for="(navItem, key) in item.children" :key="key">
						<router-link class="" active-class="active" :to="base + navItem.path" exact v-text="navItem.title || navItem.name"></router-link>
					</li>
				</ul>
				<template v-if="item.groups">
					<div class="nav-group" v-for="(group, key) in item.groups" :key="key">
						<div class="nav-group__title" @click="expandMenu">{{group.groupName}}</div>
						<ul class="pure-menu-list">
							<li class="nav-item" v-for="(navItem, key) in group.list" v-show="!navItem.disabled" :key="key">
								<router-link active-class="active" :to="base + navItem.path" exact v-text="navItem.title"></router-link>
							</li>
						</ul>
					</div>
				</template>
			</li>
		</ul>
		<!--<div id="code-sponsor-widget"></div>-->
	</div>
</template>
<script>
	export default {
		props: {
			data: Array,
			base: {
				type: String,
				default: ''
			}
		},
		data() {
			return {
				highlights: [],
				navState: [],
				isSmallScreen: false,
				isFade: false
			};
		},
		watch: {
			'$route.path'() {
				this.handlePathChange();
			},
			isFade(val) {
				this.$emit('navFade', val);
			}
		},
		computed: {
			navStyle() {
				const style = {};
				if (this.isSmallScreen) {
					style.paddingBottom = '60px';
				}
				style.opacity = this.isFade ? '0.5' : '1';
				return style;
			},
		},
		methods: {
			handleResize() {
				this.isSmallScreen = document.documentElement.clientWidth < 768;
				this.handlePathChange();
			},
			handlePathChange() {
				if (!this.isSmallScreen) {
					this.expandAllMenu();
					return;
				}
				this.$nextTick(() => {
					this.hideAllMenu();
					let activeAnchor = this.$el.querySelector('a.active');
					let ul = activeAnchor.parentNode;
					while (ul.tagName !== 'UL') {
						ul = ul.parentNode;
					}
					ul.style.height = 'auto';
				});
			},
			hideAllMenu() {
				[].forEach.call(this.$el.querySelectorAll('.pure-menu-list'), ul => {
					ul.style.height = '0';
				});
			},
			expandAllMenu() {
				[].forEach.call(this.$el.querySelectorAll('.pure-menu-list'), ul => {
					ul.style.height = 'auto';
				});
			},
			expandMenu(event) {
				if (!this.isSmallScreen) return;
				let target = event.currentTarget;
				if (!target.nextElementSibling || target.nextElementSibling.tagName !== 'UL') return;
				this.hideAllMenu();
				event.currentTarget.nextElementSibling.style.height = 'auto';
			}
		},
		created() {
			this.$on('fadeNav', () => {
				this.isFade = true;
			});
		},
		mounted() {
			this.handleResize();
			window.addEventListener('resize', this.handleResize);
		},
		beforeDestroy() {
			window.removeEventListener('resize', this.handleResize);
		}
	};
</script>
<style lang="less">
	.side-nav {
		width: 100%;
		box-sizing: border-box;
		padding-right: 30px;
		transition: opacity .3s;

		&.is-fade {
			transition: opacity 3s;
		}

		li {
			list-style: none;
		}

		ul {
			padding: 0;
			margin: 0;
			overflow: hidden;
		}

		>ul>.nav-item>a {
			margin-top: 15px;
		}

		>ul>.nav-item:nth-child(-n + 4)>a {
			margin-top: 0;
		}

		.nav-item {
			a {
				font-size: 16px;
				color: #333;
				line-height: 40px;
				height: 40px;
				margin: 0;
				padding: 0;
				text-decoration: none;
				display: block;
				position: relative;
				transition: .15s ease-out;
				font-weight: bold;

				&.active {
					color: #409EFF;
				}
			}

			.nav-item {
				a {
					display: block;
					height: 40px;
					color: #444;
					line-height: 40px;
					font-size: 14px;
					overflow: hidden;
					white-space: nowrap;
					text-overflow: ellipsis;
					font-weight: normal;

					&:hover,
					&.active {
						color: #409EFF;
					}
				}
			}

			&.sponsors {
				&>.sub-nav {
					margin-top: -10px;
				}

				&>a {
					color: #777;
					font-weight: 300;
					font-size: 14px;
				}

				.nav-item {
					display: inline-block;

					a {
						height: auto;
						display: inline-block;
						vertical-align: middle;
						margin: 8px 12px 12px 0;

						img {
							width: 42px;
						}
					}

					&:first-child a img {
						width: 36px;
					}
				}
			}
		}

		.nav-group__title {
			font-size: 12px;
			color: #999;
			line-height: 26px;
			margin-top: 15px;
		}

		#code-sponsor-widget {
			margin: 0 0 0 -20px;
		}
	}

	.nav-dropdown-list {
		width: 120px;
		margin-top: -8px;

		li {
			font-size: 14px;
		}
	}
</style>
