<template>
	<view class="imageUploadContainer">
		<view class="imageUploadList">
			<view class="imageItem" v-bind:key="index" v-for="(path,index) in imageListData">
				<image :src="BASE_URL+path.url" :class="{'dragging':isDragging(index)}" draggable="true"
					@tap="previewImage" :data-index="index" @touchstart="start" @touchmove.stop.prevent="move"
					@touchend="stop"></image>
				<view v-if="isShowDel" class="imageDel" @tap="deleteImage" :data-index="index">x</view>
			</view>
			<view v-if="isShowAdd" class="imageUpload" style="border: 0px;" @tap="selectImage">
				<image src="/static/voucher_bg.png" class="imageUpload" style="border: 0px;"></image>
			</view>
		</view>
		<image v-if="showMoveImage" class="moveImage" :style="{left:posMoveImageLeft, top:posMoveImageTop}"
			:src="moveImagePath"></image>
	</view>
</template>

<script>
	import BASE_URL from '@/common/config.js'
	export default {

		name: 'robby-image-upload',
		props: ['value', 'enableDel', 'enableAdd', 'enableDrag', 'serverUrl', 'formData', 'header', 'limit', 'fileKeyName',
			'showUploadProgress', 'serverUrlDeleteImage'
		],
		data() {
			return {
				BASE_URL,
				imageBasePos: {
					x0: -1,
					y0: -1,
					w: -1,
					h: -1,
				},
				showMoveImage: false,
				moveImagePath: '',
				moveLeft: 0,
				moveTop: 0,
				deltaLeft: 0,
				deltaTop: 0,
				dragIndex: null,
				targetImageIndex: null,
				imageList: [],
				isDestroyed: false
			}
		},
		mounted: function() {
			this.imageList = this.value

			if (this.showUploadProgress === false) {
				this.showUploadProgress = false
			} else {
				this.showUploadProgress = true
			}
		},
		destroyed: function() {
			this.isDestroyed = true
		},
		computed: {
			imageListData: function() {
				if (this.value) {
					return this.value
				}
			},
			posMoveImageLeft: function() {
				return this.moveLeft + 'px'
			},
			posMoveImageTop: function() {
				return this.moveTop + 'px'
			},
			isShowDel: function() {
				if (this.enableDel === false) {
					return false
				} else {
					return true
				}
			},
			isShowAdd: function() {
				if (this.enableAdd === false) {
					return false
				}

				if (this.limit && this.imageList.length >= this.limit) {
					return false
				}

				return true
			},
			isDragable: function() {
				if (this.enableDrag === false) {
					return false
				} else {
					return true
				}
			}
		},
		methods: {
			selectImage: function() {
				var _self = this
				if (!_self.imageList) {
					_self.imageList = []
				}

				uni.chooseImage({
					count: _self.limit ? (_self.limit - _self.imageList.length) : 999,
					success: function(e) {
						var imagePathArr = e.tempFilePaths

						//如果设置了limit限制，在web上count参数无效，这里做判断控制选择的数量是否合要求
						//在非微信小程序里，虽然可以选多张，但选择的结果会被截掉
						//在app里，会自动做选择数量的限制
						if (_self.limit) {
							var availableImageNumber = _self.limit - _self.imageList.length
							if (availableImageNumber < imagePathArr.length) {
								uni.showToast({
									title: '图片总数限制为' + _self.limit + '张，当前还可以选' +
										availableImageNumber + '张',
									icon: 'none',
									mask: false,
									duration: 2000
								});
								return
							}
						}

						//检查服务器地址是否设置，设置即表示图片要上传到服务器
						if (_self.serverUrl) {
							uni.showToast({
								title: '上传进度：0/' + imagePathArr.length,
								icon: 'none',
								mask: false
							});

							var remoteIndexStart = _self.imageList.length - imagePathArr.length
							var promiseWorkList = []
							var keyname = (_self.fileKeyName ? _self.fileKeyName : 'upload-images')
							var completeImages = 0

							for (let i = 0; i < imagePathArr.length; i++) {
								promiseWorkList.push(new Promise((resolve, reject) => {
									let remoteUrlIndex = remoteIndexStart + i
									uni.uploadFile({
										url: _self.serverUrl,
										fileType: 'image',
										header: _self.header,
										formData: _self.formData,
										filePath: imagePathArr[i],
										name: keyname,
										success: function(res) {
											if (res.statusCode === 200) {
												if (_self.isDestroyed) {
													return
												}

												completeImages++

												if (_self.showUploadProgress) {
													uni.showToast({
														title: '上传进度：' +
															completeImages +
															'/' +
															imagePathArr
															.length,
														icon: 'none',
														mask: false,
														duration: 500
													});
												}
												console.log(
													'success to upload image: ' +
													res.data)
												resolve(res.data)
											} else {
												console.log(
													'fail to upload image:' +
													res.data)
												reject('fail to upload image:' +
													remoteUrlIndex)
											}
										},
										fail: function(res) {
											console.log('fail to upload image:' +
												res)
											reject('fail to upload image:' +
												remoteUrlIndex)
										}
									})
								}))
							}
							Promise.all(promiseWorkList).then((result) => {
								if (_self.isDestroyed) {
									return
								}

								for (let i = 0; i < result.length; i++) {
									_self.imageList.push(JSON.parse(result[i]).data)
								}

								_self.$emit('add', {
									currentImages: imagePathArr,
									allImages: _self.imageList
								})
								_self.$emit('input', _self.imageList)
							})
						} else {
							for (let i = 0; i < imagePathArr.length; i++) {
								_self.imageList.push(imagePathArr[i])
							}

							_self.$emit('add', {
								currentImages: imagePathArr,
								allImages: _self.imageList
							})
							_self.$emit('input', _self.imageList)
						}
					}
				})
			},
			deleteImage: function(e) {
				var imageIndex = e.currentTarget.dataset.index
				var deletedImagePath = this.imageList[imageIndex]
				this.imageList.splice(imageIndex, 1)

				//检查删除图片的服务器地址是否设置，如果设置则调用API，在服务器端删除该图片
				if (this.serverUrlDeleteImage) {
					uni.request({
						url: this.serverUrlDeleteImage,
						method: 'GET',
						data: {
							imagePath: deletedImagePath
						},
						success: res => {
							console.log(res.data)
						}
					});
				}

				this.$emit('delete', {
					currentImage: deletedImagePath,
					allImages: this.imageList
				})
				this.$emit('input', this.imageList)
			},
			previewImage: function(e) {
				var imageIndex = e.currentTarget.dataset.index
				uni.previewImage({
					current: this.imageList[imageIndex],
					indicator: "number",
					loop: "true",
					urls: this.imageList
				})
			},
			initImageBasePos: function() {
				let paddingRate = 0.024
				var _self = this
				//计算图片基准位置
				uni.getSystemInfo({
					success: function(obj) {
						let screenWidth = obj.screenWidth
						let leftPadding = Math.ceil(paddingRate * screenWidth)
						let imageWidth = Math.ceil((screenWidth - 2 * leftPadding) / 4)

						_self.imageBasePos.x0 = leftPadding
						_self.imageBasePos.w = imageWidth
						_self.imageBasePos.h = imageWidth
					}
				})
			},
			findOverlapImage: function(posX, posY) {
				let rows = Math.floor((posX - this.imageBasePos.x0) / this.imageBasePos.w)
				let cols = Math.floor((posY - this.imageBasePos.y0) / this.imageBasePos.h)
				let indx = cols * 4 + rows
				return indx
			},
			isDragging: function(indx) {
				return this.dragIndex === indx
			},
			start: function(e) {
				console.log(this.isDragable)
				if (!this.isDragable) {
					return
				}
				this.dragIndex = e.currentTarget.dataset.index
				this.moveImagePath = this.imageList[this.dragIndex]
				this.showMoveImage = true

				//计算纵向图片基准位置
				if (this.imageBasePos.y0 === -1) {
					this.initImageBasePos()

					let basePosY = Math.floor(this.dragIndex / 4) * this.imageBasePos.h
					let currentImageOffsetTop = e.currentTarget.offsetTop
					this.imageBasePos.y0 = currentImageOffsetTop - basePosY
				}

				//设置选中图片当前左上角的坐标
				this.moveLeft = e.target.offsetLeft
				this.moveTop = e.target.offsetTop
			},
			move: function(e) {
				if (!this.isDragable) {
					return
				}
				const touch = e.touches[0]
				this.targetImageIndex = this.findOverlapImage(touch.clientX, touch.clientY)

				//初始化deltaLeft/deltaTop
				if (this.deltaLeft === 0) {
					this.deltaLeft = touch.clientX - this.moveLeft
					this.deltaTop = touch.clientY - this.moveTop
				}

				//设置移动图片位置
				this.moveLeft = touch.clientX - this.deltaLeft
				this.moveTop = touch.clientY - this.deltaTop
			},
			stop: function(e) {
				if (!this.isDragable) {
					return
				}
				if (this.dragIndex !== null && this.targetImageIndex !== null) {
					if (this.targetImageIndex < 0) {
						this.targetImageIndex = 0
					}

					if (this.targetImageIndex >= this.imageList.length) {
						this.targetImageIndex = this.imageList.length - 1
					}
					//交换图片
					if (this.dragIndex !== this.targetImageIndex) {
						this.imageList[this.dragIndex] = this.imageList[this.targetImageIndex]
						this.imageList[this.targetImageIndex] = this.moveImagePath
					}
				}

				this.dragIndex = null
				this.targetImageIndex = null
				this.deltaLeft = 0
				this.deltaTop = 0
				this.showMoveImage = false

				this.$emit('input', this.imageList)
			}
		}
	}
</script>

<style>
	.imageUploadContainer {
		padding: 10upx 5upx;
		margin: 10upx 5upx;
	}
	.dragging {
		transform: scale(1.2)
	}
	.imageUploadList {
		display: flex;
		flex-wrap: wrap;
	}
	.imageItem, .imageUpload {
		width: 160rpx;
		height: 160rpx;
		border-radius: 10rpx;
		margin-right: 20rpx;
	}
	.imageDel {
		position: relative;
		left: 120upx;
		bottom: 165upx;
		background-color: rgba(0, 0, 0, 0.5);
		width: 36upx;
		text-align: center;
		line-height: 35upx;
		border-radius: 17upx;
		color: white;
		font-size: 30upx;
		padding-bottom: 2upx;
	}
	.imageItem image, .moveImage {
		width: 160upx;
		height: 160upx;
		border-radius: 8upx;
	}
	.imageUpload {
		line-height: 130upx;
		text-align: center;
		font-size: 150upx;
		color: #D9D9D9;
		border: 1px solid #D9D9D9;
		border-radius: 8upx;
	}
	.moveImage {
		position: absolute;
	}
</style>
