<template>
    <div class="upload-container">
        <el-upload ref="upload" class="upload-demo" drag action="#" multiple :show-file-list="true"
            :before-upload="beforeUpload" :on-remove="handleRemove" :on-change="handleFileChange"
            :on-exceed="handleExceed" :file-list="files" :accept="accept" :limit="limitUploadNum"
            :auto-upload="autoUpload" :http-request="customUpload" :disabled="disabled">

            <div class="upload-content">
                <!-- 默认上传区域 -->
                <div class="upload-text">
                    <div class="main-text"> + 点击或将文件拖拽到这里上传</div>
                    <div class="tip-text">
                        <div v-if="limitUploadNum > 1">最多可上传 {{ limitUploadNum }} 个文件，</div>
                        <div>单份文件大小上限 {{ maxFileTips }}，</div>
                        <div>支持文件类型：{{ uploadType }}</div>
                    </div>
                </div>
            </div>
        </el-upload>
    </div>
</template>

<script>
import {
    uploadSmallFileByOcr,
    uploadLargeFileByOcr,
    uploadSmallFile,
    uploadLargeFile,
} from '@/api/common/uploadFile.js'

export default {
    name: 'UploadFile',
    props: {
        fileList: {
            type: Array,
            default: () => [],
        },
        maxFileTips: {
            type: String,
            default: '20MB',
        },
        uploadType: {
            type: String,
            default: 'png、jpg、jpeg',
        },
        limitUploadNum: {
            type: Number,
            default: 5,
        },
        fileUploadRule: {
            type: Object,
            default: () => ({}),
        },
        autoUpload: {
            type: Boolean,
            default: true,
        },
        type: {
            type: String,
            default: '',
        },
        disabled: {
            type: Boolean,
            default: false,
        },
    },
    data() {
        return {
            files: [],
            isUploading: false,
            uploadingFiles: new Set(),
            defaultFileSize: 1024 * 1024 * 5,
            uploadControllers: new Map(),
        }
    },
    computed: {
        accept() {
            return this.uploadType
                .split('、')
                .map((type) => `.${type}`)
                .join(',')
        },
        allowedTypes() {
            return this.uploadType.split('、')
        },
        maxSizeMB() {
            const sizeStr = this.maxFileTips.toLowerCase()
            if (sizeStr.includes('mb')) {
                return parseFloat(sizeStr)
            } else if (sizeStr.includes('kb')) {
                return parseFloat(sizeStr) / 1024
            } else if (sizeStr.includes('gb')) {
                return parseFloat(sizeStr) * 1024
            }
            return 20
        },
        mimeTypes() {
            const typeMap = {
                png: 'image/png',
                jpg: 'image/jpeg',
                jpeg: 'image/jpeg',
                pdf: 'application/pdf',
                doc: 'application/msword',
                docx: 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
                xls: 'application/vnd.ms-excel',
                xlsx: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
            }
            return this.allowedTypes.map((type) => typeMap[type] || '')
        },
    },
    watch: {
        fileList: {
            handler(newVal) {

                if (this.files.length === 0 && newVal.length > 0) {
                    this.$nextTick(() => {
                        if (this.$refs.upload) {
                            this.$refs.upload.uploadFiles = this.formatFileList(newVal)
                        }
                        this.files = this.formatFileList(newVal)
                    })
                }
            },
            immediate: true,
            deep: true
        },
    },
    methods: {
        beforeUpload(file) {
            const fileExtension = file.name.split('.').pop().toLowerCase()
            const isAllowedType = this.allowedTypes.includes(fileExtension)
            const isAllowedMimeType = this.mimeTypes.includes(file.type)
            const isLtMaxSize = file.size / 1024 / 1024 < this.maxSizeMB

            if (!isAllowedType || !isAllowedMimeType) {
                this.$message.error(`只能上传 ${this.uploadType} 格式的文件!`)
                return false
            }

            if (!isLtMaxSize) {
                this.$message.error(`文件大小不能超过 ${this.maxFileTips}!`)
                return false
            }

            if (this.files.length > this.limitUploadNum) {
                this.$message.error(`最多只能上传 ${this.limitUploadNum} 个文件!`)
                return false
            }

            return true
        },

        handleFileChange(file, fileList) {
            if (file.status === 'removed' || file.status === 'fail' || file.status === 'success') {
                return
            }

            this.files = this.formatFileList(fileList)

            if (this.autoUpload && file.status === 'ready' && !this.isUploading) {
                this.$nextTick(() => {
                    this.uploadFile(file)
                })
            }
        },

        async uploadFile(file) {
            if (this.uploadingFiles.has(file.uid)) {
                return
            }

            const controller = new AbortController()
            this.uploadControllers.set(file.uid, controller)
            this.uploadingFiles.add(file.uid)
            this.isUploading = true

            const formData = new FormData()
            formData.append('file', file.raw)
            formData.append('params', JSON.stringify(this.fileUploadRule))

            this.updateFileStatus(
                file.uid,
                'uploading',
                this.fileUploadRule.fields_json ? '识别中' : '上传中',
                null,
                0,
            )

            try {
                this.$bus.$emit(
                    'startUpload',
                    this.fileUploadRule.fields_json ? '识别中' : '上传中',
                )

                let res = null
                if (this.defaultFileSize < file.size) {
                    if (this.fileUploadRule.fields_json) {
                        res = await uploadLargeFileByOcr(formData, {
                            signal: controller.signal,
                            onUploadProgress: (progressEvent) => {
                                if (progressEvent.lengthComputable) {
                                    const percentComplete = Math.round(
                                        (progressEvent.loaded * 100) / progressEvent.total
                                    )
                                    this.updateFileStatus(file.uid, 'uploading', '', null, percentComplete)
                                }
                            }
                        })
                    } else {
                        res = await uploadLargeFile(formData, {
                            signal: controller.signal,
                            onUploadProgress: (progressEvent) => {
                                if (progressEvent.lengthComputable) {
                                    const percentComplete = Math.round(
                                        (progressEvent.loaded * 100) / progressEvent.total
                                    )
                                    this.updateFileStatus(file.uid, 'uploading', '', null, percentComplete)
                                }
                            }
                        })
                    }
                } else {
                    if (this.fileUploadRule.fields_json) {
                        res = await uploadSmallFileByOcr(formData, {
                            signal: controller.signal
                        })
                    } else {
                        res = await uploadSmallFile(formData, {
                            signal: controller.signal
                        })
                    }
                }

                if (res.code === 200) {
                    this.handleSuccess(res, file)
                } else {
                    this.handleError(new Error(res.message || '上传失败'), file)
                }
            } catch (err) {
                if (err.name === 'AbortError') {
                    console.log('上传已取消:', file.name)
                } else {
                    this.handleError(err, file)
                }
            } finally {
                this.uploadingFiles.delete(file.uid)
                this.uploadControllers.delete(file.uid)
                this.isUploading = this.uploadingFiles.size > 0
            }
        },

        async customUpload(options) {
            const { file } = options
            const uploadFileObj = this.findFileByRawFile(file)
            if (!uploadFileObj) {
                console.error('未找到对应的文件对象')
                return
            }
            this.uploadFile(uploadFileObj)
        },

        handleSuccess(response, file) {
            this.$bus.$emit('endUpload')
            this.updateFileStatus(file.uid, 'success', '', response.data, 100)
            this.$emit('file-change', this.getCurrentFiles(), this.type)
        },

        handleError(error, file) {
            console.error('上传失败:', error)
            this.$bus.$emit('endUpload')
            this.updateFileStatus(file.uid, 'fail', error.message)
            this.$emit('file-change', this.getCurrentFiles(), this.type)
        },

        handleExceed(files, fileList) {
            // 将 FileList 转换为数组
            const filesArray = Array.from(files);
            // 如果只允许上传一个文件，则替换现有文件
            if (this.limitUploadNum === 1) {
                
                // 触发删除事件
                this.$emit('del-file', { ...fileList[0], response: fileList[0].res })
                // 清空文件列表
                this.files = [];

                // 更新 el-upload 的文件列表
                this.$nextTick(() => {
                    if (this.$refs.upload) {
                        this.$refs.upload.uploadFiles = [];
                    }

                    // 添加新文件（只取第一个）
                    if (filesArray.length > 0) {
                        const newFileObj = this.createFileObject(filesArray[0]);
                        this.files.push(newFileObj);

                        if (this.autoUpload) {
                            this.$nextTick(() => {
                                this.uploadFile(newFileObj);
                            });
                        }
                    }
                });

                this.$message.success('文件已替换');
            } else {
                // 多文件模式：保持原有逻辑
                this.$message.warning(`最多只能上传 ${this.limitUploadNum} 个文件，已自动截取前 ${this.limitUploadNum} 个文件`);

                const remainingSlots = this.limitUploadNum - this.files.length;

                if (remainingSlots > 0) {
                    const filesToAdd = filesArray.slice(0, remainingSlots);
                    filesToAdd.forEach(file => {
                        const newFileObj = this.createFileObject(file);
                        this.files.push(newFileObj);

                        if (this.autoUpload) {
                            this.$nextTick(() => {
                                this.uploadFile(newFileObj);
                            });
                        }
                    });
                }
            }
        },

        handleRemove(file, fileList) {
            if (file == null) {
                return true
            }

            if (file.status === 'uploading') {
                this.cancelUpload(file)
            }

            const delFileObj = this.findFileByRawFile(file.raw)
            if (delFileObj) {
                delFileObj.response = delFileObj.res
                this.$emit('del-file', delFileObj)
            }

            this.files = this.formatFileList(fileList)
            this.$emit('file-change', this.getCurrentFiles(), this.type)
            return true
        },

        cancelUpload(file) {
            const controller = this.uploadControllers.get(file.uid)
            if (controller) {
                controller.abort()
            }
            this.updateFileStatus(file.uid, 'fail', '上传已取消')
            this.uploadingFiles.delete(file.uid)
            this.uploadControllers.delete(file.uid)
        },

        createFileObject(file) {
            return {
                name: file.name,
                size: file.size,
                type: file.type,
                raw: file,
                uid: Date.now() + Math.random(),
                status: 'ready',
                percentage: 0,
            }
        },

        findFileByRawFile(rawFile) {
            return this.files.find(item =>
                item.raw === rawFile ||
                (item.name === rawFile.name && item.size === rawFile.size)
            )
        },

        updateFileStatus(fileUid, status, statusText, responseData = null, percentage = null) {
            const fileIndex = this.files.findIndex(item => item.uid === fileUid)
            if (fileIndex !== -1) {
                const updatedFile = {
                    ...this.files[fileIndex],
                    status: status,
                }

                if (statusText) {
                    updatedFile.statusText = statusText
                }

                if (percentage !== null && percentage >= 0 && percentage <= 100) {
                    updatedFile.percentage = percentage
                } else if (status === 'uploading') {
                    updatedFile.percentage = 0
                } else if (status === 'success') {
                    updatedFile.percentage = 100
                }

                if (responseData) {
                    updatedFile.response = responseData
                    updatedFile.response.businessType = this.fileUploadRule?.fileUploadType
                    updatedFile.res = updatedFile.response
                }

                this.$set(this.files, fileIndex, updatedFile)
            }
        },

        formatFileList(fileList) {
            return fileList.map((file) => {
                const formattedFile = {
                    uid: file.uid,
                    name: file.name,
                    size: file.size,
                    type: file.type,
                    status: file.status,
                    raw: file.raw,
                }

                if (file.percentage !== undefined && file.percentage !== null) {
                    formattedFile.percentage = Math.max(0, Math.min(100, file.percentage))
                } else if (file.status === 'uploading') {
                    formattedFile.percentage = 0
                } else if (file.status === 'success') {
                    formattedFile.percentage = 100
                }

                // 保留其他属性
                if (file.response) {
                    formattedFile.response = file.response
                    formattedFile.res = file.response
                }
                if (file.filePath) formattedFile.filePath = file.filePath
                if (file.statusText) formattedFile.statusText = file.statusText

                return formattedFile
            })
        },

        getCurrentFiles() {
            return this.files.map((file) => {
                const fileObj = {
                    uid: file.uid,
                    name: file.name,
                    size: file.size,
                    type: file.type,
                    status: file.status,
                }

                if (file.raw) {
                    fileObj.raw = file.raw
                }

                if (file.response) {
                    fileObj.response = file.response
                    fileObj.response.businessType = this.fileUploadRule?.fileUploadType
                }

                return fileObj
            })
        },
    },
}
</script>

<style scoped lang="scss">
.upload-container {
    width: 100%;

    .upload-demo {
        width: 100%;

        ::v-deep .el-upload {
            width: 100%;

            .el-upload-dragger {
                width: 100%;
                height: 160px;
                border: 2px dashed #dcdfe6;
                border-radius: 8px;
                background-color: #fafafa;
                display: flex;
                align-items: center;
                justify-content: center;
                transition: all 0.3s ease;

                &:hover {
                    border-color: #409eff;
                    background-color: #f5f7fa;
                }
            }
        }
    }

    .upload-content {
        width: 100%;
        height: 100%;
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
        padding: 20px;

        .upload-text {
            text-align: center;

            .main-text {
                font-size: 16px;
                color: #1f72ea;
                margin-bottom: 8px;
                font-weight: 500;
            }

            .tip-text {
                font-size: 14px;
                color: #909399;
                line-height: 1.4;

                div {
                    margin-bottom: 2px;
                }
            }
        }
    }
}
</style>