const express = require('express')
const cors = require('cors')
const multer = require('multer')
const path = require('path')
const fs = require('fs-extra')
const { calculateFileMD5 } = require('./utils.js')
const { initDatabase, FileService } = require('../database/database.js')

const app = express()
const PORT = 3000

// 初始化数据库
initDatabase()
const fileService = new FileService()

// 确保上传目录存在
const uploadDir = path.join(process.cwd(), 'uploads')
fs.ensureDirSync(uploadDir)

// 配置 multer - 修复中文文件名问题
const storage = multer.diskStorage({
    destination: (req, file, cb) => {
        cb(null, uploadDir)
    },
    filename: (req, file, cb) => {
        // 处理中文文件名 - 使用原始文件名但确保安全
        const originalName = Buffer.from(file.originalname, 'latin1').toString('utf8')
        const ext = path.extname(originalName)
        const name = path.basename(originalName, ext)

        // 清理文件名，移除特殊字符
        const safeName = name.replace(/[^a-zA-Z0-9\u4e00-\u9fa5]/g, '_')
        const uniqueSuffix = Date.now() + '-' + Math.round(Math.random() * 1E9)
        const filename = safeName + '-' + uniqueSuffix + ext

        cb(null, filename)
    }
})

const upload = multer({
    storage,
    fileFilter: (req, file, cb) => {
        // 处理文件名编码
        file.originalname = Buffer.from(file.originalname, 'latin1').toString('utf8')
        cb(null, true)
    }
})

// 设置响应头，确保使用 UTF-8 编码
app.use((req, res, next) => {
    res.setHeader('Content-Type', 'application/json; charset=utf-8')
    next()
})

app.use(cors())
app.use(express.json({ limit: '50mb' }))
app.use(express.urlencoded({ extended: true, limit: '50mb' }))

// 文件上传接口
app.post('/api/upload', upload.single('file'), async (req, res) => {
    try {
        if (!req.file) {
            return res.status(400).json({ error: 'No file uploaded' })
        }

        // 确保文件名正确编码
        const originalName = Buffer.from(req.file.originalname, 'latin1').toString('utf8')

        const fileInfo = {
            originalName: originalName,
            fileName: req.file.filename,
            filePath: req.file.path,
            fileSize: req.file.size,
            mimeType: req.file.mimetype
        }

        // 计算 MD5
        const md5 = await calculateFileMD5(req.file.path)

        // 保存到数据库
        const fileRecord = await fileService.createFile({
            ...fileInfo,
            md5
        })

        res.json({
            success: true,
            data: fileRecord
        })
    } catch (error) {
        console.error('Upload error:', error)
        res.status(500).json({ error: 'Upload failed: ' + error.message })
    }
})

// 获取文件列表（分页）
app.get('/api/files', async (req, res) => {
    try {
        const page = parseInt(req.query.page) || 1
        const pageSize = parseInt(req.query.pageSize) || 10

        const result = await fileService.getFilesPaginated(page, pageSize)

        // 确保返回的数据使用 UTF-8 编码
        res.json(result)
    } catch (error) {
        console.error('Get files error:', error)
        res.status(500).json({ error: 'Failed to get files' })
    }
})

// 其他接口保持不变...
app.post('/api/files/:id/check-md5', async (req, res) => {
    try {
        const fileId = parseInt(req.params.id)
        const file = await fileService.getFileById(fileId)

        if (!file) {
            return res.status(404).json({ error: 'File not found' })
        }

        const currentMD5 = await calculateFileMD5(file.filePath)
        const isChanged = currentMD5 !== file.md5

        res.json({
            isChanged,
            currentMD5,
            originalMD5: file.md5,
            file
        })
    } catch (error) {
        console.error('MD5 check error:', error)
        res.status(500).json({ error: 'MD5 check failed' })
    }
})

app.put('/api/files/:id/update-md5', async (req, res) => {
    try {
        const fileId = parseInt(req.params.id)
        const { md5 } = req.body

        await fileService.updateFileMD5(fileId, md5)
        res.json({ success: true })
    } catch (error) {
        console.error('Update MD5 error:', error)
        res.status(500).json({ error: 'Update failed' })
    }
})

// 健康检查接口
app.get('/api/health', (req, res) => {
    res.json({
        status: 'OK',
        timestamp: new Date().toISOString(),
        service: 'file-management-api'
    })
})

function startServer() {
    app.listen(PORT, () => {
        console.log(`Server running on http://localhost:${PORT}`)
    })
}

module.exports = { startServer }