package controller

import (
	"fmt"
	"io"
	"log"
	"net/http"
	"path"
	"strconv"
	"strings"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/pkg/sftp"
	"golang.org/x/crypto/ssh"
	"gorm.io/gorm"

	"ezops/model"
)

// SFTPHandler 文件浏览器处理器 — 基于 SFTP 的服务器文件管理
type SFTPHandler struct {
	db *gorm.DB
}

func NewSFTPHandler(db *gorm.DB) *SFTPHandler {
	return &SFTPHandler{db: db}
}

// sftpClient 建立到目标服务器的 SFTP 连接
func (h *SFTPHandler) sftpClient(serverID uint) (*sftp.Client, *ssh.Client, error) {
	var server model.Server
	if err := h.db.First(&server, serverID).Error; err != nil {
		return nil, nil, fmt.Errorf("server not found: %w", err)
	}

	sshConfig := &ssh.ClientConfig{
		User:    server.Username,
		Timeout: 10 * time.Second,
		HostKeyCallback: ssh.InsecureIgnoreHostKey(),
	}

	switch server.AuthType {
	case "key":
		signer, err := ssh.ParsePrivateKey([]byte(server.SSHKey))
		if err != nil {
			sshConfig.Auth = []ssh.AuthMethod{ssh.Password(server.Password)}
		} else {
			sshConfig.Auth = []ssh.AuthMethod{ssh.PublicKeys(signer)}
		}
	default:
		sshConfig.Auth = []ssh.AuthMethod{ssh.Password(server.Password)}
	}

	addr := fmt.Sprintf("%s:%d", server.IP, server.Port)
	sshClient, err := ssh.Dial("tcp", addr, sshConfig)
	if err != nil {
		return nil, nil, fmt.Errorf("SSH connect failed: %w", err)
	}

	sftpClient, err := sftp.NewClient(sshClient)
	if err != nil {
		sshClient.Close()
		return nil, nil, fmt.Errorf("SFTP init failed: %w", err)
	}

	return sftpClient, sshClient, nil
}

// FileInfo JSON 响应结构
type FileItem struct {
	Name    string `json:"name"`
	Path    string `json:"path"`
	Size    int64  `json:"size"`
	IsDir   bool   `json:"is_dir"`
	ModTime string `json:"mod_time"`
	Mode    string `json:"mode"`
}

// ListFiles 列出目录内容
// GET /api/v1/servers/:id/files?path=/
func (h *SFTPHandler) ListFiles(c *gin.Context) {
	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid server id"})
		return
	}

	dirPath := c.Query("path")
	if dirPath == "" {
		dirPath = "/"
	}

	sftpClient, sshClient, err := h.sftpClient(uint(id))
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	defer sshClient.Close()
	defer sftpClient.Close()

	entries, err := sftpClient.ReadDir(dirPath)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("read dir failed: %v", err)})
		return
	}

	var items []FileItem
	for _, entry := range entries {
		items = append(items, FileItem{
			Name:    entry.Name(),
			Path:    path.Join(dirPath, entry.Name()),
			Size:    entry.Size(),
			IsDir:   entry.IsDir(),
			ModTime: entry.ModTime().Format("2006-01-02 15:04:05"),
			Mode:    entry.Mode().String(),
		})
	}

	// 构建面包屑
	breadcrumbs := buildBreadcrumbs(dirPath)

	c.JSON(http.StatusOK, gin.H{
		"path":        dirPath,
		"breadcrumbs": breadcrumbs,
		"items":       items,
	})
}

// DownloadFile 下载文件
// GET /api/v1/servers/:id/files/download?path=/etc/hosts
func (h *SFTPHandler) DownloadFile(c *gin.Context) {
	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid server id"})
		return
	}

	filePath := c.Query("path")
	if filePath == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "path required"})
		return
	}

	sftpClient, sshClient, err := h.sftpClient(uint(id))
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	defer sshClient.Close()
	defer sftpClient.Close()

	stat, err := sftpClient.Stat(filePath)
	if err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "file not found"})
		return
	}
	if stat.IsDir() {
		c.JSON(http.StatusBadRequest, gin.H{"error": "cannot download directory"})
		return
	}

	file, err := sftpClient.Open(filePath)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "open failed"})
		return
	}
	defer file.Close()

	fileName := path.Base(filePath)
	c.Header("Content-Disposition", fmt.Sprintf(`attachment; filename="%s"`, fileName))
	c.Header("Content-Type", "application/octet-stream")
	c.Header("Content-Length", fmt.Sprintf("%d", stat.Size()))
	io.Copy(c.Writer, file)
}

// UploadFile 上传文件
// POST /api/v1/servers/:id/files/upload?path=/tmp/
func (h *SFTPHandler) UploadFile(c *gin.Context) {
	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid server id"})
		return
	}

	dirPath := c.Query("path")
	if dirPath == "" {
		dirPath = "/tmp/"
	}

	file, header, err := c.Request.FormFile("file")
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "no file uploaded"})
		return
	}
	defer file.Close()

	sftpClient, sshClient, err := h.sftpClient(uint(id))
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	defer sshClient.Close()
	defer sftpClient.Close()

	destPath := path.Join(dirPath, header.Filename)
	dest, err := sftpClient.Create(destPath)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "create file failed"})
		return
	}
	defer dest.Close()

	written, err := io.Copy(dest, file)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "write failed"})
		return
	}

	log.Printf("[SFTP] Uploaded %s (%d bytes) to server %d", destPath, written, id)
	c.JSON(http.StatusOK, gin.H{"message": "uploaded", "path": destPath, "size": written})
}

// DeleteFile 删除文件或空目录
// DELETE /api/v1/servers/:id/files?path=/tmp/test.txt
func (h *SFTPHandler) DeleteFile(c *gin.Context) {
	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid server id"})
		return
	}

	filePath := c.Query("path")
	if filePath == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "path required"})
		return
	}

	sftpClient, sshClient, err := h.sftpClient(uint(id))
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	defer sshClient.Close()
	defer sftpClient.Close()

	stat, err := sftpClient.Stat(filePath)
	if err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "not found"})
		return
	}

	if stat.IsDir() {
		if err := sftpClient.RemoveDirectory(filePath); err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "remove dir failed (may not be empty)"})
			return
		}
	} else {
		if err := sftpClient.Remove(filePath); err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "remove failed"})
			return
		}
	}

	c.JSON(http.StatusOK, gin.H{"message": "deleted"})
}

// Mkdir 创建目录
// POST /api/v1/servers/:id/files/mkdir
func (h *SFTPHandler) Mkdir(c *gin.Context) {
	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid server id"})
		return
	}

	var req struct {
		Path string `json:"path"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "path required"})
		return
	}

	sftpClient, sshClient, err := h.sftpClient(uint(id))
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	defer sshClient.Close()
	defer sftpClient.Close()

	if err := sftpClient.MkdirAll(req.Path); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "mkdir failed"})
		return
	}

	c.JSON(http.StatusOK, gin.H{"message": "created", "path": req.Path})
}

// buildBreadcrumbs 构建路径面包屑
func buildBreadcrumbs(dirPath string) []map[string]string {
	if dirPath == "/" || dirPath == "" {
		return []map[string]string{{"name": "/", "path": "/"}}
	}

	parts := strings.Split(strings.Trim(dirPath, "/"), "/")
	var crumbs []map[string]string
	crumbs = append(crumbs, map[string]string{"name": "/", "path": "/"})

	accum := ""
	for _, part := range parts {
		if part == "" {
			continue
		}
		accum += "/" + part
		crumbs = append(crumbs, map[string]string{
			"name": part,
			"path": accum,
		})
	}

	return crumbs
}