package mcpclient

import (
	"context"
	"fmt"
	"os"
	"path/filepath"
	"runtime"
	"strings"
	"time"

	"github.com/ituoke/ituoke/internal/runtimeassets"
	"github.com/modelcontextprotocol/go-sdk/mcp"
)

func filesystemCommand(c ServerConfig) (ServerConfig, error) {
	name := "node"
	if runtime.GOOS == "windows" {
		name += ".exe"
	}
	node := runtimeassets.Find(filepath.Join("mcp-filesystem", name))
	entry := runtimeassets.Find(filepath.Join("mcp-filesystem", "node_modules", "@modelcontextprotocol", "server-filesystem", "dist", "index.js"))
	if node == "" || entry == "" {
		return c, fmt.Errorf("缺少内置 Filesystem MCP 运行资源，请在构建机执行 npm --prefix runtime/filesystem run stage")
	}
	c.Command = node
	c.Args = append([]string{entry}, c.Args...)
	c.Transport = "stdio"
	c.WorkingDirectory = filepath.Dir(node)
	return c, nil
}

func validateFilesystemDirs(c ServerConfig) error {
	if c.Transport != "filesystem" {
		return nil
	}
	for _, dir := range c.Args {
		info, err := os.Stat(dir)
		if err != nil || !info.IsDir() {
			return fmt.Errorf("允许目录不存在或不可访问: %s", dir)
		}
	}
	return nil
}

// AddFilesystem adds the bundled official server without machine-specific launch
// paths. A dedicated data directory is used instead of exposing the user's home.
func (s *Service) AddFilesystem() (ServerView, error) {
	views, err := s.ListServers()
	if err != nil {
		return ServerView{}, err
	}
	for _, view := range views {
		if view.Config.Transport == "filesystem" {
			return view, nil
		}
	}
	if _, err := filesystemCommand(ServerConfig{}); err != nil {
		return ServerView{}, err
	}
	dir := filepath.Join(filepath.Dir(s.path), "files")
	if err := os.MkdirAll(dir, 0700); err != nil {
		return ServerView{}, err
	}
	return s.SaveServer(ServerInput{Config: ServerConfig{Name: "Filesystem", Enabled: true, Transport: "filesystem", Args: []string{dir}, TimeoutSeconds: 20}})
}

// TestFilesystem uses a temporary subdirectory and removes only its own probe
// files. Read/write, rename and denied outside-directory access are real calls.
func (s *Service) TestFilesystem(ctx context.Context, id string) TestResult {
	start := time.Now()
	result := TestResult{Tools: []ToolInfo{}}
	s.mu.Lock()
	var c ServerConfig
	err := s.loadErr
	if i := s.index(id); i >= 0 {
		c = s.servers[i]
	} else {
		err = fmt.Errorf("MCP 服务不存在")
	}
	s.mu.Unlock()
	if err == nil && c.Transport != "filesystem" {
		err = fmt.Errorf("请选择内置 Filesystem 服务")
	}
	if err == nil {
		c, err = normalize(c)
	}
	if err == nil {
		err = validateFilesystemDirs(c)
	}
	if err == nil {
		var cancel context.CancelFunc
		ctx, cancel = context.WithTimeout(ctx, time.Duration(c.TimeoutSeconds)*time.Second)
		defer cancel()
		result.Tools, err = discover(ctx, c, Secrets{})
		if err == nil {
			err = probeFilesystem(ctx, c)
		}
	}
	result.OK = err == nil
	result.ElapsedMs = time.Since(start).Milliseconds()
	if err != nil {
		result.Message = fmt.Sprintf("文件测试失败: %v", err)
	} else {
		result.Message = "文件测试通过：创建目录、中文文件写入与读取、搜索、重命名、目录外访问拒绝"
	}
	return result
}

func probeFilesystem(ctx context.Context, c ServerConfig) error {
	// The caller explicitly requested the write test; general connection testing
	// remains discovery-only for every service.
	dir, err := os.MkdirTemp(c.Args[0], ".ituoke-mcp-test-")
	if err != nil {
		return err
	}
	defer os.RemoveAll(dir)
	outside, err := os.CreateTemp("", "ituoke-mcp-outside-*.txt")
	if err != nil {
		return err
	}
	outside.Close()
	defer os.Remove(outside.Name())
	// If the user deliberately allowed the system temp directory, a probe there
	// cannot verify the boundary, so report that limitation explicitly.
	for _, root := range c.Args {
		rel, _ := filepath.Rel(root, outside.Name())
		if rel != "" && rel != ".." && !strings.HasPrefix(rel, ".."+string(os.PathSeparator)) && !filepath.IsAbs(rel) {
			return fmt.Errorf("临时目录也在允许范围内，无法验证目录外访问；请缩小允许目录后重试")
		}
	}
	return withSession(ctx, c, Secrets{}, func(session *mcp.ClientSession) error {
		call := func(name string, args map[string]any, denied bool) (string, error) {
			r, err := session.CallTool(ctx, &mcp.CallToolParams{Name: name, Arguments: args})
			if err != nil {
				return "", err
			}
			if r.IsError != denied {
				return "", fmt.Errorf("%s: 意外的工具执行状态", name)
			}
			var text strings.Builder
			for _, content := range r.Content {
				if t, ok := content.(*mcp.TextContent); ok {
					text.WriteString(t.Text)
				}
			}
			if denied && !strings.Contains(strings.ToLower(text.String()), "access denied") {
				return "", fmt.Errorf("目录外测试未返回权限拒绝: %s", text.String())
			}
			return text.String(), nil
		}
		path := filepath.Join(dir, "资料", "测试.txt")
		if _, err := call("create_directory", map[string]any{"path": filepath.Dir(path)}, false); err != nil {
			return err
		}
		if _, err := call("write_file", map[string]any{"path": path, "content": "iTuoke 文件读写测试 ✓"}, false); err != nil {
			return err
		}
		text, err := call("read_text_file", map[string]any{"path": path}, false)
		if err != nil {
			return err
		}
		if text != "iTuoke 文件读写测试 ✓" {
			return fmt.Errorf("读回内容与写入不一致")
		}
		found, err := call("search_files", map[string]any{"path": dir, "pattern": "**/*.txt"}, false)
		if err != nil {
			return err
		}
		if !strings.Contains(found, "测试.txt") {
			return fmt.Errorf("搜索未找到测试文件")
		}
		if _, err := call("move_file", map[string]any{"source": path, "destination": filepath.Join(dir, "资料", "已重命名.txt")}, false); err != nil {
			return err
		}
		if _, err := os.Stat(path); !os.IsNotExist(err) {
			return fmt.Errorf("重命名后原路径仍存在")
		}
		moved, err := os.ReadFile(filepath.Join(dir, "资料", "已重命名.txt"))
		if err != nil || string(moved) != "iTuoke 文件读写测试 ✓" {
			return fmt.Errorf("重命名后内容不一致: %v", err)
		}
		if _, err := call("read_text_file", map[string]any{"path": outside.Name()}, true); err != nil {
			return err
		}
		if _, err := call("write_file", map[string]any{"path": outside.Name(), "content": "must be denied"}, true); err != nil {
			return err
		}
		untouched, err := os.ReadFile(outside.Name())
		if err != nil || len(untouched) != 0 {
			return fmt.Errorf("目录外文件被更改: %v", err)
		}
		return nil
	})
}