1package tools
2
3import (
4 "cmp"
5 "context"
6 _ "embed"
7 "fmt"
8 "io"
9 "net/http"
10 "os"
11 "path/filepath"
12 "strings"
13 "time"
14
15 "charm.land/fantasy"
16 "github.com/charmbracelet/crush/internal/filepathext"
17 "github.com/charmbracelet/crush/internal/permission"
18)
19
20type DownloadParams struct {
21 URL string `json:"url" description:"The URL to download from"`
22 FilePath string `json:"file_path" description:"The local file path where the downloaded content should be saved"`
23 Timeout int `json:"timeout,omitempty" description:"Optional timeout in seconds (max 600)"`
24}
25
26type DownloadPermissionsParams struct {
27 URL string `json:"url"`
28 FilePath string `json:"file_path"`
29 Timeout int `json:"timeout,omitempty"`
30}
31
32const DownloadToolName = "download"
33
34//go:embed download.md
35var downloadDescription []byte
36
37func NewDownloadTool(permissions permission.Service, workingDir string, client *http.Client) fantasy.AgentTool {
38 if client == nil {
39 transport := http.DefaultTransport.(*http.Transport).Clone()
40 transport.MaxIdleConns = 100
41 transport.MaxIdleConnsPerHost = 10
42 transport.IdleConnTimeout = 90 * time.Second
43
44 client = &http.Client{
45 Timeout: 5 * time.Minute, // Default 5 minute timeout for downloads
46 Transport: transport,
47 }
48 }
49 return fantasy.NewParallelAgentTool(
50 DownloadToolName,
51 string(downloadDescription),
52 func(ctx context.Context, params DownloadParams, call fantasy.ToolCall) (fantasy.ToolResponse, error) {
53 if params.URL == "" {
54 return fantasy.NewTextErrorResponse("URL parameter is required"), nil
55 }
56
57 if params.FilePath == "" {
58 return fantasy.NewTextErrorResponse("file_path parameter is required"), nil
59 }
60
61 if !strings.HasPrefix(params.URL, "http://") && !strings.HasPrefix(params.URL, "https://") {
62 return fantasy.NewTextErrorResponse("URL must start with http:// or https://"), nil
63 }
64
65 filePath := filepathext.SmartJoin(workingDir, params.FilePath)
66 relPath, _ := filepath.Rel(workingDir, filePath)
67 relPath = filepath.ToSlash(cmp.Or(relPath, filePath))
68
69 sessionID := GetSessionFromContext(ctx)
70 if sessionID == "" {
71 return fantasy.ToolResponse{}, fmt.Errorf("session ID is required for downloading files")
72 }
73
74 p, err := permissions.Request(ctx,
75 permission.CreatePermissionRequest{
76 SessionID: sessionID,
77 Path: filePath,
78 ToolName: DownloadToolName,
79 Action: "download",
80 Description: fmt.Sprintf("Download file from URL: %s to %s", params.URL, filePath),
81 Params: DownloadPermissionsParams(params),
82 },
83 )
84 if err != nil {
85 return fantasy.ToolResponse{}, err
86 }
87 if !p {
88 return fantasy.ToolResponse{}, permission.ErrorPermissionDenied
89 }
90
91 // Handle timeout with context
92 requestCtx := ctx
93 if params.Timeout > 0 {
94 maxTimeout := 600 // 10 minutes
95 if params.Timeout > maxTimeout {
96 params.Timeout = maxTimeout
97 }
98 var cancel context.CancelFunc
99 requestCtx, cancel = context.WithTimeout(ctx, time.Duration(params.Timeout)*time.Second)
100 defer cancel()
101 }
102
103 req, err := http.NewRequestWithContext(requestCtx, "GET", params.URL, nil)
104 if err != nil {
105 return fantasy.ToolResponse{}, fmt.Errorf("failed to create request: %w", err)
106 }
107
108 req.Header.Set("User-Agent", "crush/1.0")
109
110 resp, err := client.Do(req)
111 if err != nil {
112 return fantasy.ToolResponse{}, fmt.Errorf("failed to download from URL: %w", err)
113 }
114 defer resp.Body.Close()
115
116 if resp.StatusCode != http.StatusOK {
117 return fantasy.NewTextErrorResponse(fmt.Sprintf("Request failed with status code: %d", resp.StatusCode)), nil
118 }
119
120 // Create parent directories if they don't exist
121 if err := os.MkdirAll(filepath.Dir(filePath), 0o755); err != nil {
122 return fantasy.ToolResponse{}, fmt.Errorf("failed to create parent directories: %w", err)
123 }
124
125 // Create the output file
126 outFile, err := os.Create(filePath)
127 if err != nil {
128 return fantasy.ToolResponse{}, fmt.Errorf("failed to create output file: %w", err)
129 }
130 defer outFile.Close()
131
132 // Copy data without an explicit size limit.
133 // The overall download is still constrained by the HTTP client's timeout
134 // and any upstream server limits.
135 bytesWritten, err := io.Copy(outFile, resp.Body)
136 if err != nil {
137 return fantasy.ToolResponse{}, fmt.Errorf("failed to write file: %w", err)
138 }
139
140 contentType := resp.Header.Get("Content-Type")
141 responseMsg := fmt.Sprintf("Successfully downloaded %d bytes to %s", bytesWritten, relPath)
142 if contentType != "" {
143 responseMsg += fmt.Sprintf(" (Content-Type: %s)", contentType)
144 }
145
146 return fantasy.NewTextResponse(responseMsg), nil
147 })
148}