1package tools
2
3import (
4 "bufio"
5 "context"
6 _ "embed"
7 "fmt"
8 "io"
9 "os"
10 "path/filepath"
11 "strings"
12 "unicode/utf8"
13
14 "charm.land/fantasy"
15 "github.com/charmbracelet/crush/internal/csync"
16 "github.com/charmbracelet/crush/internal/filepathext"
17 "github.com/charmbracelet/crush/internal/lsp"
18 "github.com/charmbracelet/crush/internal/permission"
19)
20
21//go:embed view.md
22var viewDescription []byte
23
24type ViewParams struct {
25 FilePath string `json:"file_path" description:"The path to the file to read"`
26 Offset int `json:"offset,omitempty" description:"The line number to start reading from (0-based)"`
27 Limit int `json:"limit,omitempty" description:"The number of lines to read (defaults to 2000)"`
28}
29
30type ViewPermissionsParams struct {
31 FilePath string `json:"file_path"`
32 Offset int `json:"offset"`
33 Limit int `json:"limit"`
34}
35
36type viewTool struct {
37 lspClients *csync.Map[string, *lsp.Client]
38 workingDir string
39 permissions permission.Service
40}
41
42type ViewResponseMetadata struct {
43 FilePath string `json:"file_path"`
44 Content string `json:"content"`
45}
46
47const (
48 ViewToolName = "view"
49 MaxReadSize = 250 * 1024
50 DefaultReadLimit = 2000
51 MaxLineLength = 2000
52)
53
54func NewViewTool(lspClients *csync.Map[string, *lsp.Client], permissions permission.Service, workingDir string) fantasy.AgentTool {
55 return fantasy.NewAgentTool(
56 ViewToolName,
57 string(viewDescription),
58 func(ctx context.Context, params ViewParams, call fantasy.ToolCall) (fantasy.ToolResponse, error) {
59 if params.FilePath == "" {
60 return fantasy.NewTextErrorResponse("file_path is required"), nil
61 }
62
63 // Handle relative paths
64 filePath := filepathext.SmartJoin(workingDir, params.FilePath)
65
66 // Check if file is outside working directory and request permission if needed
67 absWorkingDir, err := filepath.Abs(workingDir)
68 if err != nil {
69 return fantasy.ToolResponse{}, fmt.Errorf("error resolving working directory: %w", err)
70 }
71
72 absFilePath, err := filepath.Abs(filePath)
73 if err != nil {
74 return fantasy.ToolResponse{}, fmt.Errorf("error resolving file path: %w", err)
75 }
76
77 relPath, err := filepath.Rel(absWorkingDir, absFilePath)
78 if err != nil || strings.HasPrefix(relPath, "..") {
79 // File is outside working directory, request permission
80 sessionID := GetSessionFromContext(ctx)
81 if sessionID == "" {
82 return fantasy.ToolResponse{}, fmt.Errorf("session ID is required for accessing files outside working directory")
83 }
84
85 granted := permissions.Request(
86 permission.CreatePermissionRequest{
87 SessionID: sessionID,
88 Path: absFilePath,
89 ToolCallID: call.ID,
90 ToolName: ViewToolName,
91 Action: "read",
92 Description: fmt.Sprintf("Read file outside working directory: %s", absFilePath),
93 Params: ViewPermissionsParams(params),
94 },
95 )
96
97 if !granted {
98 return fantasy.ToolResponse{}, permission.ErrorPermissionDenied
99 }
100 }
101
102 // Check if file exists
103 fileInfo, err := os.Stat(filePath)
104 if err != nil {
105 if os.IsNotExist(err) {
106 // Try to offer suggestions for similarly named files
107 dir := filepath.Dir(filePath)
108 base := filepath.Base(filePath)
109
110 dirEntries, dirErr := os.ReadDir(dir)
111 if dirErr == nil {
112 var suggestions []string
113 for _, entry := range dirEntries {
114 if strings.Contains(strings.ToLower(entry.Name()), strings.ToLower(base)) ||
115 strings.Contains(strings.ToLower(base), strings.ToLower(entry.Name())) {
116 suggestions = append(suggestions, filepath.Join(dir, entry.Name()))
117 if len(suggestions) >= 3 {
118 break
119 }
120 }
121 }
122
123 if len(suggestions) > 0 {
124 return fantasy.NewTextErrorResponse(fmt.Sprintf("File not found: %s\n\nDid you mean one of these?\n%s",
125 filePath, strings.Join(suggestions, "\n"))), nil
126 }
127 }
128
129 return fantasy.NewTextErrorResponse(fmt.Sprintf("File not found: %s", filePath)), nil
130 }
131 return fantasy.ToolResponse{}, fmt.Errorf("error accessing file: %w", err)
132 }
133
134 // Check if it's a directory
135 if fileInfo.IsDir() {
136 return fantasy.NewTextErrorResponse(fmt.Sprintf("Path is a directory, not a file: %s", filePath)), nil
137 }
138
139 // Check file size
140 if fileInfo.Size() > MaxReadSize {
141 return fantasy.NewTextErrorResponse(fmt.Sprintf("File is too large (%d bytes). Maximum size is %d bytes",
142 fileInfo.Size(), MaxReadSize)), nil
143 }
144
145 // Set default limit if not provided
146 if params.Limit <= 0 {
147 params.Limit = DefaultReadLimit
148 }
149
150 // Check if it's an image file
151 isImage, imageType := isImageFile(filePath)
152 // TODO: handle images
153 if isImage {
154 return fantasy.NewTextErrorResponse(fmt.Sprintf("This is an image file of type: %s\n", imageType)), nil
155 }
156
157 // Read the file content
158 content, lineCount, err := readTextFile(filePath, params.Offset, params.Limit)
159 isValidUt8 := utf8.ValidString(content)
160 if !isValidUt8 {
161 return fantasy.NewTextErrorResponse("File content is not valid UTF-8"), nil
162 }
163 if err != nil {
164 return fantasy.ToolResponse{}, fmt.Errorf("error reading file: %w", err)
165 }
166
167 notifyLSPs(ctx, lspClients, filePath)
168 output := "<file>\n"
169 // Format the output with line numbers
170 output += addLineNumbers(content, params.Offset+1)
171
172 // Add a note if the content was truncated
173 if lineCount > params.Offset+len(strings.Split(content, "\n")) {
174 output += fmt.Sprintf("\n\n(File has more lines. Use 'offset' parameter to read beyond line %d)",
175 params.Offset+len(strings.Split(content, "\n")))
176 }
177 output += "\n</file>\n"
178 output += getDiagnostics(filePath, lspClients)
179 recordFileRead(filePath)
180 return fantasy.WithResponseMetadata(
181 fantasy.NewTextResponse(output),
182 ViewResponseMetadata{
183 FilePath: filePath,
184 Content: content,
185 },
186 ), nil
187 })
188}
189
190func addLineNumbers(content string, startLine int) string {
191 if content == "" {
192 return ""
193 }
194
195 lines := strings.Split(content, "\n")
196
197 var result []string
198 for i, line := range lines {
199 line = strings.TrimSuffix(line, "\r")
200
201 lineNum := i + startLine
202 numStr := fmt.Sprintf("%d", lineNum)
203
204 if len(numStr) >= 6 {
205 result = append(result, fmt.Sprintf("%s|%s", numStr, line))
206 } else {
207 paddedNum := fmt.Sprintf("%6s", numStr)
208 result = append(result, fmt.Sprintf("%s|%s", paddedNum, line))
209 }
210 }
211
212 return strings.Join(result, "\n")
213}
214
215func readTextFile(filePath string, offset, limit int) (string, int, error) {
216 file, err := os.Open(filePath)
217 if err != nil {
218 return "", 0, err
219 }
220 defer file.Close()
221
222 lineCount := 0
223
224 scanner := NewLineScanner(file)
225 if offset > 0 {
226 for lineCount < offset && scanner.Scan() {
227 lineCount++
228 }
229 if err = scanner.Err(); err != nil {
230 return "", 0, err
231 }
232 }
233
234 if offset == 0 {
235 _, err = file.Seek(0, io.SeekStart)
236 if err != nil {
237 return "", 0, err
238 }
239 }
240
241 // Pre-allocate slice with expected capacity
242 lines := make([]string, 0, limit)
243 lineCount = offset
244
245 for scanner.Scan() && len(lines) < limit {
246 lineCount++
247 lineText := scanner.Text()
248 if len(lineText) > MaxLineLength {
249 lineText = lineText[:MaxLineLength] + "..."
250 }
251 lines = append(lines, lineText)
252 }
253
254 // Continue scanning to get total line count
255 for scanner.Scan() {
256 lineCount++
257 }
258
259 if err := scanner.Err(); err != nil {
260 return "", 0, err
261 }
262
263 return strings.Join(lines, "\n"), lineCount, nil
264}
265
266func isImageFile(filePath string) (bool, string) {
267 ext := strings.ToLower(filepath.Ext(filePath))
268 switch ext {
269 case ".jpg", ".jpeg":
270 return true, "JPEG"
271 case ".png":
272 return true, "PNG"
273 case ".gif":
274 return true, "GIF"
275 case ".bmp":
276 return true, "BMP"
277 case ".svg":
278 return true, "SVG"
279 case ".webp":
280 return true, "WebP"
281 default:
282 return false, ""
283 }
284}
285
286type LineScanner struct {
287 scanner *bufio.Scanner
288}
289
290func NewLineScanner(r io.Reader) *LineScanner {
291 scanner := bufio.NewScanner(r)
292 // Increase buffer size to handle large lines (e.g., minified JSON, HTML)
293 // Default is 64KB, set to 1MB
294 buf := make([]byte, 0, 64*1024)
295 scanner.Buffer(buf, 1024*1024)
296 return &LineScanner{
297 scanner: scanner,
298 }
299}
300
301func (s *LineScanner) Scan() bool {
302 return s.scanner.Scan()
303}
304
305func (s *LineScanner) Text() string {
306 return s.scanner.Text()
307}
308
309func (s *LineScanner) Err() error {
310 return s.scanner.Err()
311}