1package tools
2
3import (
4 "bufio"
5 "context"
6 "encoding/json"
7 "fmt"
8 "io"
9 "os"
10 "path/filepath"
11 "strings"
12
13 "github.com/charmbracelet/crush/internal/config"
14 "github.com/charmbracelet/crush/internal/lsp"
15)
16
17type ViewParams struct {
18 FilePath string `json:"file_path"`
19 Offset int `json:"offset"`
20 Limit int `json:"limit"`
21}
22
23type viewTool struct {
24 lspClients map[string]*lsp.Client
25}
26
27type ViewResponseMetadata struct {
28 FilePath string `json:"file_path"`
29 Content string `json:"content"`
30}
31
32const (
33 ViewToolName = "view"
34 MaxReadSize = 250 * 1024
35 DefaultReadLimit = 2000
36 MaxLineLength = 2000
37 viewDescription = `File viewing tool that reads and displays the contents of files with line numbers, allowing you to examine code, logs, or text data.
38
39WHEN TO USE THIS TOOL:
40- Use when you need to read the contents of a specific file
41- Helpful for examining source code, configuration files, or log files
42- Perfect for looking at text-based file formats
43
44HOW TO USE:
45- Provide the path to the file you want to view
46- Optionally specify an offset to start reading from a specific line
47- Optionally specify a limit to control how many lines are read
48
49FEATURES:
50- Displays file contents with line numbers for easy reference
51- Can read from any position in a file using the offset parameter
52- Handles large files by limiting the number of lines read
53- Automatically truncates very long lines for better display
54- Suggests similar file names when the requested file isn't found
55
56LIMITATIONS:
57- Maximum file size is 250KB
58- Default reading limit is 2000 lines
59- Lines longer than 2000 characters are truncated
60- Cannot display binary files or images
61- Images can be identified but not displayed
62
63WINDOWS NOTES:
64- Handles both Windows (CRLF) and Unix (LF) line endings automatically
65- File paths work with both forward slashes (/) and backslashes (\)
66- Text encoding is detected automatically for most common formats
67
68TIPS:
69- Use with Glob tool to first find files you want to view
70- For code exploration, first use Grep to find relevant files, then View to examine them
71- When viewing large files, use the offset parameter to read specific sections`
72)
73
74func NewViewTool(lspClients map[string]*lsp.Client) BaseTool {
75 return &viewTool{
76 lspClients,
77 }
78}
79
80func (v *viewTool) Info() ToolInfo {
81 return ToolInfo{
82 Name: ViewToolName,
83 Description: viewDescription,
84 Parameters: map[string]any{
85 "file_path": map[string]any{
86 "type": "string",
87 "description": "The path to the file to read",
88 },
89 "offset": map[string]any{
90 "type": "integer",
91 "description": "The line number to start reading from (0-based)",
92 },
93 "limit": map[string]any{
94 "type": "integer",
95 "description": "The number of lines to read (defaults to 2000)",
96 },
97 },
98 Required: []string{"file_path"},
99 }
100}
101
102// Run implements Tool.
103func (v *viewTool) Run(ctx context.Context, call ToolCall) (ToolResponse, error) {
104 var params ViewParams
105 if err := json.Unmarshal([]byte(call.Input), ¶ms); err != nil {
106 return NewTextErrorResponse(fmt.Sprintf("error parsing parameters: %s", err)), nil
107 }
108
109 if params.FilePath == "" {
110 return NewTextErrorResponse("file_path is required"), nil
111 }
112
113 // Handle relative paths
114 filePath := params.FilePath
115 if !filepath.IsAbs(filePath) {
116 filePath = filepath.Join(config.WorkingDirectory(), filePath)
117 }
118
119 // Check if file exists
120 fileInfo, err := os.Stat(filePath)
121 if err != nil {
122 if os.IsNotExist(err) {
123 // Try to offer suggestions for similarly named files
124 dir := filepath.Dir(filePath)
125 base := filepath.Base(filePath)
126
127 dirEntries, dirErr := os.ReadDir(dir)
128 if dirErr == nil {
129 var suggestions []string
130 for _, entry := range dirEntries {
131 if strings.Contains(strings.ToLower(entry.Name()), strings.ToLower(base)) ||
132 strings.Contains(strings.ToLower(base), strings.ToLower(entry.Name())) {
133 suggestions = append(suggestions, filepath.Join(dir, entry.Name()))
134 if len(suggestions) >= 3 {
135 break
136 }
137 }
138 }
139
140 if len(suggestions) > 0 {
141 return NewTextErrorResponse(fmt.Sprintf("File not found: %s\n\nDid you mean one of these?\n%s",
142 filePath, strings.Join(suggestions, "\n"))), nil
143 }
144 }
145
146 return NewTextErrorResponse(fmt.Sprintf("File not found: %s", filePath)), nil
147 }
148 return ToolResponse{}, fmt.Errorf("error accessing file: %w", err)
149 }
150
151 // Check if it's a directory
152 if fileInfo.IsDir() {
153 return NewTextErrorResponse(fmt.Sprintf("Path is a directory, not a file: %s", filePath)), nil
154 }
155
156 // Check file size
157 if fileInfo.Size() > MaxReadSize {
158 return NewTextErrorResponse(fmt.Sprintf("File is too large (%d bytes). Maximum size is %d bytes",
159 fileInfo.Size(), MaxReadSize)), nil
160 }
161
162 // Set default limit if not provided
163 if params.Limit <= 0 {
164 params.Limit = DefaultReadLimit
165 }
166
167 // Check if it's an image file
168 isImage, imageType := isImageFile(filePath)
169 // TODO: handle images
170 if isImage {
171 return NewTextErrorResponse(fmt.Sprintf("This is an image file of type: %s\nUse a different tool to process images", imageType)), nil
172 }
173
174 // Read the file content
175 content, lineCount, err := readTextFile(filePath, params.Offset, params.Limit)
176 if err != nil {
177 return ToolResponse{}, fmt.Errorf("error reading file: %w", err)
178 }
179
180 notifyLspOpenFile(ctx, filePath, v.lspClients)
181 output := "<file>\n"
182 // Format the output with line numbers
183 output += addLineNumbers(content, params.Offset+1)
184
185 // Add a note if the content was truncated
186 if lineCount > params.Offset+len(strings.Split(content, "\n")) {
187 output += fmt.Sprintf("\n\n(File has more lines. Use 'offset' parameter to read beyond line %d)",
188 params.Offset+len(strings.Split(content, "\n")))
189 }
190 output += "\n</file>\n"
191 output += getDiagnostics(filePath, v.lspClients)
192 recordFileRead(filePath)
193 return WithResponseMetadata(
194 NewTextResponse(output),
195 ViewResponseMetadata{
196 FilePath: filePath,
197 Content: content,
198 },
199 ), nil
200}
201
202func addLineNumbers(content string, startLine int) string {
203 if content == "" {
204 return ""
205 }
206
207 lines := strings.Split(content, "\n")
208
209 var result []string
210 for i, line := range lines {
211 line = strings.TrimSuffix(line, "\r")
212
213 lineNum := i + startLine
214 numStr := fmt.Sprintf("%d", lineNum)
215
216 if len(numStr) >= 6 {
217 result = append(result, fmt.Sprintf("%s|%s", numStr, line))
218 } else {
219 paddedNum := fmt.Sprintf("%6s", numStr)
220 result = append(result, fmt.Sprintf("%s|%s", paddedNum, line))
221 }
222 }
223
224 return strings.Join(result, "\n")
225}
226
227func readTextFile(filePath string, offset, limit int) (string, int, error) {
228 file, err := os.Open(filePath)
229 if err != nil {
230 return "", 0, err
231 }
232 defer file.Close()
233
234 lineCount := 0
235
236 scanner := NewLineScanner(file)
237 if offset > 0 {
238 for lineCount < offset && scanner.Scan() {
239 lineCount++
240 }
241 if err = scanner.Err(); err != nil {
242 return "", 0, err
243 }
244 }
245
246 if offset == 0 {
247 _, err = file.Seek(0, io.SeekStart)
248 if err != nil {
249 return "", 0, err
250 }
251 }
252
253 var lines []string
254 lineCount = offset
255
256 for scanner.Scan() && len(lines) < limit {
257 lineCount++
258 lineText := scanner.Text()
259 if len(lineText) > MaxLineLength {
260 lineText = lineText[:MaxLineLength] + "..."
261 }
262 lines = append(lines, lineText)
263 }
264
265 // Continue scanning to get total line count
266 for scanner.Scan() {
267 lineCount++
268 }
269
270 if err := scanner.Err(); err != nil {
271 return "", 0, err
272 }
273
274 return strings.Join(lines, "\n"), lineCount, nil
275}
276
277func isImageFile(filePath string) (bool, string) {
278 ext := strings.ToLower(filepath.Ext(filePath))
279 switch ext {
280 case ".jpg", ".jpeg":
281 return true, "JPEG"
282 case ".png":
283 return true, "PNG"
284 case ".gif":
285 return true, "GIF"
286 case ".bmp":
287 return true, "BMP"
288 case ".svg":
289 return true, "SVG"
290 case ".webp":
291 return true, "WebP"
292 default:
293 return false, ""
294 }
295}
296
297type LineScanner struct {
298 scanner *bufio.Scanner
299}
300
301func NewLineScanner(r io.Reader) *LineScanner {
302 return &LineScanner{
303 scanner: bufio.NewScanner(r),
304 }
305}
306
307func (s *LineScanner) Scan() bool {
308 return s.scanner.Scan()
309}
310
311func (s *LineScanner) Text() string {
312 return s.scanner.Text()
313}
314
315func (s *LineScanner) Err() error {
316 return s.scanner.Err()
317}