Add modify_file tool

pkg/cli/functions.go

@@ -156,6 +156,102 @@ Result is returned as JSON in the following format:
 			return WriteFile(path, content), nil
 		},
 	},
+	"modify_file": {
+		Tool: openai.Tool{Type: "function", Function: openai.FunctionDefinition{
+			Name: "modify_file",
+			Description: `Perform complex line-based modifications to a file.
+
+Line ranges are inclusive. If 'start_line' is specified but 'end_line' is not,
+'end_line' gets set to the last line of the file.
+
+To replace or remove a single line, *set start_line and end_line to the same value*
+
+Examples:
+* Insert the lines "hello<new line>world" at line 10, preserving other content:
+    {"path": "myfile", "operation": "insert", "start_line": 10, "content": "hello\nworld"}
+
+* Remove lines 45 up to and including 54:
+    {"path": "myfile", "operation": "remove", "start_line": 45, "end_line": 54}
+
+* Replace content from line 10 to 25:
+    {"path": "myfile", "operation": "replace", "start_line": 10, "end_line": 25, "content": "i\nwas\nhere"}
+
+* Replace contents of entire the file:
+    {"path": "myfile", "operation": "replace", "start_line": 0, "content": "i\nwas\nhere"}`,
+			Parameters: FunctionParameters{
+				Type: "object",
+				Properties: map[string]FunctionParameter{
+					"path": {
+						Type:        "string",
+						Description: "Path of the file to be modified, relative to the current working directory.",
+					},
+					"operation": {
+						Type:        "string",
+						Description: `The the type of modification to make to the file. One of: insert, remove, replace`,
+					},
+					"start_line": {
+						Type:        "integer",
+						Description: `(Optional) Where to start making a modification (insert, remove, and replace).`,
+					},
+					"end_line": {
+						Type:        "integer",
+						Description: `(Optional) Where to stop making a modification (remove or replace, end of file if omitted).`,
+					},
+					"content": {
+						Type:        "string",
+						Description: `(Optional) The content to insert, or replace with.`,
+					},
+				},
+				Required: []string{"path", "operation"},
+			},
+		}},
+		Impl: func(args map[string]interface{}) (string, error) {
+			tmp, ok := args["path"]
+			if !ok {
+				return "", fmt.Errorf("path parameter to write_file was not included.")
+			}
+			path, ok := tmp.(string)
+			if !ok {
+				return "", fmt.Errorf("Invalid path in function arguments: %v", tmp)
+			}
+			tmp, ok = args["operation"]
+			if !ok {
+				return "", fmt.Errorf("operation parameter to modify_file was not included.")
+			}
+			operation, ok := tmp.(string)
+			if !ok {
+				return "", fmt.Errorf("Invalid operation in function arguments: %v", tmp)
+			}
+			var start_line int
+			tmp, ok = args["start_line"]
+			if ok {
+				tmp, ok := tmp.(float64)
+				if !ok {
+					return "", fmt.Errorf("Invalid start_line in function arguments: %v", tmp)
+				}
+				start_line = int(tmp)
+			}
+			var end_line int
+			tmp, ok = args["end_line"]
+			if ok {
+				tmp, ok := tmp.(float64)
+				if !ok {
+					return "", fmt.Errorf("Invalid end_line in function arguments: %v", tmp)
+				}
+				end_line = int(tmp)
+			}
+			var content string
+			tmp, ok = args["content"]
+			if ok {
+				content, ok = tmp.(string)
+				if !ok {
+					return "", fmt.Errorf("Invalid content in function arguments: %v", tmp)
+				}
+			}
+
+			return ModifyFile(path, operation, content, start_line, end_line), nil
+		},
+	},
 }
 
 func resultToJson(result FunctionResult) string {
@@ -353,3 +449,70 @@ func WriteFile(path string, content string) string {
 	}
 	return resultToJson(FunctionResult{})
 }
+
+func ModifyFile(path string, operation string, content string, startLine int, endLine int) string {
+	ok, res := isPathWithinCWD(path)
+	if !ok {
+		return resultToJson(*res)
+	}
+
+	// Read the existing file's content
+	data, err := os.ReadFile(path)
+	if err != nil {
+		if !os.IsNotExist(err) {
+			return resultToJson(FunctionResult{Message: fmt.Sprintf("Could not read path: %s", err.Error())})
+		}
+		_, err = os.Create(path)
+		if err != nil {
+			return resultToJson(FunctionResult{Message: fmt.Sprintf("Could not create new file: %s", err.Error())})
+		}
+		data = []byte{}
+	}
+
+	if startLine < 0 {
+		return resultToJson(FunctionResult{Message: "start_line cannot be less than 0"})
+	}
+
+	// Split the content by newline to process lines
+	lines := strings.Split(string(data), "\n")
+	contentLines := strings.Split(strings.Trim(content, "\n"), "\n")
+
+	switch operation {
+	case "insert":
+		// Insert new lines
+		before := lines[:startLine-1]
+		after := append(contentLines, lines[startLine-1:]...)
+		lines = append(before, after...)
+	case "remove":
+		// Remove lines
+		if endLine == 0 || endLine > len(lines) {
+			endLine = len(lines)
+		}
+
+		lines = append(lines[:startLine-1], lines[endLine:]...)
+	case "replace":
+		// Replace the lines between start_line and end_line
+		if endLine == 0 || endLine > len(lines) {
+			endLine = len(lines)
+		}
+		if startLine == 0 {
+			// model likely trying to replace contents, must start at line 1
+			startLine = 1
+		}
+		before := lines[:startLine-1]
+		after := lines[endLine:]
+		lines = append(before, append(contentLines, after...)...)
+	default:
+		return resultToJson(FunctionResult{Message: fmt.Sprintf("Invalid operation: %s", operation)})
+	}
+
+	newContent := strings.Join(lines, "\n")
+
+	// Join the lines and write back to the file
+	err = os.WriteFile(path, []byte(newContent), 0644)
+	if err != nil {
+		return resultToJson(FunctionResult{Message: fmt.Sprintf("Could not write to path: %s", err.Error())})
+	}
+
+	return resultToJson(FunctionResult{Result: newContent})
+}