Update, bugfixes on diff and edit handling

internal/server/handlers_edit.go

@@ -0,0 +1,91 @@
+// Package server implements the MCP server for file operations.
+package server
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"github.com/lukaszraczylo/mcp-filepuff/internal/edit"
+	"github.com/lukaszraczylo/mcp-filepuff/pkg/errors"
+	"github.com/mark3labs/mcp-go/mcp"
+)
+
+// handleEditPreview handles the edit_preview tool.
+func (s *Server) handleEditPreview(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error) {
+	return s.handleEdit(ctx, request, false)
+}
+
+// handleEditApply handles the edit_apply tool.
+func (s *Server) handleEditApply(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error) {
+	return s.handleEdit(ctx, request, true)
+}
+
+// handleEdit is the shared implementation for edit_preview and edit_apply.
+func (s *Server) handleEdit(ctx context.Context, request mcp.CallToolRequest, apply bool) (*mcp.CallToolResult, error) {
+	file, err := request.RequireString("file")
+	if err != nil {
+		return mcp.NewToolResultError("file is required"), nil
+	}
+
+	operation, err := request.RequireString("operation")
+	if err != nil {
+		return mcp.NewToolResultError("operation is required"), nil
+	}
+
+	// Validate path
+	if !s.cfg.IsPathAllowed(file) {
+		return mcp.NewToolResultError("file is outside workspace root"), nil
+	}
+
+	// Note: We no longer validate language support here.
+	// The edit engine automatically detects whether to use AST or text mode.
+
+	// Build edit request with both AST and text-mode selectors
+	astEdit := &edit.ASTEdit{
+		File:       file,
+		Operation:  edit.EditOperation(operation),
+		NewContent: request.GetString("new_content", ""),
+		Selector: edit.ASTSelector{
+			// AST-mode selectors
+			Kind:   request.GetString("selector_kind", ""),
+			Name:   request.GetString("selector_name", ""),
+			AtLine: request.GetInt("selector_line", 0),
+			Index:  request.GetInt("selector_index", 0),
+			// Text-mode selectors
+			LineEnd:     request.GetInt("selector_line_end", 0),
+			Text:        request.GetString("selector_text", ""),
+			TextPattern: request.GetString("selector_pattern", ""),
+		},
+	}
+
+	// Perform edit
+	var result *edit.EditResult
+	if apply {
+		result, err = s.editor.Apply(ctx, astEdit)
+	} else {
+		result, err = s.editor.Preview(ctx, astEdit)
+	}
+
+	if err != nil {
+		return mcp.NewToolResultError(fmt.Sprintf("edit failed: %s", errors.SanitizeError(err))), nil
+	}
+
+	if !result.Success {
+		return mcp.NewToolResultError(result.Error), nil
+	}
+
+	// Format output
+	var output strings.Builder
+	if apply {
+		output.WriteString("**Edit Applied Successfully**\n\n")
+	} else {
+		output.WriteString("**Edit Preview**\n\n")
+	}
+
+	output.WriteString("Diff:\n```diff\n")
+	output.WriteString(result.Diff)
+	output.WriteString("```\n")
+
+	return mcp.NewToolResultText(output.String()), nil
+}