feat(server): implement file synchronization methods and publish diagnostic notifications (#47)

* feat(server): implement file synchronization methods for document notifications

* feat(server): enhance LSP notification handlers with detailed comments

* chore: update documentation for file synchronization methods

* chore: remove unused imports and clean up code structure

* feat(server): implement incremental text document updates and enhance diagnostics handling

* test(server): update test case URI for DidChangeTextDocumentParams

* fix(server): add mutex for thread-safe diagnostic generation

* feat(project): add ModifyFiles method to handle batch file changes

* refactor: remove deprecated ModTime field and associated ModifyFiles method

* feat(project): implement singleflight to prevent duplicate builder calls in cache methods

* refactor(project): remove singleflight usage from cache methods

* chore(deps): update gogen to v1.16.8 in go.mod and go.sum

* fix(deps): resolve merge conflict in go.sum and update gogen to v1.16.8

* chore(deps): update gop package from v1.3.5 to v1.3.6

* refactor(server): replace PositionOffset method with positionOffset function

Author: go-wyvern

gop/proj.go

@@ -65,7 +65,9 @@ type fileKey struct {
 type File = *FileImpl
 type FileImpl struct {
 	Content []byte
+	// Deprecated: ModTime is no longer supported due to lsp text sync specification. Use Version instead.
 	ModTime time.Time
+	Version int
 }
 
 // Project represents a project.
@@ -276,6 +278,7 @@ func (p *Project) FileCache(kind, path string) (any, error) {
 	if !ok {
 		return nil, fs.ErrNotExist
 	}
+
 	data, err := builder(p, path, file)
 	p.fileCaches.Store(key, encodeDataOrErr(data, err))
 	return data, err
@@ -290,6 +293,7 @@ func (p *Project) Cache(kind string) (any, error) {
 	if !ok {
 		return nil, ErrUnknownKind
 	}
+
 	data, err := builder(p)
 	p.caches.Store(kind, encodeDataOrErr(data, err))
 	return data, err

internal/server/server.go

@@ -7,6 +7,8 @@ import (
 	"slices"
 	"strings"
 
+	gopast "github.com/goplus/gop/ast"
+	goptoken "github.com/goplus/gop/token"
 	"github.com/goplus/goxlsw/gop"
 	"github.com/goplus/goxlsw/internal/analysis"
 	"github.com/goplus/goxlsw/internal/vfs"
@@ -242,25 +244,26 @@ func (s *Server) handleNotification(n *jsonrpc2.Notification) error {
 		if err := UnmarshalJSON(n.Params(), &params); err != nil {
 			return fmt.Errorf("failed to parse didOpen params: %w", err)
 		}
-		return errors.New("TODO")
+
+		return s.didOpen(&params)
 	case "textDocument/didChange":
 		var params DidChangeTextDocumentParams
 		if err := UnmarshalJSON(n.Params(), &params); err != nil {
 			return fmt.Errorf("failed to parse didChange params: %w", err)
 		}
-		return errors.New("TODO")
+		return s.didChange(&params)
 	case "textDocument/didSave":
 		var params DidSaveTextDocumentParams
 		if err := UnmarshalJSON(n.Params(), &params); err != nil {
 			return fmt.Errorf("failed to parse didSave params: %w", err)
 		}
-		return errors.New("TODO")
+		return s.didSave(&params)
 	case "textDocument/didClose":
 		var params DidCloseTextDocumentParams
 		if err := UnmarshalJSON(n.Params(), &params); err != nil {
 			return fmt.Errorf("failed to parse didClose params: %w", err)
 		}
-		return errors.New("TODO")
+		return s.didClose(&params)
 	}
 	return nil
 }
@@ -333,3 +336,40 @@ func (s *Server) fromDocumentURI(documentURI DocumentURI) (string, error) {
 func (s *Server) toDocumentURI(path string) DocumentURI {
 	return DocumentURI(string(s.workspaceRootURI) + path)
 }
+
+// fromPosition converts a token.Position to an LSP Position.
+func (s *Server) fromPosition(astFile *gopast.File, position goptoken.Position) Position {
+	tokenFile := s.getProj().Fset.File(astFile.Pos())
+
+	line := position.Line
+	lineStart := int(tokenFile.LineStart(line))
+	relLineStart := lineStart - tokenFile.Base()
+	lineContent := astFile.Code[relLineStart : relLineStart+position.Column-1]
+	utf16Offset := utf8OffsetToUTF16(string(lineContent), position.Column-1)
+
+	return Position{
+		Line:      uint32(position.Line - 1),
+		Character: uint32(utf16Offset),
+	}
+}
+
+// rangeForASTFilePosition returns a [Range] for the given position in an AST file.
+func (s *Server) rangeForASTFilePosition(astFile *gopast.File, position goptoken.Position) Range {
+	p := s.fromPosition(astFile, position)
+	return Range{Start: p, End: p}
+}
+
+// rangeForPos returns the [Range] for the given position.
+func (s *Server) rangeForPos(pos goptoken.Pos) Range {
+	return s.rangeForASTFilePosition(s.posASTFile(pos), s.getProj().Fset.Position(pos))
+}
+
+// posASTFile returns the AST file for the given position.
+func (s *Server) posASTFile(pos goptoken.Pos) *gopast.File {
+	return getASTPkg(s.getProj()).Files[s.posFilename(pos)]
+}
+
+// posFilename returns the filename for the given position.
+func (s *Server) posFilename(pos goptoken.Pos) string {
+	return s.getProj().Fset.Position(pos).Filename
+}