all

backend/internal/completion/service.go

@@ -0,0 +1,95 @@
+package completion
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sync"
+)
+
+var ErrInvalidRequest = errors.New("invalid completion request")
+
+type Request struct {
+	URI       string `json:"uri"`
+	Text      string `json:"text"`
+	Line      int    `json:"line"`
+	Character int    `json:"character"`
+}
+
+type Item struct {
+	Label         string `json:"label"`
+	Kind          int    `json:"kind,omitempty"`
+	Detail        string `json:"detail,omitempty"`
+	Documentation string `json:"documentation,omitempty"`
+	InsertText    string `json:"insertText,omitempty"`
+	SortText      string `json:"sortText,omitempty"`
+	FilterText    string `json:"filterText,omitempty"`
+}
+
+type Response struct {
+	Items        []Item `json:"items"`
+	IsIncomplete bool   `json:"isIncomplete"`
+}
+
+type Client interface {
+	DidOpen(ctx context.Context, uri, text string, version int) error
+	DidChange(ctx context.Context, uri, text string, version int) error
+	Completion(ctx context.Context, uri string, line, character int) (Response, error)
+}
+
+type documentState struct {
+	version int
+}
+
+type Service struct {
+	client Client
+
+	mu        sync.Mutex
+	documents map[string]*documentState
+}
+
+func NewService(client Client) *Service {
+	return &Service{
+		client:    client,
+		documents: make(map[string]*documentState),
+	}
+}
+
+func (s *Service) Complete(ctx context.Context, req Request) (Response, error) {
+	if err := validateRequest(req); err != nil {
+		return Response{}, err
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	state, opened := s.documents[req.URI]
+	if !opened {
+		if err := s.client.DidOpen(ctx, req.URI, req.Text, 1); err != nil {
+			return Response{}, fmt.Errorf("didOpen failed: %w", err)
+		}
+		s.documents[req.URI] = &documentState{version: 1}
+	} else {
+		nextVersion := state.version + 1
+		if err := s.client.DidChange(ctx, req.URI, req.Text, nextVersion); err != nil {
+			return Response{}, fmt.Errorf("didChange failed: %w", err)
+		}
+		state.version = nextVersion
+	}
+
+	resp, err := s.client.Completion(ctx, req.URI, req.Line, req.Character)
+	if err != nil {
+		return Response{}, fmt.Errorf("completion failed: %w", err)
+	}
+	return resp, nil
+}
+
+func validateRequest(req Request) error {
+	if req.URI == "" {
+		return ErrInvalidRequest
+	}
+	if req.Line < 0 || req.Character < 0 {
+		return ErrInvalidRequest
+	}
+	return nil
+}