Migrate LLM client to OpenAI SDK and implement WebUI-specific fileID handling

internal/transport/webui/bot.go

@@ -18,9 +18,10 @@ import (
 )
 
 type IncomingMessage struct {
-	ChatID string
-	UserID string
-	Text   string
+	ChatID  string
+	UserID  string
+	Text    string
+	FileIDs []string
 }
 
 type ChatHandler func(context.Context, IncomingMessage) (string, error)
@@ -37,9 +38,41 @@ type Bot struct {
 }
 
 type chatRequest struct {
-	Text      string `json:"text"`
-	SessionID string `json:"session_id"`
-	UserID    string `json:"user_id"`
+	Text      string   `json:"text"`
+	SessionID string   `json:"session_id"`
+	UserID    string   `json:"user_id"`
+	FileIDs   []string `json:"file_ids"`
+}
+
+func (r *chatRequest) UnmarshalJSON(data []byte) error {
+	type rawChatRequest struct {
+		Text           string          `json:"text"`
+		SessionID      string          `json:"session_id"`
+		SessionIDCamel string          `json:"sessionId"`
+		UserID         string          `json:"user_id"`
+		UserIDCamel    string          `json:"userId"`
+		FileIDs        json.RawMessage `json:"file_ids"`
+		FileIDsCamel   json.RawMessage `json:"fileIds"`
+		FileIDsFlat    json.RawMessage `json:"fileids"`
+		FileID         json.RawMessage `json:"file_id"`
+	}
+
+	var raw rawChatRequest
+	if err := json.Unmarshal(data, &raw); err != nil {
+		return err
+	}
+
+	r.Text = raw.Text
+	r.SessionID = firstNonEmpty(raw.SessionID, raw.SessionIDCamel)
+	r.UserID = firstNonEmpty(raw.UserID, raw.UserIDCamel)
+
+	rawIDs := firstNonEmptyRaw(raw.FileIDs, raw.FileIDsCamel, raw.FileIDsFlat, raw.FileID)
+	ids, err := decodeStringList(rawIDs)
+	if err != nil {
+		return err
+	}
+	r.FileIDs = ids
+	return nil
 }
 
 type chatResponse struct {
@@ -158,9 +191,10 @@ func (b *Bot) handleChat(w http.ResponseWriter, r *http.Request) {
 	userID := b.resolveID(req.UserID, "user")
 
 	reply, err := b.chatHandler(r.Context(), IncomingMessage{
-		ChatID: sessionID,
-		UserID: userID,
-		Text:   req.Text,
+		ChatID:  sessionID,
+		UserID:  userID,
+		Text:    req.Text,
+		FileIDs: req.FileIDs,
 	})
 	if err != nil {
 		if b.log != nil {
@@ -176,6 +210,65 @@ func (b *Bot) handleChat(w http.ResponseWriter, r *http.Request) {
 	})
 }
 
+func decodeStringList(raw json.RawMessage) ([]string, error) {
+	if len(raw) == 0 {
+		return nil, nil
+	}
+
+	var list []string
+	if err := json.Unmarshal(raw, &list); err == nil {
+		return nonEmptyIDs(list), nil
+	}
+
+	var single string
+	if err := json.Unmarshal(raw, &single); err == nil {
+		if strings.TrimSpace(single) == "" {
+			return nil, nil
+		}
+		return nonEmptyIDs(strings.Split(single, ",")), nil
+	}
+
+	return nil, fmt.Errorf("invalid file ids format")
+}
+
+func firstNonEmptyRaw(vals ...json.RawMessage) json.RawMessage {
+	for _, v := range vals {
+		if len(v) > 0 {
+			return v
+		}
+	}
+	return nil
+}
+
+func firstNonEmpty(vals ...string) string {
+	for _, v := range vals {
+		if strings.TrimSpace(v) != "" {
+			return v
+		}
+	}
+	return ""
+}
+
+func nonEmptyIDs(ids []string) []string {
+	if len(ids) == 0 {
+		return nil
+	}
+	out := make([]string, 0, len(ids))
+	seen := map[string]struct{}{}
+	for _, id := range ids {
+		id = strings.TrimSpace(id)
+		if id == "" {
+			continue
+		}
+		if _, ok := seen[id]; ok {
+			continue
+		}
+		seen[id] = struct{}{}
+		out = append(out, id)
+	}
+	return out
+}
+
 func (b *Bot) handleUpload(w http.ResponseWriter, r *http.Request) {
 	if r.Method != http.MethodPost {
 		writeJSON(w, http.StatusMethodNotAllowed, errorResponse{Error: "method not allowed"})