add service

internal/repository/interfaces.go

@@ -64,4 +64,5 @@ type SupplierRepository interface {
 type TokenUsageRepository interface {
 	Create(ctx context.Context, usage *model.TokenUsage) error
 	CreateTx(ctx context.Context, tx pgx.Tx, usage *model.TokenUsage) error
+	GetBalanceStatistics(ctx context.Context, userID int) (averageCost float64, history []*model.WriteOffHistory, err error)
 }

internal/repository/token_usage.go

@@ -2,6 +2,7 @@ package repository
 
 import (
 	"context"
+	"strconv"
 
 	"git.techease.ru/Smart-search/smart-search-back/internal/model"
 	errs "git.techease.ru/Smart-search/smart-search-back/pkg/errors"
@@ -49,3 +50,59 @@ func (r *tokenUsageRepository) createWithExecutor(ctx context.Context, exec DBTX
 
 	return nil
 }
+
+func (r *tokenUsageRepository) GetBalanceStatistics(ctx context.Context, userID int) (float64, []*model.WriteOffHistory, error) {
+	avgQuery := r.qb.Select("COALESCE(AVG(COALESCE(rtu.token_cost, 0)), 0)").
+		From("request_token_usage rtu").
+		Join("requests_for_suppliers rfs ON rtu.request_id = rfs.id").
+		Where(sq.Eq{"rfs.user_id": userID})
+
+	avgSQL, avgArgs, err := avgQuery.ToSql()
+	if err != nil {
+		return 0, nil, errs.NewInternalError(errs.DatabaseError, "failed to build average query", err)
+	}
+
+	var averageCost float64
+	if err := r.pool.QueryRow(ctx, avgSQL, avgArgs...).Scan(&averageCost); err != nil {
+		return 0, nil, errs.NewInternalError(errs.DatabaseError, "failed to get average cost", err)
+	}
+
+	historyQuery := r.qb.Select(
+		"rtu.id",
+		"TO_CHAR(rtu.created_at, 'DD-MM-YYYY')",
+		"COALESCE(rtu.token_cost, 0)",
+	).
+		From("request_token_usage rtu").
+		Join("requests_for_suppliers rfs ON rtu.request_id = rfs.id").
+		Where(sq.Eq{"rfs.user_id": userID}).
+		OrderBy("rtu.created_at DESC").
+		Limit(8)
+
+	historySQL, historyArgs, err := historyQuery.ToSql()
+	if err != nil {
+		return 0, nil, errs.NewInternalError(errs.DatabaseError, "failed to build history query", err)
+	}
+
+	rows, err := r.pool.Query(ctx, historySQL, historyArgs...)
+	if err != nil {
+		return 0, nil, errs.NewInternalError(errs.DatabaseError, "failed to get write-off history", err)
+	}
+	defer rows.Close()
+
+	var history []*model.WriteOffHistory
+	for rows.Next() {
+		var operationID int
+		var item model.WriteOffHistory
+		if err := rows.Scan(&operationID, &item.Data, &item.Amount); err != nil {
+			return 0, nil, errs.NewInternalError(errs.DatabaseError, "failed to scan write-off history", err)
+		}
+		item.OperationID = strconv.Itoa(operationID)
+		history = append(history, &item)
+	}
+
+	if err := rows.Err(); err != nil {
+		return 0, nil, errs.NewInternalError(errs.DatabaseError, "failed to iterate write-off history", err)
+	}
+
+	return averageCost, history, nil
+}