Add duplicate transaction check from log and transaction description LIKE match

app/logger.go

@@ -1,6 +1,8 @@
 package app
 
 import (
+	"bufio"
+	"encoding/json"
 	"fmt"
 	"os"
 )
@@ -20,3 +22,49 @@ func LogString(str string) {
 		fmt.Println(err)
 	}
 }
+
+func LogContainsTransactionID(transactionID string) (bool, error) {
+	if len(os.Getenv("LOG_FILE")) == 0 {
+		return false, nil
+	}
+
+	// open the log file for reading.
+	logFile, err := os.Open(os.Getenv("LOG_FILE"))
+	if err != nil {
+		return false, fmt.Errorf("error opening log file: %w", err)
+	}
+	defer logFile.Close()
+
+	// create a new scanner to read the log file line by line.
+	scanner := bufio.NewScanner(logFile)
+
+	// iterate over each line of the log file.
+	for scanner.Scan() {
+		// unmarshal the JSON data from the current line.
+		var transactionData struct {
+			Data struct {
+				StatementItem struct {
+					ID string `json:"id"`
+				} `json:"statementItem"`
+			} `json:"data"`
+		}
+		err := json.Unmarshal(scanner.Bytes(), &transactionData)
+		if err != nil {
+			// skip lines that are not valid JSON.
+			continue
+		}
+
+		// check if the transaction ID matches the given ID.
+		if transactionData.Data.StatementItem.ID == transactionID {
+			return true, nil
+		}
+	}
+
+	// check for any errors that occurred during scanning.
+	if err := scanner.Err(); err != nil {
+		return false, fmt.Errorf("error scanning log file: %w", err)
+	}
+
+	// transaction ID not found in the log file.
+	return false, nil
+}