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pkg/heroservices/billing/models/transaction.go

@@ -0,0 +1,100 @@
+package models
+
+import (
+	"encoding/binary"
+	"errors"
+	"math"
+)
+
+// Transaction represents a financial transaction in the billing system
+type Transaction struct {
+	TxID    uint32  // Transaction ID, auto-incremented
+	From    uint32  // Source account ID
+	To      uint32  // Destination account ID
+	Comment string  // Transaction comment
+	Amount  float64 // Transaction amount
+}
+
+// Serialize converts a Transaction to a binary representation
+func (t *Transaction) Serialize() []byte {
+	// Calculate the size of the serialized data
+	// 4 bytes for TxID + 4 bytes for From + 4 bytes for To +
+	// 2 bytes for comment length + len(comment) bytes + 8 bytes for amount
+	size := 4 + 4 + 4 + 2 + len(t.Comment) + 8
+	data := make([]byte, size)
+
+	// Write TxID (4 bytes)
+	binary.LittleEndian.PutUint32(data[0:4], t.TxID)
+
+	// Write From (4 bytes)
+	binary.LittleEndian.PutUint32(data[4:8], t.From)
+
+	// Write To (4 bytes)
+	binary.LittleEndian.PutUint32(data[8:12], t.To)
+
+	// Write comment length (2 bytes) and comment
+	commentLen := uint16(len(t.Comment))
+	binary.LittleEndian.PutUint16(data[12:14], commentLen)
+	copy(data[14:14+commentLen], t.Comment)
+
+	// Write amount (8 bytes)
+	amountOffset := 14 + int(commentLen)
+	binary.LittleEndian.PutUint64(data[amountOffset:amountOffset+8], math.Float64bits(t.Amount))
+
+	return data
+}
+
+// DeserializeTransaction converts a binary representation back to a Transaction
+func DeserializeTransaction(data []byte) (*Transaction, error) {
+	if len(data) < 22 { // Minimum size: 4 (TxID) + 4 (From) + 4 (To) + 2 (comment length) + 8 (amount)
+		return nil, errors.New("data too short to deserialize Transaction")
+	}
+
+	transaction := &Transaction{}
+
+	// Read TxID
+	transaction.TxID = binary.LittleEndian.Uint32(data[0:4])
+
+	// Read From
+	transaction.From = binary.LittleEndian.Uint32(data[4:8])
+
+	// Read To
+	transaction.To = binary.LittleEndian.Uint32(data[8:12])
+
+	// Read comment length and comment
+	commentLen := binary.LittleEndian.Uint16(data[12:14])
+	if 14+commentLen > uint16(len(data)) {
+		return nil, errors.New("data too short to read comment")
+	}
+	transaction.Comment = string(data[14 : 14+commentLen])
+
+	// Read amount
+	amountOffset := 14 + commentLen
+	if int(amountOffset)+8 > len(data) {
+		return nil, errors.New("data too short to read amount")
+	}
+	transaction.Amount = math.Float64frombits(binary.LittleEndian.Uint64(data[amountOffset : amountOffset+8]))
+
+	return transaction, nil
+}
+
+// Validate checks if the transaction data is valid
+func (t *Transaction) Validate() error {
+	if t.From == 0 {
+		return errors.New("source account ID cannot be zero")
+	}
+
+	if t.To == 0 {
+		return errors.New("destination account ID cannot be zero")
+	}
+
+	if t.From == t.To {
+		return errors.New("source and destination accounts cannot be the same")
+	}
+
+	if t.Amount <= 0 {
+		return errors.New("amount must be positive")
+	}
+
+	return nil
+}