using System.Text;

namespace Quadarax.Foundation.Core.Data.Transaction
{
    /// <summary>
    /// Represents a single data change transaction for an entity property.
    /// Tracks the type of change, the property affected, and the associated value.
    /// </summary>
    public class DataTransaction
    {
        #region *** Enumerations ***
        /// <summary>
        /// Defines the types of data change operations.
        /// </summary>
        public enum TransactionTypeEnum
        {
            /// <summary>
            /// Indicates a new property or entity has been added.
            /// </summary>
            Add,
            
            /// <summary>
            /// Indicates a property or entity has been removed.
            /// </summary>
            Remove,
            
            /// <summary>
            /// Indicates a property value has been modified.
            /// </summary>
            Change
        }
        #endregion

        #region *** Properties ***
        /// <summary>
        /// Gets the name of the property that was changed.
        /// </summary>
        public string PropertyName { get; private set; }
        
        /// <summary>
        /// Gets the type of transaction (Add, Remove, or Change).
        /// </summary>
        public TransactionTypeEnum TransactionType { get; private set; }
        
        /// <summary>
        /// Gets the value associated with the transaction. 
        /// May be null for Remove operations.
        /// </summary>
        public string? Value { get; private set; }
        
        /// <summary>
        /// Gets a value indicating whether the Value property contains a reference key
        /// rather than a direct property value.
        /// 
        /// When true, the Value represents a reference to another entity (foreign key).
        /// When false, the Value represents the actual property value.
        /// </summary>
        public bool IsValueKey { get; private set; }
        #endregion

        #region *** Constructor ***
        /// <summary>
        /// Initializes a new instance of the DataTransaction class.
        /// </summary>
        /// <param name="propertyName">The name of the property that was changed.</param>
        /// <param name="transactionType">The type of transaction (Add/Remove/Change).</param>
        /// <param name="value">The new value of the property, or null if the property was removed.</param>
        /// <param name="isValueKey">True if the value represents a reference key; otherwise, false.</param>
        public DataTransaction(string propertyName, TransactionTypeEnum transactionType, string? value, bool isValueKey)
        {
            PropertyName = propertyName;
            TransactionType = transactionType;
            Value = value;
            IsValueKey = isValueKey;
        }
        #endregion

        #region *** Public Overrides ***
        /// <summary>
        /// Returns a string representation of the data transaction.
        /// </summary>
        /// <returns>A formatted string containing the transaction details.</returns>
        public override string ToString()
        {
            var sb = new StringBuilder();
            sb.Append("Type=").Append(TransactionType).Append(";");
            sb.Append("Field=").Append(PropertyName).Append(";");
            sb.Append("Value=").Append(Value == null ? "<NULL>" : Value).Append(";");
            return sb.ToString();
        }
        #endregion
    }
}