Add customer communication system

LittleShop/Models/CustomerMessage.cs

@@ -0,0 +1,185 @@
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace LittleShop.Models;
+
+public enum MessageDirection
+{
+    AdminToCustomer = 0,
+    CustomerToAdmin = 1
+}
+
+public enum MessageStatus
+{
+    Pending = 0,     // Message created, waiting to be sent
+    Sent = 1,        // Message delivered to customer
+    Delivered = 2,   // Message acknowledged by bot/platform
+    Read = 3,        // Customer has read the message
+    Failed = 4       // Delivery failed
+}
+
+public enum MessageType
+{
+    OrderUpdate = 0,     // Status update about an order
+    PaymentReminder = 1, // Payment reminder
+    ShippingInfo = 2,    // Tracking/shipping information
+    CustomerService = 3, // General customer service
+    Marketing = 4,       // Marketing/promotional (requires consent)
+    SystemAlert = 5      // System-generated alerts
+}
+
+public class CustomerMessage
+{
+    [Key]
+    public Guid Id { get; set; }
+    
+    // Relationships
+    [Required]
+    public Guid CustomerId { get; set; }
+    
+    public Guid? OrderId { get; set; } // Optional - message may not be about specific order
+    
+    public Guid? AdminUserId { get; set; } // Which admin sent the message (null for system messages or unidentified admins)
+    
+    // Message Details
+    [Required]
+    public MessageDirection Direction { get; set; }
+    
+    [Required]
+    public MessageType Type { get; set; }
+    
+    [Required]
+    [StringLength(100)]
+    public string Subject { get; set; } = string.Empty;
+    
+    [Required]
+    [StringLength(4000)] // Telegram message limit is ~4096 characters
+    public string Content { get; set; } = string.Empty;
+    
+    public MessageStatus Status { get; set; } = MessageStatus.Pending;
+    
+    // Delivery Information
+    public DateTime CreatedAt { get; set; } = DateTime.UtcNow;
+    
+    public DateTime? SentAt { get; set; }
+    
+    public DateTime? DeliveredAt { get; set; }
+    
+    public DateTime? ReadAt { get; set; }
+    
+    public DateTime? FailedAt { get; set; }
+    
+    [StringLength(500)]
+    public string? FailureReason { get; set; }
+    
+    public int RetryCount { get; set; } = 0;
+    
+    public DateTime? NextRetryAt { get; set; }
+    
+    // Message Threading (for conversations)
+    public Guid? ParentMessageId { get; set; } // Reply to another message
+    
+    public Guid? ThreadId { get; set; } // Conversation thread identifier
+    
+    // Platform-specific Information
+    [StringLength(100)]
+    public string Platform { get; set; } = "Telegram"; // Telegram, Email, SMS, etc.
+    
+    [StringLength(200)]
+    public string? PlatformMessageId { get; set; } // Telegram message ID, email message ID, etc.
+    
+    // Priority and Scheduling
+    public int Priority { get; set; } = 5; // 1-10, 1 = highest priority
+    
+    public DateTime? ScheduledFor { get; set; } // For scheduled messages
+    
+    public DateTime? ExpiresAt { get; set; } // Message expires if not delivered
+    
+    // Customer Preferences
+    public bool RequiresResponse { get; set; } = false;
+    
+    public bool IsUrgent { get; set; } = false;
+    
+    public bool IsMarketing { get; set; } = false;
+    
+    // Auto-generated flags
+    public bool IsAutoGenerated { get; set; } = false;
+    
+    [StringLength(100)]
+    public string? AutoGenerationTrigger { get; set; } // e.g., "OrderStatusChanged", "PaymentOverdue"
+    
+    // Data retention
+    public bool IsArchived { get; set; } = false;
+    
+    public DateTime? ArchivedAt { get; set; }
+    
+    // Navigation properties
+    public virtual Customer Customer { get; set; } = null!;
+    public virtual Order? Order { get; set; }
+    public virtual User? AdminUser { get; set; }
+    public virtual CustomerMessage? ParentMessage { get; set; }
+    public virtual ICollection<CustomerMessage> Replies { get; set; } = new List<CustomerMessage>();
+    
+    // Helper methods
+    public bool CanRetry()
+    {
+        return Status == MessageStatus.Failed && 
+               RetryCount < 3 && 
+               (NextRetryAt == null || DateTime.UtcNow >= NextRetryAt) &&
+               (ExpiresAt == null || DateTime.UtcNow < ExpiresAt);
+    }
+    
+    public void MarkAsSent()
+    {
+        Status = MessageStatus.Sent;
+        SentAt = DateTime.UtcNow;
+    }
+    
+    public void MarkAsDelivered(string? platformMessageId = null)
+    {
+        Status = MessageStatus.Delivered;
+        DeliveredAt = DateTime.UtcNow;
+        if (!string.IsNullOrEmpty(platformMessageId))
+        {
+            PlatformMessageId = platformMessageId;
+        }
+    }
+    
+    public void MarkAsRead()
+    {
+        Status = MessageStatus.Read;
+        ReadAt = DateTime.UtcNow;
+    }
+    
+    public void MarkAsFailed(string reason)
+    {
+        Status = MessageStatus.Failed;
+        FailedAt = DateTime.UtcNow;
+        FailureReason = reason;
+        RetryCount++;
+        
+        // Exponential backoff for retries
+        if (RetryCount <= 3)
+        {
+            var delayMinutes = Math.Pow(2, RetryCount) * 5; // 10, 20, 40 minutes
+            NextRetryAt = DateTime.UtcNow.AddMinutes(delayMinutes);
+        }
+    }
+    
+    public string GetDisplayTitle()
+    {
+        var prefix = Direction == MessageDirection.AdminToCustomer ? "→" : "←";
+        var typeStr = Type switch
+        {
+            MessageType.OrderUpdate => "Order Update",
+            MessageType.PaymentReminder => "Payment",
+            MessageType.ShippingInfo => "Shipping",
+            MessageType.CustomerService => "Support",
+            MessageType.Marketing => "Marketing",
+            MessageType.SystemAlert => "System",
+            _ => "Message"
+        };
+        
+        return $"{prefix} {typeStr}: {Subject}";
+    }
+}