dmail-api/src/modules/email/services/email-notification.service.ts

import { Injectable, Logger } from "@nestjs/common";
import { firstValueFrom } from "rxjs";

import { MailServerService } from "../../mail-server/services/mail-server.service";
import { EmailGateway } from "../email.gateway";
import { MailboxResolverService } from "./mailbox-resolver.service";
import { EmailNotificationPayload } from "../interfaces/email-events.interface";

@Injectable()
export class EmailNotificationService {
  private readonly logger = new Logger(EmailNotificationService.name);

  constructor(
    private readonly emailGateway: EmailGateway,
    private readonly mailServerService: MailServerService,
    private readonly mailboxResolverService: MailboxResolverService,
  ) {}

  /**
   * Handle new incoming message and emit WebSocket notification
   * This method can be called by webhook handlers, polling services, etc.
   */
  async handleNewMessage(userId: string, messageId: number, mailboxId?: string) {
    try {
      this.logger.log(`Processing new message notification for user ${userId}, message ${messageId}`);

      // Get the mailbox ID if not provided
      const targetMailboxId = mailboxId || (await this.mailboxResolverService.getInboxMailboxId(userId));

      // Fetch the message details
      const message = await firstValueFrom(this.mailServerService.messages.getMessage(userId, targetMailboxId, messageId));

      // Determine mailbox name
      const mailboxName = await this.getMailboxName(userId, targetMailboxId);

      // Create notification payload
      const notificationPayload: EmailNotificationPayload = {
        messageId,
        userId,
        from: {
          name: message.from?.name || message.from?.address?.split("@")[0] || "Unknown",
          address: message.from?.address || "unknown@example.com",
        },
        to:
          message.to?.map((recipient) => ({
            name: recipient.name || recipient.address?.split("@")[0] || "Unknown",
            address: recipient.address || "unknown@example.com",
          })) || [],
        subject: message.subject || "No Subject",
        preview: this.extractPreview(
          typeof message.text === "string" ? message.text : Array.isArray(message.html) ? message.html.join("") : message.html || "",
        ),
        hasAttachments: Array.isArray(message.attachments) && message.attachments.length > 0,
        received: message.idate || new Date().toISOString(),
        mailboxId: targetMailboxId,
        mailboxName,
        isRead: message.seen || false,
        isFlagged: message.flagged || false,
        size: message.size || 0,
      };

      // Emit WebSocket notification
      await this.emailGateway.notifyNewMessage(notificationPayload);

      this.logger.log(`New message notification sent for user ${userId}, message ${messageId}`);

      return notificationPayload;
    } catch (error) {
      this.logger.error(
        `Failed to process new message notification for user ${userId}, message ${messageId}: ${
          error instanceof Error ? error.message : "Unknown error"
        }`,
      );
      throw error;
    }
  }

  /**
   * Handle bulk new messages (useful for initial sync or batch processing)
   */
  async handleBulkNewMessages(userId: string, messageIds: number[], mailboxId?: string) {
    this.logger.log(`Processing bulk new message notifications for user ${userId}, ${messageIds.length} messages`);

    const results = [];
    for (const messageId of messageIds) {
      try {
        const result = await this.handleNewMessage(userId, messageId, mailboxId);
        results.push(result);
      } catch (error) {
        this.logger.error(`Failed to process message ${messageId} in bulk notification: ${error}`);
      }
    }

    return results;
  }

  /**
   * Simulate new message arrival (for testing purposes)
   */
  async simulateNewMessage(userId: string, messageData: Partial<EmailNotificationPayload>) {
    this.logger.log(`Simulating new message for user ${userId}`);

    const simulatedPayload: EmailNotificationPayload = {
      messageId: Math.floor(Math.random() * 10000),
      userId,
      from: {
        name: "Test Sender",
        address: "test@example.com",
      },
      to: [
        {
          name: "Test Recipient",
          address: "recipient@example.com",
        },
      ],
      subject: "Test Message",
      preview: "This is a test message for WebSocket notification",
      hasAttachments: false,
      received: new Date().toISOString(),
      mailboxId: "inbox",
      mailboxName: "Inbox",
      isRead: false,
      isFlagged: false,
      size: 1024,
      ...messageData,
    };

    await this.emailGateway.notifyNewMessage(simulatedPayload);

    return simulatedPayload;
  }

  private async getMailboxName(userId: string, mailboxId: string): Promise<string> {
    try {
      const mailboxIds = await this.mailboxResolverService.getUserMailboxIds(userId);

      // Check which mailbox this ID corresponds to
      if (mailboxIds.inbox === mailboxId) return "Inbox";
      if (mailboxIds.sent === mailboxId) return "Sent";
      if (mailboxIds.drafts === mailboxId) return "Drafts";
      if (mailboxIds.trash === mailboxId) return "Trash";
      if (mailboxIds.junk === mailboxId) return "Junk";
      if (mailboxIds.archive === mailboxId) return "Archive";
      if (mailboxIds.favorite === mailboxId) return "Favorite";

      return "Unknown";
    } catch (error) {
      this.logger.error(`Failed to get mailbox name for ${mailboxId}: ${error}`);
      return "Unknown";
    }
  }

  private extractPreview(content: string): string {
    // Remove HTML tags and get first 150 characters
    const textContent = content.replace(/<[^>]*>/g, "").trim();
    return textContent.length > 150 ? textContent.substring(0, 150) + "..." : textContent;
  }
}