import { eq } from "drizzle-orm";
import { db } from "@/lib/db/client";
import { customers, tickets } from "@/lib/db/schema";
import { recordAgentReply, recordInternalNote, getEmailThreadContext } from "@/lib/tickets/service";
import { sendTelegramMessage, sendTelegramFile } from "@/lib/telegram/bot";
import { sendTicketReplyEmail } from "@/lib/mail/smtp";

interface AttachmentPayload {
  filename: string;
  mimeType: string;
  sizeBytes: number;
  storageKey: string;
  buffer: Buffer;
}

/**
 * Shared by the text-reply and attachment-upload admin routes: creates the
 * message (public reply or internal note) and, for public replies, delivers
 * it over the ticket's channel (email/Telegram). Not used for portal/widget
 * replies — those never need outbound channel delivery.
 */
export async function deliverAgentMessage(params: {
  ticketId: string;
  agentId: string;
  agentName: string;
  body: string;
  visibility: "public" | "internal";
  attachment?: AttachmentPayload;
}) {
  const ticket = await db.query.tickets.findFirst({ where: eq(tickets.id, params.ticketId) });
  if (!ticket) throw new Error("Ticket not found");

  const attachmentInput = params.attachment
    ? {
        filename: params.attachment.filename,
        mimeType: params.attachment.mimeType,
        sizeBytes: params.attachment.sizeBytes,
        storageKey: params.attachment.storageKey,
      }
    : undefined;

  if (params.visibility === "internal") {
    return recordInternalNote({
      ticketId: params.ticketId,
      agentId: params.agentId,
      agentName: params.agentName,
      body: params.body,
      attachments: attachmentInput ? [attachmentInput] : undefined,
    });
  }

  let emailMessageId: string | undefined;
  if (ticket.channel === "email") {
    const context = await getEmailThreadContext(params.ticketId);
    if (context) {
      emailMessageId = await sendTicketReplyEmail({
        to: context.customerEmail,
        subject: context.subject,
        body: params.body,
        inReplyTo: context.inReplyTo,
        attachment: params.attachment
          ? { filename: params.attachment.filename, content: params.attachment.buffer }
          : undefined,
      });
    }
  }

  const result = await recordAgentReply({
    ticketId: params.ticketId,
    agentId: params.agentId,
    agentName: params.agentName,
    body: params.body,
    emailMessageId,
    attachments: attachmentInput ? [attachmentInput] : undefined,
  });

  if (result.ticket.channel === "telegram") {
    const customer = await db.query.customers.findFirst({
      where: eq(customers.id, result.ticket.customerId),
    });
    if (customer?.telegramChatId) {
      if (params.attachment) {
        await sendTelegramFile(
          customer.telegramChatId,
          { buffer: params.attachment.buffer, filename: params.attachment.filename, mimeType: params.attachment.mimeType },
          params.body,
        );
      } else {
        await sendTelegramMessage(customer.telegramChatId, params.body);
      }
    }
  }

  return result;
}