import {
	type Ticket,
	db,
	type ticketAttachment,
	ticketAttachments,
	ticketMessages,
} from "@/database";
import { getPublicUrl } from "@/utils/s3";
import { asc, eq } from "drizzle-orm";

export async function generateTranscript(
	ticket: Ticket,
): Promise<[string, ticketAttachment[]]> {
	const messages = await db
		.select()
		.from(ticketMessages)
		.where(eq(ticketMessages.ticketId, ticket.id))
		.orderBy(asc(ticketMessages.createdAt));

	const attachments = await db
		.select()
		.from(ticketAttachments)
		.where(eq(ticketAttachments.ticketId, ticket.id));

	const attachmentMap = new Map<number, typeof attachments>();
	for (const att of attachments) {
		const existing = attachmentMap.get(att.messageId ?? 0) ?? [];
		attachmentMap.set(att.messageId ?? 0, [...existing, att]);
	}

	const lines = messages.map((msg) => {
		const msgAttachments = attachmentMap.get(msg.id) ?? [];
		const time = new Date(msg.createdAt).toISOString();

		const author =
			msg.authorType === "user" ? "reporter" : `<@${msg.authorId}>`;

		let text = `[${time}] ${author}: ${msg.content}`;

		if (msgAttachments.length > 0) {
			const attLines = msgAttachments
				.map((att) => {
					return `\n    (Attachment) ${att.fileName}: ${getPublicUrl(att.key)}`;
				})
				.join("");
			text += attLines;
		}

		return text;
	});

	const separator = "==================================================";
	const header = [
		separator,
		` TRANSCRIPT FOR TICKET #${ticket.anonymousId}`,
		` CREATED : ${new Date(ticket.createdAt).toISOString()}`,
		` CLOSED  : ${ticket.closedAt ? new Date(ticket.closedAt).toISOString() : new Date().toISOString()}`,
		"",
		" Times are displayed in UTC.",
		" All attachments are listed with their public URLs.",
		separator,
		"\n",
	].join("\n");

	return [header + lines.join("\n"), attachments];
}