import {
	desc,
	eq,
	asc,
	and,
	isNotNull,
	ne,
	gte,
	inArray,
	or,
} from "drizzle-orm";
import type { BunRequest } from "bun";

import _logger from "@/utils/logging";
import config, { isProd } from "@/config";
import {
	db,
	tickets,
	ticketMessages,
	moderators,
	sessions,
	attachments,
} from "@/database";
import { getUser, getUsers, hydrateTickets } from "./discord";

const logger = _logger.child({ name: "server" });

const CLIENT_ID = config.discord.app_id;
const CLIENT_SECRET = config.discord.client_secret;

const HOST = isProd ? "https://tickets.vt3e.cat" : "http://127.0.0.1:3000";
const REDIRECT_URI = `${HOST}/auth/callback`;
const FRONTEND_URL = isProd ? HOST : "http://127.0.0.1:5173";

async function getSessionUser(req: BunRequest) {
	const cookieHeader = req.headers.get("Cookie");
	if (!cookieHeader) return null;
	const sessionCookie = cookieHeader
		.split("; ")
		.find((c) => c.startsWith("session="));
	if (!sessionCookie) return null;
	const sessionId = sessionCookie.split("=")[1];

	const sessionList = await db
		.select()
		.from(sessions)
		.where(eq(sessions.id, sessionId))
		.limit(1);
	if (sessionList.length === 0) return null;

	return { id: sessionList[0].userId, username: sessionList[0].username };
}

const server = Bun.serve({
	hostname: "127.0.0.1",

	routes: {
		"/api/login": () => {
			const redirectUri = `https://discord.com/oauth2/authorize?client_id=${CLIENT_ID}&response_type=code&redirect_uri=${encodeURIComponent(REDIRECT_URI)}&scope=identify+guilds`;

			return new Response(null, {
				status: 302,
				headers: {
					Location: redirectUri,
				},
			});
		},
		"/auth/callback": {
			GET: async (req) => {
				const url = new URL(req.url);
				const code = url.searchParams.get("code");
				if (!code)
					return new Response("No code provided", {
						status: 400,
						statusText: "No code provided",
					});

				const params = new URLSearchParams();
				params.append("client_id", CLIENT_ID);
				params.append("client_secret", CLIENT_SECRET);
				params.append("grant_type", "authorization_code");
				params.append("code", code);
				params.append("redirect_uri", REDIRECT_URI);

				const tokenResponse = await fetch(
					"https://discord.com/api/oauth2/token",
					{
						method: "POST",
						body: params,
						headers: {
							"Content-Type": "application/x-www-form-urlencoded",
						},
					},
				);

				const data = await tokenResponse.json();
				if (data.error)
					return new Response(data.error_description, {
						status: 400,
						statusText: data.error,
					});

				const accessToken = data.access_token;
				const userResponse = await fetch("https://discord.com/api/users/@me", {
					headers: {
						Authorization: `Bearer ${accessToken}`,
					},
				});

				const userData = await userResponse.json();

				const sessionId = crypto.randomUUID();
				await db.insert(sessions).values({
					id: sessionId,
					userId: userData.id,
					username: userData.username,
				});

				return new Response(null, {
					status: 302,
					headers: {
						Location: `${FRONTEND_URL}/tickets`,
						"Set-Cookie": `session=${sessionId}; Path=/; HttpOnly; SameSite=Lax`,
					},
				});
			},
		},
		"/api/me": {
			GET: async (req: BunRequest) => {
				const user = await getSessionUser(req);
				if (!user) return new Response("Unauthorized", { status: 401 });

				const modCheck = await db
					.select()
					.from(moderators)
					.where(eq(moderators.user_id, user.id))
					.limit(1);
				const isMod = modCheck.length > 0;

				const profile = await getUser(user.id);

				return new Response(JSON.stringify({ profile, isMod }), {
					headers: { "Content-Type": "application/json" },
				});
			},
		},
		"/api/tickets": {
			GET: async (req: BunRequest) => {
				const user = await getSessionUser(req);
				if (!user)
					return new Response(null, {
						status: 302,
						headers: { Location: "/login" },
					});

				const modCheck = await db
					.select()
					.from(moderators)
					.where(eq(moderators.user_id, user.id))
					.limit(1);
				const isMod = modCheck.length > 0;

				const url = new URL(req.url);
				const limitStr = url.searchParams.get("limit") || "20";
				const limit = Number.parseInt(limitStr, 10);

				let allTickets;
				if (isMod) {
					allTickets = await db
						.select()
						.from(tickets)
						.limit(limit)
						.orderBy(desc(tickets.createdAt));
				} else {
					allTickets = await db
						.select()
						.from(tickets)
						.where(eq(tickets.authorId, user.id))
						.limit(limit)
						.orderBy(desc(tickets.createdAt));
				}

				const hydratedTickets = await hydrateTickets(allTickets);

				return new Response(JSON.stringify(hydratedTickets), {
					headers: { "Content-Type": "application/json" },
				});
			},
		},
		"/api/tickets/:id": {
			GET: async (req: BunRequest) => {
				const user = await getSessionUser(req);
				if (!user)
					return new Response(null, {
						status: 302,
						headers: { Location: "/login" },
					});

				const modCheck = await db
					.select()
					.from(moderators)
					.where(eq(moderators.user_id, user.id))
					.limit(1);
				const isMod = modCheck.length > 0;

				const { id } = req.params;
				const ticketId = Number.parseInt(id, 10);
				if (isNaN(ticketId)) return new Response("Invalid ID", { status: 400 });

				const ticketList = await db
					.select()
					.from(tickets)
					.where(eq(tickets.id, ticketId))
					.limit(1);
				const _ticket = ticketList[0];
				if (!_ticket) return new Response("Ticket not found", { status: 404 });

				if (!isMod && _ticket.authorId !== user.id) {
					return new Response(
						"Forbidden: You do not have permission to view this ticket.",
						{
							status: 403,
						},
					);
				}

				const messages = await db
					.select()
					.from(ticketMessages)
					.where(eq(ticketMessages.ticketId, ticketId))
					.orderBy(asc(ticketMessages.createdAt));

				const mentionRegex = /<@!?(\d+)>/g;
				const mentionedIds = messages.flatMap((m) =>
					[...m.content.matchAll(mentionRegex)].map((match) => match[1]),
				);

				const idsToFetch = [
					_ticket.authorId,
					_ticket.openedBy,
					_ticket.claimedBy,
					...messages.map((m) => m.authorId),
					...mentionedIds,
				].filter(Boolean) as string[];

				await getUsers(idsToFetch);

				const [ticket] = await hydrateTickets([_ticket]);

				const messageIds = messages.map((m) => m.id);

				const ticketAttachments = await db
					.select()
					.from(attachments)
					.where(
						or(
							and(
								eq(attachments.ownerType, "ticket"),
								eq(attachments.ownerId, ticketId),
							),
							messageIds.length > 0
								? and(
										eq(attachments.ownerType, "ticket_message"),
										inArray(attachments.ownerId, messageIds),
									)
								: undefined,
						),
					);

				const newMessages = await Promise.all(
					messages.map(async (message) => {
						const author = await getUser(message.authorId);
						const msgAttachments = ticketAttachments.filter(
							(a) =>
								a.ownerType === "ticket_message" && a.ownerId === message.id,
						);

						const mentions: Record<string, any> = {};
						const matches = [...message.content.matchAll(/<@!?(\d+)>/g)];
						for (const match of matches) {
							const id = match[1];
							if (!mentions[id]) {
								mentions[id] = await getUser(id);
							}
						}

						return {
							...message,
							author,
							attachments: msgAttachments,
							mentions,
						};
					}),
				);

				const mainTicketAttachments = ticketAttachments.filter(
					(a) => a.ownerType === "ticket" && a.ownerId === ticketId,
				);

				return new Response(
					JSON.stringify({
						ticket: { ...ticket, attachments: mainTicketAttachments },
						messages: newMessages,
					}),
					{
						headers: { "Content-Type": "application/json" },
					},
				);
			},
			DELETE: async (req: BunRequest) => {
				const user = await getSessionUser(req);
				if (!user) return new Response("Unauthorized", { status: 401 });

				const modCheck = await db
					.select()
					.from(moderators)
					.where(eq(moderators.user_id, user.id))
					.limit(1);
				if (modCheck.length === 0)
					return new Response(
						"Forbidden: You must be a moderator to delete tickets.",
						{
							status: 403,
						},
					);

				const { id } = req.params;
				const ticketId = Number.parseInt(id, 10);
				if (isNaN(ticketId)) return new Response("Invalid ID", { status: 400 });

				const deleted = await db
					.delete(tickets)
					.where(eq(tickets.id, ticketId))
					.returning();
				if (deleted.length === 0)
					return new Response("Ticket not found", { status: 404 });

				return new Response(JSON.stringify({ success: true }), {
					headers: { "Content-Type": "application/json" },
				});
			},
		},
		"/api/moderators": {
			GET: async (req: BunRequest) => {
				const user = await getSessionUser(req);
				if (!user) return new Response("Unauthorized", { status: 401 });

				const modCheck = await db
					.select()
					.from(moderators)
					.where(eq(moderators.user_id, user.id))
					.limit(1);
				if (modCheck.length === 0)
					return new Response("Forbidden", { status: 403 });

				const mods = await db.select().from(moderators);
				const ids = mods.map((mod) => mod.user_id);

				await getUsers(ids);

				const hydrated = await Promise.all(
					mods.map(async (mod) => {
						const profile = await getUser(mod.user_id);
						return { ...profile, pronouns: mod };
					}),
				);

				return new Response(JSON.stringify(hydrated), {
					headers: { "Content-Type": "application/json" },
				});
			},
		},
		"/api/stats/overall": {
			GET: async (req: BunRequest) => {
				const url = new URL(req.url);
				const daysStr = url.searchParams.get("days");
				const days = daysStr ? Number.parseInt(daysStr, 10) : null;
				const guildId = url.searchParams.get("guildId");
				const cutoffDate = days
					? new Date(Date.now() - days * 24 * 60 * 60 * 1000)
					: null;

				const closedTickets = await db
					.select()
					.from(tickets)
					.where(
						and(
							isNotNull(tickets.closedAt),
							isNotNull(tickets.closedBy),
							ne(tickets.closedBy, "reporter"),
							ne(tickets.closedBy, "system"),
							guildId ? eq(tickets.guildId, guildId) : undefined,
							cutoffDate ? gte(tickets.closedAt, cutoffDate) : undefined,
						),
					);

				const allDurations = closedTickets.map(
					(t) => t.closedAt!.getTime() - t.createdAt.getTime(),
				);

				const getStats = (durations: number[]) => {
					if (durations.length === 0) return { mean: 0, median: 0, count: 0 };
					const sum = durations.reduce((a, b) => a + b, 0);
					const mean = sum / durations.length;
					const sorted = [...durations].sort((a, b) => a - b);
					const mid = Math.floor(sorted.length / 2);
					const median =
						sorted.length % 2 !== 0
							? sorted[mid]
							: (sorted[mid - 1] + sorted[mid]) / 2;
					return { mean, median, count: durations.length };
				};

				const globalStats = getStats(allDurations);

				const hourlyDurations = new Map<number, number[]>();
				for (const t of closedTickets) {
					const hour = t.closedAt!.getHours();
					if (!hourlyDurations.has(hour)) hourlyDurations.set(hour, []);
					hourlyDurations
						.get(hour)
						?.push(t.closedAt!.getTime() - t.createdAt.getTime());
				}

				const hourly = [];
				for (let i = 0; i < 24; i++) {
					const durations = hourlyDurations.get(i) || [];
					if (durations.length === 0) continue;
					const stats = getStats(durations);
					hourly.push({ hour: i, ...stats });
				}

				return new Response(JSON.stringify({ global: globalStats, hourly }), {
					headers: { "Content-Type": "application/json" },
				});
			},
		},
		"/api/stats/leaderboard": {
			GET: async (req: BunRequest) => {
				const url = new URL(req.url);
				const daysStr = url.searchParams.get("days");
				const days = daysStr ? Number.parseInt(daysStr, 10) : null;
				const guildId = url.searchParams.get("guildId");
				const orderBy = url.searchParams.get("order_by") || "median";
				const cutoffDate = days
					? new Date(Date.now() - days * 24 * 60 * 60 * 1000)
					: null;

				const closedTickets = await db
					.select()
					.from(tickets)
					.where(
						and(
							isNotNull(tickets.closedAt),
							isNotNull(tickets.closedBy),
							ne(tickets.closedBy, "reporter"),
							ne(tickets.closedBy, "system"),
							guildId ? eq(tickets.guildId, guildId) : undefined,
							cutoffDate ? gte(tickets.closedAt, cutoffDate) : undefined,
						),
					);

				const modDurations = new Map<string, number[]>();
				for (const t of closedTickets) {
					const modId = t.closedBy;
					if (!modId) continue;
					if (!modDurations.has(modId)) modDurations.set(modId, []);
					modDurations
						.get(modId)
						?.push(t.closedAt!.getTime() - t.createdAt.getTime());
				}

				const getStats = (durations: number[]) => {
					if (durations.length === 0) return { mean: 0, median: 0, count: 0 };
					const sum = durations.reduce((a, b) => a + b, 0);
					const mean = sum / durations.length;
					const sorted = [...durations].sort((a, b) => a - b);
					const mid = Math.floor(sorted.length / 2);
					const median =
						sorted.length % 2 !== 0
							? sorted[mid]
							: (sorted[mid - 1] + sorted[mid]) / 2;
					return { mean, median, count: durations.length };
				};

				const modStats = Array.from(modDurations.entries()).map(
					([modId, durations]) => {
						const stats = getStats(durations);
						return { modId, ...stats };
					},
				);

				if (orderBy === "mean") modStats.sort((a, b) => a.mean - b.mean);
				else if (orderBy === "count")
					modStats.sort((a, b) => b.count - a.count);
				else modStats.sort((a, b) => a.median - b.median);

				const idsToFetch = modStats.map((mod) => mod.modId);
				await getUsers(idsToFetch);

				const leaderboard = await Promise.all(
					modStats.map(async (mod, i) => {
						const profile = await getUser(mod.modId);
						return {
							rank: i + 1,
							user: profile,
							...mod,
						};
					}),
				);

				return new Response(JSON.stringify(leaderboard), {
					headers: { "Content-Type": "application/json" },
				});
			},
		},
		"/api/*": () => {
			return new Response(null, { status: 404 });
		},

		"/*": async (request) => {
			const { pathname } = new URL(request.url);

			const file = Bun.file(`frontend/dist/${pathname}`);
			if (await file.exists()) return new Response(file, { status: 200 });

			const indexFile = Bun.file(`frontend/dist/index.html`);
			return new Response(indexFile, { status: 200 });
		},
	},
});

const PORT = process.env.PORT || 3000;
logger.info(`server is running at ${server.hostname}:${PORT}`);