import { Hono } from "hono";
import { db } from "../db/client.js";
import { users, vk_connections } from "../db/schema.js";
import { eq } from "drizzle-orm";
import { getSessionUserId, type AppEnv } from "../lib/auth.js";
import { render } from "../lib/render.js";
import { config } from "../config.js";

export const vkRouter = new Hono<AppEnv>();

const VK_API_URL = "https://api.vk.com/method";
const VK_OAUTH_URL = "https://oauth.vk.com/authorize";

async function requireUser(c: Parameters<typeof getSessionUserId>[0]) {
  const id = getSessionUserId(c);
  if (!id) return null;
  const [user] = await db.select().from(users).where(eq(users.id, id)).limit(1);
  return user ?? null;
}

async function fetchGroupInfo(token: string): Promise<{ groupId: string | null; groupName: string | null }> {
  try {
    const params = new URLSearchParams({
      access_token: token,
      v: config.VK_API_VERSION,
      filter: "admin",
      extended: "1",
      count: "1",
    });
    const resp = await fetch(`${VK_API_URL}/groups.get?${params}`, {
      signal: AbortSignal.timeout(15000),
    });
    if (!resp.ok) return { groupId: null, groupName: null };
    const data = await resp.json() as { error?: unknown; response?: { items?: Array<{ id: number; name: string }> } };
    if (data.error) return { groupId: null, groupName: null };
    const items = data.response?.items ?? [];
    if (items.length === 0) return { groupId: null, groupName: null };
    return { groupId: String(items[0].id), groupName: items[0].name };
  } catch {
    return { groupId: null, groupName: null };
  }
}

vkRouter.get("/vk", async (c) => {
  const user = await requireUser(c);
  if (!user) return c.redirect("/login", 303);

  const [connection] = await db.select().from(vk_connections).where(eq(vk_connections.user_id, user.id)).limit(1);
  const error = c.req.query("error") ?? null;

  return c.html(render("vk.njk", {
    user,
    connection: connection ?? null,
    error,
    vk_client_id: config.VK_CLIENT_ID,
    callback_url: `${config.BASE_URL}/vk/callback`,
  }));
});

vkRouter.get("/vk/connect", async (c) => {
  const user = await requireUser(c);
  if (!user) return c.redirect("/login", 303);
  if (!config.VK_CLIENT_ID) return c.redirect("/vk?error=no_client_id", 303);

  const params = new URLSearchParams({
    client_id: config.VK_CLIENT_ID,
    scope: "market,groups",
    redirect_uri: `${config.BASE_URL}/vk/callback`,
    display: "page",
    response_type: "token",
    v: config.VK_API_VERSION,
  });
  return c.redirect(`${VK_OAUTH_URL}?${params}`, 302);
});

vkRouter.get("/vk/callback", async (c) => {
  const user = await requireUser(c);
  if (!user) return c.redirect("/login", 303);
  return c.html(render("vk_callback.njk", { user }));
});

vkRouter.post("/vk/token", async (c) => {
  const user = await requireUser(c);
  if (!user) return c.redirect("/login", 303);

  const form = await c.req.formData();
  const token = String(form.get("token") ?? "").trim();
  if (!token) return c.redirect("/vk?error=empty_token", 303);

  const { groupId, groupName } = await fetchGroupInfo(token);
  if (!groupId) return c.redirect("/vk?error=invalid_token", 303);

  const now = new Date();
  const [existing] = await db.select().from(vk_connections).where(eq(vk_connections.user_id, user.id)).limit(1);

  if (existing) {
    await db.update(vk_connections)
      .set({ access_token: token, vk_user_id: groupId, first_name: groupName, last_name: null, is_online: true, last_checked_at: now, updated_at: now })
      .where(eq(vk_connections.id, existing.id));
  } else {
    await db.insert(vk_connections).values({
      user_id: user.id,
      access_token: token,
      vk_user_id: groupId,
      first_name: groupName,
      last_name: null,
      is_online: true,
      last_checked_at: now,
    });
  }

  return c.redirect("/connections", 303);
});

vkRouter.post("/vk/disconnect", async (c) => {
  const user = await requireUser(c);
  if (!user) return c.redirect("/login", 303);
  await db.delete(vk_connections).where(eq(vk_connections.user_id, user.id));
  return c.redirect("/connections", 303);
});