import type { OAuth2Tokens } from "arctic";
import type { Context } from "hono";
import { OauthError } from "../error.js";
import { getRelativeUrl } from "../util.js";
import type { Provider } from "./provider.js";

export interface ArcticProviderOptions {
  scopes: string[];
  clientID: string;
  clientSecret: string;
  query?: Record<string, string>;
}

interface ProviderState {
  state: string;
}

export function ArcticProvider(
  provider: new (
    clientID: string,
    clientSecret: string,
    callback: string,
  ) => {
    createAuthorizationURL(state: string, scopes: string[]): URL;
    validateAuthorizationCode(code: string): Promise<OAuth2Tokens>;
    refreshAccessToken(refreshToken: string): Promise<OAuth2Tokens>;
  },
  config: ArcticProviderOptions,
): Provider<{
  tokenset: OAuth2Tokens;
}> {
  function getClient(c: Context) {
    const callback = new URL(c.req.url);
    const pathname = callback.pathname.replace(/authorize.*$/, "callback");
    const url = getRelativeUrl(c, pathname);
    return new provider(config.clientID, config.clientSecret, url);
  }
  return {
    type: "arctic",
    init(routes, ctx) {
      routes.get("/authorize", async (c) => {
        const client = getClient(c);
        const state = crypto.randomUUID();
        await ctx.set(c, "provider", 60 * 10, {
          state,
        });
        return c.redirect(client.createAuthorizationURL(state, config.scopes));
      });

      routes.get("/callback", async (c) => {
        const client = getClient(c);
        const provider = (await ctx.get(c, "provider")) as ProviderState;
        if (!provider) return c.redirect("../authorize");
        const code = c.req.query("code");
        const state = c.req.query("state");
        if (!code) throw new Error("Missing code");
        if (state !== provider.state) throw new OauthError("invalid_request", "Invalid state");
        const tokens = await client.validateAuthorizationCode(code);
        return ctx.success(c, {
          tokenset: tokens,
        });
      });
    },
  };
}