import { getAddress, getBytes, id, Signer } from "ethers";
import { CommunityConfig } from "../config";
import { verifyAccountOwnership } from "../accounts";

export const generateConnectionMessage = (
  accountAddress: string,
  expiryTimeStamp: string,
  redirectUrl?: string
): string => {
  let message = `Signature auth for ${getAddress(
    accountAddress
  )} with expiry ${expiryTimeStamp}`;

  if (redirectUrl) {
    message += ` and redirect ${encodeURIComponent(redirectUrl)}`;
  }

  return id(message);
};

export const generateConnectedHeaders = async (
  signer: Signer,
  accountAddress: string,
  expiryTimeStamp: string,
  redirectUrl?: string
): Promise<{
  "x-sigauth-account": string;
  "x-sigauth-expiry": string;
  "x-sigauth-signature": string;
  "x-sigauth-redirect": string | undefined;
}> => {
  const message = generateConnectionMessage(
    accountAddress,
    expiryTimeStamp,
    redirectUrl
  );

  const signature = await signer.signMessage(getBytes(message));

  return {
    "x-sigauth-account": accountAddress,
    "x-sigauth-expiry": expiryTimeStamp,
    "x-sigauth-signature": signature,
    "x-sigauth-redirect": redirectUrl,
  };
};

export const createConnectedUrl = async (
  url: string,
  signer: Signer,
  accountAddress: string,
  expiryTimeStamp: string,
  redirectUrl?: string
): Promise<string> => {
  const message = generateConnectionMessage(
    accountAddress,
    expiryTimeStamp,
    redirectUrl
  );
  const signature = await signer.signMessage(getBytes(message));

  const params = new URLSearchParams({
    sigAuthAccount: accountAddress,
    sigAuthExpiry: expiryTimeStamp,
    sigAuthSignature: signature,
  });
  if (redirectUrl) {
    params.set("sigAuthRedirect", redirectUrl);
  }

  return url.includes("?")
    ? `${url}&${params.toString()}`
    : `${url}?${params.toString()}`;
};

export const verifyConnectedHeaders = async (
  config: CommunityConfig,
  headers: Headers
): Promise<string | null> => {
  const account = headers.get("x-sigauth-account");
  const expiry = headers.get("x-sigauth-expiry");
  const signature = headers.get("x-sigauth-signature");
  const redirect = headers.get("x-sigauth-redirect") || undefined;

  if (!account || !expiry || !signature) {
    const missingHeaders = [
      !account && "x-sigauth-account",
      !expiry && "x-sigauth-expiry",
      !signature && "x-sigauth-signature",
    ].filter(Boolean);

    throw new Error(
      `Invalid connection request: missing ${missingHeaders.join(", ")}`
    );
  }

  if (new Date(expiry).getTime() < Date.now()) {
    throw new Error("Connection request expired");
  }

  const message = generateConnectionMessage(account, expiry, redirect);

  const verified = await verifyAccountOwnership(
    config,
    account,
    message,
    signature
  );

  if (!verified) {
    throw new Error(
      "Invalid signature or account ownership verification failed"
    );
  }

  return verified ? account : null;
};

export const verifyConnectedUrl = async (
  config: CommunityConfig,
  options: {
    url?: string;
    params?: URLSearchParams;
  }
): Promise<string | null> => {
  if (!options.url && !options.params) {
    throw new Error("Either url or params must be provided");
  }

  const params =
    options.params || new URLSearchParams(options.url?.split("?")[1]);
  const sigAuthAccount = params.get("sigAuthAccount");
  const sigAuthExpiry = params.get("sigAuthExpiry");
  const sigAuthSignature = params.get("sigAuthSignature");
  const sigAuthRedirect = params.get("sigAuthRedirect") || undefined;

  if (!sigAuthAccount || !sigAuthExpiry || !sigAuthSignature) {
    const missingParams = [
      !sigAuthAccount && "sigAuthAccount",
      !sigAuthExpiry && "sigAuthExpiry",
      !sigAuthSignature && "sigAuthSignature",
    ].filter(Boolean);

    throw new Error(
      `Invalid connection request: missing ${missingParams.join(", ")}`
    );
  }

  // Check the expiry time
  if (new Date(sigAuthExpiry).getTime() < Date.now()) {
    throw new Error("Connection request expired");
  }

  const message = generateConnectionMessage(
    sigAuthAccount,
    sigAuthExpiry,
    sigAuthRedirect
  );

  const verified = await verifyAccountOwnership(
    config,
    sigAuthAccount,
    message,
    sigAuthSignature
  );

  return verified ? sigAuthAccount : null;
};