import { TokenList } from "@uniswap/token-lists";
import schema from "@uniswap/token-lists/src/tokenlist.schema.json";
import Ajv from "ajv";
import contenthashToUri from "./contenthashToUri";
import { parseENSAddress } from "./parseENSAddress";
import uriToHttp from "./uriToHttp";

schema.definitions.TokenInfo.properties.symbol.pattern =
  "^[a-zA-Z0-9+.\\-%/\\$]+$";
const tokenListValidator = new Ajv({ allErrors: true }).compile(schema);

/**
 * Contains the logic for resolving a list URL to a validated token list
 * @param listUrl list url
 * @param resolveENSContentHash resolves an ens name to a contenthash
 */
export default async function getTokenList(
  library: any,
  listUrl: string,
  resolveENSContentHash: (library: any, ensName: string) => Promise<string>
): Promise<TokenList> {
  const parsedENS = parseENSAddress(listUrl);
  let urls: string[];
  if (parsedENS) {
    let contentHashUri;
    try {
      contentHashUri = await resolveENSContentHash(library, parsedENS.ensName);
    } catch (error) {
      console.debug(`Failed to resolve ENS name: ${parsedENS.ensName}`, error);
      throw new Error(`Failed to resolve ENS name: ${parsedENS.ensName}`);
    }
    let translatedUri;
    try {
      translatedUri = contenthashToUri(contentHashUri);
    } catch (error) {
      console.debug("Failed to translate contenthash to URI", contentHashUri);
      throw new Error(
        `Failed to translate contenthash to URI: ${contentHashUri}`
      );
    }
    urls = uriToHttp(`${translatedUri}${parsedENS.ensPath ?? ""}`);
  } else {
    urls = uriToHttp(listUrl);
  }
  for (let i = 0; i < urls.length; i++) {
    const url = urls[i];
    const isLast = i === urls.length - 1;
    let response;
    try {
      response = await fetch(url, { credentials: "omit" });
    } catch (error) {
      console.debug("Failed to fetch list", listUrl, error);
      if (isLast) throw new Error(`Failed to download list ${listUrl}`);
      continue;
    }

    if (!response.ok) {
      if (isLast) throw new Error(`Failed to download list ${listUrl}`);
      continue;
    }

    const json = await response.json();
    if (!tokenListValidator(json)) {
      const validationErrors: string =
        tokenListValidator.errors?.reduce<string>((memo, error) => {
          const add = `${error.dataPath} ${error.message ?? ""}`;
          return memo.length > 0 ? `${memo}; ${add}` : `${add}`;
        }, "") ?? "unknown error";
      throw new Error(`Token list failed validation: ${validationErrors}`);
    }
    return json;
  }
  throw new Error("Unrecognized list URL protocol.");
}