import L from "../../utils/logger";
import fs from "fs";
import path from "path";

function getRelativePath(src: string, dst: string): string {
  if (src.slice(-1) === "/") {
    src = src.slice(0, -1);
  }

  return src.split("/").reduce((acc) => acc + "../", "") + dst;
}

async function swapComponent(pairs: [string]): Promise<void> {
  if (pairs.length % 2 === 1) {
    L.error("pairs should have even count");
    throw new Error("pairs should have even count");
  }

  for (let i = 0; i < pairs.length; i += 2) {
    const [src, dst] = pairs.slice(i, i + 2);
    L.info(`swap ${src} into ${dst}...`);

    try {
      const srcStat = fs.statSync(src);

      if (!srcStat.isDirectory()) {
        L.warn(`${src} is not a directory, skip...`);
        throw new Error(`${src} is not a directory`);
      }

      if ([".js", ".ts"].indexOf(dst.slice(-3)) === -1) {
        L.warn(`${dst} is not a js or ts file, skip...`);
        throw new Error(`${dst} is not a js or ts file`);
      }

      const dstStat = fs.statSync(dst);

      if (!dstStat.isFile()) {
        L.warn(`${dst} is not a js file, skip...`);
        throw new Error(`${dst} is not a js file`);
      }

      fs.writeFileSync(
        path.join(src, "package.json"),
        `{"main": "${getRelativePath(src, dst)}"}`
      );
    } catch (ex) {
      L.warn(`exception raised`);
      throw ex;
    }
  }
}

export { swapComponent };