import { toNative } from "./toNative";
import * as libarg from "arg";

export function Flags(vargs: string[]): any {
  return () =>
    (data: any): any => {
      data = toNative(data);
      // We always want the help flag.
      const args: {
        [key: string]: any;
      } = {};

      for (const d of data) {
        let t: any = String;
        if (typeof d[1] === "number") {
          t = Number;
        } else if (typeof d[1] === "boolean") {
          t = Boolean;
        } else if (Array.isArray(d[1])) {
          t = [String];
        }
        const numDashes = d[0].length > 1 ? 2 : 1;
        args["-".repeat(numDashes) + d[0]] = t;
      }
      const ret = libarg(args, { argv: vargs });
      for (const d of data) {
        if (!ret.hasOwnProperty("--" + d[0]) || !ret.hasOwnProperty("-" + d[0])) ret[d[0]] = d[1];
      }
      for (const key of Object.keys(ret)) {
        if (!key.startsWith("-")) continue;
        const value = ret[key];
        delete ret[key];
        const numDashes = key.length === 2 ? 1 : 2;
        ret[key.slice(numDashes)] = value;
      }
      return ret;
    };
}