import "dotenv/config";
import ms from "ms";
import ip from "ip";

export const DB_TYPE = process.env.DB_TYPE ?? "mysql";
export const DB_HOST = process.env.DB_HOST ?? "";
export const DB_PORT = Number(process.env.DB_PORT ?? 3306);
export const DB_NAME = process.env.DB_NAME ?? "";
export const DB_USERNAME = process.env.DB_USERNAME ?? "";
export const DB_PASSWORD = process.env.DB_PASSWORD ?? "";

export const SERVER_PORT = Number(process.env.SERVER_PORT ?? 5000);

export const APPLICATION_SECRET = process.env.APPLICATION_SECRET;

export const USE_SECURITY_STRICT_LIMIT = process.env.USE_SECURITY_STRICT_LIMIT ?? "true";
export const SECURITY_STRICT_LIMIT_WINDOW = (process.env.SECURITY_STRICT_LIMIT_WINDOW ?? "15m") as ms.StringValue;
export const SECURITY_STRICT_LIMIT_REQUEST_COUNT = Number(process.env.SECURITY_STRICT_LIMIT_REQUEST_COUNT ?? "15");
export const USE_SECURITY_LIMIT = process.env.USE_SECURITY_LIMIT ?? "true";
export const SECURITY_LIMIT_WINDOW = (process.env.SECURITY_LIMIT_WINDOW ?? "1m") as ms.StringValue;
export const SECURITY_LIMIT_REQUEST_COUNT = Number(process.env.SECURITY_LIMIT_REQUEST_COUNT ?? "500");

export const TRUST_PROXY = ((): Array<string> | string | boolean | number | null => {
  const proxyVal = process.env.TRUST_PROXY;
  if (!proxyVal) return null;
  if (proxyVal == "true" || proxyVal == "false") {
    return proxyVal == "true";
  }
  if (!isNaN(Number(proxyVal))) {
    return Number(proxyVal);
  }
  if (proxyVal.includes(",") && proxyVal.split(",").every((pv) => ip.isV4Format(pv) || ip.isV6Format(pv))) {
    return proxyVal.split(",");
  }
  if (ip.isV4Format(proxyVal) || ip.isV6Format(proxyVal)) {
    return proxyVal;
  }
  return null;
})();

export function configCheck() {
  if (DB_TYPE != "mysql" && DB_TYPE != "sqlite" && DB_TYPE != "postgres")
    throw new Error("set valid value to DB_TYPE (mysql|sqlite|postgres)");
  if ((DB_HOST == "" || typeof DB_HOST != "string") && DB_TYPE != "sqlite")
    throw new Error("set valid value to DB_HOST");
  if (DB_NAME == "" || typeof DB_NAME != "string") throw new Error("set valid value to DB_NAME");
  if ((DB_USERNAME == "" || typeof DB_USERNAME != "string") && DB_TYPE != "sqlite")
    throw new Error("set valid value to DB_USERNAME");
  if ((DB_PASSWORD == "" || typeof DB_PASSWORD != "string") && DB_TYPE != "sqlite")
    throw new Error("set valid value to DB_PASSWORD");

  if (isNaN(SERVER_PORT)) throw new Error("set valid numeric value to SERVER_PORT");

  if (USE_SECURITY_STRICT_LIMIT != "true" && USE_SECURITY_STRICT_LIMIT != "false")
    throw new Error("set 'true' or 'false' to USE_SECURITY_STRICT_LIMIT");
  checkMS(SECURITY_STRICT_LIMIT_WINDOW, "SECURITY_STRICT_LIMIT_WINDOW");
  if (isNaN(SECURITY_STRICT_LIMIT_REQUEST_COUNT))
    throw new Error("set valid numeric value to SECURITY_STRICT_LIMIT_REQUEST_COUNT");
  if (USE_SECURITY_LIMIT != "true" && USE_SECURITY_LIMIT != "false")
    throw new Error("set 'true' or 'false' to USE_SECURITY_LIMIT");
  checkMS(SECURITY_LIMIT_WINDOW, "SECURITY_LIMIT_WINDOW");
  if (isNaN(SECURITY_LIMIT_REQUEST_COUNT)) throw new Error("set valid numeric value to SECURITY_LIMIT_REQUEST_COUNT");

  if (!TRUST_PROXY && process.env.TRUST_PROXY) {
    throw new Error("set valid boolean, number, ip or ips value to TRUST_PROXY");
  }
}

function checkMS(input: ms.StringValue, origin: string) {
  try {
    const result = ms(input);
    if (result === undefined) {
      throw new Error(`set valid ms value to ${origin} -> [0-9]*(y|d|h|m|s)`);
    }
  } catch (e) {
    throw new Error(`set valid ms value to ${origin} -> [0-9]*(y|d|h|m|s)`);
  }
}