import * as plugins from './qenv.plugins';

export interface IKeyValueObject {
  key: string;
  value: string;
}

export class Qenv {
  public requiredEnvVars: string[] = [];
  public availableEnvVars: string[] = [];
  public missingEnvVars: string[] = [];
  public keyValueObjectArray: IKeyValueObject[] = [];
  public logger: plugins.smartlog.Smartlog;

  // filePaths
  public qenvFilePathAbsolute: string;
  public envFilePathAbsolute: string;

  constructor(
    qenvFileBasePathArg = process.cwd(),
    envFileBasePathArg,
    failOnMissing = true,
    loggerArg: plugins.smartlog.Smartlog = plugins.smartlog.defaultLogger
  ) {
    this.logger = loggerArg;

    // lets make sure paths are absolute
    this.qenvFilePathAbsolute = plugins.path.join(plugins.path.resolve(qenvFileBasePathArg), 'qenv.yml');
    this.envFilePathAbsolute = plugins.path.join(plugins.path.resolve(envFileBasePathArg), 'env.yml');

    this.getRequiredEnvVars();
    this.getAvailableEnvVars();

    this.missingEnvVars = this.getMissingEnvVars();

    // handle missing variables
    if (this.missingEnvVars.length > 0) {
      console.info('Required Env Vars are:');
      console.log(this.requiredEnvVars);
      console.error('However some Env variables could not be resolved:');
      console.log(this.missingEnvVars);
      if (failOnMissing) {
        console.error('Exiting!');
        process.exit(1);
      }
    }
  }

  public getEnvVar(envVarName): string {
    return process.env[envVarName];
  }

  public getEnvVarOnDemand(requiredEnvVar: string): string {
    // lets determine the actual env yml
    let envYml;
    try {
      envYml = plugins.smartfile.fs.toObjectSync(this.envFilePathAbsolute);
    } catch (err) {
      console.log("env file couldn't be found at " + this.envFilePathAbsolute);
      envYml = {};
    }
    let envVar: string;
      let envFileVar: string;
      let dockerSecret: string;

      // env var check
      if (process.env[requiredEnvVar]) {
        this.availableEnvVars.push(requiredEnvVar);
        envVar = process.env[requiredEnvVar];
      }

      // env file check
      if (envYml.hasOwnProperty(requiredEnvVar)) {
        envFileVar = envYml[requiredEnvVar];
        this.availableEnvVars.push(requiredEnvVar);
      }
      if (
        plugins.smartfile.fs.isDirectory('/run') &&
        plugins.smartfile.fs.isDirectory('/run/secrets') &&
        plugins.smartfile.fs.fileExists(`/run/secrets/${requiredEnvVar}`)
      ) {
        dockerSecret = plugins.smartfile.fs.toStringSync(`/run/secrets/${requiredEnvVar}`);
      }

      if ((envVar && envFileVar) || (envVar && dockerSecret) || (envFileVar && dockerSecret)) {
        this.logger.log(
          'warn',
          `found multiple candidates for ${requiredEnvVar} Choosing in the order of envVar, envFileVar, dockerSecret`
        );
      }

      let chosenVar: string = null;
      if (envVar) {
        chosenVar = envVar;
      } else if (envFileVar) {
        chosenVar = envFileVar;
      } else if (dockerSecret) {
        chosenVar = dockerSecret;
      }
      return chosenVar;
  }

  /**
   * gets the required env values
   */
  private getRequiredEnvVars = () => {
    const qenvFile = plugins.smartfile.fs.toObjectSync(this.qenvFilePathAbsolute);
    if (!qenvFile.required) {
      this.logger.log('warn', `env File does not contain a 'required' Array!`);
    }
    for (const keyArg of Reflect.ownKeys(qenvFile.required)) {
      this.requiredEnvVars.push(qenvFile.required[keyArg]);
    }
  }

  /**
   * gets the available env vars
   */
  private getAvailableEnvVars = () => {

    for (const requiredEnvVar of this.requiredEnvVars) {
      const chosenVar = this.getEnvVarOnDemand(requiredEnvVar);
      if (chosenVar) {
        this.availableEnvVars.push(requiredEnvVar);
        process.env[requiredEnvVar] = chosenVar;
        this.keyValueObjectArray.push({
          key: requiredEnvVar,
          value: chosenVar
        });
      }
    }
  }

  /**
   * gets missing env vars
   */
  private getMissingEnvVars = (): string[] => {
    const missingEnvVars: string[] = [];
    for (const envVar of this.requiredEnvVars) {
      if (!this.availableEnvVars.includes(envVar)) {
        missingEnvVars.push(envVar);
      }
    }
    return missingEnvVars;
  }
}