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

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

export class Qenv {
  requiredEnvVars: string[] = []
  availableEnvVars: string[] = []
  missingEnvVars: string[] = []
  keyValueObjectArray: IKeyValueObject[] = []
  constructor (basePathArg = process.cwd(), envYmlPathArg, failOnMissing = true) {
    getRequiredEnvVars(basePathArg, this.requiredEnvVars)
    getAvailableEnvVars(this.requiredEnvVars, envYmlPathArg, this.availableEnvVars, this.keyValueObjectArray)
    this.missingEnvVars = getMissingEnvVars(this.requiredEnvVars, this.availableEnvVars)

    // 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)
      }
    }
  }
}

let getRequiredEnvVars = (pathArg: string, requiredEnvVarsArray: string[]) => {
  let qenvFilePath = plugins.path.join(pathArg, 'qenv.yml')
  let qenvFile = plugins.smartfile.fs.toObjectSync(qenvFilePath)
  for (let keyArg in qenvFile.vars) {
    requiredEnvVarsArray.push(qenvFile.vars[ keyArg ])
  }
}

let getAvailableEnvVars = (
  requiredEnvVarsArg: string[],
  envYmlPathArg: string,
  availableEnvVarsArray: string[],
  keyValueObjectArrayArg: IKeyValueObject[]
) => {
  envYmlPathArg = plugins.path.join(envYmlPathArg, 'env.yml')
  let envYml
  try {
    envYml = plugins.smartfile.fs.toObjectSync(envYmlPathArg)
  } catch (err) {
    console.log("env file couldn't be found at " + envYmlPathArg)
    envYml = {}
  }
  for (let requiredEnvVar of requiredEnvVarsArg) {
    if (process.env[ requiredEnvVar ]) {
      availableEnvVarsArray.push(requiredEnvVar)
      keyValueObjectArrayArg.push({
        key: requiredEnvVar,
        value: process.env[ requiredEnvVar ]
      })
    } else if (envYml.hasOwnProperty(requiredEnvVar)) {
      process.env[ requiredEnvVar ] = envYml[ requiredEnvVar ]
      availableEnvVarsArray.push(requiredEnvVar)
      keyValueObjectArrayArg.push({
        key: requiredEnvVar,
        value: process.env[ requiredEnvVar ]
      })
    }
  }
}

let getMissingEnvVars = (requiredEnvVarsArray: string[], availableEnvVarsArray: string[]) => {
  return plugins.lodash.difference(requiredEnvVarsArray, availableEnvVarsArray)
}