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)
}