const Ajv = require("ajv")
const confSchema = require('./configSchema.json')

let  DynamoDBClient, GetItemCommand, marshall, unmarshall

module.exports = class configHelper {

    constructor(options){
        this.config = {}
        this.localfile = options.localfile
        this.fetchConfig = this.fetchConfigFile
        this.refreshAccessRights = this.refreshAccessRightsFile
        const ajv = new Ajv({
            allowUnionTypes: true
        })
        this.configValidator = ajv.compile(confSchema)        
    }

    isValidConfig(conf){
        if(this.configValidator(conf)) return(true)
        console.error('Invalid configuration: ', this.configValidator.errors)
        return(false)
    }

    async fetchConfigFile(){
        let curConfig = this.config
        this.config = await require(this.localfile)
        if(this.isValidConfig(this.config)) return(this.config)
        console.error(this.isValidConfig.errors)
        //revert if invalid conf
        this.config = curConfig
    }

    async refreshAccessRightsDynamo(){
        let ar =  await this.dynamoGet('accessRights')
        this.config.accessRights = ar
    }

    async refreshAccessRightsFile(){
        delete require.cache[require.resolve(this.localfile)]
        let tmp
        try { tmp = require(this.localfile) }
        catch(err) { 
            console.error('Error Reloading config !! (bad json?) => Keeping current accessRights !')
            return 
        }
        if(!tmp.accessRights) {
            console.error('Error Reloading config !! (no accessRights !) => Keeping current accessRights !')
            return           
        }
        this.config.accessRights = tmp.accessRights
    }
}