interface Number {
    pad(n: number, char?: string): string
}

Number.prototype.pad = function(n, char = "0") {
    return (new Array(n).join(char) + this).slice(-n)
}

interface Date {
    toFrDate(): string,
    toFrTime(): string,
    toSmallFrDate(): string,
    difference(start_at?: Date): string,
}

Date.prototype.toFrDate = function() {
    return `${this.getDate()}/${Number(this.getMonth() + 1).pad(2)}/${this.getFullYear()}`
}

Date.prototype.toFrTime = function(separator = 'h') {
    return `${this.getHours().pad(2, '0')}${separator}${Number(this.getMinutes()).pad(2)}`
}

Date.prototype.toSmallFrDate = function() {
    if ((new Date(this)).toFrDate() === (new Date()).toFrDate()) {
        return `${this.toFrTime()}`
    }

    return `${this.toFrDate()} ${this.toFrTime()}`
}

Date.prototype.difference = function (start_at) {
    if (!this) {
        return '--:--'
    }
    let end_at = this
    if (!start_at) {
        end_at = new Date()
        start_at = this
    }
    let timer = Math.floor((end_at.getTime() - start_at.getTime()) / 1000)
    let hours = Math.floor(timer / 3600)
    let minutes = Math.floor((timer - hours * 3600) / 60)
    let secondes = timer - hours * 3600 - minutes * 60
    return `${hours}:${String(minutes).padStart(2, '0')}:${String(secondes).padStart(2, '0')}`

}