/**
 * Helper class to log progress.
 */
export class ProgressLogger {
    /**
     * @param {number} [total] Optional: expected total number of items to process.
     */
    constructor (total) {
        this.total = total;
        this.completed = 0;
    }

    /**
     * Set the expected total number of items to process.
     * @param {number} total Total number of items to process.
     */
    setTotal (total) {
        if (this.total !== total) {
            this.total = total;
            delete this.percent;
        }
    }

    /**
     * Increment the number of items processed and log progress.
     * If a total is set, progress is logged as a percentage and only when the percentage changes.
     * If no total is set, progress is logged as a count.
     * @param {number} [count=1] Number of items processed.
     */
    increment (count = 1) {
        this.completed += count;
        if (this.total) {
            const percent = Math.floor(100 * this.completed / this.total);
            if (percent !== this.percent) {
                this.percent = percent;
                console.info(`Progress: ${this.percent}% (${this.completed}/${this.total})`);
            }
        } else {
            console.info(`Progress: ${this.completed} of unknown total`);
        }
    }
}