using System;

namespace Artemis.Core
{
    /// <summary>
    ///     Represents progress on a plugin prerequisite action
    /// </summary>
    public class PrerequisiteActionProgress : CorePropertyChanged, IProgress<(long, long)>
    {
        private long _current;
        private DateTime _lastReport;
        private long _lastReportValue;
        private double _percentage;
        private double _progressPerSecond;
        private long _total;

        /// <summary>
        ///     The current amount
        /// </summary>
        public long Current
        {
            get => _current;
            set => SetAndNotify(ref _current, value);
        }

        /// <summary>
        ///     The total amount
        /// </summary>
        public long Total
        {
            get => _total;
            set => SetAndNotify(ref _total, value);
        }

        /// <summary>
        ///     The percentage
        /// </summary>
        public double Percentage
        {
            get => _percentage;
            set => SetAndNotify(ref _percentage, value);
        }

        /// <summary>
        ///     Gets or sets the progress per second
        /// </summary>
        public double ProgressPerSecond
        {
            get => _progressPerSecond;
            set => SetAndNotify(ref _progressPerSecond, value);
        }

        #region Implementation of IProgress<in (long, long)>

        /// <inheritdoc />
        public void Report((long, long) value)
        {
            (long newCurrent, long newTotal) = value;

            TimeSpan timePassed = DateTime.Now - _lastReport;
            if (timePassed >= TimeSpan.FromSeconds(1))
            {
                ProgressPerSecond = Math.Max(0, Math.Round(1.0 / timePassed.TotalSeconds * (newCurrent - _lastReportValue), 2));
                _lastReportValue = newCurrent;
                _lastReport = DateTime.Now;
            }

            Current = newCurrent;
            Total = newTotal;
            Percentage = Math.Round((double) Current / Total * 100.0, 2);

            OnProgressReported();
        }

        #endregion

        #region Events

        /// <summary>
        ///     Occurs when progress has been reported
        /// </summary>
        public event EventHandler? ProgressReported;

        /// <summary>
        ///     Invokes the <see cref="ProgressReported" /> event
        /// </summary>
        protected virtual void OnProgressReported()
        {
            ProgressReported?.Invoke(this, EventArgs.Empty);
        }

        #endregion
    }
}