using System.Collections.Generic;
using System.Linq;

using MfGames.Gallium;

namespace MfGames.Nitride.Temporal.Schedules;

/// <summary>
/// An indexed-based schedule that uses the regular expression to get a
/// numerical value and then uses that to determine the schedule.
/// </summary>
public partial class IndexedPathRegexSchedule<TSchedule> : PathRegexScheduleBase
    where TSchedule : IndexedSchedule
{
    public IndexedPathRegexSchedule()
    {
        this.Indexes = new Dictionary<int, TSchedule>();
    }

    /// <summary>
    /// Gets or sets the dictionary that indexes the various numerical indexes
    /// to provide the scheduling.
    /// </summary>
    public Dictionary<int, TSchedule> Indexes { get; set; }

    public IndexedPathRegexSchedule<TSchedule> WithIndexes(
        Dictionary<int, TSchedule> value)
    {
        this.Indexes = value;
        return this;
    }

    /// <inheritdoc />
    protected override Entity Apply(
        Entity entity,
        int number,
        TimeService timeService)
    {
        // Figure out the entry in the index.
        var applicableKeys = this.Indexes.Keys
            .Where(a => a <= number)
            .ToList();

        if (applicableKeys.Count == 0)
        {
            return entity;
        }

        int startIndex = applicableKeys.Max(a => a);
        TSchedule schedule = this.Indexes[startIndex];

        // Pass everything into the schedule to perform the applying.
        int startOffset = number - startIndex;

        return schedule.Apply(entity, startOffset, timeService);
    }
}