using System.Collections.Generic;
using System.Linq;
using Games.Common.Randomness;
using SuperStarTrek.Resources;

using static System.StringSplitOptions;

namespace SuperStarTrek.Space;

internal class Galaxy
{
    private static readonly string[] _regionNames;
    private static readonly string[] _subRegionIdentifiers;
    private readonly QuadrantInfo[][] _quadrants;

    static Galaxy()
    {
        _regionNames = Strings.RegionNames.Split(new[] { ' ', '\n' }, RemoveEmptyEntries | TrimEntries);
        _subRegionIdentifiers = new[] { "I", "II", "III", "IV" };
    }

    internal Galaxy(IRandom random)
    {
        _quadrants = Enumerable
            .Range(0, 8)
            .Select(x => Enumerable
                .Range(0, 8)
                .Select(y => new Coordinates(x, y))
                .Select(c => QuadrantInfo.Create(c, GetQuadrantName(c), random))
                .ToArray())
            .ToArray();

        if (StarbaseCount == 0)
        {
            var randomQuadrant = this[random.NextCoordinate()];
            randomQuadrant.AddStarbase();

            if (randomQuadrant.KlingonCount < 2)
            {
                randomQuadrant.AddKlingon();
            }
        }
    }

    internal QuadrantInfo this[Coordinates coordinate] => _quadrants[coordinate.X][coordinate.Y];

    internal int KlingonCount => _quadrants.SelectMany(q => q).Sum(q => q.KlingonCount);

    internal int StarbaseCount => _quadrants.SelectMany(q => q).Count(q => q.HasStarbase);

    internal IEnumerable<IEnumerable<QuadrantInfo>> Quadrants => _quadrants;

    private static string GetQuadrantName(Coordinates coordinates) =>
        $"{_regionNames[coordinates.RegionIndex]} {_subRegionIdentifiers[coordinates.SubRegionIndex]}";

    internal IEnumerable<IEnumerable<QuadrantInfo>> GetNeighborhood(Quadrant quadrant) =>
        Enumerable.Range(-1, 3)
            .Select(dx => dx + quadrant.Coordinates.X)
            .Select(x => GetNeighborhoodRow(quadrant, x));
    private IEnumerable<QuadrantInfo> GetNeighborhoodRow(Quadrant quadrant, int x) =>
        Enumerable.Range(-1, 3)
            .Select(dy => dy + quadrant.Coordinates.Y)
            .Select(y => y < 0 || y > 7 || x < 0 || x > 7 ? null : _quadrants[x][y]);
}