using System.Collections;
using System.Collections.Generic;
using Hallucinate.GameSetup.Maze.Extensions;
using UnityEngine;

namespace Hallucinate.GameSetup.Maze
{
    public class RecursiveAlgorithm : IMazeAlgorithm
    {
        private const int StartX = 5;
        private const int StartZ = 5;
        private const int DeadEndNeighbourThreshold = 2;

        private readonly List<MapLocation> _directions = MapLocation.Directions;

        public void Generate(MazeGrid grid)
        {
            GenerateRecursive(grid, StartX, StartZ);
        }

        public IEnumerator GenerateStepByStep(MazeGrid grid, float interval)
        {
            yield return GenerateRecursiveStepByStep(grid, StartX, StartZ, interval);
        }

        private void GenerateRecursive(MazeGrid grid, int x, int z)
        {
            if (grid.CountSquareNeighbours(x, z, MazeCellType.Corridor) >= DeadEndNeighbourThreshold) return;
            
            grid.SetCell(x, z, MazeCellType.Corridor);

            List<MapLocation> shuffledDirs = new List<MapLocation>(_directions);
            shuffledDirs.Shuffle();

            foreach (var dir in shuffledDirs)
            {
                int nx = x + dir.x;
                int nz = z + dir.z;
                if (grid.IsInBounds(nx, nz))
                {
                    GenerateRecursive(grid, nx, nz);
                }
            }
        }

        private IEnumerator GenerateRecursiveStepByStep(MazeGrid grid, int x, int z, float interval)
        {
            if (grid.CountSquareNeighbours(x, z, MazeCellType.Corridor) >= DeadEndNeighbourThreshold) yield break;

            grid.SetCell(x, z, MazeCellType.Processing);
            if (interval > 0) yield return new WaitForSeconds(interval);
            
            grid.SetCell(x, z, MazeCellType.Corridor);

            List<MapLocation> shuffledDirs = new List<MapLocation>(_directions);
            shuffledDirs.Shuffle();

            foreach (var dir in shuffledDirs)
            {
                int nx = x + dir.x;
                int nz = z + dir.z;
                if (grid.IsInBounds(nx, nz))
                {
                    yield return GenerateRecursiveStepByStep(grid, nx, nz, interval);
                }
            }
        }
    }
}