using System;
using System.Collections.Generic;
using System.Drawing;
using System.Text;

namespace CoopSweeper.GameTypes
{
    class Game
    {
        private readonly Random _random = new Random();
        private static int _checkID = 0;

        public IField[,] Map { get; protected set; }

        private bool IsBomb(int bombratePercent)
        {
            int r = _random.Next(0, 100);
            return r < bombratePercent;
        }

        public void GenerateGame(int x, int y, int bombratePercent)
        {
            Map = new IField[x, y];
            for (int i = 0; i < x; i++)
            {
                for (int j = 0; j < y; j++)
                {
                    var field = new Field
                    {
                        ContainsBomb = IsBomb(bombratePercent)
                    };
                    Map[i, j] = field;
                }
            }

            UpdateSorroundingBombs();
        }

        private void UpdateSorroundingBombs()
        {
            for (int i = 0; i < Map.GetLength(0); i++)
            {
                for (int j = 0; j < Map.GetLength(1); j++)
                {
                    int bombCounter = 0;
                    foreach (var point in GetSorroundedFields(i, j))
                    {
                        if (Map[point.X, point.Y].ContainsBomb)
                            bombCounter++;
                    }

                    Map[i, j].SurroundingBombs = bombCounter;
                }
            }
        }

        private List<Point> GetSorroundedFields(int x, int y)
        {
            var points = new List<Point>();
            points.Add(new Point(x - 1, y - 1));
            points.Add(new Point(x, y - 1));
            points.Add(new Point(x + 1, y - 1));

            points.Add(new Point(x + 1, y));
            points.Add(new Point(x - 1, y));

            points.Add(new Point(x - 1, y + 1));
            points.Add(new Point(x, y + 1));
            points.Add(new Point(x + 1, y + 1));

            points.RemoveAll(point => 
                    point.X < 0 
                    || point.Y < 0 
                    || point.X >= Map.GetLength(0) 
                    || point.Y >= Map.GetLength(1));

            return points;
        }

        public void GenerateGame(int x, int y)
        {
            GenerateGame(x, y, 10);
        }

        private void CheckMap()
        {
            if (Map == null)
                throw new ArgumentNullException("The Map isn't created yet!");
        }

        public delegate void GameFinishedHandler(bool isGameWon);

        public event GameFinishedHandler GameFinished;

        private bool CheckGameFinished()
        {
            for (int i = 0; i < Map.GetLength(0); i++)
            {
                for (int j = 0; j < Map.GetLength(1); j++)
                {
                    var field = Map[i, j];

                    if (!field.ContainsBomb && field.State != FieldState.REVEALED)
                        return false;
                }
            }

            return true;
        }

        private void InternalReveal(int x, int y)
        {
            var field = Map[x, y];
            if (field.CheckID == _checkID)
                return;

            field.CheckID = _checkID;

            if (field.State != FieldState.REVEALED)
            {
                field.State = FieldState.REVEALED;
                if (field.ContainsBomb)
                    GameFinished?.Invoke(false);
                
                if (field.SurroundingBombs == 0)
                    foreach (var surField in GetSorroundedFields(x, y))
                    {
                        InternalReveal(surField.X, surField.Y);
                    }
            }

            if (CheckGameFinished())
                GameFinished?.Invoke(true);
        }

        public void Reveal(int x, int y)
        {
            CheckMap();
            _checkID++;
            InternalReveal(x, y);
        }

        public void ToggleMark(int x, int y)
        {
            CheckMap();
            var field = Map[x, y];

            switch (field.State)
            {
                case FieldState.NONE:
                    field.State = FieldState.FLAG;
                    return;
                case FieldState.FLAG:
                    field.State = FieldState.QUESTIONMARK;
                    return;
                case FieldState.QUESTIONMARK:
                    field.State = FieldState.NONE;
                    return;
            }
        }

    }
}