/*
        Wordsearch Creator
        Copyright (C) 2023 Tesses

        This program is free software: you can redistribute it and/or modify
        it under the terms of the GNU General Public License as published by
        the Free Software Foundation, either version 3 of the License, or
        (at your option) any later version.

        This program is distributed in the hope that it will be useful,
        but WITHOUT ANY WARRANTY; without even the implied warranty of
        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        GNU General Public License for more details.

        You should have received a copy of the GNU General Public License
        along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/
using System.Text;
using SixLabors.Fonts;
using SixLabors.ImageSharp;
using SixLabors.ImageSharp.Drawing.Processing;
using SixLabors.ImageSharp.PixelFormats;
using SixLabors.ImageSharp.Processing;

namespace WordSearch
{
    public class WordSearchGenerator
    {
        Random rand=new Random((int)(DateTime.Now.Ticks % int.MaxValue));
        List<string> words = new List<string>();
        List<string> wordsOg = new List<string>();
        int largestWord=0;
        public IReadOnlyList<string> Words => wordsOg;
        public int LargestWord => largestWord;

        public void AddWord(string word)
        {
            if(string.IsNullOrWhiteSpace(word)) return;
            if(word.Length > largestWord) largestWord = word.Length;
            words.Add(word.Replace(" ","").ToUpper());
            wordsOg.Add(word);
        }
        public override string ToString()
        {
            StringBuilder builder=new StringBuilder();
            var grid=GenerateGrid();
            for(int y=0;y<largestWord;y++)
            {
                for(int x=0;x<largestWord;x++)
                {
                    builder.Append(grid[x,y]);
                }
                builder.AppendLine();
            }
            builder.AppendLine();
            foreach(var word in words)
            {
                builder.AppendLine(word);
            }
            return builder.ToString();
        }
        public Image<Rgb24> GenerateImage(Font font,Rgb24 foreground,Rgb24 background)
        {
            var grid=GenerateGrid();
            StringBuilder b = new StringBuilder();
            for(int y = 0;y<largestWord;y++)
            {
                for(int x=0;x<largestWord;x++)
                {
                    if(x>0)
                    b.Append(' ');
                    b.Append(grid[x,y]);
                }
                b.AppendLine();
                b.AppendLine();
            }
            
            for(int i = 0;i<wordsOg.Count;i++)
            {
                b.Append(wordsOg[i]);
                if((i % 3) == 2)
                {
                    b.AppendLine();
                }
                else
                {
                    b.Append(' ');
                }
            }
	        b.AppendLine();
            string text= b.ToString();
            var sz=TextMeasurer.MeasureSize(text,new TextOptions(font));

            Image<Rgb24> image = new Image<Rgb24>((int)Math.Ceiling(sz.Width)+40,(int)Math.Ceiling(sz.Height)+40,background);
            image.Mutate(e=>e.DrawText(text,font,foreground,new PointF(20,20)));
            return image;
        }
        public char[,] GenerateGrid()
        {
            DateTime mustbeDoneBefore=DateTime.Now.AddMinutes(1);
            char[,] grid = new char[largestWord,largestWord];
            

            foreach(var word in words)
            {
                err:
                if(DateTime.Now > mustbeDoneBefore) throw new Exception();

                int x=rand.Next(0,largestWord);
                int y = rand.Next(0,largestWord);
                int mode = rand.Next(0,4);

                switch(mode)
                {
                    case 0:
                        //Horizontal
                        if(x+word.Length>largestWord) goto err;
                        for(int i = 0;i<word.Length;i++)
                        {
                            if(DateTime.Now > mustbeDoneBefore) throw new Exception();

                            //check whether these are all zeros
                            if(grid[x+i,y] != 0) goto err;
                        }
                        for(int i =0;i<word.Length;i++)
                        {
                            
                            grid[x+i,y] = word[i];
                        }
                        break;
                    case 1:
                        if(y+word.Length>largestWord) goto err;
                        for(int i = 0;i<word.Length;i++)
                        {
                            if(DateTime.Now > mustbeDoneBefore) throw new Exception();

                            //check whether these are all zeros
                            if(grid[x,y+i] != 0) goto err;
                        }
                        for(int i =0;i<word.Length;i++)
                        {
                            grid[x,y+i] = word[i];
                        }
                        break;
                    case 2: //\
                        if(y+word.Length>largestWord || x+word.Length> largestWord) goto err;
                        for(int i = 0;i<word.Length;i++)
                        {
                            if(DateTime.Now > mustbeDoneBefore) throw new Exception();

                            //check whether these are all zeros
                            if(grid[x+i,y+i] != 0) goto err;
                        }
                        for(int i =0;i<word.Length;i++)
                        {
                            grid[x+i,y+i] = word[i];
                        }
                        break;
                    case 3:// /
                        if(y+word.Length>largestWord || x-word.Length< 0) goto err;
                        for(int i = 0;i<word.Length;i++)
                        {
                            if(DateTime.Now > mustbeDoneBefore) throw new Exception();

                            //check whether these are all zeros
                            if(grid[x-i,y+i] != 0) goto err;
                        }
                        for(int i =0;i<word.Length;i++)
                        {
                            grid[x-i,y+i] = word[i];
                        }
                        break;
                }

            }
            for(int y=0;y<largestWord;y++)
            {
                for(int x = 0;x<largestWord;x++)
                {
                    if(grid[x,y] == 0)
                    {
                        int val=rand.Next(0,26);
                        if(val < 26)
                        {
                            grid[x,y] = (char)(val+'A');
                        }
                    }
                }
            }
            return grid;
        }
    }
}