using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection.Emit;
using System.Text;
using System.Threading.Tasks;
using System.Text.RegularExpressions;

namespace Advent24
{
    internal class Day4
    {
        public Day4()
        {
            string fileData = System.IO.File.ReadAllText(@"..\..\..\inputd4.txt");

            // get width of line to be able to navigate the text block in
            // both dimensions
            Int32 textWidth = fileData.IndexOf('\n');

            Int32 linearPosition = 0;

            Int32 numberOfXmases = 0;

            Boolean activatePart2 = true;

            Int32 numberOfX_mases = 0;

            Boolean rightBoundaryCheck, leftBoundaryCheck,
                topBoundaryCheck, bottomBoundaryCheck,
                bottomRightBoundaryCheck, topRightBoundaryCheck,
                bottomLeftBoundaryCheck, topLeftBoundaryCheck;

            if (activatePart2)
                // Find the 'A' starting from where we are currently positioned
                linearPosition = fileData.IndexOf('A', linearPosition);
            else
                // Find the 'X' starting from where we are currently positioned
                linearPosition = fileData.IndexOf('X', linearPosition);

            while (linearPosition < fileData.Length && linearPosition != -1)
            {
                Console.WriteLine("linearPosition = {0:d}", linearPosition);

                if (activatePart2)
                    // check that we're at least 2 away from the right boundary
                    rightBoundaryCheck = (fileData.IndexOf('\n', linearPosition) - linearPosition) > 1;
                else
                    // check that we're at least 4 away from the right boundary
                    rightBoundaryCheck = (fileData.IndexOf('\n', linearPosition) - linearPosition) > 3;

                if (activatePart2)
                    // check that we're at least 2 away from the left boundary
                    leftBoundaryCheck =
                        fileData.LastIndexOf('\n', linearPosition) == -1 ? // first line
                            (linearPosition >= 1) :
                            (linearPosition - fileData.LastIndexOf('\n', linearPosition)) > 1;
                else
                    // check that we're at least 4 away from the left boundary
                    leftBoundaryCheck =
                        fileData.LastIndexOf('\n', linearPosition) == -1 ? // first line
                            (linearPosition >= 3) :
                            (linearPosition - fileData.LastIndexOf('\n', linearPosition)) > 3;
                
                if (activatePart2)
                    // check that we're at least 2 away from the top boundary
                    topBoundaryCheck = (linearPosition - (textWidth+1)*1) >= 0;
                else
                    // check that we're at least 4 away from the top boundary
                    topBoundaryCheck = (linearPosition - (textWidth+1)*3) >= 0;

                if (activatePart2)
                    // check that we're at least 2 away from the bottom boundary
                    bottomBoundaryCheck = (linearPosition + (textWidth + 1) * 1) < fileData.Length;
                else
                    // check that we're at least 4 away from the bottom boundary
                    bottomBoundaryCheck = (linearPosition + (textWidth+1)*3) < fileData.Length;

                // check that we're at least 2 (part2) / 4 (part1) away from the bottom-right boundary
                bottomRightBoundaryCheck = bottomBoundaryCheck && rightBoundaryCheck;

                // check that we're at least 2 (part2) / 4 (part1) away from the top-right boundary
                topRightBoundaryCheck = topBoundaryCheck && rightBoundaryCheck;
                
                // check that we're at least 2 (part2) / 4 (part1) away from the bottom-left boundary
                bottomLeftBoundaryCheck = bottomBoundaryCheck && leftBoundaryCheck;

                // check that we're at least 2 (part2) / 4 (part1) away from the top-left boundary
                topLeftBoundaryCheck = topBoundaryCheck && leftBoundaryCheck;

                if (activatePart2)
                {
                    // check corner boundaries
                    if (
                         topRightBoundaryCheck && topLeftBoundaryCheck &&
                         bottomRightBoundaryCheck && bottomLeftBoundaryCheck
                       )
                    {
                        if (
                            // check bottom-right and top-left diagonal
                            (
                              (
                                fileData[linearPosition + (textWidth + 1) + 1] == 'S' &&
                                fileData[linearPosition - (textWidth + 1) - 1] == 'M'
                              ) ||
                              (
                                fileData[linearPosition + (textWidth + 1) + 1] == 'M' &&
                                fileData[linearPosition - (textWidth + 1) - 1] == 'S'
                              )
                            ) &&
                            // check bottom-left and top-right diagonal
                            (
                              (
                                fileData[linearPosition + (textWidth + 1) - 1] == 'S' &&
                                fileData[linearPosition - (textWidth + 1) + 1] == 'M'
                              ) ||
                              (
                                fileData[linearPosition + (textWidth + 1) - 1] == 'M' &&
                                fileData[linearPosition - (textWidth + 1) + 1] == 'S'
                              )
                            )
                           )
                            numberOfX_mases++;
                    }
                }
                else
                {
                    // check right characters
                    if (rightBoundaryCheck)
                    {
                        if (
                            fileData[linearPosition + 1] == 'M' &&
                            fileData[linearPosition + 2] == 'A' &&
                            fileData[linearPosition + 3] == 'S'
                           )
                            numberOfXmases++;
                    }

                    // check left characters
                    if (leftBoundaryCheck)
                    {
                        if (
                            fileData[linearPosition - 1] == 'M' &&
                            fileData[linearPosition - 2] == 'A' &&
                            fileData[linearPosition - 3] == 'S'
                           )
                            numberOfXmases++;
                    }

                    // check upward characters
                    if (topBoundaryCheck)
                    {
                        if (
                            fileData[linearPosition - (textWidth + 1)] == 'M' &&
                            fileData[linearPosition - (textWidth + 1) * 2] == 'A' &&
                            fileData[linearPosition - (textWidth + 1) * 3] == 'S'
                           )
                            numberOfXmases++;
                    }

                    // check downward characters
                    if (bottomBoundaryCheck)
                    {
                        if (
                            fileData[linearPosition + (textWidth + 1)] == 'M' &&
                            fileData[linearPosition + (textWidth + 1) * 2] == 'A' &&
                            fileData[linearPosition + (textWidth + 1) * 3] == 'S'
                           )
                            numberOfXmases++;
                    }

                    // check bottom-right diagonal characters
                    if (bottomRightBoundaryCheck)
                    {
                        if (
                            fileData[linearPosition + (textWidth + 1) + 1] == 'M' &&
                            fileData[linearPosition + (textWidth + 1) * 2 + 2] == 'A' &&
                            fileData[linearPosition + (textWidth + 1) * 3 + 3] == 'S'
                           )
                            numberOfXmases++;
                    }

                    // check top-right diagonal characters
                    if (topRightBoundaryCheck)
                    {
                        if (
                            fileData[linearPosition - (textWidth + 1) + 1] == 'M' &&
                            fileData[linearPosition - (textWidth + 1) * 2 + 2] == 'A' &&
                            fileData[linearPosition - (textWidth + 1) * 3 + 3] == 'S'
                           )
                            numberOfXmases++;
                    }

                    // check bottom-left diagonal characters
                    if (bottomLeftBoundaryCheck)
                    {
                        if (
                            fileData[linearPosition + (textWidth + 1) - 1] == 'M' &&
                            fileData[linearPosition + (textWidth + 1) * 2 - 2] == 'A' &&
                            fileData[linearPosition + (textWidth + 1) * 3 - 3] == 'S'
                           )
                            numberOfXmases++;
                    }

                    // check top-left diagonal characters
                    if (topLeftBoundaryCheck)
                    {
                        if (
                            fileData[linearPosition - (textWidth + 1) - 1] == 'M' &&
                            fileData[linearPosition - (textWidth + 1) * 2 - 2] == 'A' &&
                            fileData[linearPosition - (textWidth + 1) * 3 - 3] == 'S'
                           )
                            numberOfXmases++;
                    }
                }

                // increment linear position to start the search again
                // from the next character
                linearPosition++;

                if (activatePart2)
                    // Find the 'A' starting from our updated linear position
                    linearPosition = fileData.IndexOf('A', linearPosition);
                else
                    // Find the 'X' starting from our updated linear position
                    linearPosition = fileData.IndexOf('X', linearPosition);
            }

            if (activatePart2)
                Console.WriteLine("numberOfX_mases = {0:d}", numberOfX_mases);
            else
                Console.WriteLine("numberOfXmases = {0:d}", numberOfXmases);


            // to keep the console window from closing
            Console.ReadKey();
        }
    }
}