using System.Net;
using System.Runtime.CompilerServices;
using static LoadedData;

const string puzzleFileName = @"puzzle-input.txt";
const string exampleFileName = @"example-input.txt";

Part01();
Part02();


static void Part01()
{
    Console.WriteLine("\n****** UNORDERED ******\n");

    var exampleData = new LoadedData(exampleFileName);
    var puzzleData = new LoadedData(puzzleFileName);

    Console.WriteLine("exmample top crates");
    exampleData.PrintTopCrates();
    Console.WriteLine("performing ops");
    exampleData.PerformOperationsUnordered(exampleData.Operations.Count);
    Console.WriteLine("exmample top crates");
    exampleData.PrintTopCrates();

    Console.WriteLine("\n****** PUZZLE ******\n");

    Console.WriteLine("puzzle top crates");
    puzzleData.PrintTopCrates();
    Console.WriteLine("performing ops");
    puzzleData.PerformOperationsUnordered(puzzleData.Operations.Count);
    Console.WriteLine("puzzle top crates");
    puzzleData.PrintTopCrates();
}

static void Part02()
{
    Console.WriteLine("\n****** ORDERED ******\n");

    var exampleData = new LoadedData(exampleFileName);
    var puzzleData = new LoadedData(puzzleFileName);

    Console.WriteLine("exmample top crates");
    exampleData.PrintTopCrates();
    Console.WriteLine("performing ops");
    exampleData.PerformOperationsOrdered(exampleData.Operations.Count);
    Console.WriteLine("exmample top crates");
    exampleData.PrintTopCrates();

    Console.WriteLine("\n****** PUZZLE ******\n");

    Console.WriteLine("puzzle top crates");
    puzzleData.PrintTopCrates();
    Console.WriteLine("performing ops");
    puzzleData.PerformOperationsOrdered(puzzleData.Operations.Count);
    Console.WriteLine("puzzle top crates");
    puzzleData.PrintTopCrates();
}

class LoadedData
{
    public class Crate
    {
        public Crate(char c)
        {
            Name = c;
        }
        public char Name { get; set; }
    }

    public List<Crate>[] Crates { get; set; }
    public int StackCount { get { return Crates.Length; } }

    public class Operation
    {
        public Operation(int crateCount, int sourceStack, int destinationStack)
        {
            CrateCount = crateCount;
            SourceStack = sourceStack;
            DestinationStack = destinationStack;
        }

        public int CrateCount { get; set; }
        public int SourceStack { get; set; }
        public int DestinationStack { get; set; }
    }

    public List<Operation> Operations { get; set; } = new List<Operation>();
    private int operationIndex = 0;

    public void PrintTopCrates()
    {
        string printout = "";
        foreach (var stack in Crates)
        {
            printout += String.Format("{0}", stack[stack.Count - 1].Name);
        }

        Console.WriteLine(printout);
    }

    public void PerformOperationsUnordered(int count)
    {
        if (operationIndex + count > Operations.Count)
        {
            throw new ArgumentOutOfRangeException("Too many operations requested");
        }

        if (count > 0)
        {
            for (; operationIndex < Operations.Count; operationIndex++)
            {
                Operation op = Operations[operationIndex];

                for (int i = 0; i < op.CrateCount; i++)
                {
                    int sourceIndex = op.SourceStack - 1;
                    int destinationIndex = op.DestinationStack - 1;

                    var crate = Crates[sourceIndex][Crates[sourceIndex].Count - 1];
                    Crates[sourceIndex].RemoveAt(Crates[sourceIndex].Count - 1);
                    Crates[destinationIndex].Add(crate);
                }
            }
        }
    }

    public void PerformOperationsOrdered(int count)
    {
        if (operationIndex + count > Operations.Count)
        {
            throw new ArgumentOutOfRangeException("Too many operations requested");
        }

        if (count > 0)
        {
            for (; operationIndex < Operations.Count; operationIndex++)
            {
                Operation op = Operations[operationIndex];

                int sourceIndex = op.SourceStack - 1;
                int destinationIndex = op.DestinationStack - 1;
                int destStackIndex = Crates[destinationIndex].Count;
                
                for (int i = 0; i < op.CrateCount; i++)
                {                  
                    var crate = Crates[sourceIndex][Crates[sourceIndex].Count - 1];
                    Crates[sourceIndex].RemoveAt(Crates[sourceIndex].Count - 1);
                    Crates[destinationIndex].Insert(destStackIndex, crate);
                }
            }
        }
    }

    public LoadedData(string fileName)
    {
        using (StreamReader reader = File.OpenText(fileName))
        {
            while (!reader.EndOfStream)
            {
                string? line = reader.ReadLine();

                if (line == null || (line.Length+1) % 4 != 0)
                {
                    throw new InvalidDataException();
                }

                // It's the first line, create the list
                if (Crates == null)
                {
                    int length = (line.Length+1) / 4;
                    Crates = new List<Crate>[length];
                    for (int i = 0; i < Crates.Length; i++) 
                    {
                        Crates[i] = new List<Crate>();
                    }
                }

                // Validate line length
                if ((StackCount*4)-1 > line.Length)
                {
                    throw new ArgumentOutOfRangeException();
                }

                // Check for the crate number line
                if (Char.IsAsciiDigit(line[1]))
                {
                    break;
                }

                // Read in each crate
                for (int i = 0; i < StackCount; i++)
                {
                    // Read in the entry
                    char c = line[(i * 4) + 1];

                    if (c != ' ')
                    {
                        if (!Char.IsLetter(c))
                        {
                            throw new InvalidDataException();
                        }

                        Crates[i].Insert(0, new Crate(c));
                    }
                }
            }

            // Read in the empty line
            reader.ReadLine();

            while (!reader.EndOfStream)
            {
                string? line = reader.ReadLine();

                if (line == null)
                {
                    throw new InvalidDataException();
                }

                var split = line.Split(' ', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);

                if (split.Length < 5) 
                {
                    throw new InvalidDataException();
                }

                Operations.Add(new Operation(Int32.Parse(split[1]), Int32.Parse(split[3]), Int32.Parse(split[5])));
            }
        }
    }
}