using Sortering;
using System.Diagnostics;
using System.Text.RegularExpressions;

internal class Program
{
    private static int[] _ints;
    private static bool _running = true;
    private static Random _random = new Random();

    private static Dictionary<string, Action<string[]>> Commands =
        new Dictionary<string, Action<string[]>>(StringComparer.OrdinalIgnoreCase)
        {
            { "insertionsort", SortInsertion },
            { "bubblesort", SortBubble },
            { "mkarray", MkArray },
            { "print", Print },
            { "sequentialfind", SequentialFind },
            { "binaryfind", BinaryFind },
            { "exit", _ => _running = false }
        };

    private static void Main(string[] args)
    {
        while (_running)
        {
            Console.Write("> ");
            var input = ReadLineWithAutocomplete();
            if (string.IsNullOrWhiteSpace(input)) continue;

            var parts = input.Split(' ', StringSplitOptions.RemoveEmptyEntries);
            var cmd = parts[0];
            var cmdArgs = parts.Length > 1 ? parts[1..] : Array.Empty<string>();

            if (Commands.TryGetValue(cmd, out var action))
                action(cmdArgs);
            else
            {
                Console.WriteLine("Unknown command. Available:");
                foreach (var c in Commands.Keys)
                    Console.WriteLine(" - " + c);
            }
        }
    }

    // autocompletion

    private static string ReadLineWithAutocomplete()
    {
        var buffer = new List<char>();
        int cursor = 0;

        while (true)
        {
            var key = Console.ReadKey(intercept: true);

            if (key.Key == ConsoleKey.Enter)
            {
                Console.WriteLine();
                return new string(buffer.ToArray());
            }

            if (key.Key == ConsoleKey.Backspace && cursor > 0)
            {
                buffer.RemoveAt(cursor - 1);
                cursor--;
                RedrawLine(buffer, cursor);
                continue;
            }

            if (key.Key == ConsoleKey.Tab)
            {
                Autocomplete(buffer, ref cursor);
                continue;
            }

            if (!char.IsControl(key.KeyChar))
            {
                buffer.Insert(cursor, key.KeyChar);
                cursor++;
                RedrawLine(buffer, cursor);
            }
        }
    }

    private static void Autocomplete(List<char> buffer, ref int cursor)
    {
        var text = new string(buffer.ToArray());
        var parts = text.Split(' ', StringSplitOptions.RemoveEmptyEntries);

        // Only autocomplete the command (first word)
        if (parts.Length > 1)
            return;

        string prefix = parts.Length == 0 ? "" : parts[0];

        var matches = Commands.Keys
            .Where(c => c.StartsWith(prefix, StringComparison.OrdinalIgnoreCase))
            .ToList();

        if (matches.Count == 1)
        {
            buffer.Clear();
            buffer.AddRange(matches[0]);
            cursor = buffer.Count;
            RedrawLine(buffer, cursor);
        }
    }

    private static void RedrawLine(List<char> buffer, int cursor)
    {
        Console.Write("\r> ");
        Console.Write(new string(buffer.ToArray()));
        Console.Write(" ");
        Console.SetCursorPosition(2 + cursor, Console.CursorTop);
    }

    // commands

    private static void SortInsertion(string[] args)
    {
        if (_ints == null)
        {
            Console.WriteLine("No array. Use mkarray first.");
            return;
        }

        var sw = Stopwatch.StartNew();
        Sort.InsertionSort(_ints);
        sw.Stop();

        Console.WriteLine($"Sorted array in {sw.ElapsedMilliseconds} ms");
    }

    private static void SortBubble(string[] args)
    {
        if (_ints == null)
        {
            Console.WriteLine("No array. Use mkarray first.");
            return;
        }

        var sw = Stopwatch.StartNew();
        Sort.BubbleSort(_ints);
        sw.Stop();

        Console.WriteLine($"Sorted array in {sw.ElapsedMilliseconds} ms");
    }

    private static void SequentialFind(string[] args)
    {
        if (_ints == null)
        {
            Console.WriteLine("No array. Use mkarray first.");
            return;
        }

        if (args.Length < 1 || !int.TryParse(args[0], out int value))
        {
            Console.WriteLine("Usage: find <value>");
            return;
        }

        var sw = Stopwatch.StartNew();
        int match = Sort.SequentialFind(_ints, value);

        sw.Stop();

        if (match == -1)
            Console.WriteLine($"Found no match in {sw.ElapsedMilliseconds} ms");
        else
            Console.WriteLine($"Found match at {match} in {sw.ElapsedMilliseconds} ms");
    }

    private static void BinaryFind(string[] args)
    {
        if (_ints == null)
        {
            Console.WriteLine("No array. Use mkarray first.");
            return;
        }

        if (args.Length < 1 || !int.TryParse(args[0], out int value))
        {
            Console.WriteLine("Usage: find <value>");
            return;
        }

        var sw = Stopwatch.StartNew();
        int match = Sort.BinaryFind(_ints, value);

        sw.Stop();

        if (match == -1)
            Console.WriteLine($"Found no match in {sw.ElapsedMilliseconds} ms");
        else
            Console.WriteLine($"Found match at {match} in {sw.ElapsedMilliseconds} ms");
    }

    private static void Print(string[] args)
    {
        if (_ints == null)
        {
            Console.WriteLine("No array.");
            return;
        }

        for (int i = 0; i < _ints.Length; i++)
            Console.WriteLine(_ints[i]);
    }

    private static void MkArray(string[] args)
    {
        if (args.Length < 1 || !int.TryParse(args[0], out int count) || count <= 0)
        {
            Console.WriteLine("Usage: mkarray <size>");
            return;
        }

        _ints = new int[count];
        for (int i = 0; i < count; i++)
            _ints[i] = _random.Next(1000 + (int)(count * 0.1));

        Console.WriteLine($"Created array with {count} elements");
    }
}