using System;
using System.IO;
using Pipliz;

namespace ScarabolMods
{
    [ModLoader.ModManager]
    public static class CommandsModEntries
    {
        public static string MOD_PREFIX = "mods.scarabol.commands.";
        public static string ModDirectory;

        [ModLoader.ModCallback(ModLoader.EModCallbackType.OnAssemblyLoaded, "scarabol.commands.assemblyload")]
        public static void OnAssemblyLoaded(string path)
        {
            ModDirectory = Path.GetDirectoryName(path);
        }

        [ModLoader.ModCallback(ModLoader.EModCallbackType.AfterStartup, "scarabol.commands.registercallbacks")]
        public static void AfterStartup()
        {
            Log.Write("Loaded Commands Mod 6.0.10 by Scarabol");
        }
    }

    public static class PlayerHelper
    {
        public static bool TryGetPlayer(string identifier, out Players.Player targetPlayer, out string error)
        {
            return TryGetPlayer(identifier, out targetPlayer, out error, false);
        }

        public static bool TryGetPlayer(string identifier, out Players.Player targetPlayer, out string error, bool includeOffline)
        {
            targetPlayer = null;
            if (identifier.StartsWith("'"))
            {
                if (identifier.EndsWith("'"))
                {
                    identifier = identifier.Substring(1, identifier.Length - 2);
                }
                else
                {
                    error = "missing ' after playername";
                    return false;
                }
            }
            if (identifier.Length < 1)
            {
                error = "no playername given";
                return false;
            }
            ulong steamid;
            if (ulong.TryParse(identifier, out steamid))
            {
                Steamworks.CSteamID csteamid = new Steamworks.CSteamID(steamid);
                if (csteamid.IsValid())
                {
                    NetworkID networkId = new NetworkID(csteamid);
                    error = "";
                    if (Players.TryGetPlayer(networkId, out targetPlayer))
                    {
                        return true;
                    }
                    else
                    {
                        targetPlayer = null;
                    }
                }
            }
            int closestDist = int.MaxValue;
            Players.Player closestMatch = null;
            foreach (var player in Players.PlayerDatabase.ValuesAsList)
            {
                if (!player.IsConnected && !includeOffline)
                {
                    continue;
                }
                if (player.Name != null)
                {
                    if (string.Equals(player.Name, identifier, StringComparison.InvariantCultureIgnoreCase))
                    {
                        if (targetPlayer == null)
                        {
                            targetPlayer = player;
                        }
                        else
                        {
                            targetPlayer = null;
                            error = "duplicate player name, pls use SteamID";
                            return false;
                        }
                    }
                    else
                    {
                        int levDist = LevenshteinDistance.Compute(player.Name.ToLower(), identifier.ToLower());
                        if (levDist < closestDist)
                        {
                            closestDist = levDist;
                            closestMatch = player;
                        }
                        else if (levDist == closestDist)
                        {
                            closestMatch = null;
                        }
                    }
                }
            }
            if (targetPlayer != null)
            {
                error = "";
                return true;
            }
            else if (closestMatch != null && (closestDist < closestMatch.Name.Length * 0.2))
            {
                error = "";
                targetPlayer = closestMatch;
                Log.Write($"Name '{identifier}' did not match, picked closest match '{targetPlayer.Name}' instead");
                return true;
            }
            error = "player not found";
            return false;
        }
    }

    // src: https://www.dotnetperls.com/levenshtein
    static class LevenshteinDistance
    {
        public static int Compute(string s, string t)
        {
            var n = s.Length;
            var m = t.Length;
            int[,] d = new int[n + 1, m + 1];
            if (n == 0)
            {
                return m;
            }
            if (m == 0)
            {
                return n;
            }
            for (var i = 0; i <= n; d[i, 0] = i++)
            {
            }
            for (var j = 0; j <= m; d[0, j] = j++)
            {
            }
            for (var i = 1; i <= n; i++)
            {
                for (var j = 1; j <= m; j++)
                {
                    var cost = (t[j - 1] == s[i - 1]) ? 0 : 1;
                    d[i, j] = System.Math.Min(
                      System.Math.Min(d[i - 1, j] + 1, d[i, j - 1] + 1),
                      d[i - 1, j - 1] + cost);
                }
            }
            return d[n, m];
        }
    }
}