using System;
using System.Text;
using System.Text.RegularExpressions;

namespace DeukBot4.MessageHandlers.CommandHandler.RequestStructure
{
    public static class ParameterMatcher
    {
        public enum ParameterType
        {
            Word,
            Number,
            Remainder,
            User,
            Timespan,
        }

        public static string[] GenerateRegex(Command command)
        {
            var arr = new string[command.ParameterTypes.Length];
            for (var index = 0; index < command.ParameterTypes.Length; index++)
            {
                var commandParameterType = command.ParameterTypes[index];

                var builder              = new StringBuilder();
                for (var i = 0; i < commandParameterType.Length; i++)
                {
                    var parameterType = commandParameterType[i];
                    builder.Append(GetParameterRegex(parameterType, i + 1));
                }

                arr[index] = builder.ToString();
            }
            return arr;
        }

        private static string GetParameterRegex(ParameterType type, int index)
        {
            switch (type)
            {
                case ParameterType.Word:
                    return $" *(?<{index}>\\w+)";
                case ParameterType.Number:
                    return $" *(?<{index}>\\d+)(?:$| |\n)";
                case ParameterType.Remainder:
                    return $" *(?<{index}>.*)";
                case ParameterType.User:
                    return $" *(?:<@!*(?<{index}>\\d+)>|(?<{index}>\\d+)|(?<{index}>\\w+)(?:$| |\n))";
                case ParameterType.Timespan:
                    return $" *(?<{index}>\\d+\\.*\\d*[smhd])";
                default:
                    throw new ArgumentOutOfRangeException(nameof(type), type, null);
            }
        }

        public static RequestParameter[] GetParameterValues(Command command, string parameterString)
        {
            for (var index = 0; index < command.ParametersMatchers.Length; index++)
            {
                var parameterTypes = command.ParameterTypes[index];
                var pattern = command.ParametersMatchers[index];
                Match matches;
                try
                {
                    matches = Regex.Match(parameterString, pattern);
                }
                catch (Exception e)
                {
                    Logger.Main.LogError(e.ToString());
                    return command.RequireParameterMatch ? null : new RequestParameter[0];
                }
                if (matches.Success)
                {
                    var arr = new RequestParameter[matches.Groups.Count - 1];
                    for (var i = 1; i < matches.Groups.Count; i++)
                    {
                        var group = matches.Groups[i];
                        arr[i - 1] = new RequestParameter(group.Value, parameterTypes[i - 1]);
                    }
                    return arr;
                }
            }

            return command.RequireParameterMatch ? null : new RequestParameter[0];
        }
    }
}