using System.Text.RegularExpressions;
using Parsley;

namespace TempusReader
{
    internal class TimeLexer : Lexer
    {
        private const RegexOptions PatternRegexOptions = RegexOptions.IgnoreCase;

        public const string DaysPattern = @"(days|day|d)";
        public const string HoursPattern = @"(hours|hour|hrs|hr)";
        public const string MinutesPattern = @"(minutes|minute|mins|min|m)";
        public const string SecondsPattern = @"(seconds|second|sec|s)";
        public const string MillisecondsPattern = @"(milliseconds|ms)";
        public const string InTimePattern = @"in";
        public const string FromNowTimePattern = @"from(\s+)now";
        public const string AgoTimePattern = @"ago";

        public TimeLexer() : base(NumberWord, Number, Milliseconds, Seconds, Minutes, Hours, Days, InTime, FromNowTime, AgoTime, Yesterday, Tomorrow, Separator, Whitespace)
        {
        }

        public static readonly TokenKind Separator = new Pattern("separator", @",|(and)", skippable: true);
        public static readonly TokenKind Whitespace = new Pattern("whitespace", @"\s+", skippable: true);
        public static readonly TokenKind Number = new Pattern("number", @"(?=0(?!\d)|[1-9])\d+((\.|\:)\d+)?");
        public static readonly TokenKind NumberWord = new Pattern("number", @"(one|two|three|four|five|six|seven|eight|nine|ten)");

        public static readonly Pattern Milliseconds = new Pattern("milliseconds", MillisecondsPattern, PatternRegexOptions);
        public static readonly Pattern Seconds = new Pattern("seconds", SecondsPattern, PatternRegexOptions);
        public static readonly Pattern Minutes = new Pattern("minutes", MinutesPattern, PatternRegexOptions);
        public static readonly Pattern Hours = new Pattern("hours", HoursPattern, PatternRegexOptions);
        public static readonly Pattern Days = new Pattern("days", DaysPattern, PatternRegexOptions);
        public static readonly Pattern InTime = new Pattern("future", InTimePattern, PatternRegexOptions);
        public static readonly Pattern FromNowTime = new Pattern("future", FromNowTimePattern, PatternRegexOptions);
        public static readonly Pattern AgoTime = new Pattern("past", AgoTimePattern, PatternRegexOptions);

        public static readonly Pattern Yesterday = new Pattern("past", "yesterday", PatternRegexOptions);
        public static readonly Pattern Tomorrow = new Pattern("future", "tomorrow", PatternRegexOptions);
    }
}