From 270e16a3cb20ad68e819a74dc72d7ca486cea713 Mon Sep 17 00:00:00 2001
From: mctaylors <cantsendmails@mctaylors.ru>
Date: Thu, 28 Dec 2023 09:56:52 +0300
Subject: [PATCH] fully functional TimeSpanParser

Signed-off-by: mctaylors <cantsendmails@mctaylors.ru>
---
 src/Parsers/TimeSpanParser.cs | 97 ++++++++++++++++++++++++++++++++---
 1 file changed, 91 insertions(+), 6 deletions(-)

diff --git a/src/Parsers/TimeSpanParser.cs b/src/Parsers/TimeSpanParser.cs
index ef5dd1c..a8d2aa5 100644
--- a/src/Parsers/TimeSpanParser.cs
+++ b/src/Parsers/TimeSpanParser.cs
@@ -1,15 +1,25 @@
-using JetBrains.Annotations;
+using System.Globalization;
+using System.Text.RegularExpressions;
+using JetBrains.Annotations;
 using Remora.Commands.Parsers;
 using Remora.Results;
 
 namespace Octobot.Parsers;
 
 /// <summary>
-/// Parses <see cref="TimeSpan"/>.
+///     Parses <see cref="TimeSpan"/> from <see cref="string"/>.
 /// </summary>
+/// <returns>
+///     Parsed <see cref="TimeSpan"/>.
+/// </returns>
+/// <remarks>
+///     If parse wasn't successful, <see cref="TimeSpanParser"/> will return <see cref="TimeSpan.Zero"/>.
+/// </remarks>
 [PublicAPI]
-public class TimeSpanParser : AbstractTypeParser<TimeSpan>
+public partial class TimeSpanParser : AbstractTypeParser<TimeSpan>
 {
+    private static readonly Regex Pattern = ParseRegex();
+
     public static Result<TimeSpan> TryParse(string timeSpanString, CancellationToken ct = default)
     {
         if (timeSpanString.StartsWith('-'))
@@ -17,8 +27,83 @@ public class TimeSpanParser : AbstractTypeParser<TimeSpan>
             return TimeSpan.Zero;
         }
 
-        var parser = new Remora.Commands.Parsers.TimeSpanParser();
-        var parseResult = parser.TryParseAsync(timeSpanString, ct).AsTask().GetAwaiter().GetResult();
-        return !parseResult.IsDefined(out var @in) ? TimeSpan.Zero : @in;
+        timeSpanString = timeSpanString.Trim();
+
+        if (TimeSpan.TryParse(timeSpanString, DateTimeFormatInfo.InvariantInfo, out var parsedTimeSpan))
+        {
+            return parsedTimeSpan;
+        }
+
+        var matches = ParseRegex().Matches(timeSpanString);
+        if (matches.Count is 0)
+        {
+            return TimeSpan.Zero;
+        }
+
+        var timeSpan = TimeSpan.Zero;
+        foreach (var groups in matches.Select(match => match.Groups
+                     .Cast<Group>()
+                     .Where(g => g.Success)
+                     .Skip(1)
+                     .Select(g => (g.Name, g.Value))))
+        {
+            foreach ((var key, var groupValue) in groups)
+            {
+                return !double.TryParse(groupValue, out var parsedGroupValue)
+                    ? TimeSpan.Zero
+                    : ParseFromRegex(timeSpan, key, groupValue, parsedGroupValue);
+            }
+        }
+
+        return timeSpan;
     }
+
+    private static Result<TimeSpan> ParseFromRegex(TimeSpan timeSpan,
+        string key, string groupValue, double parsedGroupValue)
+    {
+        if (key is "Years" or "Months")
+        {
+            if (!int.TryParse(groupValue, out var parsedIntegerValue))
+            {
+                return TimeSpan.Zero;
+            }
+
+            switch (key)
+            {
+                case "Years":
+                {
+                    var now = DateTimeOffset.UtcNow;
+                    var then = now.AddYears(parsedIntegerValue);
+
+                    timeSpan += then - now;
+                    break;
+                }
+                case "Months":
+                {
+                    var now = DateTimeOffset.UtcNow;
+                    var then = now.AddMonths(parsedIntegerValue);
+
+                    timeSpan += then - now;
+                    break;
+                }
+            }
+
+            return timeSpan;
+        }
+
+        timeSpan += key switch
+        {
+            "Weeks" => TimeSpan.FromDays(parsedGroupValue * 7),
+            "Days" => TimeSpan.FromDays(parsedGroupValue),
+            "Hours" => TimeSpan.FromHours(parsedGroupValue),
+            "Minutes" => TimeSpan.FromMinutes(parsedGroupValue),
+            "Seconds" => TimeSpan.FromSeconds(parsedGroupValue),
+            _ => throw new ArgumentOutOfRangeException(key)
+        };
+
+        return timeSpan;
+    }
+
+    [GeneratedRegex("(?<Years>\\d+(?=y|л|г))|(?<Months>\\d+(?=mo|мес))|(?<Weeks>\\d+(?=w|н|нед))|(?<Days>\\d+(?=d|дн))|(?<Hours>\\d+(?=h|ч))|(?<Minutes>\\d+(?=m|min|мин|м))|(?<Seconds>\\d+(?=s|sec|с|сек))")]
+    private static partial Regex ParseRegex();
 }