DiscordChatExporter/DiscordChatExporter.Core/Markdown/Parsing/AggregateMatcher.cs

using System.Collections.Generic;

namespace DiscordChatExporter.Core.Markdown.Parsing;

internal class AggregateMatcher<T> : IMatcher<T>
{
    private readonly IReadOnlyList<IMatcher<T>> _matchers;

    public AggregateMatcher(IReadOnlyList<IMatcher<T>> matchers)
    {
        _matchers = matchers;
    }

    public AggregateMatcher(params IMatcher<T>[] matchers)
        : this((IReadOnlyList<IMatcher<T>>) matchers)
    {
    }

    public ParsedMatch<T>? TryMatch(StringSegment segment)
    {
        ParsedMatch<T>? earliestMatch = null;

        // Try to match the input with each matcher and get the match with the lowest start index
        foreach (var matcher in _matchers)
        {
            // Try to match
            var match = matcher.TryMatch(segment);

            // If there's no match - continue
            if (match is null)
                continue;

            // If this match is earlier than previous earliest - replace
            if (earliestMatch is null || match.Segment.StartIndex < earliestMatch.Segment.StartIndex)
                earliestMatch = match;

            // If the earliest match starts at the very beginning - break,
            // because it's impossible to find a match earlier than that
            if (earliestMatch.Segment.StartIndex == segment.StartIndex)
                break;
        }

        return earliestMatch;
    }
}