BeatLyrics/BeatLyrics.Tool/DataProvider/OnlineLyric/LyricProvider.cs

using BeatLyrics.Tool.DataProvider.OnlineLyric.Models;
using BeatLyrics.Tool.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace BeatLyrics.Tool.DataProvider.OnlineLyric
{
    public abstract class LyricProvider
    {
        private static readonly Regex RegexLrc = new Regex(@"\[(\d{2})\:(\d{2})[\.\:](\d{2,3})\](.*)", RegexOptions.Compiled);

        public abstract LyricSearchResultItem[] Search(string songName, string artist);

        public abstract bool GetDetail(LyricSearchResultItem input);

        public static List<LyricDetailExt> ParseLrc(string input, int duration)
        {
            var matches = RegexLrc.Matches(input);

            var ret = new List<LyricDetailExt>();

            foreach (Match match in matches)
            {
                var sameList = new List<LyricDetailExt>();
                var p = match;

                string text;
                do
                {
                    var timeStamp = $"{p.Groups[1]}:{p.Groups[2]},{p.Groups[3].Value.PadLeft(3, '0')}";
                    text = p.Groups[4].Value;

                    var item = new LyricDetailExt
                    {
                        TimeMs = (int)TimeSpan.ParseExact(timeStamp, @"mm\:ss\,fff", null).TotalMilliseconds,
                        Text = text,
                    };
                    ret.Add(item);
                    sameList.Add(item);

                    p = RegexLrc.Match(text); // handle multi time stamp tag
                } while (p.Success);

                if (sameList.Count <= 1) continue;
                foreach (var same in sameList) same.Text = text;
            }

            ret = ret.GroupBy(p => new { p.TimeMs, p.Text }).Select(q => q.First()).ToList();

            ret = ret.Where(p => false == string.IsNullOrWhiteSpace(p.Text)).OrderBy(p => p.TimeMs).ToList();

            for (var i = 0; i < ret.Count; i++)
            {
                var item = ret[i];
                var nextItem = ret.Count > i + 1 ? ret[i + 1] : null;

                if (nextItem != null) item.DurationMs = nextItem.TimeMs - item.TimeMs;
                else item.DurationMs = duration - item.TimeMs;

                if (item.DurationMs < 0) item.DurationMs = 1000;
            }

            return ret;
        }
    }
}