using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;

namespace Nikse.SubtitleEdit.Core.SubtitleFormats
{
    public class SwiftTextLineNOAndDur : SubtitleFormat
    {
        private enum ExpectingLine
        {
            TimeCodes,
            Text
        }

        private Paragraph _paragraph;
        private StringBuilder _text = new StringBuilder();
        private ExpectingLine _expecting = ExpectingLine.TimeCodes;

        private static readonly Regex RegexTimeCodes = new Regex(@"^SUBTITLE: \d+\s+TIMEIN:\s*[0123456789-]+:[0123456789-]+:[0123456789-]+:[0123456789-]+\s*DURATION:\s*[0123456789-]+:[0123456789-]+\s+TIMEOUT:\s*[0123456789-]+:[0123456789-]+:[0123456789-]+:[0123456789-]+$", RegexOptions.Compiled);

        public override string Extension => ".txt";

        public override string Name => "Swift text line# +dur";

        public override bool IsMine(List<string> lines, string fileName)
        {
            if (lines != null && lines.Count > 2 && !string.IsNullOrEmpty(lines[0]) && lines[0].Contains("{QTtext}"))
                return false;

            return base.IsMine(lines, fileName);
        }

        public override string ToText(Subtitle subtitle, string title)
        {
            //SUBTITLE: 1   TIMEIN: 00:00:07:01 DURATION: 03:11 TIMEOUT: 00:00:10:12
            //Voor de oorlog

            //SUBTITLE: 2   TIMEIN: 00:00:10:16 DURATION: 01:08 TIMEOUT: 00:00:11:24
            //Ik ben Marie Pinhas. Ik ben geboren
            //in Thessaloniki in Griekenland,

            //SUBTITLE: 3   TIMEIN: 00:00:12:12 DURATION: 02:10 TIMEOUT: 00:00:14:22
            //op 6 maart '31,
            //in een heel oude Griekse familie.

            const string paragraphWriteFormat = "SUBTITLE: {1}\tTIMEIN: {0}\tDURATION: {4}\tTIMEOUT: {2}\r\n{3}\r\n";

            var sb = new StringBuilder();
            int count = 1;
            foreach (Paragraph p in subtitle.Paragraphs)
            {
                // to avoid rounding errors in duration
                var startFrame = MillisecondsToFramesMaxFrameRate(p.StartTime.Milliseconds);
                var endFrame = MillisecondsToFramesMaxFrameRate(p.EndTime.Milliseconds);
                var durationCalc = new Paragraph(
                        new TimeCode(p.StartTime.Hours, p.StartTime.Minutes, p.StartTime.Seconds, FramesToMillisecondsMax999(startFrame)),
                        new TimeCode(p.EndTime.Hours, p.EndTime.Minutes, p.EndTime.Seconds, FramesToMillisecondsMax999(endFrame)),
                        string.Empty);

                string startTime = $"{p.StartTime.Hours:00}:{p.StartTime.Minutes:00}:{p.StartTime.Seconds:00}:{startFrame:00}";
                string timeOut = $"{p.EndTime.Hours:00}:{p.EndTime.Minutes:00}:{p.EndTime.Seconds:00}:{endFrame:00}";
                string timeDuration = $"{durationCalc.Duration.Seconds:00}:{MillisecondsToFramesMaxFrameRate(durationCalc.Duration.Milliseconds):00}";
                sb.AppendLine(string.Format(paragraphWriteFormat, startTime, count, timeOut, p.Text, timeDuration));
                count++;
            }
            return sb.ToString().Trim();
        }

        public override void LoadSubtitle(Subtitle subtitle, List<string> lines, string fileName)
        {
            _paragraph = new Paragraph();
            _expecting = ExpectingLine.TimeCodes;
            _errorCount = 0;

            subtitle.Paragraphs.Clear();
            foreach (string line in lines)
            {
                ReadLine(subtitle, line);
                if (_text.Length > 1000)
                    return;
            }
            if (_text != null && _text.ToString().TrimStart().Length > 0)
            {
                _paragraph.Text = _text.ToString().Trim();
                subtitle.Paragraphs.Add(_paragraph);
            }

            subtitle.Renumber();
        }

        private void ReadLine(Subtitle subtitle, string line)
        {
            switch (_expecting)
            {
                case ExpectingLine.TimeCodes:
                    if (TryReadTimeCodesLine(line, _paragraph))
                    {
                        _text = new StringBuilder();
                        _expecting = ExpectingLine.Text;
                    }
                    else if (!string.IsNullOrWhiteSpace(line))
                    {
                        _errorCount++;
                        _expecting = ExpectingLine.Text; // lets go to next paragraph
                    }
                    break;
                case ExpectingLine.Text:
                    if (!string.IsNullOrWhiteSpace(line))
                    {
                        _text.AppendLine(line.TrimEnd());
                    }
                    else if (_paragraph != null && _paragraph.EndTime.TotalMilliseconds > 0)
                    {
                        _paragraph.Text = _text.ToString().Trim();
                        subtitle.Paragraphs.Add(_paragraph);
                        _paragraph = new Paragraph();
                        _expecting = ExpectingLine.TimeCodes;
                    }
                    else
                    {
                        _errorCount++;
                    }
                    break;
            }
        }

        private static bool TryReadTimeCodesLine(string line, Paragraph paragraph)
        {
            line = line.Trim();
            if (RegexTimeCodes.IsMatch(line))
            {
                //SUBTITLE: 1   TIMEIN: 00:00:07:01 DURATION: 03:11 TIMEOUT: 00:00:10:12
                string s = line.Replace("SUBTITLE:", string.Empty).Replace("TIMEIN", string.Empty).Replace("DURATION", string.Empty).Replace("TIMEOUT", string.Empty).RemoveChar(' ').Replace("\t", string.Empty);
                string[] parts = s.Split(':');
                try
                {
                    int startHours = int.Parse(parts[1]);
                    int startMinutes = int.Parse(parts[2]);
                    int startSeconds = int.Parse(parts[3]);
                    int startMilliseconds = FramesToMillisecondsMax999(int.Parse(parts[4]));

                    int endHours = 0;
                    if (parts[5 + 2] != "--")
                        endHours = int.Parse(parts[5 + 2]);
                    int endMinutes = 0;
                    if (parts[6 + 2] != "--")
                        endMinutes = int.Parse(parts[6 + 2]);
                    int endSeconds = 0;
                    if (parts[7 + 2] != "--")
                        endSeconds = int.Parse(parts[7 + 2]);
                    int endMilliseconds = 0;
                    if (parts[8 + 2] != "--")
                        endMilliseconds = FramesToMillisecondsMax999(int.Parse(parts[8 + 2]));

                    paragraph.StartTime = new TimeCode(startHours, startMinutes, startSeconds, startMilliseconds);
                    paragraph.EndTime = new TimeCode(endHours, endMinutes, endSeconds, endMilliseconds);
                    return true;
                }
                catch
                {
                    return false;
                }
            }
            return false;
        }

    }
}