TinySite.Commands.ParseDocumentCommand.ParseMetadataHeaderFromContent C# (CSharp) Method

        private string ParseMetadataHeaderFromContent(string content)
        {
            var startOfLine = 0;
            var endOfLine = -1;
            var preambleOpened = false;
            var preambleSkipped = false;

            while ((endOfLine = content.IndexOf("\n", startOfLine)) > 0)
            {
                var line = content.Substring(startOfLine, endOfLine - startOfLine + 1).TrimEnd();

                // Eat any blank lines or comments at the top of the document or in the header.
                //
                if (String.IsNullOrEmpty(line) || line.StartsWith(";") || line.StartsWith("//"))
                {
                    startOfLine = endOfLine + 1;

                    continue;
                }

                // If start or end of header.
                if (line.StartsWith("---"))
                {
                    startOfLine = endOfLine + 1;

                    if (preambleOpened || preambleSkipped)
                    {
                        // Eat any blank lines after the preamble.
                        while ((endOfLine = content.IndexOf("\n", startOfLine)) > 0)
                        {
                            line = content.Substring(startOfLine, endOfLine - startOfLine + 1).TrimEnd();

                            if (!String.IsNullOrEmpty(line))
                            {
                                break;
                            }

                            startOfLine = endOfLine + 1;
                        }

                        break;
                    }

                    preambleOpened = true;
                }
                else // try to parse for metadata.
                {
                    var match = MetadataKeyValue.Match(line);
                    if (match.Success)
                    {
                        if (!preambleOpened)
                        {
                            preambleSkipped = true;
                        }

                        dynamic complexValue;

                        var key = match.Groups[1].Value.ToLowerInvariant();
                        var value = match.Groups[2].Value.Trim();
                        switch (key)
                        {
                            case "date":
                                this.Date = ParseDateTimeSmarter(value);
                                break;

                            case "draft":
                            case "ignore":
                            case "ignored":
                                this.Draft = ParseBoolen(value);
                                break;

                            case "tag":
                            case "tags":
                                var tags = ParseArray(value);
                                this.Metadata.Add("tags", tags);
                                break;

                            default:
                                if (TryParseComplexValue(value, content, startOfLine + match.Groups[2].Index, ref endOfLine, out complexValue))
                                {
                                    this.Metadata.Add(key, complexValue);
                                }
                                else
                                {
                                    this.HandleDefaultMetdata(key, value);
                                }
                                break;
                        }
                    }
                    else if (!preambleOpened) // no preamble and not metadata means we're done with the header.
                    {
                        break;
                    }

                    startOfLine = endOfLine + 1;
                }
            }

            return content.Substring(startOfLine).TrimEnd();
        }