using Microsoft.Extensions.Logging;

namespace File_Folder_Helper.Helpers;

internal static class HelperKanbanMetadata
{

    private static List<(int, int, string, FileInfo)> GetCollectionFromIndex(string sourceDirectory, string[] lines)
    {
        List<(int, int, string, FileInfo)> results = new();
        string line;
        FileInfo fileInfo;
        string[] segments;
        int groupCount = 0;
        string? group = null;
        for (int i = 0; i < lines.Length; i++)
        {
            line = lines[i];
            if (line.Length < 4)
                continue;
            if (line[..3] == "## ")
            {
                group = line[3..];
                groupCount += 1;
                continue;
            }
            if (group is null || line[..3] != "- [" || line[^1] != ')')
                continue;
            segments = line.Split("](");
            if (segments.Length != 2)
                continue;
            fileInfo = new(Path.Combine(sourceDirectory, segments[1][..^1]));
            if (!fileInfo.Exists)
                continue;
            results.Add((groupCount, i, group, fileInfo));
        }
        return results;
    }

    internal static void SetMetadata(ILogger log, Models.AppSettings appSettings, string sourceDirectory)
    {
        string statusLine;
        List<string> lines;
        LineNumber lineNumber;
        if (log is null)
            throw new NullReferenceException();
        string fullPath = Path.GetFullPath(sourceDirectory);
        if (!Directory.Exists(fullPath))
            _ = Directory.CreateDirectory(fullPath);
        List<(MarkdownFile, string[])> collection;
        collection = HelperMarkdown.GetCollection(appSettings, HelperMarkdown.GetFiles(appSettings, fullPath));
        string indexFile = Path.Combine(fullPath, "index.md");
        if (File.Exists(indexFile))
        {
            string[] indexFileLines = File.ReadAllLines(indexFile);
            List<(int, int, string, FileInfo)> collectionFromIndex = GetCollectionFromIndex(sourceDirectory, indexFileLines);
            foreach ((int groupCount, int itemLineNumber, string group, FileInfo fileInfo) in collectionFromIndex)
            {
                if (itemLineNumber == 0)
                    throw new NotSupportedException();
                (lines, lineNumber) = HelperMarkdown.GetStatusAndMetaEndLineNumbers(fileInfo);
                if (!lines.Any())
                    continue;
                statusLine = $"status: \"{groupCount}-{group}\"";
                indexFileLines[itemLineNumber] = $"{fileInfo.LastWriteTime.Ticks}~~~{indexFileLines[itemLineNumber]}";
                if (lineNumber.MetaEnd is null)
                    throw new NotSupportedException($"{nameof(SetMetadata)} must be executed first!");
                if (lineNumber.Status is null)
                    lines.Insert(lineNumber.MetaEnd.Value, statusLine);
                else
                {
                    if (lines[lineNumber.Status.Value] == statusLine)
                        continue;
                    lines[lineNumber.Status.Value] = statusLine;
                }
                File.WriteAllLines(fileInfo.FullName, lines);
            }
            File.WriteAllLines(indexFile, indexFileLines);
        }
    }

}