// TODO: Refactor to be more like Package code. This is messy
// Substring should be replaced with a .split(": ")
// Also Directly assign to the values instead of using temporary variables.
using Serilog;

namespace EdgeInstaller;

public sealed partial class ReleaseData
{
    public DateTime Date { get; private set; }
    public List<string> Architectures { get; private set; }
    public List<PackageFile> PackageFiles { get; private set; }


    public ReleaseData(string Release)
    {
        Log.Information("Creating new ReleaseData object");

        if (Release == "")
        {
            throw new ArgumentException(
                    message: "Empty release provided to ReleaseData",
                    paramName: "Release");
        }


        // Pull release apart
        List<string> ReleaseLines = Release.Split("\n", StringSplitOptions.RemoveEmptyEntries).ToList();

        Log.Debug("ReleaseLines = {@releaselines}", ReleaseLines);

        Date = DateTime.Parse(
                ReleaseLines.Where(
                    Line => Line.Contains("Date:"))
                .First()
                .Split(": ")
                .Last()
                );

        // Safely find and add the possible architectures
        string ArchitecturesLine =
            ReleaseLines.Where(
                    Line => Line.Contains("Architectures:"))
            .FirstOrDefault("");
        Log.Debug("Arch line: {archline}", ArchitecturesLine);
        if (ArchitecturesLine == "")
        {
            throw _lineFormatException("architectures");
        }
        Architectures = ArchitecturesLine
                .Split(": ").Last() // We only want items after the label
                .Split(" ", StringSplitOptions.RemoveEmptyEntries)
                .ToList();
		// Cope with files being in binary-arch sometimes.
		List<string> BinArchs = new();
		foreach (var arch in Architectures)
		{
			BinArchs.Add("binary-" + arch);
		}
		Architectures.AddRange(BinArchs);
        Log.Debug("Extracted architectures {@architectures}", Architectures);


        /*
		* Package files are grabbed here. It is worth noting that empty files
		* are removed (along with the .gz versions) this avoids displaying impossible
		* options to the user
		*/


        // First split the Lines to only get the file data
        // NOTE: This is probably the cleanest way to do this.
        List<string> SHA256FileData = ReleaseLines.Where((_, index) =>
            index > ReleaseLines.IndexOf("SHA256:") &&
            index < ReleaseLines.IndexOf("SHA512:")
            ).ToList();
        Log.Debug("SHA256FileData = {@data}", SHA256FileData);

        // Now process these lines to get the data we need
        List<PackageFile> releasePackageFiles = new();
        foreach (var fileData in SHA256FileData)
        {
            Log.Debug("fileData = {filedata}", fileData);
            string[] splitData = fileData.Split(' ', StringSplitOptions.RemoveEmptyEntries);
            Log.Debug("splitData = {@splitData}", splitData);
            string checksum = splitData[0];
            int size = int.Parse(splitData[1]);
            string filename = splitData[2];
            releasePackageFiles.Add(new PackageFile(filename, checksum, size));
        }

        // remove any empty files (and the .gz version of them)
        // NOTE: Empty gz files still have a size due to headers
        // WARN: The `.ToList` is essential to ensure we COPY the list and not use references to the original items
        var emptyFiles = releasePackageFiles
            .Where(package => package.size == 0)
            .ToList();

        foreach (var file in emptyFiles)
        {
            releasePackageFiles
                .RemoveAll(package =>
                    package.filename == file.filename ||
                    package.filename == $"{file.filename}.gz"
                );
        }

        PackageFiles = releasePackageFiles;

        // After removing the empty files we need to make sure that we remove the architectures that don't have any files

        foreach (var arch in Architectures.ToList())
        /*
         * WARN: `.ToList` is used again to copy the list so we can iterate and operate
		 * on the list at the same time. This could be unsafe, but in this scenario
		 * should never cause any issues.
		 */
        {
            if (PackageFiles.Where(file => file.filename.Contains($"main/{arch}/")).Count() == 0) // match on "/arch/"
            {
				Log.Debug("removing /{arch}/", arch);
                Architectures.Remove(arch);
            }
        }
		if (Architectures.Count == 0)
		{
		    throw new Exception("Architectures is null");
		}
    }


    private static FormatException _lineFormatException(string field)
    {
        return new FormatException($"Release does not contain a valid {field} line");
    }
}



public record PackageFile(string filename, string Checksum, int size);