using System.IO.Compression;
using System.Reflection;
using System.Text;
using System.Xml.Serialization;
using PluginLoader.Compiler;
using PluginLoader.Network;
using ProtoBuf;
using Sandbox.Graphics.GUI;

namespace PluginLoader.Data;

[ProtoContract]
public class GitHubPlugin : PluginData
{
    private const string pluginFile = "plugin.dll";
    private const string commitHashFile = "commit.sha1";
    private string cacheDir, assemblyName;

    public GitHubPlugin()
    {
        Status = PluginStatus.None;
    }

    public override string Source => "GitHub";

    [ProtoMember(1)] public string Commit { get; set; }

    [ProtoMember(2)]
    [XmlArray]
    [XmlArrayItem("Directory")]
    public string[] SourceDirectories { get; set; }

    public void Init(string mainDirectory)
    {
        var nameArgs = Id.Split(new[] { '/', '\\' }, StringSplitOptions.RemoveEmptyEntries);
        if (nameArgs.Length != 2)
            throw new("Invalid GitHub name: " + Id);

        if (SourceDirectories != null)
            for (var i = SourceDirectories.Length - 1; i >= 0; i--)
            {
                var path = SourceDirectories[i].Replace('\\', '/').TrimStart('/');

                if (path.Length == 0)
                {
                    SourceDirectories.RemoveAtFast(i);
                    continue;
                }

                if (path[path.Length - 1] != '/')
                    path += '/';

                SourceDirectories[i] = path;
            }

        assemblyName = MakeSafeString(nameArgs[1]);
        cacheDir = Path.Combine(mainDirectory, "GitHub", nameArgs[0], nameArgs[1]);
    }

    private string MakeSafeString(string s)
    {
        var sb = new StringBuilder();
        foreach (var ch in s)
            if (char.IsLetterOrDigit(ch))
                sb.Append(ch);
            else
                sb.Append('_');
        return sb.ToString();
    }

    public override Assembly? GetAssembly()
    {
        if (!Directory.Exists(cacheDir))
            Directory.CreateDirectory(cacheDir);

        Assembly? a;

        var dllFile = Path.Combine(cacheDir, pluginFile);
        var commitFile = Path.Combine(cacheDir, commitHashFile);
        if (!File.Exists(dllFile) || !File.Exists(commitFile) || File.ReadAllText(commitFile) != Commit)
        {
            var lbl = Main.Instance.Splash;
            lbl.SetText($"Downloading '{FriendlyName}'");
            var data = CompileFromSource(x => lbl.SetBarValue(x));
            File.WriteAllBytes(dllFile, data);
            File.WriteAllText(commitFile, Commit);
            Status = PluginStatus.Updated;
            lbl.SetText($"Compiled '{FriendlyName}'");
            a = Assembly.Load(data);
        }
        else
        {
            a = Assembly.LoadFile(dllFile);
        }

        Version = a.GetName().Version;
        return a;
    }


    public byte[] CompileFromSource(Action<float> callback = null)
    {
        var compiler = new RoslynCompiler();
        using (var s = GitHub.DownloadRepo(Id, Commit, out var fileName))
        using (var zip = new ZipArchive(s))
        {
            callback?.Invoke(0);
            for (var i = 0; i < zip.Entries.Count; i++)
            {
                var entry = zip.Entries[i];
                CompileFromSource(compiler, entry);
                callback?.Invoke(i / (float)zip.Entries.Count);
            }

            callback?.Invoke(1);
        }

        return compiler.Compile(assemblyName + '_' + Path.GetRandomFileName(), out _);
    }

    private void CompileFromSource(RoslynCompiler compiler, ZipArchiveEntry entry)
    {
        if (AllowedZipPath(entry.FullName))
            using (var entryStream = entry.Open())
            {
                compiler.Load(entryStream, entry.FullName);
            }
    }

    private bool AllowedZipPath(string path)
    {
        if (!path.EndsWith(".cs", StringComparison.OrdinalIgnoreCase))
            return false;

        if (SourceDirectories == null || SourceDirectories.Length == 0)
            return true;

        path = RemoveRoot(path); // Make the base of the path the root of the repository

        foreach (var dir in SourceDirectories)
            if (path.StartsWith(dir, StringComparison.Ordinal))
                return true;
        return false;
    }

    private string RemoveRoot(string path)
    {
        path = path.Replace('\\', '/').TrimStart('/');
        var index = path.IndexOf('/');
        if (index >= 0 && index + 1 < path.Length)
            return path.Substring(index + 1);
        return path;
    }

    public override void Show()
    {
        MyGuiSandbox.OpenUrl("https://github.com/" + Id, UrlOpenMode.SteamOrExternalWithConfirm);
    }
}