using System.Xml;
using System.Xml.Linq;
using CVRManager.Models;

namespace CVRManager.Services;

public static class AccountService
{
    const string ProfilePrefix = "cvrm-";

    public record Found(string Name, string Username, string UserId, string AccessKey);

    public static string ProfileName(GameAccount a) => ProfilePrefix + a.Id;

    static string ProfilePath(string gameDir, GameAccount a) => Path.Combine(gameDir, "ChilloutVR_Data", $"autologin-{ProfileName(a)}.profile");

    public static string WriteProfile(string gameDir, GameAccount a)
    {
        var key = TokenVault.Unprotect(a.AccessKey);
        if (key.Length == 0) throw new InvalidOperationException($"The access key for {a.Name} could not be read; add the account again.");
        var doc = new XElement("LoginProfile",
            new XElement("UserId", a.UserId),
            new XElement("Username", a.Username),
            new XElement("AccessKey", key));
        File.WriteAllText(ProfilePath(gameDir, a), doc.ToString());
        return ProfileName(a);
    }

    public static IEnumerable<Found> Scan(IEnumerable<string> gameDirs)
    {
        foreach (var dir in gameDirs)
        {
            var data = Path.Combine(dir, "ChilloutVR_Data");
            if (!Directory.Exists(data)) continue;
            foreach (var file in Directory.EnumerateFiles(data, "autologin*.profile"))
            {
                if (Path.GetFileName(file).StartsWith("autologin-" + ProfilePrefix, StringComparison.OrdinalIgnoreCase)) continue;
                if (Read(file) is { } found) yield return found;
            }
        }
    }

    static Found? Read(string path)
    {
        try
        {
            var root = XDocument.Load(path).Root;
            if (root == null || root.Name != "LoginProfile") return null;
            string Value(string name) => root.Element(name)?.Value.Trim() ?? "";
            var username = Value("Username");
            var key = Value("AccessKey");
            if (username.Length == 0 || key.Length == 0) return null;
            var stem = Path.GetFileNameWithoutExtension(path)["autologin".Length..].TrimStart('_', '-');
            return new Found(stem.Length > 0 ? stem : username, username, Value("UserId"), key);
        }
        catch (Exception e) when (e is IOException or UnauthorizedAccessException or XmlException) { return null; }
    }
}