namespace Aeshnidae.LootTables;

/// <summary>
/// ACE's code-side loot tables made editable at runtime. See Tables for how; the staff
/// site (/staff/loot, "Code tables") writes <see cref="Settings.OverridesFile"/> and runs
/// /loottables-apply, and reads <see cref="Settings.CatalogFile"/> to show what is there.
/// No Harmony patches: the tables are data, edited in place.
/// </summary>
public class Mod : IHarmonyMod
{
    public static readonly string Name = typeof(Mod).Assembly.GetName().Name!;

    public static readonly string ModPath = Path.Combine(ModManager.ModPath, Name);

    public static ModContainer? Container => ModManager.GetModContainerByPath(ModPath);

    public static Settings Settings { get; private set; } = new();

    private bool _disposed;

    public void Initialize()
    {
        Settings = Settings.Load(ModPath);

        try
        {
            Tables.Discover();
            var result = ApplyNow();
            ModManager.Log($"[{Name}] {Tables.All.Count} code-side loot tables found; {result.Applied} overridden" +
                           (result.Errors.Count > 0 ? $"; {result.Errors.Count} override(s) refused: {string.Join(" | ", result.Errors)}" : ""));
        }
        catch (Exception ex)
        {
            // Retail stays in force: nothing is written to a table until every step before it worked.
            ModManager.Log($"[{Name}] could not start: {ex}", ModManager.LogLevel.Error);
        }
    }

    /// <summary>Reads the overrides file, applies it where nothing is rolling, writes the catalogue.</summary>
    public static Tables.ApplyResult ApplyNow()
    {
        var file = Settings.ReadOverrides(ModPath);
        Tables.ApplyResult? result = null;
        OnWorldThread(() => result = Tables.Apply(file));
        result ??= new Tables.ApplyResult(0, ["the world thread did not run the apply within 15 s - nothing changed; try again"], []);
        Tables.WriteCatalog(Path.Combine(ModPath, Settings.CatalogFile), result);
        return result;
    }

    /// <summary>
    /// Runs the action between the landblock ticks, when no loot is being rolled - or at once
    /// while the world is closed (starting up, shutting down), when nothing is rolling anyway.
    /// </summary>
    public static void OnWorldThread(Action action)
    {
        if (WorldManager.WorldStatus != WorldManager.WorldStatusState.Open)
        {
            action();
            return;
        }
        using var done = new ManualResetEventSlim();
        Exception? error = null;
        WorldManager.EnqueueAction(new ActionEventDelegate(() =>
        {
            try { action(); }
            catch (Exception ex) { error = ex; }
            finally { done.Set(); }
        }));
        if (done.Wait(TimeSpan.FromSeconds(15)) && error is not null)
            throw new InvalidOperationException("apply failed on the world thread", error);
    }

    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }

    protected virtual void Dispose(bool disposing)
    {
        if (_disposed)
            return;
        if (disposing)
        {
            // Retail back in the tables, so the next load (a hot reload) snapshots retail and
            // not this load's overrides.
            try { OnWorldThread(Tables.RestoreRetail); }
            catch (Exception ex) { ModManager.Log($"[{Name}] could not restore retail on unload: {ex.Message}", ModManager.LogLevel.Warn); }
            ModManager.Log($"[{Name}] shut down (retail restored)");
        }
        _disposed = true;
    }
}