namespace Aeshnidae.Mule;

/// <summary>
/// /mule-data [page] - the vault as the Aelrynth plugins read it (RynthInventory's Global
/// Inventory shows it with icons). The same contents /mule list prints, one chat line per
/// page in the CompanionFeed shape, so a player without the plugin loses nothing and the
/// plugin can do nothing a player could not type.
///
///     ~ael1 {"t":"mule","page":1,"pages":3,"count":57,"max":1000,"items":[...]}
///
/// An item is {"o":objectId,"w":wcid,"n":name,"i":icon,"u":underlay,"v":overlay,
/// "s":stack,"m":maxStack,"y":itemType,"e":uiEffects}. Read-only: nothing here moves or
/// loads anything, and a vault still loading answers {"t":"mule","ready":false}, never an
/// empty list (the same rule every /mule verb follows).
/// </summary>
public static class MuleData
{
    // A chat line must stay well inside one network message; ~130 bytes an item.
    public const int PerPage = 25;

    [CommandHandler("mule-data", AccessLevel.Player, CommandHandlerFlag.RequiresWorld, -1,
        "The vault as data, one page a line, for the Aelrynth plugins. /mule list is the human version.",
        "/mule-data [page]")]
    public static void Handle(Session session, params string[] parameters)
    {
        var player = session?.Player;

        if (player is null)
            return;

        if (!Mod.Settings.Enabled || !MuleDb.Ready)
        {
            CompanionFeed.Send(session, new { t = "mule", ready = false, why = "closed" });
            return;
        }

        try
        {
            var accountId = player.Account?.AccountId ?? 0;
            var handle = Vault.Get(accountId, out _);

            if (handle is null || !handle.Ready || handle.Fault.Length > 0)
            {
                CompanionFeed.Send(session, new { t = "mule", ready = false, why = handle?.Fault.Length > 0 ? "fault" : "loading" });
                return;
            }

            var page = parameters is { Length: > 0 } && int.TryParse(parameters[0], out var p) && p > 0 ? p : 1;

            // The order /mule list uses: newest first (later links, then later placement).
            List<WorldObject> all;
            lock (Vault.Gate(accountId))
            {
                all = handle.Links
                    .Select((link, seq) => (link, seq))
                    .SelectMany(x => x.link.Inventory.Values.Select(i => (item: i, x.seq, pos: i.PlacementPosition ?? 0)))
                    .OrderByDescending(x => x.seq)
                    .ThenByDescending(x => x.pos)
                    .Select(x => x.item)
                    .ToList();
            }

            var pages = Math.Max(1, (all.Count + PerPage - 1) / PerPage);
            page = Math.Clamp(page, 1, pages);

            var items = all.Skip((page - 1) * PerPage).Take(PerPage).Select(i => new
            {
                o = i.Guid.Full,
                w = i.WeenieClassId,
                n = i.Name,
                i = i.IconId,
                u = i.IconUnderlayId == 0 ? (uint?)null : i.IconUnderlayId,
                v = i.IconOverlayId == 0 ? (uint?)null : i.IconOverlayId,
                s = i.StackSize is > 1 ? i.StackSize : null,
                m = i.MaxStackSize is > 1 ? i.MaxStackSize : null,
                y = (uint)(i.ItemType),
                e = i.UiEffects is { } fx && (uint)fx != 0 ? (uint?)fx : null,
            }).ToList();

            CompanionFeed.Send(session, new { t = "mule", ready = true, page, pages, count = all.Count, max = Mod.Settings.MaxItems, items });
        }
        catch (Exception ex)
        {
            ModManager.Log($"[{Mod.Name}] /mule-data failed for {player.Name}: {ex}", ModManager.LogLevel.Error);
            CompanionFeed.Send(session, new { t = "mule", ready = false, why = "error" });
        }
    }
}