using System.Collections.Generic;
using NeoModLoader.services;
using UnityEngine;

namespace IdleSpectator;

/// <summary>
/// Captures subspecies creation during map gen / before spectator is on,
/// then drains a few as Curiosity once the world is playable.
/// </summary>
public static class SpeciesDiscovery
{
    private const float DrainIntervalSecondsDefault = 12f;
    private const float NotReadyBackoffSecondsDefault = 5f;
    private const int MaxBuffered = 24;
    private const int MaxDrainPerSession = 8;
    private const int MaxNotReadyAttempts = 8;

    private static float _drainInterval = DrainIntervalSecondsDefault;
    private static float _notReadyBackoff = NotReadyBackoffSecondsDefault;

    private static readonly List<PendingSpecies> Pending = new List<PendingSpecies>();
    private static readonly HashSet<string> SeenAssets = new HashSet<string>();
    private static readonly HashSet<string> PresentedAssets = new HashSet<string>();
    private static float _lastDrainAt = -999f;
    private static int _drainedThisSession;

    private struct PendingSpecies
    {
        public string AssetId;
        public Vector3 Position;
        public Subspecies Subspecies;
        public int NotReadyAttempts;
    }

    public static int PendingCount => Pending.Count;

    public static bool IsPending(string assetId)
    {
        return !string.IsNullOrEmpty(assetId) && Pending.Exists(p => p.AssetId == assetId);
    }

    public static int DrainedThisSession => _drainedThisSession;

    public static void OnSpectatorEnabled()
    {
        _drainedThisSession = 0;
        _lastDrainAt = Time.unscaledTime - _drainInterval + 2f;
    }

    public static void OnSpectatorDisabled()
    {
        // Keep buffer so re-enabling can still discover; clear session drain counter only.
        _drainedThisSession = 0;
    }

    /// <summary>
    /// Harness-only: shorten drain interval. Uses unscaled time (game 5x does not help).
    /// </summary>
    public static void SetHarnessFastTiming(bool enabled)
    {
        _drainInterval = enabled ? 0.75f : DrainIntervalSecondsDefault;
        _notReadyBackoff = enabled ? 0.35f : NotReadyBackoffSecondsDefault;
    }

    /// <summary>Harness: clear presented/seen so the same asset can be re-tested.</summary>
    public static void HarnessResetTracking()
    {
        PresentedAssets.Clear();
        SeenAssets.Clear();
        Pending.Clear();
        _drainedThisSession = 0;
        _lastDrainAt = Time.unscaledTime - _drainInterval;
    }

    /// <summary>Harness: buffer a living asset as if newSpecies fired during load.</summary>
    public static bool HarnessNoteAsset(string assetId, Vector3 position)
    {
        if (string.IsNullOrEmpty(assetId))
        {
            return false;
        }

        ActorAsset asset = AssetManager.actor_library?.get(assetId);
        if (asset == null)
        {
            return false;
        }

        SeenAssets.Remove(assetId);
        PresentedAssets.Remove(assetId);
        for (int i = Pending.Count - 1; i >= 0; i--)
        {
            if (Pending[i].AssetId == assetId)
            {
                Pending.RemoveAt(i);
            }
        }

        NoteCreated(asset, null, mutation: false, subspecies: null);
        if (Pending.Count > 0)
        {
            PendingSpecies last = Pending[Pending.Count - 1];
            if (last.AssetId == assetId && position != Vector3.zero)
            {
                last.Position = position;
                Pending[Pending.Count - 1] = last;
            }
        }

        return Pending.Exists(p => p.AssetId == assetId);
    }

    /// <summary>Harness: ignore drain interval and attempt one drain immediately.</summary>
    public static bool HarnessForceDrainOnce()
    {
        _lastDrainAt = Time.unscaledTime - _drainInterval - 0.05f;
        int before = _drainedThisSession;
        int pendingBefore = Pending.Count;
        Update();
        return _drainedThisSession > before || Pending.Count < pendingBefore;
    }

    public static void NoteCreated(ActorAsset asset, WorldTile tile, bool mutation, Subspecies subspecies)
    {
        if (mutation || asset == null || string.IsNullOrEmpty(asset.id))
        {
            return;
        }

        if (!SeenAssets.Add(asset.id))
        {
            return;
        }

        // Already shown via live path before buffer ran - nothing to queue.
        if (PresentedAssets.Contains(asset.id))
        {
            return;
        }

        if (Pending.Count >= MaxBuffered)
        {
            Pending.RemoveAt(0);
        }

        Vector3 pos = tile != null ? tile.posV3 : Vector3.zero;
        Pending.Add(new PendingSpecies
        {
            AssetId = asset.id,
            Position = pos,
            Subspecies = subspecies,
            NotReadyAttempts = 0
        });
    }

    /// <summary>
    /// Live newSpecies path already tipped this asset - drop any buffered copy.
    /// </summary>
    public static void MarkPresented(string assetId)
    {
        if (string.IsNullOrEmpty(assetId))
        {
            return;
        }

        PresentedAssets.Add(assetId);
        SeenAssets.Add(assetId);
        for (int i = Pending.Count - 1; i >= 0; i--)
        {
            if (Pending[i].AssetId == assetId)
            {
                Pending.RemoveAt(i);
            }
        }
    }

    public static bool WasPresented(string assetId)
    {
        return !string.IsNullOrEmpty(assetId) && PresentedAssets.Contains(assetId);
    }

    public static void Update()
    {
        if (!SpectatorMode.Active || !Config.game_loaded || World.world == null)
        {
            return;
        }

        if (SmoothLoader.isLoading())
        {
            return;
        }

        if (_drainedThisSession >= MaxDrainPerSession || Pending.Count == 0)
        {
            return;
        }

        float now = Time.unscaledTime;
        if (now - _lastDrainAt < _drainInterval)
        {
            return;
        }

        // Wait until the director can actually show a curiosity tip.
        if (!InterestDirector.WouldAcceptCuriosity())
        {
            return;
        }

        int index = FindNextReadyIndex();
        if (index < 0)
        {
            // Front items not spawnable yet - retry later without dequeue flap.
            _lastDrainAt = now - _drainInterval + _notReadyBackoff;
            return;
        }

        PendingSpecies next = Pending[index];
        ActorAsset asset = AssetManager.actor_library?.get(next.AssetId);
        if (asset == null)
        {
            Pending.RemoveAt(index);
            return;
        }

        InterestEvent curiosity = WorldActivityScanner.FromNewSpecies(next.Subspecies, asset, null);
        if (curiosity == null)
        {
            next.NotReadyAttempts++;
            if (next.NotReadyAttempts >= MaxNotReadyAttempts)
            {
                Pending.RemoveAt(index);
                LogService.LogInfo($"[IdleSpectator] Discovery skip (never spawned): {next.AssetId}");
            }
            else
            {
                Pending[index] = next;
            }

            _lastDrainAt = now - _drainInterval + _notReadyBackoff;
            return;
        }

        // Prefer the recorded spawn tile when the unit search used a weak position.
        if (next.Position != Vector3.zero && curiosity.Position == Vector3.zero)
        {
            curiosity.Position = next.Position;
        }

        Pending.RemoveAt(index);
        PresentedAssets.Add(next.AssetId);
        _lastDrainAt = now;
        _drainedThisSession++;
        InterestCollector.EnqueueDirect(curiosity);
        LogService.LogInfo($"[IdleSpectator] Discovery drain: {next.AssetId} ({_drainedThisSession}/{MaxDrainPerSession}, queued={Pending.Count})");
    }

    private static int FindNextReadyIndex()
    {
        for (int i = 0; i < Pending.Count; i++)
        {
            PendingSpecies next = Pending[i];
            if (PresentedAssets.Contains(next.AssetId))
            {
                Pending.RemoveAt(i);
                i--;
                continue;
            }

            ActorAsset asset = AssetManager.actor_library?.get(next.AssetId);
            if (asset == null)
            {
                Pending.RemoveAt(i);
                i--;
                continue;
            }

            if (WorldActivityScanner.FromNewSpecies(next.Subspecies, asset, null) != null)
            {
                return i;
            }
        }

        return -1;
    }
}