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

namespace IdleSpectator;

/// <summary>
/// Scores live world activity across civs and wild mobs (wiki-aligned).
/// Throttled to ~2 Hz while Spectator is active.
/// </summary>
public static class WorldActivityScanner
{
    private static readonly HashSet<string> SpectacleAssets = new HashSet<string>
    {
        "dragon",
        "greg",
        "demon",
        "evil_mage",
        "necromancer",
        "ufo",
        "cold_one",
        "walker",
        "snowman",
        "bandit",
        "tumor_monster",
        "bioblob",
        "assimilator",
        "lil_pumpkin",
        "fire_elemental",
        "skeleton",
        "zombie",
        "ghost",
        "mush"
    };

    private static readonly System.Random Rng = new System.Random();
    private static float _lastScanAt = -999f;
    private static InterestEvent _cachedBest;
    private static InterestEvent _cachedBattle;
    private const float ScanInterval = 0.5f;
    private static float _lastEmptyLogAt = -999f;

    public static InterestEvent FindBestLiveTarget()
    {
        EnsureScanned();
        if (_cachedBest == null && Time.unscaledTime - _lastEmptyLogAt > 15f)
        {
            _lastEmptyLogAt = Time.unscaledTime;
            LogService.LogInfo("[IdleSpectator] No live units to follow yet");
        }

        return Clone(_cachedBest);
    }

    public static InterestEvent FindHottestBattle()
    {
        EnsureScanned();
        return Clone(_cachedBattle);
    }

    private static void EnsureScanned()
    {
        if (Time.unscaledTime - _lastScanAt < ScanInterval)
        {
            return;
        }

        _lastScanAt = Time.unscaledTime;
        ScanNow();
    }

    private static void ScanNow()
    {
        _cachedBattle = BuildHottestBattle();
        InterestEvent bestUnit = BuildBestScoredUnit();

        // Prefer an active battle when it is meaningfully hotter than quiet unit watching.
        if (_cachedBattle != null)
        {
            _cachedBest = _cachedBattle;
            return;
        }

        _cachedBest = bestUnit;
    }

    private static InterestEvent BuildHottestBattle()
    {
        HashSet<BattleContainer> battles = BattleKeeperManager.get();
        if (battles == null || battles.Count == 0)
        {
            return null;
        }

        BattleContainer best = null;
        int bestDeaths = 0;
        foreach (BattleContainer battle in battles)
        {
            if (battle?.tile == null)
            {
                continue;
            }

            int deaths = battle.getDeathsTotal();
            if (deaths > bestDeaths)
            {
                bestDeaths = deaths;
                best = battle;
            }
        }

        if (best == null || bestDeaths < 1)
        {
            return null;
        }

        Vector3 pos = best.tile.posV3;
        Actor nearby = FindNearestAliveUnit(pos, 14f);
        return new InterestEvent
        {
            Tier = InterestTier.Action,
            Score = 50f + bestDeaths,
            Position = pos,
            FollowUnit = nearby,
            Label = bestDeaths >= 6 ? $"Battle ({bestDeaths} fallen)" : $"Skirmish ({bestDeaths} fallen)",
            CreatedAt = Time.unscaledTime,
            AssetId = "live_battle"
        };
    }

    private static InterestEvent BuildBestScoredUnit()
    {
        Dictionary<string, int> speciesCounts = new Dictionary<string, int>();
        List<Actor> alive = new List<Actor>(128);
        foreach (Actor actor in EnumerateAliveUnits())
        {
            if (actor.asset != null && actor.asset.is_boat)
            {
                continue;
            }

            alive.Add(actor);
            string speciesId = actor.asset != null ? actor.asset.id : "unknown";
            speciesCounts.TryGetValue(speciesId, out int count);
            speciesCounts[speciesId] = count + 1;
        }

        if (alive.Count == 0)
        {
            return null;
        }

        Actor best = null;
        float bestScore = float.MinValue;
        List<Actor> nearTies = new List<Actor>();

        for (int i = 0; i < alive.Count; i++)
        {
            Actor actor = alive[i];
            float score = ScoreActor(actor, speciesCounts);
            if (score > bestScore + 0.01f)
            {
                bestScore = score;
                best = actor;
                nearTies.Clear();
                nearTies.Add(actor);
            }
            else if (Mathf.Abs(score - bestScore) <= 2f)
            {
                nearTies.Add(actor);
            }
        }

        if (nearTies.Count > 1)
        {
            best = nearTies[Rng.Next(nearTies.Count)];
            bestScore = ScoreActor(best, speciesCounts);
        }

        if (best == null)
        {
            return null;
        }

        InterestTier tier = InterestTier.Ambient;
        if (best.isFavorite() || best.isKing() || best.isCityLeader())
        {
            tier = InterestTier.Story;
        }
        else if (best.has_attack_target || (best.data != null && best.data.kills >= 10))
        {
            tier = InterestTier.Action;
        }
        else if (IsSpectacle(best) || IsSingletonSpecies(best, speciesCounts))
        {
            tier = InterestTier.Curiosity;
        }

        return new InterestEvent
        {
            Tier = tier,
            Score = bestScore,
            Position = best.current_position,
            FollowUnit = best,
            Label = FormatUnitLabel(best, speciesCounts),
            CreatedAt = Time.unscaledTime,
            AssetId = best.asset != null ? best.asset.id : "scored_unit"
        };
    }

    /// <summary>Public wrappers for dossier / harness (same logic as private scorers).</summary>
    public static Dictionary<string, int> CountSpeciesPopulations()
    {
        Dictionary<string, int> speciesCounts = new Dictionary<string, int>();
        foreach (Actor actor in EnumerateAliveUnits())
        {
            if (actor?.asset == null)
            {
                continue;
            }

            string id = actor.asset.id;
            if (!speciesCounts.ContainsKey(id))
            {
                speciesCounts[id] = 0;
            }

            speciesCounts[id]++;
        }

        return speciesCounts;
    }

    public static float ScoreActorPublic(Actor actor, Dictionary<string, int> speciesCounts)
    {
        return ScoreActor(actor, speciesCounts);
    }

    public static bool IsSpectaclePublic(Actor actor)
    {
        return IsSpectacle(actor);
    }

    public static bool IsSingletonSpeciesPublic(Actor actor, Dictionary<string, int> speciesCounts)
    {
        return IsSingletonSpecies(actor, speciesCounts);
    }

    public static string FormatUnitLabelPublic(Actor actor, Dictionary<string, int> speciesCounts)
    {
        return FormatUnitLabel(actor, speciesCounts);
    }

    private static float ScoreActor(Actor actor, Dictionary<string, int> speciesCounts)
    {
        float score = 0f;
        if (actor.isFavorite())
        {
            score += 50f;
        }

        if (actor.isKing())
        {
            score += 40f;
        }
        else if (actor.isCityLeader())
        {
            score += 35f;
        }
        else if (actor.is_profession_warrior)
        {
            score += 12f;
        }

        if (actor.has_attack_target)
        {
            score += 30f;
        }

        int kills = actor.data != null ? actor.data.kills : 0;
        score += Mathf.Min(25, kills);

        string speciesId = actor.asset != null ? actor.asset.id : "unknown";
        if (speciesCounts.TryGetValue(speciesId, out int pop) && pop == 1)
        {
            score += 15f;
        }

        if (actor.subspecies != null)
        {
            // Nascent lineage: few members in subspecies asset unit set if available.
            try
            {
                int subCount = CountSubspeciesMembers(actor.subspecies);
                if (subCount > 0 && subCount <= 3)
                {
                    score += 10f;
                }
            }
            catch
            {
                // ignore
            }
        }

        if (IsSpectacle(actor))
        {
            score += 8f;
        }

        score += Mathf.Min(10f, actor.renown / 100f);
        // Tiny jitter so equal sheep do not stick forever.
        score += (actor.getID() % 7) * 0.01f;
        return score;
    }

    private static int CountSubspeciesMembers(Subspecies subspecies)
    {
        int count = 0;
        // Prefer actor.asset.units filtered by subspecies when possible.
        if (subspecies == null)
        {
            return 0;
        }

        foreach (Actor unit in EnumerateAliveUnits())
        {
            if (unit.subspecies == subspecies)
            {
                count++;
                if (count > 8)
                {
                    return count;
                }
            }
        }

        return count;
    }

    private static bool IsSpectacle(Actor actor)
    {
        if (actor?.asset == null)
        {
            return false;
        }

        string id = actor.asset.id;
        if (SpectacleAssets.Contains(id))
        {
            return true;
        }

        // Loose match for variant ids.
        foreach (string key in SpectacleAssets)
        {
            if (id.Contains(key))
            {
                return true;
            }
        }

        return false;
    }

    private static bool IsSingletonSpecies(Actor actor, Dictionary<string, int> speciesCounts)
    {
        if (actor?.asset == null)
        {
            return false;
        }

        return speciesCounts.TryGetValue(actor.asset.id, out int pop) && pop == 1;
    }

    private static string FormatUnitLabel(Actor actor, Dictionary<string, int> speciesCounts)
    {
        string name = SafeName(actor);
        string species = actor.asset != null ? actor.asset.id : "creature";
        if (actor.isFavorite())
        {
            return $"Favorite: {name}";
        }

        if (actor.isKing())
        {
            string kingdom = actor.kingdom != null ? actor.kingdom.name : "realm";
            return $"King {name} of {kingdom}";
        }

        if (actor.isCityLeader())
        {
            string city = actor.city != null ? actor.city.name : "town";
            return $"Leader {name} of {city}";
        }

        if (actor.has_attack_target)
        {
            return $"Fighting: {name}";
        }

        if (IsSpectacle(actor))
        {
            return $"Spectacle: {name} ({species})";
        }

        if (IsSingletonSpecies(actor, speciesCounts))
        {
            return $"Lone {species}: {name}";
        }

        int kills = actor.data != null ? actor.data.kills : 0;
        if (kills > 0)
        {
            return $"{name} ({species}, {kills} kills)";
        }

        return $"{name} ({species})";
    }

    public static InterestEvent FromNewSpecies(Subspecies subspecies, ActorAsset asset, WorldTile tile)
    {
        if (asset == null)
        {
            return null;
        }

        Vector3 pos = tile != null ? tile.posV3 : Vector3.zero;
        Actor follow = FindMatchingSpeciesUnit(asset, subspecies, pos, 30f);
        if (follow != null)
        {
            pos = follow.current_position;
        }

        // No matching unit yet = ghost tip (wrong creature gets focused). Skip until one exists.
        if (follow == null)
        {
            return null;
        }

        return new InterestEvent
        {
            Tier = InterestTier.Curiosity,
            Score = 5f,
            Position = pos,
            FollowUnit = follow,
            Label = $"New species: {asset.id}",
            CreatedAt = Time.unscaledTime,
            AssetId = asset.id
        };
    }

    /// <summary>
    /// Nearest living unit, optionally restricted to a specific actor asset id.
    /// </summary>
    public static Actor FindNearestAliveUnit(Vector3 pos, float maxDist, string requireAssetId = null)
    {
        // Freshly spawned units are often on asset.units before units_only_alive updates.
        if (!string.IsNullOrEmpty(requireAssetId))
        {
            Actor fromAsset = FindAliveOnAssetList(requireAssetId, pos, maxDist);
            if (fromAsset != null)
            {
                return fromAsset;
            }
        }

        Actor best = null;
        float bestDist = maxDist * maxDist;
        foreach (Actor actor in EnumerateAliveUnits())
        {
            if (requireAssetId != null
                && (actor.asset == null || actor.asset.id != requireAssetId))
            {
                continue;
            }

            float dx = actor.current_position.x - pos.x;
            float dy = actor.current_position.y - pos.y;
            float d2 = dx * dx + dy * dy;
            if (d2 < bestDist)
            {
                bestDist = d2;
                best = actor;
            }
        }

        return best;
    }

    /// <summary>
    /// Any living unit of this asset id (asset.units first, then world scan).
    /// </summary>
    public static Actor FindAliveByAssetId(string assetId, Vector3 nearPos, float maxDist = 5000f)
    {
        if (string.IsNullOrEmpty(assetId))
        {
            return null;
        }

        return FindNearestAliveUnit(nearPos, maxDist, assetId);
    }

    private static Actor FindAliveOnAssetList(string assetId, Vector3 nearPos, float maxDist)
    {
        ActorAsset asset = AssetManager.actor_library?.get(assetId);
        if (asset?.units == null)
        {
            return null;
        }

        Actor best = null;
        float bestDist = maxDist * maxDist;
        foreach (Actor unit in asset.units)
        {
            if (unit == null || !unit.isAlive())
            {
                continue;
            }

            float dx = unit.current_position.x - nearPos.x;
            float dy = unit.current_position.y - nearPos.y;
            float d2 = dx * dx + dy * dy;
            if (d2 < bestDist)
            {
                bestDist = d2;
                best = unit;
            }
        }

        return best;
    }

    private static Actor FindMatchingSpeciesUnit(ActorAsset asset, Subspecies subspecies, Vector3 nearPos, float maxDist)
    {
        if (asset?.units != null)
        {
            foreach (Actor unit in asset.units)
            {
                if (unit != null && unit.isAlive() && (subspecies == null || unit.subspecies == subspecies))
                {
                    return unit;
                }
            }
        }

        return FindNearestAliveUnit(nearPos, maxDist, asset != null ? asset.id : null);
    }

    private static IEnumerable<Actor> EnumerateAliveUnits()
    {
        return EnumerateAliveUnitsPublic();
    }

    public static IEnumerable<Actor> EnumerateAliveUnitsPublic()
    {
        List<Actor> prepared = World.world?.units?.units_only_alive;
        if (prepared != null && prepared.Count > 0)
        {
            for (int i = 0; i < prepared.Count; i++)
            {
                Actor actor = prepared[i];
                if (actor != null && actor.isAlive())
                {
                    yield return actor;
                }
            }

            yield break;
        }

        if (World.world?.units == null)
        {
            yield break;
        }

        foreach (Actor actor in World.world.units)
        {
            if (actor != null && actor.isAlive())
            {
                yield return actor;
            }
        }
    }

    private static string SafeName(Actor actor)
    {
        try
        {
            string name = actor.getName();
            if (!string.IsNullOrEmpty(name))
            {
                return name;
            }
        }
        catch
        {
            // ignore
        }

        return actor.asset != null ? actor.asset.id : "creature";
    }

    private static InterestEvent Clone(InterestEvent source)
    {
        if (source == null)
        {
            return null;
        }

        return new InterestEvent
        {
            Tier = source.Tier,
            Score = source.Score,
            Position = source.Position,
            FollowUnit = source.FollowUnit,
            Label = source.Label,
            CreatedAt = Time.unscaledTime,
            AssetId = source.AssetId
        };
    }
}