using HarmonyLib;
using UnityEngine;

namespace NecromancerTome
{
	/// <summary>
	/// Necromancer's Knife (BACKLOG.md item 5, user request 2026-08-28): a zombie hit by the
	/// knife carries buffNecroVictim (buffs.xml) until it dies. On death, it's guaranteed to drop
	/// a green "Жертва" loot bag (EntityLootContainerVictim in entityclasses.xml) instead of
	/// whatever the normal random loot roll would have given it.
	///
	/// Two patch points, found the hard way (2026-08-28, "лута всё ещё нет" after confirming via
	/// the CharmPatch.cs-style AddBuff log that the debuff itself WAS being applied fine):
	///
	///   1. Patch_EntityAlive_dropItemOnDeath_VictimBag - the actual gate. Confirmed by
	///      decompiling EntityAlive.dropItemOnDeath(): it only calls DropBagServer() at all if
	///      `lootDropProb > rand.RandomFloat` passes first - vanilla zombies have LootDropProb
	///      around .04 (4%), so DropBagServer() simply never runs for ~96% of deaths. The first
	///      version of this file only patched DropBagServer() itself, which was correct once
	///      inside it but never got a chance to run for most kills - confirmed by the "AddBuff
	///      Added" log firing repeatedly while the "zombie died" log from the DropBagServer patch
	///      never fired even once for a real, logged kill. This Prefix on dropItemOnDeath() calls
	///      DropBagServer() directly for a Victim-tagged zombie, bypassing the probability roll
	///      entirely, then skips the rest of the original method (the only other thing it does -
	///      dropping a non-AI entity's own inventory - never applies to a zombie anyway, hasAI is
	///      always true for those).
	///   2. Patch_Entity_DropBagServer_VictimBag - decides WHICH bag. Confirmed by decompiling
	///      Entity.DropBagServer(): it reads entityClass.lootDrops/LootDropPick(rand) - a STATIC
	///      per-species value from the zombie's own entity_class (XML's LootDropEntityClass
	///      property), not anything a live buff or CVar can influence declaratively (unlike the
	///      knife's damage, which only needed a CVar the passive_effect system already reads
	///      live) - this needed an actual Harmony patch, not an XML trick.
	///
	/// Both are Prefixes returning false: they fully replace what they intercept rather than
	/// running alongside it.
	/// </summary>
	[HarmonyPatch(typeof(EntityAlive), "dropItemOnDeath")]
	public static class Patch_EntityAlive_dropItemOnDeath_VictimBag
	{
		public static bool Prefix(EntityAlive __instance)
		{
			// Diagnostic-only, added 2026-08-28: unconditional, before any branching, to answer
			// definitively whether Harmony is even entering this method at all - "лута всё ещё
			// нет" after the first fix, but with zero sign of even the unconditional part of this
			// Prefix ever running (not even a false-branch silently returning - literally no log
			// line at all), which is otherwise unexplained since decompiling
			// EntityAlive.OnEntityDeath() confirms it calls dropItemOnDeath() directly,
			// unconditionally, right after the exact "Entity X killed by Y" line seen in the log.
			Debug.Log("[NecromancerTome] VictimPatch: dropItemOnDeath Prefix entered for " + __instance.entityId + " (" + __instance.GetType().Name + "), hasVictimBuff=" + (__instance.Buffs != null && __instance.Buffs.HasBuff(Patch_Entity_DropBagServer_VictimBag.VictimBuffName)));
			if (__instance.Buffs == null || !__instance.Buffs.HasBuff(Patch_Entity_DropBagServer_VictimBag.VictimBuffName))
			{
				return true;
			}
			Debug.Log("[NecromancerTome] VictimPatch: " + __instance.entityId + " died carrying buffNecroVictim - forcing guaranteed bag, bypassing LootDropProb roll");
			__instance.DropBagServer();
			return false;
		}
	}

	[HarmonyPatch(typeof(Entity), "DropBagServer")]
	public static class Patch_Entity_DropBagServer_VictimBag
	{
		public const string VictimBuffName = "buffNecroVictim";
		public const string VictimContainerClassName = "EntityLootContainerVictim";

		public static bool Prefix(Entity __instance)
		{
			if (!(__instance is EntityAlive alive) || alive.Buffs == null || !alive.Buffs.HasBuff(VictimBuffName))
			{
				return true;
			}
			if (!SingletonMonoBehaviour<ConnectionManager>.Instance.IsServer || __instance is EntityLootContainer)
			{
				// Same guard the original method opens with - not our place to override these cases.
				return true;
			}

			int containerClassId = EntityClass.GetId(VictimContainerClassName);
			if (containerClassId == -1)
			{
				Debug.LogWarning("[NecromancerTome] VictimPatch: entity class '" + VictimContainerClassName + "' not found, falling back to normal loot");
				return true;
			}

			Vector3 pos = __instance.GetPosition();
			pos.y += 0.9f;
			Entity spawned = EntityFactory.CreateEntity(containerClassId, pos, Vector3.zero);
			if (spawned is EntityLootContainer lootContainer)
			{
				GameManager.Instance.World.SpawnEntityInWorld(lootContainer);
				Debug.Log("[NecromancerTome] VictimPatch: " + __instance.entityId + " (victim) dropped guaranteed loot bag " + lootContainer.entityId);
			}
			else
			{
				Debug.LogWarning("[NecromancerTome] VictimPatch: created entity for '" + VictimContainerClassName + "' wasn't an EntityLootContainer");
			}
			return false;
		}
	}
}