using ProjectM.Simulation;
using Unity.Entities;
using Unity.Mathematics;
using Unity.Transforms;

namespace ProjectM.Server
{
    /// <summary>
    /// The ONE per-enemy spawn-stamp for expedition ROOM enemies, shared by RoomEnemyDirectorSystem (wave drip) and
    /// BossAISystem (phase-two summon). Keeps the teardown/relevancy/clear-count contract in a single place so a boss
    /// add can never silently drop a tag: <see cref="ZoneEnemyTag"/> (counted by the room-clear gate),
    /// <see cref="RoomTag"/> (the RoomTeardown filter — Room byte MUST equal the current room), and
    /// <see cref="RegionTag"/>{Expedition} (relevancy — an untagged add would leak to base players, a Base-tagged one
    /// would hide from the expedition party). Scale preserved via <c>baked.WithPosition</c> (never FromPosition, which
    /// resets the [GhostField] Scale). Returns the spawned entity so a caller can layer extra (e.g. boss HP/scale).
    /// </summary>
    public static class ZoneEnemySpawnUtil
    {
        public static Entity Spawn(EntityCommandBuffer ecb, Entity prefab, in LocalTransform baked, float3 pos, byte region, byte room)
        {
            var enemy = ecb.Instantiate(prefab);
            ecb.SetComponent(enemy, baked.WithPosition(pos)); // preserve the baked [GhostField] Scale
            ecb.AddComponent(enemy, new RegionTag { Region = region });
            ecb.AddComponent<ZoneEnemyTag>(enemy);

            return enemy;
        }
    }
}