using SepCore.Debugger;
using SepCore.Entity;
using Unity.Mathematics;
using UnityEngine;

namespace SepCore.Simulation
{
    public sealed partial class SimulationWorld
    {
        #region Collision Broad Phase

        private void PrepareCollisionCandidatesForFrame()
        {
            _collisionCandidateQueryScheduled = false;

            if (!_collisionQueryInputs.IsCreated || !_collisionCandidates.IsCreated ||
                !_enemyCollisionBuckets.IsCreated)
            {
                ResetCollisionRuntimeStats();
                ClearAreaCollisionTransientBuffers();
                return;
            }

            int projectileCount = _projectiles.Count;
            int areaQueryCount = _areaCollisionRequests.Count;
            if (projectileCount == 0 && areaQueryCount == 0)
            {
                ResetCollisionRuntimeStats();
                return;
            }

            float queryRadius = Mathf.Max(0.01f, _projectileCollisionQueryRadius);
            int maxCandidatesPerQuery = Mathf.Max(1, _projectileMaxCandidatesPerQuery);
            float maxQueryRadius = queryRadius;
            int queryId = 0;
            int projectileQueryCount = 0;
            int builtAreaQueryCount = 0;
            using (CustomProfilerMarker.Collision_BuildQueries.Auto())
            {
                for (int i = 0; i < projectileCount; i++)
                {
                    if (!_projectiles.Life[i].Active)
                    {
                        continue;
                    }

                    ProjectileTransformSim projectileTransform = _projectiles.Transform[i];
                    ProjectileIdentitySim projectileIdentity = _projectiles.Identity[i];
                    AddProjectileCollisionQuery(queryId, in projectileTransform, in projectileIdentity, queryRadius,
                        maxCandidatesPerQuery);
                    queryId++;
                    projectileQueryCount++;
                }

                for (int i = 0; i < areaQueryCount; i++)
                {
                    AreaCollisionRequestData request = _areaCollisionRequests[i];
                    AddAreaCollisionQuery(queryId, request.SourceEntityId, request.SourceOwnerEntityId,
                        request.SourceWasActiveAtQueryTime, in request.Center, request.Radius, request.MaxTargets,
                        request.ShapeType, in request.Direction, request.HalfAngleDeg, request.HalfWidth,
                        request.HalfLength);
                    queryId++;
                    builtAreaQueryCount++;
                    if (request.Radius > maxQueryRadius)
                    {
                        maxQueryRadius = request.Radius;
                    }
                }
            }

            _lastProjectileCollisionQueryCount = projectileQueryCount;
            _lastAreaCollisionQueryCount = builtAreaQueryCount;
            _lastCollisionQueryCount = projectileQueryCount + builtAreaQueryCount;
            _lastResolvedAreaHitCount = 0;

            if (_collisionQueryInputs.Length == 0)
            {
                _lastCollisionCandidateCount = 0;
                _lastProjectileCollisionCandidateCount = 0;
                _lastAreaCollisionCandidateCount = 0;
                _lastCollisionCellSize = 0f;
                _lastCollisionHasEnemyTargets = _enemies.Count > 0;
                return;
            }

            float autoCellSize = maxQueryRadius * 2f;
            float configuredCellSize = _projectileCollisionCellSize > 0f ? _projectileCollisionCellSize : autoCellSize;
            float cellSize = Mathf.Max(0.1f, configuredCellSize);
            bool hasEnemyTargets = _enemies.Count > 0;
            _lastCollisionCellSize = cellSize;
            _lastCollisionHasEnemyTargets = hasEnemyTargets;

            using (CustomProfilerMarker.Collision_BuildBuckets.Auto())
            {
                if (hasEnemyTargets)
                {
                    CollisionQuerySystem.BuildEnemyCollisionBuckets(_enemies, _enemyCollisionBuckets, cellSize);
                }
            }

            using (CustomProfilerMarker.Collision_QueryCandidates.Auto())
            {
                bool hasPlayerTarget = TryGetPlayerCollisionTarget(out int playerTargetEntityId,
                    out float3 playerPosition);
                _collisionCandidateQueryScheduled = CollisionQuerySystem.ScheduleCandidateQuery(
                    _collisionQueryInputs, _collisionCandidates, _enemyCollisionBuckets, _enemies, hasEnemyTargets,
                    hasPlayerTarget, playerTargetEntityId, playerPosition, cellSize,
                    out _collisionCandidateQueryHandle);
            }
        }

        private void CompleteCollisionCandidatesForFrame()
        {
            if (_collisionCandidateQueryScheduled)
            {
                _collisionCandidateQueryHandle.Complete();
                _collisionCandidateQueryScheduled = false;
            }

            CountCollisionCandidatesBySourceType(out int projectileCandidateCount, out int areaCandidateCount);
            _lastProjectileCollisionCandidateCount = projectileCandidateCount;
            _lastAreaCollisionCandidateCount = areaCandidateCount;
            _lastCollisionCandidateCount = projectileCandidateCount + areaCandidateCount;
        }

        private void CountCollisionCandidatesBySourceType(out int projectileCandidateCount, out int areaCandidateCount)
        {
            projectileCandidateCount = 0;
            areaCandidateCount = 0;

            if (!_collisionCandidates.IsCreated)
            {
                return;
            }

            for (int i = 0; i < _collisionCandidates.Length; i++)
            {
                CollisionCandidateData candidate = _collisionCandidates[i];
                if (candidate.SourceType == SimulationCollision.SourceTypeProjectile)
                {
                    projectileCandidateCount++;
                }
                else if (candidate.SourceType == SimulationCollision.SourceTypeArea)
                {
                    areaCandidateCount++;
                }
            }
        }

        private static bool TryGetPlayerCollisionTarget(out int playerEntityId, out float3 playerPosition)
        {
            playerEntityId = PlayerEntityId;
            playerPosition = default;

            if (!TryGetAliveTargetableEntity(playerEntityId, out TargetableObject playerTarget))
            {
                return false;
            }

            Transform playerTransform = playerTarget.CachedTransform;
            if (playerTransform == null)
            {
                return false;
            }

            Vector3 position = playerTransform.position;
            playerPosition = new float3(position.x, position.y, position.z);
            return true;
        }

        #endregion
    }
}