Add initial game systems and input handling for player interactions

Assets/Scripts/Presentation/PresentSpawner.cs

@@ -0,0 +1,112 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using Core;
+using UnityEngine;
+using Random = UnityEngine.Random;
+
+namespace Presentation
+{
+    public class PresentSpawner : MonoBehaviour
+    {
+        [Header("Pooling")]
+        [SerializeField] private Present presentPrefab;
+        [SerializeField] private int poolSize = 20;
+        
+        [Header("Spawning")]
+        [SerializeField] private Transform[] spawnPoints;
+        [SerializeField] private float spawnInterval = 1.5f;
+        [SerializeField] private float burstChance = 0.3f;
+        [SerializeField] private Vector2 initialDirection = Vector2.right;
+        
+        private Queue<Present> _pool = new();
+        private List<Present> _activePresents = new();
+        private bool _isSpawning;
+
+        private void Awake()
+        {
+            for (var i = 0; i < poolSize; i++)
+            {
+                CreateNewPresent();
+            }
+        }
+
+        private Present CreateNewPresent()
+        {
+            var p = Instantiate(presentPrefab, transform);
+            p.gameObject.SetActive(false);
+            p.Configure(this);
+            
+            _pool.Enqueue(p);
+            return p;
+        }
+
+        private Present GetPresent()
+        {
+            if (_pool.Count == 0) CreateNewPresent();
+            
+            var p = _pool.Dequeue();
+            p.gameObject.SetActive(true);
+            _activePresents.Add(p);
+            return p;
+        }
+
+        public void ReturnToPool(Present p)
+        {
+            if (!p.gameObject.activeSelf) return;
+            
+            p.gameObject.SetActive(false);
+            _activePresents.Remove(p);
+            _pool.Enqueue(p);
+        }
+
+        public void StartSpawning()
+        {
+            _isSpawning = true;
+            GameEvents.GameOver += StopSpawning;
+            StartCoroutine(SpawnRoutine());
+        }
+
+        public void StopSpawning()
+        {
+            _isSpawning = false;
+            GameEvents.GameOver -= StopSpawning;
+            StopAllCoroutines();
+            
+            
+            foreach (var p in _activePresents.ToArray()) ReturnToPool(p);
+            _activePresents.Clear();
+        }
+
+        private IEnumerator SpawnRoutine()
+        {
+            while (_isSpawning)
+            {
+                SpawnOne();
+
+                if (Random.value < burstChance)
+                {
+                    yield return new WaitForSeconds(0.2f);
+                    SpawnOne();
+                }
+
+                //TODO: Difficulty scaling
+                yield return new WaitForSeconds(spawnInterval);
+            }
+        }
+
+        private void SpawnOne()
+        {
+            var p = GetPresent();
+            
+            var rb = p.GetComponent<Rigidbody2D>();
+            rb.linearVelocity = Vector2.zero;
+            rb.angularVelocity = 0f;
+            
+            var index = Random.Range(0, spawnPoints.Length);
+            p.transform.position = spawnPoints[index].position;
+            p.transform.rotation = Quaternion.identity;
+            rb.AddForce(initialDirection + new Vector2(Random.Range(-1f,1f), Random.Range(-1f,1f)), ForceMode2D.Impulse);
+        }
+    }
+}