using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;


public class WaveSpawner : MonoBehaviour
{
    [SerializeField]
    float timeBetweenSpawns, timeBetweenWaves;


    [SerializeField]
    Transform[] spawnPoints;


    [SerializeField]
    Text waveCount;


    int currentWave = 0, spawnPointIndex = 0, remainingEnemies;


    float bonusPoints = 0;


    List<GameObject> currentWaveTanks = new List<GameObject>();


    bool waveSpawned = false;


    static WaveSpawner instance;


    public static WaveSpawner Instance
    {
        get { return instance; }
    }


    public List<GameObject> CurrentWaveTanks
    {
        get { return currentWaveTanks; }
    }


    public int CurrentWave
    {
        get { return currentWave; }
    }


    private void Awake()
    {
        if (instance != null && instance != this)
            Destroy(this);
        instance = this;
    }


    private void Start()
    {
        StartCoroutine("SpawnWave");
    }


    private void Update()
    {
        if (waveSpawned)
        {
            bonusPoints = Mathf.Clamp(bonusPoints - Time.deltaTime, 0f, Mathf.Infinity);
        }
    }


    IEnumerator SpawnWave()
    {
        waveSpawned = false;
        currentWave++;
        waveCount.text = "<" + currentWave + ">";
        remainingEnemies = currentWave;
        for (int i = 0; i < currentWave && i < 100; i++)
        {
            currentWaveTanks.Add(GameManager.Instance.EnemyPool.GetObject(spawnPoints[spawnPointIndex].transform.position, spawnPoints[spawnPointIndex].transform.rotation));
            spawnPointIndex = (spawnPointIndex + 1) % spawnPoints.Length;
            yield return new WaitForSeconds(timeBetweenSpawns);
        }
        bonusPoints = 60f * currentWave;
        waveSpawned = true;
    }


    public void TankDestroyed(GameObject tank)
    {
        if (currentWaveTanks.Contains(tank))
            currentWaveTanks.Remove(tank);
        GameManager.Instance.EnemyPool.RePoolObject(tank);
        remainingEnemies--;
        if (currentWaveTanks.Count < 1 && waveSpawned)
        {
            UIManager.Instance.AddScore((int)bonusPoints);
            GameManager.Instance.Score = (int)bonusPoints;
            StartCoroutine("NextWave");
        }
    }


    IEnumerator NextWave()
    {
        for (int i = (int)timeBetweenWaves; i > 0; i--)
        {
            waveCount.text = ">" + i + "<";
            yield return new WaitForSeconds(1);
        }
        StartCoroutine("SpawnWave");
    }
}


}