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

/// <summary>
/// User interface loading progress.
/// </summary>
using UnityEngine.Events;



namespace WorldStreamer2
{
    public class UILoadingStreamer : MonoBehaviour
    {
        [Tooltip("List of streamers objects that should affect loading screen. Drag and drop here all your streamer objects from scene hierarchy which should be used in loading screen.")]
        /// <summary>
        /// The streamers.
        /// </summary>
        public Streamer[] streamers;

        /// <summary>
        /// The progress image.
        /// </summary>
        public Image progressImg;

        [Tooltip("Time in seconds that you give your loading screen to get data from whole streamers about scene that they must load before loading screen will be switched off.")]
        /// <summary>
        /// The wait time after end of loading.
        /// </summary>
        public float waitTime = 2;

        public UnityEvent onDone;

        /// <summary>
        /// Awake this instance, and set fill to 0.
        /// </summary>
        void Awake()
        {
            foreach (var item in streamers)
            {
                item.loadingStreamer = this;
                item.showLoadingScreen = true;
            }
            progressImg.fillAmount = 0;
        }

        /// <summary>
        /// Update this instance, and sets current progress of streaming.
        /// </summary>
        void Update()
        {
            if (streamers.Length > 0)
            {

                bool initialized = true;

                progressImg.fillAmount = 0;
                foreach (var item in streamers)
                {
                    progressImg.fillAmount += item.LoadingProgress / (float)streamers.Length;
                    initialized = initialized && item.initialized;
                }
                if (initialized)
                {
                    if (progressImg.fillAmount >= 1)
                    {
                        if (onDone != null)
                            onDone.Invoke();
                        StartCoroutine(TurnOff());
                    }
                }

            }
            else
                Debug.Log("No streamer Attached");
        }

        public IEnumerator TurnOff()
        {
            yield return new WaitForSeconds(waitTime);
            gameObject.SetActive(false);
        }

        /// <summary>
        /// Show progress bar and resets fill.
        /// </summary>
        public void Show()
        {
            progressImg.fillAmount = 0;
            gameObject.SetActive(true);
        }

    }
}