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

public class Logger : MonoBehaviour
{
    [Range(1, 5)]
    public float duration = 3.0f;
    public Color color = Color.white;

    List<KeyValuePair<string, float>> log_history = new List<KeyValuePair<string, float>>();
    List<int> out_of_date;
    GUIStyle style;

    float line_height;

    public float updateInterval = 0.1f;
    private double lastInterval;
    private int frames = 0;
    private float currFPS;
    private bool viewFPS = true;
    public bool enableFPS
    {
        set{
            viewFPS = !viewFPS;
        }
        get{
            return viewFPS;
        }
    }
    private void Start()
    {
        log_history = new List<KeyValuePair<string, float>>();
        out_of_date = new List<int>();
        style = new GUIStyle();
        lastInterval = Time.realtimeSinceStartup;
        frames = 0;
    }

    private void Update()
    {
        line_height = Screen.height * 0.05f;
        style.fontSize = (int)line_height;

        out_of_date.Clear();
        for (int i = log_history.Count - 1; i >= 0; i--)
        {
            if (Time.time - log_history[i].Value > duration)
                out_of_date.Add(i);
        }

        foreach (var i in out_of_date)
        {
            log_history.RemoveAt(i);
        }

        CountFPS();
    }

    void OnEnable()
    {
        Application.logMessageReceived += HandleLog;
    }

    void OnDisable()
    {
        Application.logMessageReceived -= HandleLog;
    }

    void HandleLog(string logString, string stackTrace, LogType type)
    {
        if(log_history == null || logString == null)
        {
            Debug.Log("");
        }
        log_history.Add(new KeyValuePair<string, float>(logString, Time.time));
    }

    void CountFPS()
    {
        ++frames;
        float timeNow = Time.realtimeSinceStartup;
        if (timeNow > lastInterval + updateInterval)
        {
            currFPS = (float)(frames / (timeNow - lastInterval));
            frames = 0;
            lastInterval = timeNow;
        }
    }

    void OnGUI()
    {
        //if (GUI.Button(new Rect(10, 10, 150, 100), "I am a button"))
            //print("You clicked the button!");

        float offset = 15.0f;
        Rect position = new Rect(offset, Screen.height - line_height * 2.0f, Screen.width - offset * 2.0f, line_height);

        if (viewFPS)
        {
            style.normal.textColor = new Color(color.r, color.g, color.b, 1);
            GUI.Label(position, string.Format("fps: {0}", currFPS.ToString("f2")), style);
            position.y = position.y - line_height;
        }
      
        for (int i = log_history.Count - 1; i >= 0; i--)
        {
            var ls = log_history[i];
            float a = 1.0f - Mathf.Pow((Time.time - ls.Value) / duration, 2.2f);
            style.normal.textColor = new Color(color.r, color.g, color.b, a);
            GUI.Label(position, ls.Key + string.Format(" {0}", Time.time - ls.Value), style);
            position.y = position.y - line_height;
        }
    }
}