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

public class HealthBar : MonoBehaviour
{
    public float ScalingFactor;

    private RectTransform rectTransform;

    private RectTransform mainBar;
    private TextMeshProUGUI text;
    private List<RectTransform> bars;
    private RectTransform border;
    private RawImage border1img, border2img;

    private PlayerController player;

    private void Awake()
    {
        rectTransform = GetComponent<RectTransform>();

        mainBar = transform.Find("Range").GetComponent<RectTransform>();
        bars = new List<RectTransform>();
        for (int i = 0; i < transform.childCount; i++)
        {
            Transform child = transform.GetChild(i);
            if (child.name.StartsWith("Overheal ")) bars.Add(child.GetComponent<RectTransform>());
        }
        bars.Sort((a, b) => int.Parse(a.name.Substring(9)).CompareTo(int.Parse(b.name.Substring(9))));
        bars.Insert(0, mainBar);

        player = FindObjectOfType<PlayerController>();
        text = mainBar.Find("Display").GetComponent<TextMeshProUGUI>();
        border = transform.Find("Border").GetComponent<RectTransform>();

        border1img = border.GetChild(0).GetComponent<RawImage>();
        border2img = border.GetChild(1).GetComponent<RawImage>();

        Tick(true);
    }

    private int currentHealthBefore;
    private float prevHealth;
    private void Update() => Tick(false);
    private void Tick(bool instant)
    {
        float size = Mathf.Log10(player.BaseStats.MaxHealth) * ScalingFactor;
        float desiredHealth = player.CurrentHealth;
        float ratio = desiredHealth / player.BaseStats.MaxHealth;
        float borderSize = 16 + 8 * Mathf.Max(0, Mathf.Ceil(ratio - 1));

        float curAlpha = border1img.color.r;
        if (player.CurrentHealth < currentHealthBefore)
        {
            // Calculate difference and add white flash.
            float addAlpha = (float)(currentHealthBefore - player.CurrentHealth) / player.BaseStats.MaxHealth;
            addAlpha = Mathf.Pow(addAlpha, 0.5f);

            curAlpha = 1 - (1 - addAlpha) * (1 - curAlpha);
        }

        curAlpha = Mathf.Lerp(curAlpha, 0, Time.deltaTime * 5);
        border1img.color = new Color(curAlpha, curAlpha, curAlpha, 1);
        border2img.color = new Color(curAlpha, curAlpha, curAlpha, 1);

        if (!instant)
        {
            desiredHealth = Mathf.Lerp(prevHealth, desiredHealth, Time.deltaTime * 5);
            ratio = desiredHealth / player.BaseStats.MaxHealth;
            borderSize = Mathf.Lerp(border.sizeDelta.y, 16 + 8 * Mathf.Max(0, Mathf.Ceil(ratio * 0.999f - 1)), Time.deltaTime * 20);
        }

        for (int i = 0; i < bars.Count; i++)
        {
            float thisPart = Mathf.Clamp01(ratio);
            RectTransform bar = bars[i];
            rectTransform.sizeDelta = new Vector2(size, rectTransform.sizeDelta.y);
            bar.sizeDelta = new Vector2((thisPart - 1) * size, 0);
            bar.localPosition = new Vector2(0.5f * size * thisPart, bar.localPosition.y);
            ratio--;
        }
        text.text = Mathf.RoundToInt(desiredHealth).ToString();

        border.sizeDelta = new Vector2(border.sizeDelta.x, borderSize);
        border.localPosition = new Vector2(border.localPosition.x, -8 - borderSize / 2);

        prevHealth = desiredHealth;
        currentHealthBefore = player.CurrentHealth;
    }

    public void DecreaseCurrentHealthBefore() => currentHealthBefore--; // Goofy ahh hack.
}