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

// 主相机
[ExecuteAlways]
public class MainCamera : SingletonMB<MainCamera>
{
	#region inspector
	[Serializable]
	public struct Region
	{
		[SerializeField] public float l;
		[SerializeField] public float r;
		[SerializeField] public float t;
		[SerializeField] public float b;
	}

	public new Camera camera { get; private set; }

    public Vector3 offset = Vector3.zero;

	[SerializeField] private float z;

	[SerializeField] private Region region;

	[SerializeField] private float moveSpeed;

	[SerializeField] private AnimationCurve speedCurve;

	[SerializeField] private float threshold;
	#endregion

	private LensEffectHandler m_LensEffectHandler;
	public LensEffectHandler lensEffectHandler
	{
		get
		{
			if (m_LensEffectHandler == null)
				m_LensEffectHandler = this.gameObject.GetOrAddComponent<LensEffectHandler>();
			return m_LensEffectHandler;
		}
	}

	private Vector2 position2D
	{
		get
		{
			return transform.position;
		}
		set
		{
			transform.position = new Vector3(value.x, value.y, transform.position.z);
		}
	}

	private Vector3 position
	{
		get
		{
			return transform.position;
		}
		set
		{
			transform.position = value;
		}
	}

	protected override void Awake()
    {
        base.Awake();
        camera = gameObject.GetComponent<Camera>();
    }

	private void Start()
	{
		Vector3 pos = transform.position;
		pos.z = this.z;
		transform.position = pos;

		Quaternion rot = Quaternion.LookRotation(Vector3.forward);
		transform.rotation = rot;
	}

	void FollowPlayerCharacter()
	{
		if (UnitManager.Instance == null || UnitManager.Instance.pc == null)
			return;

		Region region = this.region;

		//if (!UnitManager.Instance.pc.isTowardRight)
		//{
		//	region.l = -this.region.r;
		//	region.r = -this.region.l;
		//}

		Vector3 camPos = position;

		Vector3 worldPos = UnitManager.Instance.pc.transform.position + offset;

		Vector2 viewPos = ((Vector2)camera.WorldToViewportPoint(worldPos)) * 2 - Vector2.one;

		Vector3 dir = (worldPos - camPos).normalized;
		float dest = (worldPos - camPos).magnitude;
		float curve = speedCurve.Evaluate((threshold - Mathf.Clamp(dest, 0f, threshold)) / threshold);
		Vector3 move = curve * dir * moveSpeed * Time.deltaTime;

		if (IsInRegion(viewPos, region))
		{
			if(!IsInCenter(viewPos))
			{
				position2D = camPos + move;
				if((worldPos - position).magnitude <= 0.1f)
				{
					position2D = worldPos;
				}
			}
			return;
		}
		position2D = camPos + move;
		if ((worldPos - position).magnitude <= 0.1f)
		{
			position2D = worldPos;
		}
	}

	bool IsInRegion(Vector2 p, Region region)
	{
		return p.x > region.l
			&& p.x < region.r
			&& p.y > region.b
			&& p.y < region.t;
	}

	bool IsInCenter(Vector2 p)
	{
		return p.x == (region.l + region.r) / 2 && p.y == (region.t + region.b) / 2;
	}

	void Update()
    {
		FollowPlayerCharacter();
    }

	public void OnGUI()
	{
		if(MainCameraDebug.OnGUIHandlers != null)
			MainCameraDebug.OnGUIHandlers.Invoke();
	}

}