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

[ExecuteInEditMode]
public class VerticalText : BaseMeshEffect
{

	[Tooltip("字和字之间的距离")]
	public float spacing = 1;
	public float lineSpacing = 1;
	public float textSpacing = 1;
	public float xOffset = 0;
	public float yOffset = 0;

	public override void ModifyMesh(VertexHelper helper)
	{
		if (!IsActive())
			return;

		List<UIVertex> verts = new List<UIVertex>();
		helper.GetUIVertexStream(verts);

		Text text = GetComponent<Text>();

		TextGenerator tg = text.cachedTextGenerator;

		lineSpacing = text.fontSize * text.lineSpacing;
		textSpacing = text.fontSize * spacing;

		xOffset = text.rectTransform.sizeDelta.x / 2 - text.fontSize / 2;
		yOffset = text.rectTransform.sizeDelta.y / 2 - text.fontSize / 2;

		List<UILineInfo> lines = new List<UILineInfo>();
		tg.GetLines(lines);

		for (int i = 0; i < lines.Count; i++)
		{
			UILineInfo line = lines[i];

			int step = i;
			if (i + 1 < lines.Count)
			{
				UILineInfo line2 = lines[i + 1];

				int current = 0;

				for (int j = line.startCharIdx; j < line2.startCharIdx - 1; j++)
				{
					ModifyText(helper, j, current++, step);
				}
			}
			else if (i + 1 == lines.Count)
			{
				int current = 0;
				for (int j = line.startCharIdx; j < tg.characterCountVisible; j++)
				{
					ModifyText(helper, j, current++, step);
				}
			}
		}
	}

	void ModifyText(VertexHelper helper, int i, int charYPos, int charXPos)
	{
		UIVertex lb = new UIVertex();
		helper.PopulateUIVertex(ref lb, i * 4);

		UIVertex lt = new UIVertex();
		helper.PopulateUIVertex(ref lt, i * 4 + 1);

		UIVertex rt = new UIVertex();
		helper.PopulateUIVertex(ref rt, i * 4 + 2);

		UIVertex rb = new UIVertex();
		helper.PopulateUIVertex(ref rb, i * 4 + 3);

		Vector3 center = Vector3.Lerp(lb.position, rt.position, 0.5f);
		Matrix4x4 move = Matrix4x4.TRS(-center, Quaternion.identity, Vector3.one);

		float x = -charXPos * lineSpacing + xOffset;
		float y = -charYPos * textSpacing + yOffset;

		Vector3 pos = new Vector3(x, y, 0);
		Matrix4x4 place = Matrix4x4.TRS(pos, Quaternion.identity, Vector3.one);
		Matrix4x4 transform = place * move;

		lb.position = transform.MultiplyPoint(lb.position);
		lt.position = transform.MultiplyPoint(lt.position);
		rt.position = transform.MultiplyPoint(rt.position);
		rb.position = transform.MultiplyPoint(rb.position);

		helper.SetUIVertex(lb, i * 4);
		helper.SetUIVertex(lt, i * 4 + 1);
		helper.SetUIVertex(rt, i * 4 + 2);
		helper.SetUIVertex(rb, i * 4 + 3);
	}
}