package alui

import (
	"opslag.de/schobers/geom"
)

var _ Control = &Margins{}

type Margins struct {
	Proxy

	Top, Left, Bottom, Right float32

	bounds geom.RectangleF32
}

func NewMargins(target Control, margins ...float32) *Margins {
	m := &Margins{Proxy: Proxy{Target: target}}
	switch len(margins) {
	case 1:
		m.Top, m.Left, m.Bottom, m.Right = margins[0], margins[0], margins[0], margins[0]
	case 2:
		m.Top, m.Left, m.Bottom, m.Right = margins[0], margins[1], margins[0], margins[1]
	case 3:
		m.Top, m.Left, m.Bottom, m.Right = margins[0], margins[1], margins[2], margins[1]
	case 4:
		m.Top, m.Left, m.Bottom, m.Right = margins[0], margins[1], margins[2], margins[3]
	default:
		panic("expected 1 (all same), 2 (vertical, horizontal), 3 (top, horizontal, bottom) or 4 margins (all separately specified)")
	}
	return m
}

func (m *Margins) Bounds() geom.RectangleF32 { return m.bounds }

func (m *Margins) DesiredSize(ctx *Context) geom.PointF32 {
	return m.Proxy.DesiredSize(ctx).Add2D(m.Left+m.Right, m.Top+m.Bottom)
}

func (m *Margins) inset(bounds geom.RectangleF32) geom.RectangleF32 {
	return geom.RectF32(bounds.Min.X+m.Left, bounds.Min.Y+m.Top, bounds.Max.X-m.Right, bounds.Max.Y-m.Bottom)
}

func (m *Margins) Layout(ctx *Context, bounds geom.RectangleF32) {
	m.bounds = bounds
	target := m.inset(bounds)
	m.Proxy.Layout(ctx, target)
}

func (m *Margins) Render(ctx *Context, bounds geom.RectangleF32) {
	target := m.inset(bounds)
	m.Proxy.Render(ctx, target)
}