package world

import (
	"image"
	"image/color"
	"testing"

	"github.com/stretchr/testify/require"
)

type pointRadiusTheme struct {
	id     string
	radius float64
}

func (t pointRadiusTheme) ID() string   { return t.id }
func (t pointRadiusTheme) Name() string { return t.id }

func (t pointRadiusTheme) BackgroundColor() color.Color { return color.RGBA{A: 255} }
func (t pointRadiusTheme) BackgroundImage() image.Image { return nil }

func (t pointRadiusTheme) BackgroundTileMode() BackgroundTileMode     { return BackgroundTileNone }
func (t pointRadiusTheme) BackgroundScaleMode() BackgroundScaleMode   { return BackgroundScaleNone }
func (t pointRadiusTheme) BackgroundAnchorMode() BackgroundAnchorMode { return BackgroundAnchorWorld }

func (t pointRadiusTheme) PointStyle() Style {
	return Style{FillColor: color.RGBA{A: 255}, PointRadiusPx: t.radius}
}
func (t pointRadiusTheme) LineStyle() Style {
	return Style{StrokeColor: color.RGBA{A: 255}, StrokeWidthPx: 1}
}
func (t pointRadiusTheme) CircleStyle() Style {
	return Style{FillColor: color.RGBA{A: 255}, StrokeColor: color.RGBA{A: 255}, StrokeWidthPx: 1}
}

func (t pointRadiusTheme) PointClassOverride(PointClassID) (StyleOverride, bool) {
	return StyleOverride{}, false
}
func (t pointRadiusTheme) LineClassOverride(LineClassID) (StyleOverride, bool) {
	return StyleOverride{}, false
}
func (t pointRadiusTheme) CircleClassOverride(CircleClassID) (StyleOverride, bool) {
	return StyleOverride{}, false
}

func TestRender_ThemeChange_AppliesWithoutReindex_UsesLatestObjectStyles(t *testing.T) {
	t.Parallel()

	w := NewWorld(10, 10)

	// Build index once.
	w.IndexOnViewportChange(100, 100, 1.0)

	// Theme A: point radius 2
	w.SetTheme(pointRadiusTheme{id: "A", radius: 2})

	_, err := w.AddPoint(5, 5)
	require.NoError(t, err)

	// Ensure the point is actually present in grid (it will be, because Add triggers rebuild via index state).
	// Render once.
	params := RenderParams{
		ViewportWidthPx:  100,
		ViewportHeightPx: 100,
		MarginXPx:        0,
		MarginYPx:        0,
		CameraXWorldFp:   5 * SCALE,
		CameraYWorldFp:   5 * SCALE,
		CameraZoom:       1.0,
	}

	d1 := &fakePrimitiveDrawer{}
	require.NoError(t, w.Render(d1, params))

	p1 := d1.CommandsByName("AddPoint")
	require.NotEmpty(t, p1)
	r1 := p1[0].Args[2]
	require.Equal(t, 2.0, r1)

	// Theme B: point radius 7. Change theme, but DO NOT reindex.
	w.SetTheme(pointRadiusTheme{id: "B", radius: 7})

	d2 := &fakePrimitiveDrawer{}
	require.NoError(t, w.Render(d2, params))

	p2 := d2.CommandsByName("AddPoint")
	require.NotEmpty(t, p2)
	r2 := p2[0].Args[2]
	require.Equal(t, 7.0, r2)
}