package world

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

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

type testTheme struct{}

func (testTheme) ID() string   { return "t1" }
func (testTheme) Name() string { return "Theme1" }

func (testTheme) BackgroundColor() color.Color { return color.RGBA{R: 1, G: 2, B: 3, A: 255} }
func (testTheme) BackgroundImage() image.Image { return nil }

func (testTheme) BackgroundTileMode() BackgroundTileMode     { return BackgroundTileRepeat }
func (testTheme) BackgroundScaleMode() BackgroundScaleMode   { return BackgroundScaleNone }
func (testTheme) BackgroundAnchorMode() BackgroundAnchorMode { return BackgroundAnchorWorld }
func (testTheme) PointClassOverride(PointClassID) (StyleOverride, bool) {
	return StyleOverride{}, false
}
func (testTheme) LineClassOverride(LineClassID) (StyleOverride, bool) { return StyleOverride{}, false }
func (testTheme) CircleClassOverride(CircleClassID) (StyleOverride, bool) {
	return StyleOverride{}, false
}

func (testTheme) PointStyle() Style {
	return Style{
		FillColor:        color.RGBA{R: 9, A: 255},
		StrokeColor:      nil,
		StrokeWidthPx:    0,
		StrokeDashes:     nil,
		StrokeDashOffset: 0,
		PointRadiusPx:    4,
	}
}
func (testTheme) LineStyle() Style {
	return Style{
		FillColor:        nil,
		StrokeColor:      color.RGBA{G: 9, A: 255},
		StrokeWidthPx:    3,
		StrokeDashes:     []float64{2, 2},
		StrokeDashOffset: 1,
		PointRadiusPx:    0,
	}
}
func (testTheme) CircleStyle() Style {
	return Style{
		FillColor:        color.RGBA{B: 9, A: 255},
		StrokeColor:      color.RGBA{A: 255},
		StrokeWidthPx:    2,
		StrokeDashes:     nil,
		StrokeDashOffset: 0,
		PointRadiusPx:    0,
	}
}

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

	w := NewWorld(10, 10)

	// Built-ins should remain stable (1/2/3).
	require.Equal(t, StyleIDDefaultLine, StyleID(1))
	require.Equal(t, StyleIDDefaultCircle, StyleID(2))
	require.Equal(t, StyleIDDefaultPoint, StyleID(3))

	// Set a custom theme.
	w.SetTheme(testTheme{})

	// Theme defaults should NOT be built-in IDs anymore.
	require.NotEqual(t, StyleIDDefaultLine, w.themeDefaultLineStyleID)
	require.NotEqual(t, StyleIDDefaultCircle, w.themeDefaultCircleStyleID)
	require.NotEqual(t, StyleIDDefaultPoint, w.themeDefaultPointStyleID)

	ls, ok := w.styles.Get(w.themeDefaultLineStyleID)
	require.True(t, ok)
	require.Equal(t, 3.0, ls.StrokeWidthPx)
	require.Equal(t, []float64{2, 2}, ls.StrokeDashes)
	require.Equal(t, 1.0, ls.StrokeDashOffset)

	cs, ok := w.styles.Get(w.themeDefaultCircleStyleID)
	require.True(t, ok)
	require.Equal(t, 2.0, cs.StrokeWidthPx)

	ps, ok := w.styles.Get(w.themeDefaultPointStyleID)
	require.True(t, ok)
	require.Equal(t, 4.0, ps.PointRadiusPx)
}

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

	w := NewWorld(10, 10)
	w.SetTheme(testTheme{})

	// Minimal index.
	w.resetGrid(2 * SCALE)

	params := RenderParams{
		ViewportWidthPx:  10,
		ViewportHeightPx: 10,
		MarginXPx:        0,
		MarginYPx:        0,
		CameraXWorldFp:   5 * SCALE,
		CameraYWorldFp:   5 * SCALE,
		CameraZoom:       1.0,
	}

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

	// Should clear with theme background color via ClearAllTo(bg).
	require.NotEmpty(t, d.CommandsByName("ClearAllTo"))
}

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

	w := NewWorld(10, 10)
	w.SetTheme(testTheme{})

	w.resetGrid(2 * SCALE)

	params := RenderParams{
		ViewportWidthPx:  10,
		ViewportHeightPx: 10,
		MarginXPx:        0,
		MarginYPx:        0,
		CameraXWorldFp:   5 * SCALE,
		CameraYWorldFp:   5 * SCALE,
		CameraZoom:       1.0,
		Options: &RenderOptions{
			BackgroundColor: color.RGBA{R: 200, A: 255},
		},
	}

	d := &fakePrimitiveDrawer{}
	require.NoError(t, w.Render(d, params))
	require.NotEmpty(t, d.CommandsByName("ClearAllTo"))
}