package world

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

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

const (
	testPointClassExtended  PointClassID  = 1
	testCircleClassExtended CircleClassID = 1
)

type classThemeA struct{}

func (classThemeA) ID() string                                 { return "classA" }
func (classThemeA) Name() string                               { return "classA" }
func (classThemeA) BackgroundColor() color.Color               { return color.RGBA{A: 255} }
func (classThemeA) BackgroundImage() image.Image               { return nil }
func (classThemeA) BackgroundTileMode() BackgroundTileMode     { return BackgroundTileNone }
func (classThemeA) BackgroundScaleMode() BackgroundScaleMode   { return BackgroundScaleNone }
func (classThemeA) BackgroundAnchorMode() BackgroundAnchorMode { return BackgroundAnchorWorld }

func (classThemeA) PointStyle() Style {
	return Style{FillColor: color.RGBA{R: 10, A: 255}, PointRadiusPx: 2}
}
func (classThemeA) LineStyle() Style {
	return Style{StrokeColor: color.RGBA{G: 10, A: 255}, StrokeWidthPx: 1}
}
func (classThemeA) CircleStyle() Style {
	return Style{FillColor: color.RGBA{B: 10, A: 255}, StrokeColor: color.RGBA{A: 255}, StrokeWidthPx: 1}
}

func (classThemeA) PointClassOverride(c PointClassID) (StyleOverride, bool) {
	if c == testPointClassExtended {
		r := 6.0
		return StyleOverride{PointRadiusPx: &r}, true
	}
	return StyleOverride{}, false
}
func (classThemeA) LineClassOverride(LineClassID) (StyleOverride, bool) {
	return StyleOverride{}, false
}
func (classThemeA) CircleClassOverride(c CircleClassID) (StyleOverride, bool) {
	if c == testCircleClassExtended {
		w := 3.0
		return StyleOverride{StrokeWidthPx: &w}, true
	}
	return StyleOverride{}, false
}

type classThemeB struct{ classThemeA }

func (classThemeB) ID() string   { return "classB" }
func (classThemeB) Name() string { return "classB" }
func (classThemeB) PointStyle() Style {
	return Style{FillColor: color.RGBA{R: 99, A: 255}, PointRadiusPx: 3}
}
func (classThemeB) CircleStyle() Style {
	return Style{FillColor: color.RGBA{B: 99, A: 255}, StrokeColor: color.RGBA{A: 255}, StrokeWidthPx: 2}
}

func (classThemeB) PointClassOverride(c PointClassID) (StyleOverride, bool) {
	if c == testPointClassExtended {
		r := 9.0
		return StyleOverride{PointRadiusPx: &r}, true
	}
	return StyleOverride{}, false
}

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

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

	id, err := w.AddPoint(1, 1, PointWithClass(testPointClassExtended))
	require.NoError(t, err)

	p := w.objects[id].(Point)
	s1, ok := w.styles.Get(p.StyleID)
	require.True(t, ok)
	require.Equal(t, 6.0, s1.PointRadiusPx)

	w.SetTheme(classThemeB{})

	p2 := w.objects[id].(Point)
	s2, ok := w.styles.Get(p2.StyleID)
	require.True(t, ok)
	require.Equal(t, 9.0, s2.PointRadiusPx)
}

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

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

	// class would set point radius to 6, but user override sets it to 12.
	rUser := 12.0
	id, err := w.AddPoint(1, 1,
		PointWithClass(testPointClassExtended),
		PointWithStyleOverride(StyleOverride{PointRadiusPx: &rUser}),
	)
	require.NoError(t, err)

	p := w.objects[id].(Point)
	s1, ok := w.styles.Get(p.StyleID)
	require.True(t, ok)
	require.Equal(t, 12.0, s1.PointRadiusPx)

	// After theme change, class would set to 9, but user override must still win.
	w.SetTheme(classThemeB{})
	p2 := w.objects[id].(Point)
	s2, ok := w.styles.Get(p2.StyleID)
	require.True(t, ok)
	require.Equal(t, 12.0, s2.PointRadiusPx)
}