package world

import (
	"testing"

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

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

	w := NewWorld(10, 10)
	w.resetGrid(2 * SCALE)

	// Same tile. Priorities deliberately mixed.
	_, err := w.AddCircle(5, 5, 1, CircleWithPriority(500))
	require.NoError(t, err)

	_, err = w.AddLine(1, 5, 9, 5, LineWithPriority(100))
	require.NoError(t, err)

	_, err = w.AddPoint(5, 6, PointWithPriority(300))
	require.NoError(t, err)

	for _, obj := range w.objects {
		w.indexObject(obj)
	}

	params := RenderParams{
		ViewportWidthPx:  10,
		ViewportHeightPx: 10,
		MarginXPx:        0,
		MarginYPx:        0,
		CameraXWorldFp:   5 * SCALE,
		CameraYWorldFp:   5 * SCALE,
		CameraZoom:       1.0,
		Options:          &RenderOptions{
			// default: wrap on
		},
	}

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

	// We verify the first occurrence of each primitive kind follows priority order.
	// Since each object is drawn with Add* + Fill/Stroke immediately, order should match.
	cmds := d.Commands()
	firstLine := indexOfFirst(cmds, "AddLine")
	firstCircle := indexOfFirst(cmds, "AddCircle")
	firstPoint := indexOfFirst(cmds, "AddPoint")

	require.NotEqual(t, -1, firstLine)
	require.NotEqual(t, -1, firstCircle)
	require.NotEqual(t, -1, firstPoint)

	require.Less(t, firstLine, firstPoint)
	require.Less(t, firstPoint, firstCircle) // 300 before 500
}

func indexOfFirst(cmds []fakeDrawerCommand, name string) int {
	for i, c := range cmds {
		if c.Name == name {
			return i
		}
	}
	return -1
}