## T-1120: tests for AtlasViewer's public view-transform API (set_view() /
## get_view_offset(), paired with the pre-existing get_view_zoom()).
##
## Added for the Atlas screenshot capture matrix harness, which needs to set
## deterministic zoom/pan without simulating mouse wheel events against
## viewer internals (_view_zoom/_view_offset were previously private-only,
## review flagged reaching into them from visual_capture.gd as the wrong
## layer to poke at — this is the public surface instead).
class_name TestAtlasViewApi
extends GdUnitTestSuite


func test_set_view_applies_zoom_and_offset() -> void:
	var v: AtlasViewer = auto_free(AtlasViewer.new())
	add_child(v)  # _canvas resolves in _ready(); a bare .new() crashes _apply_transform
	v.set_view(3.0, Vector2(100.0, -40.0))
	assert_that(v.get_view_zoom()).is_equal_approx(3.0, 0.001)
	assert_that(v.get_view_offset()).is_equal(Vector2(100.0, -40.0))


## MIN_ZOOM/MAX_ZOOM are 0.5/8.0 (atlas_viewer.gd) — set_view() must clamp the
## same way _zoom_at()/_fit_to_view() do, so a caller can't push the view into
## a range the rest of the viewer doesn't expect.
func test_set_view_clamps_zoom_to_min_max() -> void:
	var v: AtlasViewer = auto_free(AtlasViewer.new())
	add_child(v)

	v.set_view(0.01, Vector2.ZERO)
	assert_that(v.get_view_zoom()).is_equal_approx(AtlasViewer.MIN_ZOOM, 0.001)

	v.set_view(1000.0, Vector2.ZERO)
	assert_that(v.get_view_zoom()).is_equal_approx(AtlasViewer.MAX_ZOOM, 0.001)


## Getter round-trip: what set_view() writes is exactly what get_view_zoom()/
## get_view_offset() read back (within the clamp), across a few values —
## guards against an off-by-transform bug (e.g. accidentally reading
## _canvas.scale/_canvas.position instead of the cached _view_zoom/_view_offset).
func test_view_getters_round_trip_after_set_view() -> void:
	var v: AtlasViewer = auto_free(AtlasViewer.new())
	add_child(v)

	var cases: Array = [
		[1.0, Vector2.ZERO],
		[2.0, Vector2(50.0, 25.0)],
		[4.0, Vector2(-200.0, 300.0)],
		[AtlasViewer.MIN_ZOOM, Vector2(10.0, 10.0)],
		[AtlasViewer.MAX_ZOOM, Vector2(-10.0, -10.0)],
	]
	for c: Array in cases:
		var zoom: float = c[0]
		var offset: Vector2 = c[1]
		v.set_view(zoom, offset)
		assert_that(v.get_view_zoom()).override_failure_message(
			"zoom round-trip failed for input %.2f" % zoom
		).is_equal_approx(zoom, 0.001)
		assert_that(v.get_view_offset()).override_failure_message(
			"offset round-trip failed for input %s" % offset
		).is_equal(offset)


## set_view() must drive the same _canvas transform _apply_transform() drives
## for mouse-wheel zoom/drag pan — otherwise the harness would set state the
## getters report correctly but the viewport never actually renders.
func test_set_view_updates_canvas_transform() -> void:
	var v: AtlasViewer = auto_free(AtlasViewer.new())
	add_child(v)
	v.set_view(2.5, Vector2(15.0, -5.0))
	var canvas: Node2D = v.get_node("AtlasCanvas")
	assert_that(canvas.scale).is_equal(Vector2(2.5, 2.5))
	assert_that(canvas.position).is_equal(Vector2(15.0, -5.0))