## T-1182 tests: step_canvas_cache.gd — the client-side in-memory LRU cache
## for decoded step-canvas payloads. Keyed on (body_id, rung, center, extent,
## min_wl_m), the exact tuple server/src/atlas/step_canvas.rs's own
## StepCanvasCache keys on. Mirrors test_atlas_window_cache.gd's own
## conventions (the surviving LRU shape this file is adapted from).
class_name TestStepCanvasCache
extends GdUnitTestSuite

const StepCanvasCache := preload("res://ui/implant/apps/atlas/step_canvas/step_canvas_cache.gd")


func test_make_key_distinguishes_body_rung_center_and_extent() -> void:
	var k1 := StepCanvasCache.make_key("GJ1c", "District", Vector2i(10, 20), Vector2i(64, 64))
	var k2 := StepCanvasCache.make_key("GJ1d", "District", Vector2i(10, 20), Vector2i(64, 64))
	var k3 := StepCanvasCache.make_key("GJ1c", "Chunk", Vector2i(10, 20), Vector2i(64, 64))
	var k4 := StepCanvasCache.make_key("GJ1c", "District", Vector2i(11, 20), Vector2i(64, 64))
	var k5 := StepCanvasCache.make_key("GJ1c", "District", Vector2i(10, 20), Vector2i(32, 32))
	assert_str(k1).is_not_equal(k2)
	assert_str(k1).is_not_equal(k3)
	assert_str(k1).is_not_equal(k4)
	assert_str(k1).is_not_equal(k5)


## Global collapses center/extent to a fixed sentinel regardless of what's
## passed — every Global request for the same body_id must land on ONE slot.
func test_make_key_global_ignores_center_and_extent() -> void:
	var k1 := StepCanvasCache.make_key("GJ1c", "Global", Vector2i(10, 20), Vector2i(64, 64))
	var k2 := StepCanvasCache.make_key("GJ1c", "Global", Vector2i(999, -999), Vector2i(1, 1))
	assert_str(k1).is_equal(k2)


func test_miss_returns_null_and_has_reports_false() -> void:
	var cache := StepCanvasCache.new()
	assert_that(cache.get_canvas("GJ1c", "District", Vector2i.ZERO, Vector2i(64, 64))).is_null()
	assert_bool(cache.has("GJ1c", "District", Vector2i.ZERO, Vector2i(64, 64))).is_false()


func test_put_then_get_round_trips_exact_canvas() -> void:
	var cache := StepCanvasCache.new()
	var canvas := {"width": 64, "height": 64}
	cache.put("GJ1c", "District", Vector2i(10, 20), Vector2i(64, 64), canvas)
	assert_bool(cache.has("GJ1c", "District", Vector2i(10, 20), Vector2i(64, 64))).is_true()
	assert_that(cache.get_canvas("GJ1c", "District", Vector2i(10, 20), Vector2i(64, 64))).is_equal(
		canvas
	)


## D-227: a canvas fetched once is valid FOREVER for that exact key — no
## expiry, no invalidation path.
func test_cached_canvas_never_expires() -> void:
	var cache := StepCanvasCache.new()
	var canvas := {"width": 1}
	cache.put("GJ1c", "Chunk", Vector2i.ZERO, Vector2i(1, 1), canvas)
	for _i in range(50):
		assert_that(cache.get_canvas("GJ1c", "Chunk", Vector2i.ZERO, Vector2i(1, 1))).is_equal(canvas)


func test_different_rungs_at_identical_center_extent_do_not_collide() -> void:
	var cache := StepCanvasCache.new()
	var district_canvas := {"rung": "District"}
	var chunk_canvas := {"rung": "Chunk"}
	cache.put("GJ1c", "District", Vector2i(10, 20), Vector2i(64, 64), district_canvas)
	cache.put("GJ1c", "Chunk", Vector2i(10, 20), Vector2i(64, 64), chunk_canvas)
	assert_int(cache.size()).is_equal(2)
	assert_that(cache.get_canvas("GJ1c", "District", Vector2i(10, 20), Vector2i(64, 64))).is_equal(
		district_canvas
	)
	assert_that(cache.get_canvas("GJ1c", "Chunk", Vector2i(10, 20), Vector2i(64, 64))).is_equal(
		chunk_canvas
	)


func test_put_overwrites_existing_key() -> void:
	var cache := StepCanvasCache.new()
	cache.put("GJ1c", "District", Vector2i.ZERO, Vector2i(64, 64), {"v": 1})
	cache.put("GJ1c", "District", Vector2i.ZERO, Vector2i(64, 64), {"v": 2})
	assert_int(cache.size()).is_equal(1)
	assert_that(cache.get_canvas("GJ1c", "District", Vector2i.ZERO, Vector2i(64, 64))).is_equal(
		{"v": 2}
	)


func test_eviction_drops_least_recently_used_on_overflow() -> void:
	var cache := StepCanvasCache.new(2)
	cache.put("GJ1c", "District", Vector2i(0, 0), Vector2i(64, 64), {"id": "a"})
	cache.put("GJ1c", "District", Vector2i(1, 0), Vector2i(64, 64), {"id": "b"})
	cache.put("GJ1c", "District", Vector2i(2, 0), Vector2i(64, 64), {"id": "c"})

	assert_int(cache.size()).is_equal(2)
	assert_bool(cache.has("GJ1c", "District", Vector2i(0, 0), Vector2i(64, 64))).override_failure_message(
		"oldest entry should have been evicted"
	).is_false()
	assert_bool(cache.has("GJ1c", "District", Vector2i(2, 0), Vector2i(64, 64))).is_true()


func test_get_touches_entry_and_protects_it_from_eviction() -> void:
	var cache := StepCanvasCache.new(2)
	cache.put("GJ1c", "District", Vector2i(0, 0), Vector2i(64, 64), {"id": "a"})
	cache.put("GJ1c", "District", Vector2i(1, 0), Vector2i(64, 64), {"id": "b"})
	cache.get_canvas("GJ1c", "District", Vector2i(0, 0), Vector2i(64, 64))
	cache.put("GJ1c", "District", Vector2i(2, 0), Vector2i(64, 64), {"id": "c"})

	assert_bool(cache.has("GJ1c", "District", Vector2i(0, 0), Vector2i(64, 64))).override_failure_message(
		"touched entry should survive eviction"
	).is_true()
	assert_bool(cache.has("GJ1c", "District", Vector2i(1, 0), Vector2i(64, 64))).override_failure_message(
		"untouched entry should be the one evicted"
	).is_false()


func test_max_entries_clamped_to_at_least_one() -> void:
	var cache := StepCanvasCache.new(0)
	cache.put("GJ1c", "District", Vector2i(0, 0), Vector2i(64, 64), {"id": "a"})
	cache.put("GJ1c", "District", Vector2i(1, 0), Vector2i(64, 64), {"id": "b"})
	assert_int(cache.size()).is_equal(1)


func test_clear_empties_the_cache() -> void:
	var cache := StepCanvasCache.new()
	cache.put("GJ1c", "District", Vector2i.ZERO, Vector2i(64, 64), {"id": "a"})
	cache.clear()
	assert_int(cache.size()).is_equal(0)
	assert_bool(cache.has("GJ1c", "District", Vector2i.ZERO, Vector2i(64, 64))).is_false()