## T-1138 (D-226 T-1124 amendment §5 entry revision): tests for the planetary
## AtlasViewer's click-through descent — the fixed view (no drag-pan/wheel-
## zoom), the pixel-to-DistrictPos inverse mapping (atlas_descend_geometry.gd),
## and the city-click-wins disambiguation rule.
class_name TestAtlasDescendEntry
extends GdUnitTestSuite

const AtlasDescendGeometry := preload("res://ui/implant/apps/atlas/atlas_descend_geometry.gd")


# =============================================================================
# atlas_descend_geometry.gd — pure geometry (no scene tree needed)
# =============================================================================


## The default n=32 window's real footprint is 32 * 2.048 km = 65.536 km, so
## the label reads "~66 x 66 km" (rounded) — pins the number the amendment's
## "honest labeling" resolution depends on.
func test_reticle_label_extent_matches_district_window_default_n() -> void:
	var label: Dictionary = AtlasDescendGeometry.reticle_label(Vector2(100.0, 100.0))
	var expected_km: float = 32.0 * 2048.0 / 1000.0
	assert_str(label["text"]).is_equal("~%.0f × %.0f km" % [expected_km, expected_km])


func test_reticle_label_position_offsets_from_center() -> void:
	var center := Vector2(50.0, 60.0)
	var label: Dictionary = AtlasDescendGeometry.reticle_label(center)
	var pos: Vector2 = label["position"]
	assert_float(pos.x).is_greater(center.x)  # offset to the right, per §5's resolution


## Eight segments (four L-shaped bracket corners, two arms each) — every
## segment's "from" endpoint is exactly one of the four corner anchors, and no
## segment has zero length (a degenerate reticle would be invisible).
func test_reticle_segments_has_eight_nonzero_segments() -> void:
	var segments: Array = AtlasDescendGeometry.reticle_segments(Vector2(200.0, 150.0))
	assert_int(segments.size()).is_equal(8)
	for seg: Array in segments:
		assert_that(seg[0]).override_failure_message(
			"a reticle segment must not be zero-length"
		).is_not_equal(seg[1])


## The reticle's overall bounding box is centered on `center` and sized by
## DESCEND_RETICLE_SIZE — a regression guard against an off-center or
## mis-scaled bracket.
func test_reticle_segments_centered_on_input_point() -> void:
	var center := Vector2(300.0, 300.0)
	var segments: Array = AtlasDescendGeometry.reticle_segments(center)
	var min_pt := Vector2(INF, INF)
	var max_pt := Vector2(-INF, -INF)
	for seg: Array in segments:
		for p: Vector2 in seg:
			min_pt.x = minf(min_pt.x, p.x)
			min_pt.y = minf(min_pt.y, p.y)
			max_pt.x = maxf(max_pt.x, p.x)
			max_pt.y = maxf(max_pt.y, p.y)
	var bbox_center: Vector2 = (min_pt + max_pt) * 0.5
	assert_float(bbox_center.x).is_equal_approx(center.x, 0.01)
	assert_float(bbox_center.y).is_equal_approx(center.y, 0.01)


# =============================================================================
# district_pos_at — pixel-to-DistrictPos inverse mapping
# =============================================================================


## No radius (tiny test body fallback, matches the server's own derive_district
## fallback): the district grid IS the heightmap grid 1:1, so a canvas point
## maps to the nearest integer district coordinate directly.
func test_district_pos_at_no_radius_is_1to1_pixel_mapping() -> void:
	var pos: Vector2i = AtlasDescendGeometry.district_pos_at(
		Vector2(12.4, 7.6), 100.0, 100.0, 0.0
	)
	assert_that(pos).is_equal(Vector2i(12, 8))


func test_district_pos_at_zero_texture_size_is_safe() -> void:
	var pos: Vector2i = AtlasDescendGeometry.district_pos_at(Vector2(10.0, 10.0), 0.0, 0.0, 6371.0)
	assert_that(pos).is_equal(Vector2i.ZERO)


## The equatorial center of the texture (px = tex_w/2) is district column
## district_cols/2 on a body with a radius (equator wraps at district (0,0)
## per the server's own doc: "district (0,0) sits at lon 0 / the equator").
##
## The TRUE equator pixel row is `(tex_h - 1) * 0.5`, NOT `tex_h * 0.5` (PR
## #187 review, Hoshe): the server's forward map (district_profile.rs:1436)
## divides by `ta.h.saturating_sub(1)`, so row 0 and row (h-1) are the real
## clamped pole endpoints and the midpoint between them is `(h-1)/2`. This
## test originally sampled `tex_h * 0.5`, which is NOT that midpoint for any
## finite tex_h — it happened to still round to district row 0 under BOTH the
## pre-fix buggy formula and the fix, at this specific radius/tex_h pair,
## which is exactly why this equator-only sample masked the ÷tex_h bug
## instead of catching it (see the off-equator round-trip tests below for the
## real regression coverage). Corrected here to the genuine equator pixel so
## this test asserts something true about the fixed formula, not a
## coincidence of the old one.
func test_district_pos_at_center_of_texture_is_near_equator_row_zero() -> void:
	var radius_km := 6371.0
	var tex_w := 1024.0
	var tex_h := 512.0
	var true_equator_py: float = (tex_h - 1.0) * 0.5
	var pos: Vector2i = AtlasDescendGeometry.district_pos_at(
		Vector2(0.0, true_equator_py), tex_w, tex_h, radius_km
	)
	assert_int(pos.y).override_failure_message(
		"the true equator pixel ((tex_h-1)/2) must map to row 0"
	).is_equal(0)


## Panning across the texture's full width sweeps through the FULL district
## column range (not clamped to a tiny sub-range) — a coarse sanity check that
## district_cols is actually being derived from the body's circumference, not
## left at some degenerate default.
func test_district_pos_at_sweeps_full_column_range_across_texture_width() -> void:
	var radius_km := 6371.0
	var tex_w := 1024.0
	var tex_h := 512.0
	var left: Vector2i = AtlasDescendGeometry.district_pos_at(
		Vector2(0.0, tex_h * 0.5), tex_w, tex_h, radius_km
	)
	var right: Vector2i = AtlasDescendGeometry.district_pos_at(
		Vector2(tex_w - 1.0, tex_h * 0.5), tex_w, tex_h, radius_km
	)
	# An Earth-radius body has thousands of equatorial districts (circumference
	# ~40,075 km / 2.048 km per district ≈ 19,568) — near-full-width should
	# sweep a large fraction of that, not a handful of columns.
	assert_int(absi(right.x - left.x)).is_greater(1000)


# =============================================================================
# Off-equator round-trip (PR #187 review, Hoshe — BLOCKING, live-repro'd bug):
# district_pos_at's row inverse divided by tex_h instead of (tex_h - 1),
# matching the WRONG symmetry with the column inverse (which correctly
# divides by the plain tex_w, since longitude wraps and has no edge case).
# The server's forward map (district_profile.rs:1436) uses
# ta.h.saturating_sub(1) for the SAME reason the ground-truth inverse
# (aliveness_probe.rs:511, `row / (ta_h - 1) - 0.5`) does: latitude CLAMPS at
# the poles, so row 0 / row (h-1) are real endpoints the division must land
# on exactly. This class of bug — a client-side twin of a server coordinate
# mapping silently drifting out of sync — is exactly what Tyre's C2 review
# criterion requires a round-trip drift guard for; that is what every test in
# this section is. The suite previously missed it because the only
# real-radius latitude sample was py = tex_h*0.5 (test above), the ONE point
## where the buggy (÷tex_h) and correct (÷(tex_h-1)) formulas round to the
# same integer district row — never exercising the asymmetry the fix targets.
# =============================================================================


## Forward-maps a district row to its heightmap pixel row using the server's
## OWN formula, transcribed here (district_profile.rs:1436):
##   let lat_frac = (dy * DISTRICT_M / meridian_m).clamp(-0.5, 0.5);
##   let py = (0.5 + lat_frac) * ta.h.saturating_sub(1);
## `dy` is a DistrictPos.y component (not a pixel) — the caller supplies the
## same `district_rows_half`-scaled value district_pos_at()'s inverse would
## need to recover, so this function and district_pos_at() are meant to be
## exact inverses of one another for any row within the clamped range.
static func _server_forward_map_row(district_row: int, tex_h: float, radius_km: float) -> float:
	var meridian_m: float = PI * radius_km * 1000.0
	var district_m: float = AtlasDescendGeometry.DISTRICT_M
	var lat_frac: float = clampf((float(district_row) * district_m) / meridian_m, -0.5, 0.5)
	return (0.5 + lat_frac) * (tex_h - 1.0)


## The actual regression: forward-map three off-equator district rows (one
## per hemisphere, plus a near-pole extreme) to pixel rows via the server's
## transcribed formula, then assert district_pos_at() recovers each EXACT
## row from that pixel. Fails outright under the pre-fix ÷tex_h formula for
## every row here except (coincidentally) very near the equator.
func test_district_pos_at_round_trips_off_equator_rows_against_server_forward_map() -> void:
	var radius_km := 6238.4  # GJ380c (server/data/systems.db) — a real body, not a round number
	var tex_w := 1024.0
	var tex_h := 512.0
	var col := 400  # arbitrary — this test is about the row axis only

	# One row per hemisphere (moderate latitude) + one extreme near-pole row.
	# meridian_m / DISTRICT_M ≈ 9,569 for this radius, so district_rows_half
	# ≈ 4,785 — these rows sit well inside that range without saturating the
	# clamp (except the "near pole" case, deliberately close to the edge).
	var test_rows: Array = [-1200, 900, -4700]

	for district_row: int in test_rows:
		var forward_py: float = _server_forward_map_row(district_row, tex_h, radius_km)
		var recovered: Vector2i = AtlasDescendGeometry.district_pos_at(
			Vector2(float(col), forward_py), tex_w, tex_h, radius_km
		)
		assert_int(recovered.y).override_failure_message(
			(
				"row round-trip failed: district_row=%d -> forward pixel py=%.4f -> "
				+ "district_pos_at recovered row=%d (drift=%d)"
			) % [district_row, forward_py, recovered.y, recovered.y - district_row]
		).is_equal(district_row)


## Same round-trip, restated as an explicit non-equator drift guard: the
## pre-fix bug produced a WRONG but still-integer row (Hoshe's live repro:
## forward row 50, buggy inverse returned 45 — a 5-district, ~10.2 km drift)
## — a coarse "is it roughly right" tolerance would have passed that. This
## asserts EXACT equality specifically at a moderate off-equator row, not an
## approximate one, so a reintroduced ÷tex_h regression fails loudly again.
func test_district_pos_at_off_equator_row_is_not_off_by_a_few_districts() -> void:
	var radius_km := 6238.4
	var tex_w := 1024.0
	var tex_h := 512.0
	var district_row := 2500
	var forward_py: float = _server_forward_map_row(district_row, tex_h, radius_km)
	var recovered: Vector2i = AtlasDescendGeometry.district_pos_at(
		Vector2(512.0, forward_py), tex_w, tex_h, radius_km
	)
	assert_int(recovered.y).is_equal(district_row)


# =============================================================================
# AtlasViewer — fixed view (no drag-pan/wheel-zoom) + click-through descent
# =============================================================================


## T-1120 capture API (set_view/get_view_offset/get_view_zoom) must survive
## the removal of user pan/zoom — this is the ticket's own explicit note, and
## the visual-golden harness depends on it.
func test_set_view_still_works_after_pan_zoom_removal() -> void:
	var v: AtlasViewer = auto_free(AtlasViewer.new())
	add_child(v)
	v.set_view(3.0, Vector2(50.0, -20.0))
	assert_that(v.get_view_zoom()).is_equal_approx(3.0, 0.001)
	assert_that(v.get_view_offset()).is_equal(Vector2(50.0, -20.0))


## Clicking (with no heightmap loaded — the guard AtlasViewer's _gui_input
## checks first) must not emit a descend request — there is nothing to
## descend into yet.
func test_no_descend_signal_without_a_loaded_heightmap() -> void:
	var v: AtlasViewer = auto_free(AtlasViewer.new())
	add_child(v)
	var received: Array = []
	v.district_descend_requested.connect(func(c: Vector2i) -> void: received.append(c))
	# _heightmap_texture stays null (no show_body() call) — _gui_input's
	# early-return guard should prevent any click handling at all.
	var mb := InputEventMouseButton.new()
	mb.button_index = MOUSE_BUTTON_LEFT
	mb.pressed = true
	mb.position = Vector2(100.0, 100.0)
	v._gui_input(mb)
	assert_int(received.size()).is_equal(0)


## RegionalScreen forwards AtlasViewer's district_descend_requested verbatim —
## the nav-stack wiring atlas_app.gd depends on.
func test_regional_screen_forwards_district_descend_requested() -> void:
	var screen: RegionalScreen = auto_free(RegionalScreen.new())
	add_child(screen)
	var received: Array = []
	screen.district_descend_requested.connect(func(c: Vector2i) -> void: received.append(c))
	screen._viewer.district_descend_requested.emit(Vector2i(5, 7))
	assert_int(received.size()).is_equal(1)
	assert_that(received[0]).is_equal(Vector2i(5, 7))


# =============================================================================
# PR #187 review (Araminta — broken promise): the descend reticle must be
# hidden while hovering a city marker — _hovered_city already flares white as
# the "click here for city data" signal, and _try_click_city wins the click
# over descent, so drawing the reticle at the same time promised a descent
# the click would never perform. State-level tests (per the review's own
# "state-level is fine" allowance): assert _should_draw_descend_reticle()'s
# condition directly against _hover_active/_hovered_city/_heightmap_texture,
# rather than a pixel-diff on the actual draw call.
# =============================================================================


static func _one_pixel_texture() -> ImageTexture:
	var img := Image.create(1, 1, false, Image.FORMAT_RGB8)
	return ImageTexture.create_from_image(img)


## Hovering EMPTY map (no city under the cursor) -> reticle SHOWS.
func test_descend_reticle_shows_when_hovering_empty_map() -> void:
	var v: AtlasViewer = auto_free(AtlasViewer.new())
	add_child(v)
	v._heightmap_texture = _one_pixel_texture()
	v._hover_active = true
	v._hovered_city = {}
	assert_bool(v._should_draw_descend_reticle()).override_failure_message(
		"reticle must show when hovering the open map (no city under cursor)"
	).is_true()


## Hovering a CITY marker -> reticle HIDES, even though _hover_active is true
## (this is the exact bug: pre-fix, _hovered_city was never consulted here).
func test_descend_reticle_hides_when_hovering_a_city() -> void:
	var v: AtlasViewer = auto_free(AtlasViewer.new())
	add_child(v)
	v._heightmap_texture = _one_pixel_texture()
	v._hover_active = true
	v._hovered_city = {"name": "Ridgeback", "pos": [10, 20]}
	assert_bool(v._should_draw_descend_reticle()).override_failure_message(
		"reticle must hide while hovering a city — the click would open city"
		+ " data (_try_click_city wins), not descend"
	).is_false()


## Not hovering at all (_hover_active false) -> reticle HIDES regardless of
## _hovered_city — the pre-existing base condition, guarded here so the city
## fix can't accidentally invert it.
func test_descend_reticle_hides_when_not_hovering() -> void:
	var v: AtlasViewer = auto_free(AtlasViewer.new())
	add_child(v)
	v._heightmap_texture = _one_pixel_texture()
	v._hover_active = false
	v._hovered_city = {}
	assert_bool(v._should_draw_descend_reticle()).is_false()