"""R4-1 — intrinsic shading integration certification (CI-safe: fake model,
no torch).

build_intrinsic_shade_map is fed a synthetic scene with a KNOWN decomposition:
a checker/stripe albedo (the old floor's pattern — must NOT transfer) times a
smooth linear shading field (a daylight gradient + a soft contact shadow —
MUST transfer). The intrinsic.pipeline module is faked in sys.modules to
return the ground-truth shading, so what's certified is the integration:
key handling, inverse-encoding decode, boundary fill, linear->display
conversion, normalisation, encoding, and every fallback path.

Checks:
  1. engages on a clean scene and reproduces the display-space shading on the
     floor interior (the lighting survives)
  2. albedo-blind: the checker pattern's contrast does not reach the output
     (the artifact class N3 patched — patterns, any orientation — is dead
     by construction)
  3. boundary-safe: bright non-floor shading (furniture) does not halo into
     the floor edge band (the desk/curtain light-leak)
  4. inverse-shading key ('inv_shd') is decoded, not used raw
  5. fallbacks: no model / pipeline raises / no shading key / empty mask
     all return (None, default) so the caller falls back to the heuristic
"""

import sys
import types

import cv2
import numpy as np

H, W = 480, 640
GAMMA = 2.2

# --- fake intrinsic.pipeline BEFORE extracting app code ----------------------
_fake_results = {}


def _fake_run_pipeline(models, img, device=None):
    if isinstance(_fake_results.get("exc"), Exception):
        raise _fake_results["exc"]
    return dict(_fake_results)


_pkg = types.ModuleType("intrinsic")
_mod = types.ModuleType("intrinsic.pipeline")
_mod.run_pipeline = _fake_run_pipeline
_pkg.pipeline = _mod
sys.modules["intrinsic"] = _pkg
sys.modules["intrinsic.pipeline"] = _mod

# --- real implementations from app.py ----------------------------------------
src = open("app.py").read()
ns = {"np": np, "cv2": cv2, "intrinsic_models": object(), "device": "cpu"}
for fn in ["_adaptive_shade_range", "_encode_shade", "repair_intrinsic_floor_shading", "build_intrinsic_shade_map"]:
    start = src.index(f"def {fn}")
    end = src.index("\ndef ", start + 10)
    exec(compile(src[start:end], "app.py", "exec"), ns)
build_intrinsic_shade_map = ns["build_intrinsic_shade_map"]


def scene():
    """Floor = lower half. Albedo checker x smooth linear shading."""
    yy, xx = np.mgrid[0:H, 0:W].astype(np.float64)
    mask = np.zeros((H, W), np.uint8)
    mask[H // 2 :, :] = 1

    albedo = np.where(((xx // 40).astype(int) + (yy // 40).astype(int)) % 2 == 0, 0.75, 0.35)

    shading = 0.35 + 0.55 * (yy / H)
    blob = 0.45 * np.exp(-(((xx - W * 0.7) / 70.0) ** 2 + ((yy - H * 0.8) / 50.0) ** 2))
    shading = np.clip(shading - blob, 0.05, 1.5)

    img_lin = albedo * shading
    img = (np.clip(img_lin, 0, 1) ** (1 / GAMMA) * 255).astype(np.uint8)
    img = np.stack([img] * 3, axis=2)
    return img, mask, shading, albedo


def decode(enc, rng):
    lo, hi = rng
    return lo + enc.astype(np.float64) / 255.0 * (hi - lo)


def expected_display(shading, mask):
    med = float(np.median(shading[mask > 0]))
    return np.power(np.clip(shading / med, 0, None), 1 / GAMMA)


def main():
    ok = True
    img, mask, shading, albedo = scene()

    # 1 — engages + reproduces display-space shading on the interior
    _fake_results.clear()
    _fake_results["gry_shd"] = shading.astype(np.float32)
    enc, rng = build_intrinsic_shade_map(img, mask)
    if enc is None:
        print("  [FAIL] did not engage on a clean scene")
        print("\nR4-1 SIM CHECKS FAILED")
        return 1
    rel = decode(enc.reshape(H, W), rng)
    want = expected_display(shading, mask)
    interior = cv2.erode(mask, np.ones((41, 41), np.uint8)) > 0
    # the encoder clips to the adaptive range; compare where 'want' is in-range
    in_rng = (want > min(rng) + 0.02) & (want < max(rng) - 0.02)
    sel = interior & in_rng
    err = np.abs(rel[sel] - want[sel])
    good = float(err.mean()) < 0.02 and float(np.percentile(err, 99)) < 0.06
    print(f"  [{'PASS' if good else 'FAIL'}] lighting survives: mean err {err.mean():.4f}, "
          f"p99 {np.percentile(err, 99):.4f} (display space)")
    ok &= good

    # 2 — albedo-blind: checker cells must not differ in the output
    cell_a = sel & (((np.indices((H, W))[1] // 40) + (np.indices((H, W))[0] // 40)) % 2 == 0)
    cell_b = sel & ~cell_a
    # compare horizontally adjacent same-row cells via local means
    diff = abs(float(rel[cell_a].mean()) - float(rel[cell_b].mean()))
    alb_contrast = abs(float(albedo[cell_a].mean()) - float(albedo[cell_b].mean()))
    good = diff < 0.01 and alb_contrast > 0.3
    print(f"  [{'PASS' if good else 'FAIL'}] albedo-blind: checker leakage {diff:.4f} "
          f"(albedo contrast {alb_contrast:.2f} in, <0.01 out)")
    ok &= good

    # 3 — boundary-safe: blazing-bright furniture shading above the floor
    bright = shading.copy()
    bright[mask == 0] = 5.0
    _fake_results.clear()
    _fake_results["gry_shd"] = bright.astype(np.float32)
    enc_b, rng_b = build_intrinsic_shade_map(img, mask)
    rel_b = decode(enc_b.reshape(H, W), rng_b)
    edge_band = (mask > 0) & (np.indices((H, W))[0] < H // 2 + 12)
    band_sel = edge_band & in_rng
    err_b = np.abs(rel_b[band_sel] - want[band_sel])
    good = float(err_b.mean()) < 0.04 and float(err_b.max()) < 0.12
    print(f"  [{'PASS' if good else 'FAIL'}] boundary-safe: edge-band err mean "
          f"{err_b.mean():.4f}, max {err_b.max():.4f} with 5x furniture shading")
    ok &= good

    # 4 — inverse-shading key decoded
    _fake_results.clear()
    _fake_results["inv_shd"] = (1.0 / (shading + 1.0)).astype(np.float32)
    enc_i, rng_i = build_intrinsic_shade_map(img, mask)
    good = enc_i is not None
    if good:
        rel_i = decode(enc_i.reshape(H, W), rng_i)
        err_i = np.abs(rel_i[sel] - want[sel])
        good = float(err_i.mean()) < 0.02
        print(f"  [{'PASS' if good else 'FAIL'}] inv_shd decoded: mean err {err_i.mean():.4f}")
    else:
        print("  [FAIL] inv_shd: did not engage")
    ok &= good

    # 5 — R4-1 v2 glare repair: the model inverts specular glare into a dark
    # blob (2026-06-12 dataset, room 2). Photo: bright glare patch on the
    # floor; model: shading collapses there. The repaired output must sit at
    # the ambient level, not the dip — while the REAL shadow (photo-dark,
    # check 1) keeps transferring.
    yy, xx = np.indices((H, W)).astype(np.float64)
    glare_zone = ((xx - W * 0.3) ** 2 + ((yy - H * 0.75) * 1.4) ** 2) < 45.0 ** 2
    img_g = img.copy()
    img_g[glare_zone & (mask > 0)] = 250
    inverted = shading.copy()
    inverted[glare_zone & (mask > 0)] = 0.12
    _fake_results.clear()
    _fake_results["gry_shd"] = inverted.astype(np.float32)
    enc_g, rng_g = build_intrinsic_shade_map(img_g, mask)
    rel_g = decode(enc_g.reshape(H, W), rng_g)
    core = glare_zone & interior
    ring = (~glare_zone) & interior & (
        ((xx - W * 0.3) ** 2 + ((yy - H * 0.75) * 1.4) ** 2) < 90.0 ** 2
    )
    dip = float(rel_g[ring].mean()) - float(rel_g[core].mean())
    good = dip < 0.06
    print(f"  [{'PASS' if good else 'FAIL'}] glare repair: blob dip {dip:.3f} "
          f"below ambient (<0.06; was an inverted dark blob)")
    ok &= good

    # 6 — R4-1 v2 grout-ghost removal: thin dark lines in the model's
    # shading (the OLD floor's grout grooves) must not reach the output;
    # the wide soft shadow survives via check 1.
    ghost = shading.copy()
    line_mask = (mask > 0) & (((xx + 2 * yy) % 60) < 3)
    ghost[line_mask] *= 0.72
    _fake_results.clear()
    _fake_results["gry_shd"] = ghost.astype(np.float32)
    enc_l, rng_l = build_intrinsic_shade_map(img, mask)
    rel_l = decode(enc_l.reshape(H, W), rng_l)
    on_line = line_mask & sel
    off_line = (~line_mask) & sel
    leak = abs(float(rel_l[on_line].mean()) - float(rel_l[off_line].mean()))
    good = leak < 0.02
    print(f"  [{'PASS' if good else 'FAIL'}] grout-ghost removal: line leakage "
          f"{leak:.4f} (<0.02; lines were 28% deep)")
    ok &= good

    # 7 — fallback paths all return None (caller then uses the heuristic)
    cases = []
    _fake_results.clear()
    _fake_results["albedo_only"] = shading.astype(np.float32)
    cases.append(("no shading key", build_intrinsic_shade_map(img, mask)[0] is None))
    _fake_results.clear()
    _fake_results["exc"] = RuntimeError("model exploded")
    cases.append(("pipeline raises", build_intrinsic_shade_map(img, mask)[0] is None))
    _fake_results.clear()
    _fake_results["gry_shd"] = shading.astype(np.float32)
    cases.append(("empty mask", build_intrinsic_shade_map(img, np.zeros_like(mask))[0] is None))
    saved = ns["intrinsic_models"]
    ns["intrinsic_models"] = None
    cases.append(("model not loaded", build_intrinsic_shade_map(img, mask)[0] is None))
    ns["intrinsic_models"] = saved
    for label, passed in cases:
        print(f"  [{'PASS' if passed else 'FAIL'}] fallback: {label} -> None")
        ok &= passed

    print("\n" + ("ALL R4-1 SIM CHECKS PASSED" if ok else "R4-1 SIM CHECKS FAILED"))
    return 0 if ok else 1


if __name__ == "__main__":
    raise SystemExit(main())