#!/usr/bin/env python3
"""Check px68k's render of the packed layout against the same reference MAME is
judged on (tools/bench/verify_frame256.py, criterion 3 and 4).

    python3 tools/bench/gvpack/verify_gvpack.py <raw> [blob]

<raw> is 256x256 palette INDICES straight out of px68k's Grp_DrawLine8.
"""
import struct, sys
import numpy as np

raw  = sys.argv[1] if len(sys.argv) > 1 else "tmp/gvpack_px68k.raw"
blob = sys.argv[2] if len(sys.argv) > 2 else "tmp/frame256p.bin"

g = np.frombuffer(open(raw, "rb").read(), np.uint8).reshape(256, 256)
d = open(blob, "rb").read()
W, H = struct.unpack(">HH", d[4:8])
pal = np.frombuffer(d[8:8+768], np.uint8).reshape(256, 3).astype(int)
idx = np.frombuffer(d[8+768:8+768+W*H], np.uint8).reshape(H, W)

yoff = (256 - H) // 2
act  = g[yoff:yoff+H]

fail = []
if not np.array_equal(act, idx):
    bad = act != idx
    fail.append(f"active area index-exact: {bad.sum()} px differ "
                f"(left half {bad[:, :128].sum()}, right half {bad[:, 128:].sum()})")

bars = np.concatenate([g[:yoff], g[yoff+H:]])
if bars.size and (bars != 255).any():
    fail.append(f"letterbox not the reserved black index 255: "
                f"{(bars != 255).sum()} px")

if (act == 0).any():
    fail.append(f"index 0 appeared in the picture: {(act == 0).sum()} px "
                f"-- it is the transparency key and must stay unused")

for x in fail:
    print("FAIL " + x)
if fail:
    sys.exit(1)

p6 = lambda v: ((v << 2) | (v >> 4)) & 0xFF
f = pal >> 3
render = lambda I: p6((f << 1) | I[:, None])
I = (((render(np.ones(256, int)) - pal) ** 2).sum(1)
     < ((render(np.zeros(256, int)) - pal) ** 2).sum(1)).astype(int)
mse = ((render(I)[act].astype(int) - pal[idx]) ** 2).mean()
print(f"OK  {raw}: px68k renders the packed layout index-exact over {W}x{H}, "
      f"letterbox on the reserved black")
print(f"    palette ceiling vs 24-bit palettised source: "
      f"{10*np.log10(255**2/mse):.2f} dB")