import struct

DUMP = r"C:/Users/vikto/Documents/Claude/rt-4d/radio-spi-dump.bin"
with open(DUMP, "rb") as f:
    cal = f.read(0x1000)

REC = 0x70  # 112
# marker pair at rec+0x02..0x0f (0x22 within a record starting at 0x20). Let's define records start at 0x20?
# But 0x00..0x1f is a header. Actually let's test both: if records start at 0, marker would be at 0x22 within rec0 -> offset 0x22.
# If records start at 0x20, then rec starts 0x20, marker at rec+0x02.
# Let's align records to start where the marker pair begins minus 2.
# positions of the FIRST marker of each pair: 0x22, 0x92, 0x102 ... step 0x70. So record_base = 0x22-0x02 = 0x20.
# Header region 0x00..0x1f (32 bytes).

hdr = cal[0:0x20]
print("HEADER 0x00-0x1f:")
print(" ".join(f"{b:02x}" for b in hdr))
print()

# number of records that fit: (0x1000-0x20)/0x70
base = 0x20
nrec = (0x1000 - base)//REC
print("records fit:", nrec, "leftover:", (0x1000-base) - nrec*REC)

# How many are non-zero (populated)?
def dump_rec(idx):
    off = base + idx*REC
    r = cal[off:off+REC]
    print(f"--- record {idx} @ 0x{off:03x} ---")
    for i in range(0, REC, 16):
        row = r[i:i+16]
        hexs = " ".join(f"{b:02x}" for b in row)
        asc = "".join(chr(b) if 32<=b<127 else "." for b in row)
        print(f"  +{i:02x}  {hexs}  {asc}")

# Show all record byte0 (first byte) which seems to be an index/counter: 0a,11,00,00,...
print("\nrecord first bytes (offset +0x00) and +0x01:")
for idx in range(nrec):
    off = base+idx*REC
    print(f"  rec{idx:2d} @0x{off:03x}: b0={cal[off]:02x} b1={cal[off+1]:02x}")

# detect last populated record (non all-zero)
last = -1
for idx in range(nrec):
    off = base+idx*REC
    if any(b!=0 for b in cal[off:off+REC]):
        last = idx
print("last populated record index:", last)