#!/usr/bin/env python3
# verify.py -- re-read specific flash regions N times to check whether the
# bytes are stable (real flash) or vary (C2 read errors). Also re-reads the
# known-intact 0xE800 page as a control.
import os, sys, time, select, termios

DEV = os.environ.get("C2PROBE_DEV", "/dev/cu.usbmodem2101")
sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
import cdc

REGIONS = [
    ("0xE800 (control, intact)", 0xE800, 256),
    ("0xEDFF (big diff run)",    0xEDFF, 256),
    ("0xEF00 (within diff run)", 0xEF00, 128),
    ("0xF1D0 (scattered diffs)",  0xF1D0, 64),
    ("0xF200 (diff)",             0xF200, 16),
    ("0xF800 (6B diff @app end)", 0xF800, 16),
    ("0xFC00 (gap region)",       0xFC00, 64),
]
N = 4

def main():
    fd = cdc.open_port()
    cdc.drain(fd, 0.4)
    r = cdc.cmd(fd, "piinit", 12)
    print("piinit:", r)
    if r.strip() != "ok piinit":
        print("piinit failed"); return 1
    for name, addr, n in REGIONS:
        reads = []
        ok = True
        for _ in range(N):
            lc = n if n < 256 else 0
            r = cdc.cmd(fd, f"read {addr:04x} {lc}", 12).strip()
            if r.startswith("data "):
                parts = r.split()
                try:
                    reads.append(bytes.fromhex(parts[3]))
                except (IndexError, ValueError):
                    reads.append(None); ok = False
            else:
                reads.append(None); ok = False
        # stability check
        good = [b for b in reads if b is not None and len(b) == n]
        stable = len(set(good)) == 1 and len(good) == N
        print(f"\n{name}  @0x{addr:04x} len={n}")
        if not good:
            print("  ALL READS FAILED")
            continue
        for i, b in enumerate(reads):
            tag = "ok " if (b is not None and len(b)==n) else "FAIL"
            print(f"  [{i}] {tag} {b.hex() if b else ''}")
        print(f"  stable={stable}  distinct={len(set(good))}")
    return 0

if __name__ == "__main__":
    sys.exit(main())