style: increase ReadoutPanel font sizes and add CSV test fixture for data logging

src/pygui/backend/license/license_manager.py

@@ -0,0 +1,126 @@
+"""C#-compatible wafer license file parsing.
+
+License files are AES-128-CBC encrypted `.bin` blobs named
+``X00000-00.bin`` where ``X`` is the wafer family code, ``00000`` the
+5-digit serial number, and ``00`` the 2-digit license level. The blob is
+``ciphertext || iv`` (IV is the trailing 16 bytes). The decrypted text is
+a fixed-offset record::
+
+    [0:6]   serial       e.g. "A00001"
+    [7:15]  mfg date     8 hex chars
+    [16:18] level        2 decimal digits ("00" basic, "01"+ adds replay)
+    [19:27] license date 8 hex chars
+
+The key is hardcoded to match the C# application exactly
+"""
+
+import logging
+import re
+from dataclasses import dataclass
+from pathlib import Path
+
+from pygui.backend.crypto.crypto_helper import CryptoHelper
+
+log = logging.getLogger(__name__)
+
+LICENSE_KEY = b"ThisIsA16ByteKey"
+LICENSE_FILENAME_RE = re.compile(r"^[A-Z]\d{5}-\d{2}\.bin$")
+
+_MIN_TEXT_LEN = 27
+
+
+# ===== License Record =====
+@dataclass(frozen=True)
+class License:
+    """One parsed license file (all fields as stored in the file)."""
+
+    serial: str        # "A00001"
+    level: str         # "00".."03"
+    mfg_date_hex: str  # 8 hex chars
+    lic_date_hex: str  # 8 hex chars
+
+    @property
+    def level_int(self) -> int:
+        """Level as int; -1 if unparseable."""
+        try:
+            return int(self.level, 10)
+        except ValueError:
+            return -1
+
+    @property
+    def mfg_date_decimal(self) -> str:
+        """Mfg date shown as decimal (C# grid does Convert.ToInt64(hex, 16))."""
+        return _hex_to_decimal(self.mfg_date_hex)
+
+    @property
+    def lic_date_decimal(self) -> str:
+        """License date shown as decimal, same conversion as the C# grid."""
+        return _hex_to_decimal(self.lic_date_hex)
+
+
+def _hex_to_decimal(hex_str: str) -> str:
+    try:
+        return str(int(hex_str, 16))
+    except ValueError:
+        return ""
+
+
+# ===== Blob Parsing =====
+def split_data_iv(blob: bytes) -> tuple[bytes, bytes]:
+    """Split a license blob into (ciphertext, iv) — IV is the last 16 bytes."""
+    if len(blob) < 32:
+        raise ValueError("License blob too short")
+    return blob[:-16], blob[-16:]
+
+
+def parse_license_blob(blob: bytes) -> License | None:
+    """Decrypt and parse one license blob. None if malformed."""
+    try:
+        data, iv = split_data_iv(blob)
+        message = CryptoHelper.decrypt_aes(data, LICENSE_KEY, iv)
+        text = message.decode("utf-8")
+    except (ValueError, UnicodeDecodeError) as exc:
+        log.warning("Undecryptable license blob: %s", exc)
+        return None
+
+    if len(text) < _MIN_TEXT_LEN:
+        log.warning("License text too short (%d chars)", len(text))
+        return None
+
+    return License(
+        serial=text[0:6],
+        mfg_date_hex=text[7:15],
+        level=text[16:18],
+        lic_date_hex=text[19:27],
+    )
+
+
+# ===== Directory Scan =====
+def read_license_files(licenses_dir: str | Path) -> list[License]:
+    """Parse every valid license .bin in the directory.
+
+    A file counts only if its name matches ``X00000-00.bin`` AND equals
+    ``{serial}-{level}.bin`` from its own decrypted payload — same
+    tamper check as the C# app.
+    """
+    directory = Path(licenses_dir)
+    if not directory.is_dir():
+        return []
+
+    licenses: list[License] = []
+    for path in sorted(directory.glob("*.bin")):
+        if not LICENSE_FILENAME_RE.match(path.name):
+            continue
+        try:
+            blob = path.read_bytes()
+        except OSError as exc:
+            log.warning("Cannot read license file %s: %s", path, exc)
+            continue
+        lic = parse_license_blob(blob)
+        if lic is None:
+            continue
+        if path.name != f"{lic.serial}-{lic.level}.bin":
+            log.warning("License filename mismatch: %s", path.name)
+            continue
+        licenses.append(lic)
+    return licenses