Initial commit: MVP tidtakingssystem

- Backend: FastAPI, EXIF-parser, EasyOCR, SQLite
- Frontend: React admin (startliste, passeringer, gjennomgang, resultater)
- Docker: docker-compose med depot/processed/data-volumer

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/exif_parser.py

@@ -0,0 +1,156 @@
+"""
+Parse og normaliser EXIF-metadata fra bilder.
+Returnerer et strukturert dict eller kaster ExifError ved manglende/ugyldig data.
+"""
+
+import re
+from dataclasses import dataclass
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Optional
+
+import piexif
+from PIL import Image
+
+
+class ExifError(ValueError):
+    pass
+
+
+@dataclass
+class ImageMetadata:
+    timestamp_utc: datetime
+    gps_lat: float
+    gps_lon: float
+    gps_alt: Optional[float]
+    station: Optional[str]  # fra ImageDescription eller CameraLabel
+
+
+def _rational_to_float(rational) -> float:
+    """Konverter EXIF rational (teller, nevner) til float."""
+    if isinstance(rational, tuple):
+        num, den = rational
+        if den == 0:
+            return 0.0
+        return num / den
+    return float(rational)
+
+
+def _parse_gps_coord(dms_rationals, ref: str) -> float:
+    """Konverter GPS DMS rationals + referanse til desimalgrader."""
+    deg = _rational_to_float(dms_rationals[0])
+    min_ = _rational_to_float(dms_rationals[1])
+    sec = _rational_to_float(dms_rationals[2])
+    value = deg + min_ / 60.0 + sec / 3600.0
+    if ref in ("S", "W"):
+        value = -value
+    return value
+
+
+def _parse_timestamp(exif_dict: dict) -> datetime:
+    """
+    Hent tidsstempel fra DateTimeOriginal + SubSecTimeOriginal.
+    Returnerer datetime i UTC. Kaster ExifError hvis manglende.
+    """
+    ifd0 = exif_dict.get("Exif", {})
+
+    raw_dt = ifd0.get(piexif.ExifIFD.DateTimeOriginal)
+    if not raw_dt:
+        raise ExifError("Mangler DateTimeOriginal i EXIF")
+
+    if isinstance(raw_dt, bytes):
+        raw_dt = raw_dt.decode("ascii", errors="replace")
+
+    # Format: "2024:06:15 10:23:45"
+    try:
+        dt = datetime.strptime(raw_dt.strip(), "%Y:%m:%d %H:%M:%S")
+    except ValueError as e:
+        raise ExifError(f"Ugyldig DateTimeOriginal-format: {raw_dt!r}") from e
+
+    # Sub-sekunder
+    raw_sub = ifd0.get(piexif.ExifIFD.SubSecTimeOriginal)
+    microseconds = 0
+    if raw_sub:
+        if isinstance(raw_sub, bytes):
+            raw_sub = raw_sub.decode("ascii", errors="replace")
+        sub_str = raw_sub.strip()
+        if sub_str.isdigit():
+            # Pad/truncate til 6 siffer (mikrosekunder)
+            sub_str = (sub_str + "000000")[:6]
+            microseconds = int(sub_str)
+
+    dt = dt.replace(microsecond=microseconds, tzinfo=timezone.utc)
+    return dt
+
+
+def _parse_gps(exif_dict: dict) -> tuple[float, float, Optional[float]]:
+    """
+    Hent GPS-koordinater. Kaster ExifError hvis lat/lon mangler.
+    """
+    gps = exif_dict.get("GPS", {})
+
+    lat_dms = gps.get(piexif.GPSIFD.GPSLatitude)
+    lat_ref = gps.get(piexif.GPSIFD.GPSLatitudeRef)
+    lon_dms = gps.get(piexif.GPSIFD.GPSLongitude)
+    lon_ref = gps.get(piexif.GPSIFD.GPSLongitudeRef)
+
+    if not (lat_dms and lat_ref and lon_dms and lon_ref):
+        raise ExifError("Mangler GPS-koordinater (lat/lon) i EXIF")
+
+    if isinstance(lat_ref, bytes):
+        lat_ref = lat_ref.decode("ascii")
+    if isinstance(lon_ref, bytes):
+        lon_ref = lon_ref.decode("ascii")
+
+    lat = _parse_gps_coord(lat_dms, lat_ref)
+    lon = _parse_gps_coord(lon_dms, lon_ref)
+
+    alt = None
+    alt_raw = gps.get(piexif.GPSIFD.GPSAltitude)
+    if alt_raw:
+        alt = _rational_to_float(alt_raw)
+        alt_ref = gps.get(piexif.GPSIFD.GPSAltitudeRef, 0)
+        if alt_ref == 1:
+            alt = -alt
+
+    return lat, lon, alt
+
+
+def _parse_station(exif_dict: dict) -> Optional[str]:
+    """Hent stasjonsnavn fra ImageDescription."""
+    ifd0 = exif_dict.get("0th", {})
+    desc = ifd0.get(piexif.ImageIFD.ImageDescription)
+    if desc:
+        if isinstance(desc, bytes):
+            desc = desc.decode("utf-8", errors="replace")
+        return desc.strip() or None
+    return None
+
+
+def parse_image(path: Path) -> ImageMetadata:
+    """
+    Les EXIF fra bildefil og returner ImageMetadata.
+    Kaster ExifError hvis påkrevde felt mangler.
+    """
+    try:
+        img = Image.open(path)
+        raw_exif = img.info.get("exif")
+        if not raw_exif:
+            raise ExifError("Bildet har ingen EXIF-data")
+        exif_dict = piexif.load(raw_exif)
+    except ExifError:
+        raise
+    except Exception as e:
+        raise ExifError(f"Kunne ikke lese EXIF: {e}") from e
+
+    timestamp = _parse_timestamp(exif_dict)
+    lat, lon, alt = _parse_gps(exif_dict)
+    station = _parse_station(exif_dict)
+
+    return ImageMetadata(
+        timestamp_utc=timestamp,
+        gps_lat=lat,
+        gps_lon=lon,
+        gps_alt=alt,
+        station=station,
+    )