From 084676eca04f4df2beacd2937f1441a68a8edb58 Mon Sep 17 00:00:00 2001
From: Mathias <mathias2784@web.de>
Date: Tue, 6 Oct 2026 07:52:36 +0200
Subject: [PATCH] metadata writer: some progress

---
 .env.template                    |  2 ++
 src/photools3/llm_session.py     |  4 +---
 src/photools3/metadata_writer.py | 33 ++++++++++++++++++++++++++++++++
 src/photools3/settings.py        |  5 +++++
 test/test_metadata_writer.py     |  8 ++++++++
 5 files changed, 49 insertions(+), 3 deletions(-)
 create mode 100644 test/test_metadata_writer.py

diff --git a/.env.template b/.env.template
index 69a0aea..a23d47b 100644
--- a/.env.template
+++ b/.env.template
@@ -1,3 +1,5 @@
 LLM_API_BASE_URL = "http://localhost:1234/v1"
 LLM_API_KEY = "not-relevant"
 LLM_DEFAULT_TEMPERATURE = 1.0
+
+METADATA_PREFIX = "photools:"
diff --git a/src/photools3/llm_session.py b/src/photools3/llm_session.py
index e3b1f4a..430e2c4 100644
--- a/src/photools3/llm_session.py
+++ b/src/photools3/llm_session.py
@@ -17,12 +17,10 @@ from photools3.models import (
     LlmResponseQuality,
 )
 from photools3.photo import Photo
-from photools3.settings import Settings
+from photools3.settings import settings
 
 logger = logging.getLogger(__name__)
 
-settings = Settings()  # type: ignore[reportCallIssue]
-
 
 class LlmSession:
     base_url: str = str(settings.llm_api_base_url)
diff --git a/src/photools3/metadata_writer.py b/src/photools3/metadata_writer.py
index 6f92e91..ca7714a 100644
--- a/src/photools3/metadata_writer.py
+++ b/src/photools3/metadata_writer.py
@@ -1,15 +1,48 @@
 import logging
 from pathlib import Path
+from typing import Annotated, Any
+
+import exiftool
+from pydantic import StringConstraints
+
+from photools3.settings import settings
 
 log = logging.getLogger(__name__)
 
 # File extensions that should use XMP sidecars
 SIDECAR_EXTENSIONS = {".dng", ".nef", ".cr2", ".cr3", ".arw", ".raf", ".orf", ".rw2"}
 
+XmpKey = Annotated[str, StringConstraints(pattern=r"^\w+\:\w+")]
 
 type Caption = str | None
 type Keywords = list[str] | None
 type Color = str | None
+type XmpMetadata = dict[str, Any]
+
+XMO_KEYS_CAPTION: list[XmpKey] = [
+    "EXIF:ImageDescription",
+    "XMP:Description",
+    "IPTC:Caption-Abstract",
+]
+
+XMP_KEYS_TAG: list[XmpKey] = [
+    "XMP:HierarchicalSubject",
+    "XMP:Subject",
+    "IPTC:Keywords",
+]
+
+
+def _prefixed(txt: str) -> str:
+    return f"{settings.metadata_prefix} {txt}"
+
+
+def read_metadata(path: Path) -> XmpMetadata | None:
+    try:
+        with exiftool.ExifToolHelper() as exif:
+            return exif.get_metadata([str(path)])[0]
+    except Exception as exc:  # noqa: BLE001
+        log.error(f"Could not read metadata from {path}: {exc}")
+
 
 
 class MetadataWriter:
diff --git a/src/photools3/settings.py b/src/photools3/settings.py
index 3e0d1b4..22d65cb 100644
--- a/src/photools3/settings.py
+++ b/src/photools3/settings.py
@@ -18,3 +18,8 @@ class Settings(BaseSettings):
     llm_api_base_url: Url
     llm_api_key: str
     llm_default_temperature: float
+
+    metadata_prefix: str
+
+
+settings = Settings()  # type: ignore[reportCallIssue]
diff --git a/test/test_metadata_writer.py b/test/test_metadata_writer.py
new file mode 100644
index 0000000..dc0a938
--- /dev/null
+++ b/test/test_metadata_writer.py
@@ -0,0 +1,8 @@
+
+from photools3.metadata_writer import read_metadata
+from test.test_photo import PATHS_DNG_EXAMPLES
+
+
+def test_read_metadata():
+    result = read_metadata(PATHS_DNG_EXAMPLES[0])
+    assert result