From 1366e3b3e76a5c9856a7a6b14a27836de9aa1903 Mon Sep 17 00:00:00 2001
From: Mathias Scheider <mathias2784@web.de>
Date: Sun, 4 Oct 2026 07:54:33 +0200
Subject: [PATCH] metadata-writer: first skeleton

---
 pyproject.toml                   |  1 +
 src/photools3/metadata_writer.py | 46 ++++++++++++++++++++++++++++++++
 uv.lock                          | 13 ++++++++-
 3 files changed, 59 insertions(+), 1 deletion(-)
 create mode 100644 src/photools3/metadata_writer.py

diff --git a/pyproject.toml b/pyproject.toml
index e004ca3..b758f24 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -13,6 +13,7 @@ dependencies = [
     "pillow>=12.3.0",
     "pydantic>=2.13.5",
     "pydantic-settings>=2.15.0",
+    "pyexiftool>=0.5.6",
     "pytest>=9.1.1",
     "ruff>=0.16.9",
     "typer>=0.12.0",
diff --git a/src/photools3/metadata_writer.py b/src/photools3/metadata_writer.py
new file mode 100644
index 0000000..6f92e91
--- /dev/null
+++ b/src/photools3/metadata_writer.py
@@ -0,0 +1,46 @@
+import logging
+from pathlib import Path
+
+log = logging.getLogger(__name__)
+
+# File extensions that should use XMP sidecars
+SIDECAR_EXTENSIONS = {".dng", ".nef", ".cr2", ".cr3", ".arw", ".raf", ".orf", ".rw2"}
+
+
+type Caption = str | None
+type Keywords = list[str] | None
+type Color = str | None
+
+
+class MetadataWriter:
+    """
+    Write metadata (captions and keywords) to image files.
+    For DNG files, creates/updates XMP sidecar files.
+    """
+
+    def __init__(
+        self, force_sidecar: bool = False, append: bool = True, prefix: str = "photools"
+    ):
+        self.force_sidecar = force_sidecar
+        self.append = append
+        self.prefix = prefix
+
+    def write_caption(self, path: Path, caption: Caption): ...
+
+    def write_keywords(self, path: Path, keywords: Keywords): ...
+
+    def write_color(self, path: Path, color: Color): ...
+
+    def write(
+        self,
+        path: Path,
+        caption: Caption = None,
+        keywords: Keywords = None,
+        color: Color = None,
+    ):
+        if caption is not None:
+            self.write_caption(path, caption)
+        if keywords is not None:
+            self.write_keywords(path, keywords)
+        if color is not None:
+            self.write_color(path, color)
diff --git a/uv.lock b/uv.lock
index 4f2abe4..dca5d71 100644
--- a/uv.lock
+++ b/uv.lock
@@ -1,5 +1,5 @@
 version = 1
-revision = 3
+revision = 5
 requires-python = ">=3.14"
 
 [[package]]
@@ -580,6 +580,7 @@ dependencies = [
     { name = "pillow" },
     { name = "pydantic" },
     { name = "pydantic-settings" },
+    { name = "pyexiftool" },
     { name = "pytest" },
     { name = "ruff" },
     { name = "typer" },
@@ -593,6 +594,7 @@ requires-dist = [
     { name = "pillow", specifier = ">=12.3.0" },
     { name = "pydantic", specifier = ">=2.13.5" },
     { name = "pydantic-settings", specifier = ">=2.15.0" },
+    { name = "pyexiftool", specifier = ">=0.5.6" },
     { name = "pytest", specifier = ">=9.1.1" },
     { name = "ruff", specifier = ">=0.16.9" },
     { name = "typer", specifier = ">=0.12.0" },
@@ -746,6 +748,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/30/a4/2bffa9f8e804325a09867f0e9d30795c80ea9f8d62560bd1b6ad6220eb2f/pydantic_settings-2.15.0-py3-none-any.whl", hash = "sha256:0ba092c291c94baceb5eff768aa0d56400a457585bc0175925a5a5510303da42", size = 69413, upload-time = "2026-08-07T09:24:55.839Z" },
 ]
 
+[[package]]
+name = "pyexiftool"
+version = "0.5.6"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/5e/48/406da6691d15abf3c8d399bce8bc588709a5b54e857fd7c22dad2f90c33c/PyExifTool-0.5.6.tar.gz", hash = "sha256:22a972c1c212d1ad5f61916fded5057333dcc48fb8e42eed12d2ff9665b367ae", size = 56365, upload-time = "2023-10-22T23:18:18.819Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/fc/b9/175e9a1f8f3f94b22f622f0fcac853ae2c43cb4ac6034f849269c6086dac/PyExifTool-0.5.6-py3-none-any.whl", hash = "sha256:ac7d7836d2bf373f20aa558528f6b2222c4c0d896ed28c951a3ff8e6cec05a87", size = 51243, upload-time = "2023-10-22T23:18:16.614Z" },
+]
+
 [[package]]
 name = "pygments"
 version = "2.21.0"