1 files changed, 40 insertions, 0 deletions
diff --git a/deckit/config.py b/deckit/config.py
new file mode 100644
index 0000000..151207b
--- /dev/null
+++ b/deckit/config.py
@@ -0,0 +1,40 @@
+"""Configuration loading and validation for deck-it."""
+
+import os
+import re
+import sys
+import tomllib
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parent.parent
+MONITOR_NAME = re.compile(r"[A-Za-z0-9_-]{1,32}")
+
+
+def user_config_path() -> Path:
+    return Path(os.environ.get("XDG_CONFIG_HOME", Path.home() / ".config")) / "deck-it" / "config.toml"
+
+
+def config_error(cfg: dict) -> str | None:
+    d, ports = cfg.get("display", {}), cfg.get("ports", {})
+    if not MONITOR_NAME.fullmatch(str(d.get("name", "TAB"))):
+        return "display.name must be letters, digits, - or _"
+    refresh = d.get("refresh", 60)
+    if not isinstance(refresh, int) or not 1 <= refresh <= 240:
+        return "display.refresh must be a number from 1 to 240"
+    for key in ("command_center", "display"):
+        if key in ports:
+            v = ports[key]
+            if not isinstance(v, int) or not 1024 <= v <= 65535:
+                return f"ports.{key} must be a number from 1024 to 65535"
+    if ports.get("command_center", 8765) == ports.get("display", 5900):
+        return "ports.command_center and ports.display must differ"
+    return None
+
+
+def load_config() -> dict:
+    path = user_config_path() if user_config_path().is_file() else ROOT / "config.toml"
+    with open(path, "rb") as f:
+        cfg = tomllib.load(f)
+    if err := config_error(cfg):
+        sys.exit(f"{path}: {err}")
+    return cfg