feat: daemon status, restart, live preview

Add daemon.py module to control hyprsunset daemon via subprocess:
- is_running() checks daemon status using pgrep
- live_preview() pushes temperature/gamma/identity to running daemon via hyprctl
- restart() kills existing daemon and launches new detached process

All subprocess calls are mocked in tests; no real processes are touched.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

1 files changed, 45 insertions, 0 deletions

diff --git a/hyprsunset_qt/daemon.py b/hyprsunset_qt/daemon.py
new file mode 100644
index 0000000..7bf0e47
--- /dev/null
+++ b/hyprsunset_qt/daemon.py
@@ -0,0 +1,45 @@
+"""Control the hyprsunset daemon: status, restart, live preview via hyprctl."""
+
+from __future__ import annotations
+
+import shlex
+import subprocess
+from typing import Optional
+
+
+def is_running() -> bool:
+    return subprocess.run(
+        ["pgrep", "-x", "hyprsunset"],
+        stdout=subprocess.DEVNULL,
+        stderr=subprocess.DEVNULL,
+    ).returncode == 0
+
+
+def live_preview(
+    temperature: Optional[int] = None,
+    gamma: Optional[float] = None,
+    identity: bool = False,
+) -> None:
+    """Push values to the running daemon over IPC. No file write, no restart."""
+    if identity:
+        subprocess.run(["hyprctl", "hyprsunset", "identity"], check=False)
+        return
+    if temperature is not None:
+        subprocess.run(
+            ["hyprctl", "hyprsunset", "temperature", str(temperature)],
+            check=False,
+        )
+    if gamma is not None:
+        # IPC gamma is integer percent; profile gamma is a 0-2 float.
+        pct = str(round(gamma * 100))
+        subprocess.run(["hyprctl", "hyprsunset", "gamma", pct], check=False)
+
+
+def restart(command: str = "hyprsunset") -> None:
+    subprocess.run(["pkill", "hyprsunset"], check=False)
+    subprocess.Popen(
+        shlex.split(command),
+        stdout=subprocess.DEVNULL,
+        stderr=subprocess.DEVNULL,
+        start_new_session=True,
+    )