add dev run command

dev.py

@@ -4,7 +4,9 @@ import shlex
 import shutil
 import subprocess
 import sys
+import time
 
+from datetime import datetime
 from gemi import __version__
 from pathlib import Path
 from tempfile import TemporaryDirectory
@@ -12,15 +14,23 @@ from tempfile import TemporaryDirectory
 try:
 	import click
 
-except ImportError:
-	proc = subprocess.run([sys.executable, "-m", "pip", "install", "click"], check = False)
+	from watchdog.observers import Observer
+	from watchdog.events import PatternMatchingEventHandler
 
-	if proc.returncode != 0:
+except ImportError:
+	CMD = f"{sys.executable} -m pip install watchdog click"
+	PROC = subprocess.run(shlex.split(CMD), check = False)
+
+	if PROC.returncode != 0:
 		sys.exit()
 		
-	print("Successfully installed click")
+	print("Successfully installed click and watchdog")
+
 	import click
 
+	from watchdog.observers import Observer
+	from watchdog.events import PatternMatchingEventHandler
+
 
 REPO = Path(__file__).resolve().parent
 
@@ -93,5 +103,85 @@ def cli_install():
 	subprocess.run(shlex.split(f"{sys.executable} -m pip install -e .[dev,doc]"), check = False)
 
 
+@cli.command("run")
+def cli_run():
+	print("Starting process watcher")
+
+	handler = WatchHandler()
+	handler.run_proc()
+
+	watcher = Observer()
+	watcher.schedule(handler, str(REPO.joinpath("gemi")), recursive=True)
+	watcher.start()
+
+	try:
+		while True:
+			handler.proc.stdin.write(sys.stdin.read().encode("UTF-8")) # type: ignore
+			handler.proc.stdin.flush() # type: ignore
+
+	except KeyboardInterrupt:
+		pass
+
+	handler.kill_proc()
+	watcher.stop()
+	watcher.join()
+
+
+class WatchHandler(PatternMatchingEventHandler):
+	patterns = ["*.py"]
+	cmd = [sys.executable, "-m", "gemi.server"]
+
+
+	def __init__(self):
+		PatternMatchingEventHandler.__init__(self)
+
+		self.proc: subprocess.Popen | None = None
+		self.last_restart: datetime | None = None
+
+
+	def kill_proc(self):
+		if not self.proc or self.proc.poll() is not None:
+			return
+
+		print(f"Terminating process {self.proc.pid}")
+		self.proc.terminate()
+		sec = 0.0
+
+		while self.proc.poll() is None:
+			time.sleep(0.1)
+			sec += 0.1
+
+			if sec >= 5:
+				print("Failed to terminate. Killing process...")
+				self.proc.kill()
+				break
+
+		print("Process terminated")
+
+
+	def run_proc(self, restart=False):
+		timestamp = datetime.timestamp(datetime.now())
+		self.last_restart = timestamp if not self.last_restart else 0
+
+		if restart:
+			if timestamp - 3 < self.last_restart:
+				return
+
+			self.kill_proc()
+
+		self.proc = subprocess.Popen(self.cmd, stdin = subprocess.PIPE)
+		self.last_restart = timestamp
+
+		print(f"Started process with PID {self.proc.pid}", self.proc.pid)
+		print("Command:", " ".join(self.cmd))
+
+
+	def on_any_event(self, event):
+		if event.event_type not in ["modified", "created", "deleted"]:
+			return
+
+		self.run_proc(restart = True)
+
+
 if __name__ == "__main__":
 	cli()