Python: Implement state callbacks using decorators

4 files changed, 87 insertions, 20 deletions

diff --git a/wrappers/python/eduvpncommon/__init__.py b/wrappers/python/eduvpncommon/__init__.py
index ff329a0..073af39 100644
--- a/wrappers/python/eduvpncommon/__init__.py
+++ b/wrappers/python/eduvpncommon/__init__.py
@@ -3,14 +3,20 @@ from collections import defaultdict
 import pathlib
 import platform
 
-_lib_prefixes = defaultdict(lambda: "lib", {
-    "windows": "",
-})
-
-_lib_suffixes = defaultdict(lambda: ".so", {
-    "windows": ".dll",
-    "darwin": ".dylib",
-})
+_lib_prefixes = defaultdict(
+    lambda: "lib",
+    {
+        "windows": "",
+    },
+)
+
+_lib_suffixes = defaultdict(
+    lambda: ".so",
+    {
+        "windows": ".dll",
+        "darwin": ".dylib",
+    },
+)
 
 _os = platform.system().lower()
 
@@ -19,9 +25,10 @@ _libfile = f"{_lib_prefixes[_os]}{_libname}{_lib_suffixes[_os]}"
 # Library should have been copied to the lib/ folder
 lib = cdll.LoadLibrary(str(pathlib.Path(__file__).parent / "lib" / _libfile))
 
+
 class DataError(Structure):
-    _fields_ = [('data', c_void_p),
-                ('error', c_void_p)]
+    _fields_ = [("data", c_void_p), ("error", c_void_p)]
+
 
 VPNStateChange = CFUNCTYPE(None, c_char_p, c_char_p, c_char_p)
 
@@ -33,6 +40,7 @@ lib.GetServersList.argtypes, lib.GetServersList.restype = [], DataError
 # See https://stackoverflow.com/questions/13445568/python-ctypes-how-to-free-memory-getting-invalid-pointer-error
 lib.FreeString.argtypes, lib.FreeString.restype = [c_void_p], None
 
+
 def GetPtrString(ptr):
     if ptr:
         string = cast(ptr, c_char_p).value
diff --git a/wrappers/python/eduvpncommon/error.py b/wrappers/python/eduvpncommon/error.py
index ce0cec1..59f0607 100644
--- a/wrappers/python/eduvpncommon/error.py
+++ b/wrappers/python/eduvpncommon/error.py
@@ -1,5 +1,6 @@
 from enum import Enum
 
+
 class GoError(Exception):
     message_dict: dict
     code: Enum
diff --git a/wrappers/python/eduvpncommon/main.py b/wrappers/python/eduvpncommon/main.py
index ac13344..9a4931f 100644
--- a/wrappers/python/eduvpncommon/main.py
+++ b/wrappers/python/eduvpncommon/main.py
@@ -1,21 +1,72 @@
-from . import lib, VPNStateChange, GetDataError
+from . import lib, VPNStateChange, GetDataError, GetPtrString
 from ctypes import *
+from enum import Enum
+import functools
 
-@VPNStateChange
-def state_change(old, new, data):
-    print(f"Python: State change {old.decode()} {new.decode()} DATA {data.decode()}")
+class StateType(Enum):
+    Enter = 1
+    Leave = 2
 
 # Registers the python app with the Go code
 # name: The name of the app to be registered
 # url: The url of the server to connect to, FIXME: To be removed
 # state_callback: The callback to trigger whenever a state is changed, FIXME: Remove whenever this wrapper has implemented callbacks using function decorations
 def Register(name, config_directory, state_callback):
-    name_bytes = name.encode('utf-8')
-    dir_bytes = config_directory.encode('utf-8')
-    lib.Register(name_bytes, dir_bytes, state_callback)
+    name_bytes = name.encode("utf-8")
+    dir_bytes = config_directory.encode("utf-8")
+    ptr_err = lib.Register(name_bytes, dir_bytes, state_callback)
+    err_string = GetPtrString(ptr_err)
+    return err_string
+
+
+class EduVPN(object):
+    def __init__(self, name, config_directory):
+        self.event_handler = EventHandler()
+        self.name = name
+        self.config_directory = config_directory
+
+    def register(self) -> bool:
+        closure = VPNStateChange(
+            lambda old_state, new_state, data: self.callback(
+                old_state.decode(), new_state.decode(), data.decode()
+            )
+        )
+        return Register(self.name, self.config_directory, closure) == ""
+
+    @property
+    def event(self):
+        return self.event_handler
+
+    def callback(self, old_state, new_state, data):
+        self.event.run(old_state, new_state, data)
+
+
+class EventHandler(object):
+    def __init__(self):
+        self.handlers = {}
+
+    def on(self, state, state_type):
+        def wrapped_f(func):
+            if (state, state_type) not in self.handlers:
+                self.handlers[(state, state_type)] = []
+            self.handlers[(state, state_type)].append(func)
+            return func
+        return wrapped_f
+
+    def run_state(self, state, state_type, data):
+        if (state, state_type) not in self.handlers:
+            return
+        for func in self.handlers[(state, state_type)]:
+            func(data)
+
+    def run(self, old_state, new_state, data):
+        if old_state == new_state:
+            return
+        self.run_state(old_state, StateType.Leave, data)
+        self.run_state(new_state, StateType.Enter, data)
+
 
 def GetDiscoServers():
     servers, serversErr = GetDataError(lib.GetServersList())
     organizations, organizationsErr = GetDataError(lib.GetOrganizationsList())
     return servers, serversErr, organizations, organizationsErr
-
diff --git a/wrappers/python/main.py b/wrappers/python/main.py
index 5383799..a248b71 100644
--- a/wrappers/python/main.py
+++ b/wrappers/python/main.py
@@ -1,5 +1,12 @@
 import eduvpncommon.main as eduvpn
 
-eduvpn.Register("org.eduvpn.app.linux", "configs", eduvpn.state_change)
 
-print(eduvpn.GetDiscoServers())
+_eduvpn = eduvpn.EduVPN("org.eduvpn.app.linux", "configs")
+
+
+@_eduvpn.event.on("REGISTERED", eduvpn.StateType.Enter)
+def registered(data):
+    print(f"REGISTERED PYTHON WITH DATA {data}")
+
+
+_eduvpn.register()