From 76ea80b1784e209a2490fbdac25f215036c961ec Mon Sep 17 00:00:00 2001
From: norohind <60548839+norohind@users.noreply.github.com>
Date: Sun, 10 Apr 2022 23:08:31 +0300
Subject: [PATCH] Introduce hooks support

---
 FAPI/__init__.py  |  5 ++++
 Hook.py           | 11 +++++++++
 HookSystem.py     | 58 +++++++++++++++++++++++++++++++++++++++++++++++
 hooks/testHook.py | 11 +++++++++
 4 files changed, 85 insertions(+)
 create mode 100644 Hook.py
 create mode 100644 HookSystem.py
 create mode 100644 hooks/testHook.py

diff --git a/FAPI/__init__.py b/FAPI/__init__.py
index a32b9b2..734db8f 100644
--- a/FAPI/__init__.py
+++ b/FAPI/__init__.py
@@ -1,5 +1,8 @@
 from . import Queries
 import DB
+import HookSystem
+
+hook_system = HookSystem.HookSystem()
 
 
 def update_squad(squad_id: int, suppress_absence=False) -> None | int:
@@ -15,10 +18,12 @@ def update_squad(squad_id: int, suppress_absence=False) -> None | int:
         # Squad not found FDEV
         if not suppress_absence:
             operation_id = DB.delete_squadron(squad_id)
+            hook_system.notify_deleted(operation_id)
 
     else:
         # Then we got valid squad_info dict
         news_info = Queries.get_squad_news(squad_id)
         operation_id = DB.insert_info_news(news_info, squad_info)
+        hook_system.notify_inserted(operation_id)
 
     return operation_id
diff --git a/Hook.py b/Hook.py
new file mode 100644
index 0000000..0ac0a79
--- /dev/null
+++ b/Hook.py
@@ -0,0 +1,11 @@
+from abc import ABC, abstractmethod
+
+
+class Hook(ABC):  # See at Hook class as to observer in observer pattern
+    """
+    In order to implement hook, subclass this class and pass instance to HookSystem.add_hook
+    """
+
+    @abstractmethod
+    def update(self, operation_id: int) -> None:
+        raise NotImplemented
diff --git a/HookSystem.py b/HookSystem.py
new file mode 100644
index 0000000..a3a1e2f
--- /dev/null
+++ b/HookSystem.py
@@ -0,0 +1,58 @@
+import os
+import functools
+import threading
+from Hook import Hook
+import importlib.machinery
+
+
+def check_int(func: callable) -> callable:
+    @functools.wraps(func)
+    def decorated(self, operation_id: int | None) -> None:
+        if type(operation_id) == int:
+            return func(self, operation_id)
+
+    return decorated
+
+
+class HookSystem:
+    hooks_inserted: list[Hook] = list()
+    hooks_deleted: list[Hook] = list()
+
+    def __init__(self):
+        # hooks load
+        for file_name in sorted(os.listdir('hooks')):
+            if file_name.endswith('.py') and not file_name[0] in ['.', '_']:
+                path = os.path.join('hooks', file_name)
+                hook_name = file_name[:-3]
+                module = importlib.machinery.SourceFileLoader(hook_name, path).load_module()
+                setup_func = getattr(module, 'setup', None)
+                if setup_func is not None:
+                    setup_func(self)
+
+                else:
+                    raise AttributeError(f'No setup method in {file_name} hook')
+
+    def add_on_insert_hook(self, hook: Hook) -> None:
+        self.hooks_inserted.append(hook)
+
+    def remove_on_insert_hook(self, hook: Hook) -> None:
+        self.hooks_inserted.remove(hook)
+
+    def add_on_delete_hook(self, hook: Hook) -> None:
+        self.hooks_deleted.append(hook)
+
+    def remove_on_delete_hook(self, hook: Hook) -> None:
+        self.hooks_deleted.remove(hook)
+
+    @check_int
+    def notify_inserted(self, operation_id: int | None) -> None:
+        self._notify(operation_id, self.hooks_inserted)
+
+    @check_int
+    def notify_deleted(self, operation_id: int) -> None:
+        self._notify(operation_id, self.hooks_deleted)
+
+    @staticmethod
+    def _notify(operation_id, hooks: list[Hook]) -> None:
+        for hook in hooks:
+            threading.Thread(target=hook.update, args=(operation_id,)).start()
diff --git a/hooks/testHook.py b/hooks/testHook.py
new file mode 100644
index 0000000..3f5b872
--- /dev/null
+++ b/hooks/testHook.py
@@ -0,0 +1,11 @@
+from HookSystem import HookSystem
+from Hook import Hook
+
+
+class testHook(Hook):
+    def update(self, operation_id: int) -> None:
+        print('update')
+
+
+def setup(hook_system: HookSystem) -> None:
+    hook_system.add_on_insert_hook(testHook())