Add most basic Todo family relations.

[plomtask] / plomtask / todos.py

diff --git a/plomtask/todos.py b/plomtask/todos.py
index 7150f0d702c44ec89e170e5381b20c8e61ea42ae..7faea73b74df9c4b5a8f68f6dceced09f27c9b67 100644 (file)
--- a/plomtask/todos.py
+++ b/plomtask/todos.py
@@ -4,7 +4,8 @@ from sqlite3 import Row
 from plomtask.db import DatabaseConnection
 from plomtask.days import Day
 from plomtask.processes import Process
-from plomtask.exceptions import NotFoundException
+from plomtask.exceptions import (NotFoundException, BadFormatException,
+                                 HandledException)
 
 
 class Todo:
@@ -16,38 +17,74 @@ class Todo:
         self.process = process
         self.is_done = is_done
         self.day = day
-
-    def __eq__(self, other: object) -> bool:
-        return isinstance(other, self.__class__) and self.id_ == other.id_
+        self.children: list[Todo] = []
 
     @classmethod
-    def from_table_row(cls, row: Row, db_conn: DatabaseConnection) -> Todo:
-        """Make Todo from database row."""
-        return cls(id_=row[0],
+    def from_table_row(cls, db_conn: DatabaseConnection, row: Row) -> Todo:
+        """Make Todo from database row, write to DB cache."""
+        todo = cls(id_=row[0],
                    process=Process.by_id(db_conn, row[1]),
                    is_done=row[2],
                    day=Day.by_date(db_conn, row[3]))
+        assert todo.id_ is not None
+        db_conn.cached_todos[todo.id_] = todo
+        return todo
 
     @classmethod
-    def by_id(cls, db_conn: DatabaseConnection, id_: int) -> Todo:
-        """Get Todo of .id_=id_."""
-        for row in db_conn.exec('SELECT * FROM todos WHERE id = ?', (id_,)):
-            return cls.from_table_row(row, db_conn)
-        raise NotFoundException(f'Todo of ID not found: {id_}')
+    def by_id(cls, db_conn: DatabaseConnection, id_: int | None) -> Todo:
+        """Get Todo of .id_=id_ and children (from DB cache if possible)."""
+        if id_ in db_conn.cached_todos.keys():
+            todo = db_conn.cached_todos[id_]
+        else:
+            todo = None
+            for row in db_conn.exec('SELECT * FROM todos WHERE id = ?',
+                                    (id_,)):
+                todo = cls.from_table_row(db_conn, row)
+                break
+            if todo is None:
+                raise NotFoundException(f'Todo of ID not found: {id_}')
+            for row in db_conn.exec('SELECT child FROM todo_children '
+                                    'WHERE parent = ?', (id_,)):
+                todo.children += [cls.by_id(db_conn, row[0])]
+        assert isinstance(todo, Todo)
+        return todo
 
     @classmethod
     def by_date(cls, db_conn: DatabaseConnection, date: str) -> list[Todo]:
         """Collect all Todos for Day of date."""
         todos = []
-        for row in db_conn.exec('SELECT * FROM todos WHERE day = ?', (date,)):
-            todos += [cls.from_table_row(row, db_conn)]
+        for row in db_conn.exec('SELECT id FROM todos WHERE day = ?', (date,)):
+            todos += [cls.by_id(db_conn, row[0])]
         return todos
 
+    def add_child(self, child: Todo) -> None:
+        """Add child to self.children, guard against recursion"""
+        def walk_steps(node: Todo) -> None:
+            if node.id_ == self.id_:
+                raise BadFormatException('bad child choice causes recursion')
+            for child in node.children:
+                walk_steps(child)
+        if self.id_ is None:
+            raise HandledException('Can only add children to saved Todos.')
+        if child.id_ is None:
+            raise HandledException('Can only add saved children to Todos.')
+        if child in self.children:
+            raise BadFormatException('cannot adopt same child twice')
+        walk_steps(child)
+        self.children += [child]
+
     def save(self, db_conn: DatabaseConnection) -> None:
-        """Write self to DB."""
+        """Write self and children to DB and its cache."""
         if self.process.id_ is None:
             raise NotFoundException('Process of Todo without ID (not saved?)')
         cursor = db_conn.exec('REPLACE INTO todos VALUES (?,?,?,?)',
                               (self.id_, self.process.id_,
                                self.is_done, self.day.date))
         self.id_ = cursor.lastrowid
+        assert self.id_ is not None
+        db_conn.cached_todos[self.id_] = self
+        db_conn.exec('DELETE FROM todo_children WHERE parent = ?',
+                     (self.id_,))
+        for child in self.children:
+            db_conn.exec('INSERT INTO todo_children VALUES (?, ?)',
+                         (self.id_, child.id_))