generate state of library from log

Author: jackharrhy

cli.py

@@ -3,15 +3,22 @@
 import typer
 from devtools import debug
 
-from library.parse import parse_log
+import library
 
 app = typer.Typer()
 
 
 @app.command()
-def cmd_parse_log():
+def parse_log():
     log_path = Path("./log.toml")
-    debug(parse_log(log_path))
+    debug(library.parse.parse_log(log_path))
+
+
+@app.command()
+def state_from_log():
+    log_path = Path("./log.toml")
+    log = library.parse.parse_log(log_path)
+    debug(library.parse.state_from_log(log))
 
 
 if __name__ == "__main__":

library/__init__.py

@@ -0,0 +1,2 @@
+from library.parse import *
+from library.models import *

library/models.py

@@ -43,4 +43,19 @@ class Action(BaseModel):
 
 
 class Log(BaseModel):
-    actions: List[Action]
+    actions: List[Action] = []
+
+
+class StateUser(User):
+    owned_books: List[Book] = []
+    held_books: List[Book] = []
+
+
+class StateBook(Book):
+    owned_by: User
+    held_by: User
+
+
+class State(BaseModel):
+    users: List[StateUser] = []
+    books: List[StateBook] = []

library/parse.py

@@ -1,9 +1,53 @@
 from pathlib import Path
+from typing import List
 
 import toml
 
-from library.models import Log
+from library.models import (
+    Book,
+    Log,
+    AddBook,
+    AddUser,
+    LendBook,
+    State,
+    StateBook,
+    StateUser,
+    User,
+)
 
 
 def parse_log(log_path: Path) -> Log:
     return Log(**toml.loads(log_path.read_text()))
+
+
+def find_user(users: List[StateUser], name: str):
+    return next(u for u in users if u.name == name)
+
+
+def find_book(books: List[StateBook], id: str):
+    return next(b for b in books if b.id == id)
+
+
+def state_from_log(log: Log) -> State:
+    state = State()
+
+    for action in [a.__root__ for a in log.actions]:
+        if isinstance(action, AddUser):
+            state.users.append(StateUser(**action.dict()))
+        elif isinstance(action, AddBook):
+            state_owner = find_user(state.users, action.user)
+            state_owner.owned_books.append(action.book)
+            state_owner.held_books.append(action.book)
+            owner = User(**state_owner.dict())
+            book = StateBook(**action.book.dict(), owned_by=owner, held_by=owner)
+            state.books.append(book)
+        elif isinstance(action, LendBook):
+            from_user = find_user(state.users, action.from_user)
+            to_user = find_user(state.users, action.to_user)
+            state_book = find_book(state.books, action.book_id)
+            state_book.held_by = User(**to_user.dict())
+            book = Book(**state_book.dict())
+            from_user.held_books.remove(book)
+            to_user.held_books.append(book)
+
+    return state