Initial commit

Backend/Users.py

@@ -0,0 +1,170 @@
+from __future__ import annotations
+
+import hashlib
+import hmac
+import secrets
+import tomllib
+
+from pathlib import Path
+from typing import Any
+
+import tomli_w
+
+from Settings import GetDataDirectory
+
+
+Pbkdf2Iterations = 260_000
+
+UserColourOptions = ["Red", "Orange", "Yellow", "Green", "Blue", "Purple"]
+DefaultUserColour = "Purple"
+
+AllowedAvatarExtensions = {".png", ".jpg", ".jpeg", ".gif", ".webp"}
+
+
+def GetUsersPath():
+    return GetDataDirectory() / "Users.toml"
+
+
+def GetAvatarDirectory() -> Path:
+    return GetDataDirectory() / "Avatars"
+
+
+def HashPassword(Password: str) -> str:
+    Salt = secrets.token_hex(16)
+    DerivedKey = hashlib.pbkdf2_hmac(
+        "sha256", Password.encode("utf-8"), bytes.fromhex(Salt), Pbkdf2Iterations
+    )
+    return f"pbkdf2_sha256${Pbkdf2Iterations}${Salt}${DerivedKey.hex()}"
+
+
+def VerifyPassword(Password: str, StoredHash: str) -> bool:
+    try:
+        Algorithm, IterationsText, Salt, HashHex = StoredHash.split("$")
+    except ValueError:
+        return False
+
+    if Algorithm != "pbkdf2_sha256":
+        return False
+
+    DerivedKey = hashlib.pbkdf2_hmac(
+        "sha256", Password.encode("utf-8"), bytes.fromhex(Salt), int(IterationsText)
+    )
+    return hmac.compare_digest(DerivedKey.hex(), HashHex)
+
+
+def LoadUsers() -> dict[str, dict[str, Any]]:
+    UsersPath = GetUsersPath()
+
+    if not UsersPath.is_file():
+        return {}
+
+    with UsersPath.open("rb") as UsersFile:
+        Loaded = tomllib.load(UsersFile)
+
+    return Loaded.get("Users", {})
+
+
+def SaveUsers(Users: dict[str, dict[str, Any]]) -> None:
+    GetDataDirectory().mkdir(parents=True, exist_ok=True)
+
+    with GetUsersPath().open("wb") as UsersFile:
+        tomli_w.dump({"Users": Users}, UsersFile)
+
+
+def AnyUsersExist() -> bool:
+    return len(LoadUsers()) > 0
+
+
+def GetUser(Username: str) -> dict[str, Any] | None:
+    return LoadUsers().get(Username)
+
+
+def CreateUser(Username: str, Password: str, IsAdmin: bool, Colour: str = DefaultUserColour) -> None:
+    if not Username or not Username.strip():
+        raise ValueError("Username cannot be empty.")
+
+    if not Password:
+        raise ValueError("Password cannot be empty.")
+
+    if Colour not in UserColourOptions:
+        Colour = DefaultUserColour
+
+    Users = LoadUsers()
+
+    if Username in Users:
+        raise ValueError(f"User '{Username}' already exists.")
+
+    Users[Username] = {
+        "PasswordHash": HashPassword(Password),
+        "IsAdmin": IsAdmin,
+        "Colour": Colour,
+    }
+    SaveUsers(Users)
+
+
+def UpdateUserColour(Username: str, Colour: str) -> None:
+    if Colour not in UserColourOptions:
+        raise ValueError(f"Invalid colour: {Colour}")
+
+    Users = LoadUsers()
+
+    if Username not in Users:
+        raise ValueError("User not found.")
+
+    Users[Username]["Colour"] = Colour
+    SaveUsers(Users)
+
+
+def VerifyLogin(Username: str, Password: str) -> dict[str, Any] | None:
+    User = GetUser(Username)
+
+    if User is None:
+        return None
+
+    if not VerifyPassword(Password, User["PasswordHash"]):
+        return None
+
+    return {
+        "Username": Username,
+        "IsAdmin": User.get("IsAdmin", False),
+        "Colour": User.get("Colour", DefaultUserColour),
+    }
+
+
+def ListUsers() -> list[dict[str, Any]]:
+    Users = LoadUsers()
+    return [
+        {
+            "Username": Name,
+            "IsAdmin": Data.get("IsAdmin", False),
+            "Colour": Data.get("Colour", DefaultUserColour),
+        }
+        for Name, Data in Users.items()
+    ]
+
+
+def SaveAvatar(Username: str, FileBytes: bytes, Extension: str) -> None:
+    Extension = Extension.lower()
+
+    if Extension not in AllowedAvatarExtensions:
+        raise ValueError(f"Unsupported image type: {Extension}")
+
+    Directory = GetAvatarDirectory()
+    Directory.mkdir(parents=True, exist_ok=True)
+
+    # Remove any previous avatar for this user under a different extension.
+    for ExistingPath in Directory.glob(f"{Username}.*"):
+        ExistingPath.unlink()
+
+    AvatarPath = Directory / f"{Username}{Extension}"
+    AvatarPath.write_bytes(FileBytes)
+
+
+def GetAvatarPath(Username: str) -> Path | None:
+    Directory = GetAvatarDirectory()
+
+    if not Directory.is_dir():
+        return None
+
+    Matches = sorted(Directory.glob(f"{Username}.*"))
+    return Matches[0] if Matches else None