from sqlalchemy.ext.asyncio import AsyncSession

from app.users import repository
from app.users.models import User
from app.users.schemas import UserRead, UserSearchRead


async def get_user_by_id(db: AsyncSession, user_id: int) -> User | None:
    return await repository.get_user_by_id(db, user_id)


async def get_user_by_email(db: AsyncSession, email: str) -> User | None:
    return await repository.get_user_by_email(db, email)


async def get_user_by_username(db: AsyncSession, username: str) -> User | None:
    return await repository.get_user_by_username(db, username)


async def search_users_by_username(
    db: AsyncSession,
    *,
    query: str,
    limit: int = 20,
    exclude_user_id: int | None = None,
) -> list[User]:
    safe_limit = max(1, min(limit, 50))
    return await repository.search_users_by_username(
        db,
        query=query,
        limit=safe_limit,
        exclude_user_id=exclude_user_id,
    )


async def update_user_profile(
    db: AsyncSession,
    user: User,
    *,
    name: str | None = None,
    username: str | None = None,
    bio: str | None = None,
    avatar_url: str | None = None,
    allow_private_messages: bool | None = None,
    privacy_private_messages: str | None = None,
    privacy_last_seen: str | None = None,
    privacy_avatar: str | None = None,
    privacy_group_invites: str | None = None,
) -> User:
    if name is not None:
        user.name = name
    if username is not None:
        user.username = username
    if bio is not None:
        user.bio = bio
    if avatar_url is not None:
        user.avatar_url = avatar_url
    if allow_private_messages is not None:
        user.allow_private_messages = allow_private_messages
        if privacy_private_messages is None:
            user.privacy_private_messages = "everyone" if allow_private_messages else "nobody"
    if privacy_private_messages is not None:
        user.privacy_private_messages = privacy_private_messages
        user.allow_private_messages = privacy_private_messages != "nobody"
    if privacy_last_seen is not None:
        user.privacy_last_seen = privacy_last_seen
    if privacy_avatar is not None:
        user.privacy_avatar = privacy_avatar
    if privacy_group_invites is not None:
        user.privacy_group_invites = privacy_group_invites
    await db.commit()
    await db.refresh(user)
    return user


async def block_user(db: AsyncSession, *, user_id: int, blocked_user_id: int) -> None:
    await repository.block_user(db, user_id=user_id, blocked_user_id=blocked_user_id)
    await db.commit()


async def unblock_user(db: AsyncSession, *, user_id: int, blocked_user_id: int) -> None:
    await repository.unblock_user(db, user_id=user_id, blocked_user_id=blocked_user_id)
    await db.commit()


async def has_block_relation_between_users(db: AsyncSession, *, user_a_id: int, user_b_id: int) -> bool:
    return await repository.has_block_relation_between_users(db, user_a_id=user_a_id, user_b_id=user_b_id)


async def list_blocked_users(db: AsyncSession, *, user_id: int) -> list[User]:
    return await repository.list_blocked_users(db, user_id=user_id)


async def add_contact(db: AsyncSession, *, user_id: int, contact_user_id: int) -> None:
    await repository.add_contact(db, user_id=user_id, contact_user_id=contact_user_id)
    await db.commit()


async def remove_contact(db: AsyncSession, *, user_id: int, contact_user_id: int) -> None:
    await repository.remove_contact(db, user_id=user_id, contact_user_id=contact_user_id)
    await db.commit()


async def list_contacts(db: AsyncSession, *, user_id: int) -> list[User]:
    return await repository.list_contacts(db, user_id=user_id)


async def can_view_user_avatar(db: AsyncSession, *, target_user: User, viewer_user_id: int) -> bool:
    if target_user.id == viewer_user_id:
        return True
    if target_user.privacy_avatar == "everyone":
        return True
    if target_user.privacy_avatar == "nobody":
        return False
    return await repository.is_user_in_contacts(db, owner_user_id=target_user.id, candidate_user_id=viewer_user_id)


async def can_view_user_last_seen(db: AsyncSession, *, target_user: User, viewer_user_id: int) -> bool:
    if target_user.id == viewer_user_id:
        return True
    if target_user.privacy_last_seen == "everyone":
        return True
    if target_user.privacy_last_seen == "nobody":
        return False
    return await repository.is_user_in_contacts(db, owner_user_id=target_user.id, candidate_user_id=viewer_user_id)


async def can_invite_user_to_groups(db: AsyncSession, *, target_user: User, actor_user_id: int) -> bool:
    if target_user.id == actor_user_id:
        return False
    if target_user.privacy_group_invites == "everyone":
        return True
    return await repository.is_user_in_contacts(db, owner_user_id=target_user.id, candidate_user_id=actor_user_id)


async def can_user_receive_private_messages(db: AsyncSession, *, target_user: User, actor_user_id: int) -> bool:
    if target_user.id == actor_user_id:
        return True
    policy = target_user.privacy_private_messages or ("everyone" if target_user.allow_private_messages else "nobody")
    if policy == "everyone":
        return True
    if policy == "nobody":
        return False
    return await repository.is_user_in_contacts(db, owner_user_id=target_user.id, candidate_user_id=actor_user_id)


async def serialize_user_for_viewer(db: AsyncSession, *, target_user: User, viewer_user_id: int) -> UserRead:
    payload = UserRead.model_validate(target_user).model_dump()
    payload["allow_private_messages"] = bool(target_user.privacy_private_messages != "nobody")
    if not await can_view_user_avatar(db, target_user=target_user, viewer_user_id=viewer_user_id):
        payload["avatar_url"] = None
    if target_user.id != viewer_user_id:
        payload["allow_private_messages"] = True
        payload["privacy_private_messages"] = "everyone"
        payload["privacy_last_seen"] = "everyone"
        payload["privacy_avatar"] = "everyone"
        payload["privacy_group_invites"] = "everyone"
        payload["twofa_enabled"] = False
    return UserRead.model_validate(payload)


async def serialize_user_search_for_viewer(db: AsyncSession, *, target_user: User, viewer_user_id: int) -> UserSearchRead:
    payload = UserSearchRead.model_validate(target_user).model_dump()
    if not await can_view_user_avatar(db, target_user=target_user, viewer_user_id=viewer_user_id):
        payload["avatar_url"] = None
    return UserSearchRead.model_validate(payload)