from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy.ext.asyncio import AsyncSession

from app.auth.service import get_current_user
from app.database.session import get_db
from app.users.models import User
from app.users.schemas import ContactByEmailRequest, UserProfileUpdate, UserRead, UserSearchRead
from app.users.service import (
    add_contact,
    block_user,
    get_user_by_id,
    get_user_by_email,
    get_user_by_username,
    list_blocked_users,
    list_contacts,
    has_block_relation_between_users,
    remove_contact,
    search_users_by_username,
    serialize_user_for_viewer,
    serialize_user_search_for_viewer,
    unblock_user,
    update_user_profile,
)

router = APIRouter(prefix="/users", tags=["users"])


@router.get("/me", response_model=UserRead)
async def read_me(current_user: User = Depends(get_current_user)) -> UserRead:
    return current_user


@router.get("/search", response_model=list[UserSearchRead])
async def search_users(
    query: str,
    limit: int = 20,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> list[UserSearchRead]:
    if len(query.strip().lstrip("@")) < 2:
        return []
    users = await search_users_by_username(
        db,
        query=query,
        limit=limit,
        exclude_user_id=current_user.id,
    )
    return [await serialize_user_search_for_viewer(db, target_user=user, viewer_user_id=current_user.id) for user in users]


@router.put("/profile", response_model=UserRead)
async def update_profile(
    payload: UserProfileUpdate,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> UserRead:
    if payload.username and payload.username != current_user.username:
        username_owner = await get_user_by_username(db, payload.username)
        if username_owner:
            raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="Username already taken")

    updated = await update_user_profile(
        db,
        current_user,
        name=payload.name,
        username=payload.username,
        bio=payload.bio,
        avatar_url=payload.avatar_url,
        allow_private_messages=payload.allow_private_messages,
        privacy_private_messages=payload.privacy_private_messages,
        privacy_last_seen=payload.privacy_last_seen,
        privacy_avatar=payload.privacy_avatar,
        privacy_group_invites=payload.privacy_group_invites,
    )
    return await serialize_user_for_viewer(db, target_user=updated, viewer_user_id=current_user.id)


@router.get("/blocked", response_model=list[UserSearchRead])
async def read_blocked_users(
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> list[UserSearchRead]:
    users = await list_blocked_users(db, user_id=current_user.id)
    return [await serialize_user_search_for_viewer(db, target_user=user, viewer_user_id=current_user.id) for user in users]


@router.get("/contacts", response_model=list[UserSearchRead])
async def read_contacts(
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> list[UserSearchRead]:
    users = await list_contacts(db, user_id=current_user.id)
    return [await serialize_user_search_for_viewer(db, target_user=user, viewer_user_id=current_user.id) for user in users]


@router.post("/{user_id}/contacts", status_code=status.HTTP_204_NO_CONTENT)
async def add_contact_endpoint(
    user_id: int,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> None:
    if user_id == current_user.id:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail="Cannot add yourself")
    target = await get_user_by_id(db, user_id)
    if not target:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="User not found")
    is_blocked = await has_block_relation_between_users(db, user_a_id=current_user.id, user_b_id=user_id)
    if is_blocked:
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="Cannot add contact while blocked")
    await add_contact(db, user_id=current_user.id, contact_user_id=user_id)


@router.post("/contacts/by-email", status_code=status.HTTP_204_NO_CONTENT)
async def add_contact_by_email_endpoint(
    payload: ContactByEmailRequest,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> None:
    target = await get_user_by_email(db, payload.email)
    if not target:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="User not found")
    if target.id == current_user.id:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail="Cannot add yourself")
    is_blocked = await has_block_relation_between_users(db, user_a_id=current_user.id, user_b_id=target.id)
    if is_blocked:
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="Cannot add contact while blocked")
    await add_contact(db, user_id=current_user.id, contact_user_id=target.id)


@router.delete("/{user_id}/contacts", status_code=status.HTTP_204_NO_CONTENT)
async def remove_contact_endpoint(
    user_id: int,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> None:
    if user_id == current_user.id:
        return
    await remove_contact(db, user_id=current_user.id, contact_user_id=user_id)


@router.post("/{user_id}/block", status_code=status.HTTP_204_NO_CONTENT)
async def block_user_endpoint(
    user_id: int,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> None:
    if user_id == current_user.id:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail="Cannot block yourself")
    target = await get_user_by_id(db, user_id)
    if not target:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="User not found")
    await block_user(db, user_id=current_user.id, blocked_user_id=user_id)


@router.delete("/{user_id}/block", status_code=status.HTTP_204_NO_CONTENT)
async def unblock_user_endpoint(
    user_id: int,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> None:
    if user_id == current_user.id:
        return
    await unblock_user(db, user_id=current_user.id, blocked_user_id=user_id)


@router.get("/{user_id}", response_model=UserRead)
async def read_user(user_id: int, db: AsyncSession = Depends(get_db), _current_user: User = Depends(get_current_user)) -> UserRead:
    user = await get_user_by_id(db, user_id)
    if not user:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="User not found")
    return await serialize_user_for_viewer(db, target_user=user, viewer_user_id=_current_user.id)