from typing import List

from fastapi import APIRouter, Depends, HTTPException, status

from app.api.deps import (
    get_current_user,
    get_training_repository,
    get_user_repository,
    require_superuser,
)
from app.core.database.repository import TrainingRepository
from app.core.database.user_repository import UserRepository
from app.core.dto.training import TrainingDTO
from app.core.dto.user import UserDTO, UserRole
from app.core.parsers.obsidian import parse_training_data
from app.schemas.trainings import TrainingUpdate


router = APIRouter()


async def _check_participant(
    repository: UserRepository, user_id: int, role: UserRole
) -> None:
    user = await repository.get(user_id)
    if user is None or user.role != role:
        raise HTTPException(
            status_code=422, detail=f"User {user_id} is not an existing {role.value}"
        )


async def _get_editable_training(
    training_id: int, user: UserDTO, repository: TrainingRepository
) -> TrainingDTO:
    """A training the user may change: their own (as the trainee), or any for a superuser.

    The trainer can only see the training. A training the user can't see at all is a 404.
    """
    training = await repository.get(training_id, viewer=user)
    if training is None:
        raise HTTPException(status_code=404, detail="Training not found")
    if not (user.is_superuser or training.trainee_id == user.id):
        raise HTTPException(status_code=403, detail="Only the trainee can change a training")
    return training


@router.get("/obsidian/", dependencies=[Depends(require_superuser)])
async def obsidian_trainings_list():
    return {"data": parse_training_data()}


@router.get("/", response_model=List[TrainingDTO])
async def get_trainings_list(
    user: UserDTO = Depends(get_current_user),
    repository: TrainingRepository = Depends(get_training_repository),
):
    """Trainings the user takes part in (all of them for a superuser)."""
    return await repository.list(viewer=user)


@router.get("/{training_id}/", response_model=TrainingDTO)
async def get_training(
    training_id: int,
    user: UserDTO = Depends(get_current_user),
    repository: TrainingRepository = Depends(get_training_repository),
):
    training = await repository.get(training_id, viewer=user)
    if training is None:
        raise HTTPException(status_code=404, detail="Training not found")
    return training


@router.post("/", response_model=TrainingDTO, status_code=status.HTTP_201_CREATED)
async def create_training(
    payload: TrainingUpdate,
    user: UserDTO = Depends(get_current_user),
    repository: TrainingRepository = Depends(get_training_repository),
    user_repository: UserRepository = Depends(get_user_repository),
):
    """Create a training. Only a superuser may create it for another trainee."""
    if payload.trainee_id != user.id:
        if not user.is_superuser:
            raise HTTPException(
                status_code=403, detail="Only a superuser can create a training for another user"
            )
        await _check_participant(user_repository, payload.trainee_id, UserRole.trainee)
    if payload.trainer_id is not None:
        await _check_participant(user_repository, payload.trainer_id, UserRole.trainer)
    training_id = await repository.save(TrainingDTO.model_validate(payload.model_dump()))
    return await repository.get(training_id)


@router.put("/{training_id}/", response_model=TrainingDTO)
async def update_training(
    training_id: int,
    payload: TrainingUpdate,
    user: UserDTO = Depends(get_current_user),
    repository: TrainingRepository = Depends(get_training_repository),
    user_repository: UserRepository = Depends(get_user_repository),
):
    """Replace the training: its date, trainee, trainer, exercises and approaches."""
    current = await _get_editable_training(training_id, user, repository)
    if payload.trainee_id != current.trainee_id:
        if not user.is_superuser:
            raise HTTPException(
                status_code=403, detail="Only a superuser can change the trainee"
            )
        await _check_participant(user_repository, payload.trainee_id, UserRole.trainee)
    if payload.trainer_id is not None:
        await _check_participant(user_repository, payload.trainer_id, UserRole.trainer)
    training = TrainingDTO.model_validate(payload.model_dump())
    if not await repository.replace(training_id, training):
        raise HTTPException(status_code=404, detail="Training not found")
    return await repository.get(training_id)


@router.delete("/{training_id}/")
async def delete_training(
    training_id: int,
    user: UserDTO = Depends(get_current_user),
    repository: TrainingRepository = Depends(get_training_repository),
):
    await _get_editable_training(training_id, user, repository)
    await repository.delete([training_id])
    return {"status": "ok"}