import uuid

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

from app.core.deps import get_current_user, get_db_session, require_study_member, require_study_roles
from app.crud import audit as audit_crud
from app.crud import subject as subject_crud
from app.crud import study as study_crud
from app.schemas.subject import SubjectCreate, SubjectRead, SubjectUpdate

router = APIRouter()


async def _ensure_study_exists(db: AsyncSession, study_id: uuid.UUID):
    study = await study_crud.get(db, study_id)
    if not study:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="项目不存在")
    return study


@router.post(
    "/",
    response_model=SubjectRead,
    status_code=status.HTTP_201_CREATED,
    dependencies=[Depends(require_study_roles(["PM", "CRA"]))],
)
async def create_subject(
    study_id: uuid.UUID,
    subject_in: SubjectCreate,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> SubjectRead:
    await _ensure_study_exists(db, study_id)
    try:
        subject = await subject_crud.create_subject(db, study_id, subject_in)
    except ValueError as exc:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(exc)) from exc
    await audit_crud.log_action(
        db,
        study_id=study_id,
        entity_type="subject",
        entity_id=subject.id,
        action="CREATE_SUBJECT",
        detail=f"受试者 {subject.subject_no} 已创建",
        operator_id=current_user.id,
        operator_role=current_user.role,
    )
    return subject


@router.get(
    "/",
    response_model=list[SubjectRead],
    dependencies=[Depends(require_study_member())],
)
async def list_subjects(
    study_id: uuid.UUID,
    site_id: uuid.UUID | None = None,
    status_filter: str | None = None,
    subject_no: str | None = None,
    db: AsyncSession = Depends(get_db_session),
) -> list[SubjectRead]:
    await _ensure_study_exists(db, study_id)
    subjects = await subject_crud.list_subjects(
        db, study_id, site_id=site_id, status=status_filter, subject_no=subject_no
    )
    return list(subjects)


@router.get(
    "/{subject_id}",
    response_model=SubjectRead,
    dependencies=[Depends(require_study_member())],
)
async def get_subject(
    study_id: uuid.UUID,
    subject_id: uuid.UUID,
    db: AsyncSession = Depends(get_db_session),
) -> SubjectRead:
    await _ensure_study_exists(db, study_id)
    subject = await subject_crud.get_subject(db, subject_id)
    if not subject or subject.study_id != study_id:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="受试者不存在")
    return subject


@router.patch(
    "/{subject_id}",
    response_model=SubjectRead,
    dependencies=[Depends(require_study_roles(["PM", "CRA"]))],
)
async def update_subject(
    study_id: uuid.UUID,
    subject_id: uuid.UUID,
    subject_in: SubjectUpdate,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> SubjectRead:
    await _ensure_study_exists(db, study_id)
    subject = await subject_crud.get_subject(db, subject_id)
    if not subject or subject.study_id != study_id:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="受试者不存在")
    old_status = subject.status
    updated = await subject_crud.update_subject(db, subject, subject_in)
    # auto-generate visits when enrolled
    if subject_in.status and subject_in.status == "ENROLLED" and (subject_in.enrollment_date or updated.enrollment_date):
        await subject_crud.generate_default_visits(db, updated)
    detail = None
    if subject_in.status and subject_in.status != old_status:
        detail = f"受试者 {updated.subject_no} 状态 {old_status} -> {subject_in.status}"
    await audit_crud.log_action(
        db,
        study_id=study_id,
        entity_type="subject",
        entity_id=subject_id,
        action="SUBJECT_STATUS_CHANGE" if detail else "UPDATE_SUBJECT",
        detail=detail or "受试者已更新",
        operator_id=current_user.id,
        operator_role=current_user.role,
    )
    return updated


@router.delete(
    "/{subject_id}",
    status_code=status.HTTP_204_NO_CONTENT,
    dependencies=[Depends(require_study_roles(["PM", "CRA"]))],
)
async def delete_subject(
    study_id: uuid.UUID,
    subject_id: uuid.UUID,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> None:
    await _ensure_study_exists(db, study_id)
    subject = await subject_crud.get_subject(db, subject_id)
    if not subject or subject.study_id != study_id:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="受试者不存在")
    await subject_crud.delete_subject(db, subject)
    await audit_crud.log_action(
        db,
        study_id=study_id,
        entity_type="subject",
        entity_id=subject_id,
        action="DELETE_SUBJECT",
        detail=f"受试者 {subject_id} 已删除",
        operator_id=current_user.id,
        operator_role=current_user.role,
    )