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, require_study_not_locked
from app.crud import audit as audit_crud
from app.crud import site as site_crud
from app.crud import subject as subject_crud
from app.crud import study as study_crud
from app.crud import visit as visit_crud
from app.schemas.visit import VisitCreate, VisitRead, VisitUpdate

router = APIRouter()


async def _ensure_subject(db: AsyncSession, study_id: uuid.UUID, subject_id: uuid.UUID):
    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="参与者不存在")
    return subject


async def _ensure_subject_active(db: AsyncSession, subject) -> None:
    if not subject or not subject.site_id:
        return
    site = await site_crud.get_site(db, subject.site_id)
    if not site or not site.is_active:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="中心已停用")


@router.get(
    "/",
    response_model=list[VisitRead],
    dependencies=[Depends(require_study_member())],
)
async def list_visits(
    study_id: uuid.UUID,
    subject_id: uuid.UUID,
    db: AsyncSession = Depends(get_db_session),
) -> list[VisitRead]:
    await _ensure_subject(db, study_id, subject_id)
    visits = await visit_crud.list_visits(db, subject_id)
    return list(visits)


@router.post(
    "/",
    response_model=VisitRead,
    status_code=status.HTTP_201_CREATED,
    dependencies=[Depends(require_study_roles(["PM", "CRA"])), Depends(require_study_not_locked())],
)
async def create_visit(
    study_id: uuid.UUID,
    subject_id: uuid.UUID,
    visit_in: VisitCreate,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> VisitRead:
    subject = await _ensure_subject(db, study_id, subject_id)
    await _ensure_subject_active(db, subject)
    if visit_in.subject_id != subject_id:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="参与者不匹配")
    visit = await visit_crud.create_visit(
        db,
        study_id=study_id,
        visit_in=visit_in,
        subject=subject,
        visit_code=visit_in.visit_code,
        planned_date=visit_in.planned_date,
    )
    if visit_in.visit_code == "V1" and visit_in.planned_date:
        study = await study_crud.get(db, study_id)
        if study:
            await visit_crud.create_followup_visits(
                db,
                study_id=study_id,
                subject=subject,
                base_date=visit_in.planned_date,
                visit_total=study.visit_total,
                visit_interval_days=study.visit_interval_days,
                window_start_offset=study.visit_window_start_offset,
                window_end_offset=study.visit_window_end_offset,
            )
    await audit_crud.log_action(
        db,
        study_id=study_id,
        entity_type="visit",
        entity_id=visit.id,
        action="CREATE_VISIT",
        detail=f"访视 {visit.visit_code} 已创建",
        operator_id=current_user.id,
        operator_role=current_user.role,
    )
    return visit


@router.patch(
    "/{visit_id}",
    response_model=VisitRead,
    dependencies=[Depends(require_study_roles(["PM", "CRA"])), Depends(require_study_not_locked())],
)
async def update_visit(
    study_id: uuid.UUID,
    subject_id: uuid.UUID,
    visit_id: uuid.UUID,
    visit_in: VisitUpdate,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> VisitRead:
    subject = await _ensure_subject(db, study_id, subject_id)
    await _ensure_subject_active(db, subject)
    visit = await visit_crud.get_visit(db, visit_id)
    if not visit or visit.subject_id != subject_id or visit.study_id != study_id:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="访视不存在")
    if visit_in.status == "DONE" and not visit_in.actual_date:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="状态为已完成时必须填写实际日期")
    updated = await visit_crud.update_visit(db, visit, visit_in)
    detail = None
    if visit_in.status:
        detail = f"访视 {visit.visit_code} {visit.status} -> {visit_in.status}"
    await audit_crud.log_action(
        db,
        study_id=study_id,
        entity_type="visit",
        entity_id=visit_id,
        action="VISIT_STATUS_CHANGE" if detail else "UPDATE_VISIT",
        detail=detail or "访视已更新",
        operator_id=current_user.id,
        operator_role=current_user.role,
    )
    return updated


@router.delete(
    "/{visit_id}",
    status_code=status.HTTP_204_NO_CONTENT,
    dependencies=[Depends(require_study_roles(["PM", "CRA"])), Depends(require_study_not_locked())],
)
async def delete_visit(
    study_id: uuid.UUID,
    subject_id: uuid.UUID,
    visit_id: uuid.UUID,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> None:
    subject = await _ensure_subject(db, study_id, subject_id)
    await _ensure_subject_active(db, subject)
    visit = await visit_crud.get_visit(db, visit_id)
    if not visit or visit.subject_id != subject_id or visit.study_id != study_id:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="访视不存在")
    await visit_crud.delete_visit(db, visit)
    await audit_crud.log_action(
        db,
        study_id=study_id,
        entity_type="visit",
        entity_id=visit_id,
        action="DELETE_VISIT",
        detail=f"访视 {visit_id} 已删除",
        operator_id=current_user.id,
        operator_role=current_user.role,
    )