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 milestone as milestone_crud
from app.crud import study as study_crud
from app.schemas.milestone import MilestoneCreate, MilestoneRead, MilestoneUpdate

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="Study not found")
    return study


@router.post(
    "/",
    response_model=MilestoneRead,
    status_code=status.HTTP_201_CREATED,
    dependencies=[Depends(require_study_roles(["PM"]))],
)
async def create_milestone(
    study_id: uuid.UUID,
    milestone_in: MilestoneCreate,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> MilestoneRead:
    await _ensure_study_exists(db, study_id)
    milestone = await milestone_crud.create(db, study_id, milestone_in)
    await audit_crud.log_action(
        db,
        study_id=study_id,
        entity_type="milestone",
        entity_id=milestone.id,
        action="CREATE_MILESTONE",
        detail=f"Milestone {milestone.id} created",
        operator_id=current_user.id,
        operator_role=current_user.role,
    )
    return milestone


@router.get(
    "/",
    response_model=list[MilestoneRead],
    dependencies=[Depends(require_study_member())],
)
async def list_milestones(
    study_id: uuid.UUID,
    db: AsyncSession = Depends(get_db_session),
) -> list[MilestoneRead]:
    await _ensure_study_exists(db, study_id)
    milestones = await milestone_crud.list_milestones(db, study_id)
    return list(milestones)


@router.patch(
    "/{milestone_id}",
    response_model=MilestoneRead,
    dependencies=[Depends(require_study_roles(["PM"]))],
)
async def update_milestone(
    study_id: uuid.UUID,
    milestone_id: uuid.UUID,
    milestone_in: MilestoneUpdate,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> MilestoneRead:
    await _ensure_study_exists(db, study_id)
    milestone = await milestone_crud.get(db, milestone_id)
    if not milestone or milestone.study_id != study_id:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Milestone not found")
    old_status = milestone.status
    updated = await milestone_crud.update(db, milestone, milestone_in)
    detail = None
    if milestone_in.status and milestone_in.status != old_status:
        detail = f"milestone {milestone_id} status {old_status} -> {milestone_in.status}"
    await audit_crud.log_action(
        db,
        study_id=study_id,
        entity_type="milestone",
        entity_id=milestone_id,
        action="UPDATE_MILESTONE",
        detail=detail or "Milestone updated",
        operator_id=current_user.id,
        operator_role=current_user.role,
    )
    return updated