import uuid
from datetime import date

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 attachment as attachment_crud
from app.crud import milestone as milestone_crud
from app.crud import study as study_crud
from app.crud import user as user_crud
from app.crud import site as site_crud
from app.schemas.milestone import MilestoneCreate, MilestoneRead, MilestoneUpdate
from app.schemas.user import UserDisplay
from app.schemas.milestone import SiteDisplay

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)
    if milestone_in.planned_date and milestone_in.planned_date < date.today():
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="计划日期不得早于今天")
    milestone = await milestone_crud.create(db, study_id, milestone_in)
    owner = None
    site = None
    if milestone.owner_id:
        owner = await user_crud.get_by_id(db, milestone.owner_id)
    if milestone.site_id:
        site = await site_crud.get_site(db, milestone.site_id)
    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 MilestoneRead(
        id=milestone.id,
        study_id=milestone.study_id,
        type=milestone.type,
        name=milestone.name,
        planned_date=milestone.planned_date,
        actual_date=milestone.actual_date,
        status=milestone.status,
        owner_id=milestone.owner_id,
        site_id=milestone.site_id,
        owner=UserDisplay.model_validate(owner) if owner else None,
        site=SiteDisplay.model_validate(site) if site else None,
        notes=milestone.notes,
        created_at=milestone.created_at,
        updated_at=milestone.updated_at,
    )


@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)
    owner_ids = {m.owner_id for m in milestones if m.owner_id}
    site_ids = {m.site_id for m in milestones if m.site_id}
    users_map = await user_crud.get_users_by_ids(db, owner_ids)
    sites_map = await site_crud.get_sites_by_ids(db, site_ids)
    result: list[MilestoneRead] = []
    for m in milestones:
        owner = users_map.get(m.owner_id)
        site = sites_map.get(m.site_id)
        result.append(
            MilestoneRead(
                id=m.id,
                study_id=m.study_id,
                type=m.type,
                name=m.name,
                planned_date=m.planned_date,
                actual_date=m.actual_date,
                status=m.status,
                owner_id=m.owner_id,
                site_id=m.site_id,
                owner=UserDisplay.model_validate(owner) if owner else None,
                site=SiteDisplay.model_validate(site) if site else None,
                notes=m.notes,
                created_at=m.created_at,
                updated_at=m.updated_at,
            )
        )
    return result


@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")
    if milestone_in.planned_date and milestone_in.planned_date < date.today():
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="计划日期不得早于今天")
    if milestone_in.actual_date and milestone_in.actual_date < date.today():
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="实际日期不得早于今天")
    if milestone_in.actual_date:
        attachments = await attachment_crud.list_attachments(db, study_id, "ethics_node", milestone_id)
        if not attachments:
            raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="请先上传伦理批件后再更新实际日期")
        milestone_in.status = "DONE"
    old_status = milestone.status
    updated = await milestone_crud.update(db, milestone, milestone_in)
    owner = None
    site = None
    if updated.owner_id:
        owner = await user_crud.get_by_id(db, updated.owner_id)
    if updated.site_id:
        site = await site_crud.get_site(db, updated.site_id)
    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 MilestoneRead(
        id=updated.id,
        study_id=updated.study_id,
        type=updated.type,
        name=updated.name,
        planned_date=updated.planned_date,
        actual_date=updated.actual_date,
        status=updated.status,
        owner_id=updated.owner_id,
        site_id=updated.site_id,
        owner=UserDisplay.model_validate(owner) if owner else None,
        site=SiteDisplay.model_validate(site) if site else None,
        notes=updated.notes,
        created_at=updated.created_at,
        updated_at=updated.updated_at,
    )


@router.delete(
    "/{milestone_id}",
    status_code=status.HTTP_204_NO_CONTENT,
    dependencies=[Depends(require_study_member())],
)
async def delete_milestone(
    study_id: uuid.UUID,
    milestone_id: uuid.UUID,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> None:
    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")
    await milestone_crud.delete_milestone(db, milestone)
    await audit_crud.log_action(
        db,
        study_id=study_id,
        entity_type="milestone",
        entity_id=milestone_id,
        action="DELETE_MILESTONE",
        detail=f"Milestone {milestone_id} deleted",
        operator_id=current_user.id,
        operator_role=current_user.role,
    )
    return None