import uuid
from decimal import Decimal
from typing import Any

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

from app.core.deps import get_cra_site_scope, get_current_user, get_db_session, get_operator_role_label, is_system_admin, require_study_not_locked, require_api_permission
from app.core.project_permissions import role_has_api_permission
from app.crud import audit as audit_crud
from app.crud import contract_fee as contract_fee_crud
from app.crud import contract_fee_payment as payment_crud
from app.crud import member as member_crud
from app.crud import site as site_crud
from app.crud import user as user_crud
from app.crud import study as study_crud
from app.schemas.contract_fee import ContractFeeCreate, ContractFeeDetail, ContractFeeListItem, ContractFeeRead, ContractFeeUpdate
from app.schemas.contract_fee_payment import (
    ContractFeePaymentCreate,
    ContractFeePaymentRead,
    ContractFeePaymentUpdate,
)
from app.schemas.fee_common import FeeApiResponse
from app.schemas.attachment import AttachmentRead
from app.schemas.user import UserDisplay
from app.models.attachment import Attachment

router = APIRouter()


async def _ensure_study_access(db: AsyncSession, study_id: uuid.UUID, current_user, endpoint_key: str):
    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")
    if is_system_admin(current_user):
        return None
    membership = await member_crud.get_member(db, study_id, current_user.id)
    if not membership or not membership.is_active:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="不是项目成员")
    allowed = await role_has_api_permission(db, study_id, membership.role_in_study, endpoint_key)
    if not allowed:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="接口权限不足")
    return membership


async def _ensure_center_active(db: AsyncSession, study_id: uuid.UUID, center_id: uuid.UUID | None):
    if not center_id:
        return
    site = await site_crud.get_site(db, center_id)
    if not site or site.study_id != study_id or not site.is_active:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="中心已停用")


def _parse_optional_uuid(value: str | None, detail: str) -> uuid.UUID | None:
    if not value:
        return None
    try:
        return uuid.UUID(str(value))
    except ValueError as exc:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail=detail) from exc


def _resolve_contract_fee_list_query(
    request: Request,
    study_id: uuid.UUID | None,
    center_id: uuid.UUID | None,
) -> tuple[uuid.UUID, uuid.UUID | None]:
    query = request.query_params
    resolved_study_id = study_id or _parse_optional_uuid(query.get("projectId"), "项目 ID 格式错误")
    if not resolved_study_id:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail="缺少项目 ID")

    resolved_center_id = center_id or _parse_optional_uuid(query.get("centerId"), "中心 ID 格式错误")
    return resolved_study_id, resolved_center_id


def _to_decimal(value: Any) -> Decimal:
    if isinstance(value, Decimal):
        return value
    if value is None:
        return Decimal("0")
    try:
        return Decimal(str(value))
    except Exception:
        return Decimal("0")


def _validate_payment_rules(data: ContractFeePaymentCreate | ContractFeePaymentUpdate):
    if data.is_verified is True and data.is_paid is False:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="核销需先打款")
    if data.is_paid and not data.paid_date:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="已打款需填写打款日期")
    if data.is_verified and not data.verified_date:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="已核销需填写核销日期")


@router.get(
    "/contracts",
    response_model=FeeApiResponse[list[ContractFeeListItem]],
    dependencies=[Depends(get_current_user)],
)
async def list_contract_fees(
    request: Request,
    study_id: uuid.UUID | None = None,
    center_id: uuid.UUID | None = None,
    q: str | None = None,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> FeeApiResponse[list[ContractFeeListItem]]:
    resolved_study_id, resolved_center_id = _resolve_contract_fee_list_query(request, study_id, center_id)
    await _ensure_study_access(db, resolved_study_id, current_user, "fees_contracts:read")
    cra_scope = await get_cra_site_scope(db, resolved_study_id, current_user)
    center_ids = cra_scope[0] if cra_scope else None
    if resolved_center_id and center_ids is not None and resolved_center_id not in center_ids:
        return FeeApiResponse(data=[], meta={"total": 0})
    rows = await contract_fee_crud.list_contract_fees(
        db,
        resolved_study_id,
        center_id=resolved_center_id,
        center_ids=center_ids,
        q=q,
    )
    items: list[ContractFeeListItem] = []
    for contract, center_name, paid_total, verified_total, last_paid_date, last_verified_date in rows:
        paid_total_decimal = _to_decimal(paid_total)
        verified_total_decimal = _to_decimal(verified_total)
        contract_amount_decimal = _to_decimal(contract.contract_amount)
        unpaid_balance = contract_amount_decimal - paid_total_decimal
        unverified_balance = paid_total_decimal - verified_total_decimal
        items.append(
            ContractFeeListItem(
                id=contract.id,
                study_id=contract.study_id,
                center_id=contract.center_id,
                contract_no=contract.contract_no,
                signed_date=contract.signed_date,
                contract_amount=contract_amount_decimal,
                currency=contract.currency,
                remark=contract.remark,
                contract_cases=contract.contract_cases,
                actual_cases=contract.actual_cases,
                settlement_amount=_to_decimal(contract.settlement_amount) if contract.settlement_amount else None,
                final_payment_amount=_to_decimal(contract.final_payment_amount) if contract.final_payment_amount else None,
                created_at=contract.created_at,
                updated_at=contract.updated_at,
                center_name=center_name or "",
                paid_total=paid_total_decimal,
                verified_total=verified_total_decimal,
                unpaid_balance=unpaid_balance,
                unverified_balance=unverified_balance,
                last_paid_date=last_paid_date,
                last_verified_date=last_verified_date,
            )
        )
    return FeeApiResponse(data=items, meta={"total": len(items)})


@router.get(
    "/contracts/{contract_id}",
    response_model=FeeApiResponse[ContractFeeDetail],
    dependencies=[Depends(get_current_user)],
)
async def get_contract_fee(
    contract_id: uuid.UUID,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> FeeApiResponse[ContractFeeDetail]:
    contract = await contract_fee_crud.get_contract_fee(db, contract_id)
    if not contract:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="合同费用不存在")
    await _ensure_study_access(db, contract.study_id, current_user, "fees_contracts:read")
    cra_scope = await get_cra_site_scope(db, contract.study_id, current_user)
    if cra_scope and contract.center_id not in cra_scope[0]:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="权限不足")

    payments = await payment_crud.list_payments(db, contract.id)
    attachment_types = ["contract_fee_contract", "contract_fee_voucher", "contract_fee_invoice"]
    result = await db.execute(
        select(Attachment).where(
            Attachment.entity_id == contract.id,
            Attachment.entity_type.in_(attachment_types),
            Attachment.is_deleted.is_(False),
        )
    )
    attachments = result.scalars().all()
    user_ids = {a.uploaded_by for a in attachments if a.uploaded_by}
    users_map = await user_crud.get_users_by_ids(db, user_ids)

    attachments_map: dict[str, list[AttachmentRead]] = {
        "contract": [],
        "voucher": [],
        "invoice": [],
    }
    for attachment in attachments:
        key = attachment.entity_type.replace("contract_fee_", "", 1)
        attachments_map.setdefault(key, [])
        user = users_map.get(attachment.uploaded_by)
        attachments_map[key].append(
            AttachmentRead(
                id=attachment.id,
                filename=attachment.filename,
                file_size=attachment.file_size,
                content_type=attachment.content_type,
                uploaded_by_id=attachment.uploaded_by,
                uploaded_by=UserDisplay.model_validate(user) if user else None,
                uploaded_at=attachment.uploaded_at,
            )
        )

    payment_reads = [ContractFeePaymentRead.model_validate(payment) for payment in payments]

    detail = ContractFeeDetail(
        id=contract.id,
        study_id=contract.study_id,
        center_id=contract.center_id,
        contract_no=contract.contract_no,
        signed_date=contract.signed_date,
        contract_amount=_to_decimal(contract.contract_amount),
        currency=contract.currency,
        remark=contract.remark,
        contract_cases=contract.contract_cases,
        actual_cases=contract.actual_cases,
        settlement_amount=_to_decimal(contract.settlement_amount) if contract.settlement_amount else None,
        final_payment_amount=_to_decimal(contract.final_payment_amount) if contract.final_payment_amount else None,
        created_at=contract.created_at,
        updated_at=contract.updated_at,
        payments=payment_reads,
        attachments=attachments_map,
    )

    return FeeApiResponse(data=detail)


@router.post(
    "/contracts",
    response_model=FeeApiResponse[ContractFeeRead],
    status_code=status.HTTP_201_CREATED,
    dependencies=[Depends(get_current_user), Depends(require_study_not_locked())],
)
async def create_contract_fee(
    contract_in: ContractFeeCreate,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> FeeApiResponse[ContractFeeRead]:
    await _ensure_study_access(db, contract_in.study_id, current_user, "fees_contracts:create")
    existing = await contract_fee_crud.get_contract_fee_by_study_center(
        db, contract_in.study_id, contract_in.center_id
    )
    if existing:
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="该中心已存在合同费用")

    site = await site_crud.get_site(db, contract_in.center_id)
    if not site or site.study_id != contract_in.study_id or not site.is_active:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="中心不存在或已停用")

    contract = await contract_fee_crud.create_contract_fee(db, contract_in)
    await audit_crud.log_action(
        db,
        study_id=contract.study_id,
        entity_type="contract_fee",
        entity_id=contract.id,
        action="CREATE_CONTRACT_FEE",
        detail="合同费用已创建",
        operator_id=current_user.id,
        operator_role=await get_operator_role_label(db, contract.study_id, current_user),
    )
    return FeeApiResponse(data=ContractFeeRead.model_validate(contract))


@router.patch(
    "/contracts/{contract_id}",
    response_model=FeeApiResponse[ContractFeeRead],
    dependencies=[Depends(get_current_user), Depends(require_study_not_locked())],
)
async def update_contract_fee(
    contract_id: uuid.UUID,
    contract_in: ContractFeeUpdate,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
    ) -> FeeApiResponse[ContractFeeRead]:
    contract = await contract_fee_crud.get_contract_fee(db, contract_id)
    if not contract:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="合同费用不存在")
    await _ensure_study_access(db, contract.study_id, current_user, "fees_contracts:update")
    await _ensure_center_active(db, contract.study_id, contract.center_id)
    contract = await contract_fee_crud.update_contract_fee(db, contract, contract_in)
    await audit_crud.log_action(
        db,
        study_id=contract.study_id,
        entity_type="contract_fee",
        entity_id=contract_id,
        action="UPDATE_CONTRACT_FEE",
        detail="合同费用已更新",
        operator_id=current_user.id,
        operator_role=await get_operator_role_label(db, contract.study_id, current_user),
    )
    return FeeApiResponse(data=ContractFeeRead.model_validate(contract))


@router.delete(
    "/contracts/{contract_id}",
    status_code=status.HTTP_204_NO_CONTENT,
    dependencies=[Depends(get_current_user), Depends(require_study_not_locked())],
)
async def delete_contract_fee(
    contract_id: uuid.UUID,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> None:
    contract = await contract_fee_crud.get_contract_fee(db, contract_id)
    if not contract:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="合同费用不存在")
    await _ensure_study_access(db, contract.study_id, current_user, "fees_contracts:delete")
    await _ensure_center_active(db, contract.study_id, contract.center_id)
    await contract_fee_crud.delete_contract_fee(db, contract)
    await audit_crud.log_action(
        db,
        study_id=contract.study_id,
        entity_type="contract_fee",
        entity_id=contract_id,
        action="DELETE_CONTRACT_FEE",
        detail="合同费用已删除",
        operator_id=current_user.id,
        operator_role=await get_operator_role_label(db, contract.study_id, current_user),
    )


@router.post(
    "/contracts/{contract_id}/payments",
    response_model=FeeApiResponse[ContractFeePaymentRead],
    status_code=status.HTTP_201_CREATED,
    dependencies=[Depends(get_current_user), Depends(require_study_not_locked())],
)
async def create_contract_payment(
    contract_id: uuid.UUID,
    payment_in: ContractFeePaymentCreate,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> FeeApiResponse[ContractFeePaymentRead]:
    contract = await contract_fee_crud.get_contract_fee(db, contract_id)
    if not contract:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="合同费用不存在")
    await _ensure_study_access(db, contract.study_id, current_user, "fees_contracts:update")
    _validate_payment_rules(payment_in)
    payment = await payment_crud.create_payment(db, contract_id, payment_in)
    await audit_crud.log_action(
        db,
        study_id=contract.study_id,
        entity_type="contract_fee_payment",
        entity_id=payment.id,
        action="CREATE_CONTRACT_FEE_PAYMENT",
        detail="合同费用分期已创建",
        operator_id=current_user.id,
        operator_role=await get_operator_role_label(db, contract.study_id, current_user),
    )
    return FeeApiResponse(data=ContractFeePaymentRead.model_validate(payment))


@router.patch(
    "/payments/{payment_id}",
    response_model=FeeApiResponse[ContractFeePaymentRead],
    dependencies=[Depends(get_current_user), Depends(require_study_not_locked())],
)
async def update_contract_payment(
    payment_id: uuid.UUID,
    payment_in: ContractFeePaymentUpdate,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> FeeApiResponse[ContractFeePaymentRead]:
    payment = await payment_crud.get_payment(db, payment_id)
    if not payment:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="分期记录不存在")
    contract = await contract_fee_crud.get_contract_fee(db, payment.contract_fee_id)
    if not contract:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="合同费用不存在")
    await _ensure_study_access(db, contract.study_id, current_user, "fees_contracts:update")
    merged_payment = ContractFeePaymentCreate(
        amount=payment_in.amount if payment_in.amount is not None else payment.amount,
        paid_date=payment_in.paid_date if payment_in.paid_date is not None else payment.paid_date,
        verified_date=payment_in.verified_date if payment_in.verified_date is not None else payment.verified_date,
        is_paid=payment_in.is_paid if payment_in.is_paid is not None else payment.is_paid,
        is_verified=payment_in.is_verified if payment_in.is_verified is not None else payment.is_verified,
        remark=payment_in.remark if payment_in.remark is not None else payment.remark,
    )
    _validate_payment_rules(merged_payment)
    payment = await payment_crud.update_payment(db, payment, payment_in)
    await audit_crud.log_action(
        db,
        study_id=contract.study_id,
        entity_type="contract_fee_payment",
        entity_id=payment_id,
        action="UPDATE_CONTRACT_FEE_PAYMENT",
        detail="合同费用分期已更新",
        operator_id=current_user.id,
        operator_role=await get_operator_role_label(db, contract.study_id, current_user),
    )
    return FeeApiResponse(data=ContractFeePaymentRead.model_validate(payment))


@router.delete(
    "/payments/{payment_id}",
    status_code=status.HTTP_204_NO_CONTENT,
    dependencies=[Depends(get_current_user), Depends(require_study_not_locked())],
)
async def delete_contract_payment(
    payment_id: uuid.UUID,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> None:
    payment = await payment_crud.get_payment(db, payment_id)
    if not payment:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="分期记录不存在")
    contract = await contract_fee_crud.get_contract_fee(db, payment.contract_fee_id)
    if not contract:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="合同费用不存在")
    await _ensure_study_access(db, contract.study_id, current_user, "fees_contracts:update")
    await payment_crud.delete_payment(db, payment)
    await payment_crud.resequence_payments(db, contract.id)
    await audit_crud.log_action(
        db,
        study_id=contract.study_id,
        entity_type="contract_fee_payment",
        entity_id=payment_id,
        action="DELETE_CONTRACT_FEE_PAYMENT",
        detail="合同费用分期已删除",
        operator_id=current_user.id,
        operator_role=await get_operator_role_label(db, contract.study_id, current_user),
    )