import hashlib
import uuid
from dataclasses import asdict
from datetime import date, timedelta
from pathlib import Path
from typing import Any

from sqlalchemy.orm import Session

from app.audit import service as audit
from app.config import get_settings
from app.db.session import session_scope
from app.errors import AppError, conflict, not_found
from app.identity.models import User
from app.imports.adapters import detect_adapter, magic_kind
from app.imports.adapters.base import SourceRow, StatementDraft, record_fingerprint
from app.imports.blob import get_blob_store, new_object_key
from app.imports.crypto import decrypt_file, encrypt_file
from app.imports.models import (
    DedupCandidate,
    ParseRun,
    SourceRecord,
    SourceRecordLink,
    StatementDocument,
)
from app.ledger.models import Account, Operation
from app.ledger.service import (
    create_expense,
    create_income,
    create_transfer,
    ensure_period_open_for_date,
)


def _document(db: Session, *, space_id: uuid.UUID, document_id: uuid.UUID) -> StatementDocument:
    document = (
        db.query(StatementDocument).filter_by(id=document_id, space_id=space_id).one_or_none()
    )
    if document is None:
        raise not_found("IMPORT_NOT_FOUND", "Statement import not found")
    return document


def create_document(
    db: Session,
    *,
    space_id: uuid.UUID,
    user: User,
    filename: str,
    raw: bytes,
    account_id: uuid.UUID | None,
) -> tuple[StatementDocument, bool]:
    settings = get_settings()
    if not raw or len(raw) > settings.max_upload_bytes:
        raise AppError(
            "File size is outside the allowed range", code="IMPORT_SIZE_INVALID", status_code=413
        )
    kind = magic_kind(raw)
    if kind is None:
        raise AppError(
            "Only XLSX and text-layer PDF statements are supported",
            code="IMPORT_TYPE_INVALID",
            status_code=415,
        )
    suffix = Path(filename).suffix.casefold()
    if suffix not in ({".xlsx"} if kind == "xlsx" else {".pdf"}):
        raise AppError(
            "File extension does not match its content",
            code="IMPORT_TYPE_MISMATCH",
            status_code=422,
        )
    if account_id is not None:
        account = db.query(Account.id).filter_by(id=account_id, space_id=space_id).one_or_none()
        if account is None:
            raise not_found("LEDGER_ACCOUNT_NOT_FOUND", "Account not found")
    digest = hashlib.sha256(raw).hexdigest()
    existing = (
        db.query(StatementDocument)
        .filter_by(space_id=space_id, content_sha256=digest)
        .one_or_none()
    )
    if existing is not None:
        return existing, False
    encrypted = encrypt_file(raw)
    object_key = new_object_key()
    get_blob_store().put(object_key, encrypted.ciphertext)
    try:
        document = StatementDocument(
            space_id=space_id,
            account_id=account_id,
            original_filename=Path(filename).name[:300],
            size_bytes=len(raw),
            content_sha256=digest,
            object_key=object_key,
            dek_wrapped=encrypted.dek_wrapped,
            dek_wrap_nonce=encrypted.wrap_nonce,
            content_nonce=encrypted.content_nonce,
            status="queued",
            uploaded_by_user_id=user.id,
        )
        db.add(document)
        db.flush()
    except Exception:
        get_blob_store().delete(object_key)
        raise
    audit.record(
        db,
        event_type="import.uploaded",
        space_id=space_id,
        user_id=user.id,
        detail={"document_id": str(document.id), "size_bytes": len(raw)},
    )
    return document, True


def _draft_json(draft: StatementDraft) -> dict[str, Any]:
    value = asdict(draft)
    for key in ("period_start", "period_end"):
        item = value[key]
        value[key] = item.isoformat() if item else None
    for row in value["rows"]:
        for key in ("occurred_on", "posted_on"):
            item = row[key]
            row[key] = item.isoformat() if item else None
    return value


def _source_from_row(
    *, space_id: uuid.UUID, document_id: uuid.UUID, run_id: uuid.UUID, row: SourceRow
) -> SourceRecord:
    critical_warnings = {"occurred_date_missing", "amount_unparseable"}
    warnings = list(row.warnings)
    if row.direction not in {"in", "out"}:
        warnings.append("direction_invalid")
    if row.amount_kopecks == 0:
        warnings.append("amount_zero")
    return SourceRecord(
        space_id=space_id,
        document_id=document_id,
        parse_run_id=run_id,
        external_id=row.external_id,
        occurred_on=row.occurred_on,
        posted_on=row.posted_on,
        amount_kopecks=abs(row.amount_kopecks),
        direction=row.direction,
        description=row.description,
        mcc=row.mcc,
        bank_category=row.bank_category,
        location=row.location,
        row_ref=row.row_ref,
        field_warnings={"codes": sorted(set(warnings))} if warnings else None,
        critical=(
            bool(set(warnings) & critical_warnings)
            or row.amount_kopecks == 0
            or row.direction not in {"in", "out"}
        ),
        record_fp=record_fingerprint(row.occurred_on, abs(row.amount_kopecks), row.description),
    )


def _build_candidates(db: Session, *, document: StatementDocument, run: ParseRun) -> bool:
    pending = False
    for source in db.query(SourceRecord).filter_by(parse_run_id=run.id).all():
        duplicate = None
        if source.external_id:
            matches = (
                db.query(SourceRecord)
                .join(ParseRun, ParseRun.id == SourceRecord.parse_run_id)
                .filter(
                    SourceRecord.space_id == document.space_id,
                    SourceRecord.id != source.id,
                    SourceRecord.external_id == source.external_id,
                    ParseRun.adapter_id == run.adapter_id,
                )
                .all()
            )
            duplicate = matches[0] if len(matches) == 1 else None
        if duplicate is None:
            matches = (
                db.query(SourceRecord)
                .filter(
                    SourceRecord.space_id == document.space_id,
                    SourceRecord.id != source.id,
                    SourceRecord.record_fp == source.record_fp,
                    SourceRecord.direction == source.direction,
                )
                .all()
            )
            duplicate = matches[0] if len(matches) == 1 else None
        if duplicate is not None:
            link = db.query(SourceRecordLink).filter_by(source_record_id=duplicate.id).one_or_none()
            db.add(
                DedupCandidate(
                    space_id=document.space_id,
                    source_record_id=source.id,
                    candidate_kind="duplicate",
                    existing_source_record_id=duplicate.id,
                    existing_operation_id=link.operation_id if link else None,
                    confidence="strong" if source.external_id else "possible",
                )
            )
            pending = True
            continue
        if source.occurred_on is None:
            continue
        opposite = "in" if source.direction == "out" else "out"
        transfer_matches = (
            db.query(SourceRecord)
            .join(SourceRecordLink, SourceRecordLink.source_record_id == SourceRecord.id)
            .filter(
                SourceRecord.space_id == document.space_id,
                SourceRecord.id != source.id,
                SourceRecord.amount_kopecks == source.amount_kopecks,
                SourceRecord.direction == opposite,
                SourceRecord.occurred_on >= source.occurred_on - timedelta(days=1),
                SourceRecord.occurred_on <= source.occurred_on + timedelta(days=1),
            )
            .all()
        )
        if len(transfer_matches) == 1:
            counterpart = transfer_matches[0]
            link = db.query(SourceRecordLink).filter_by(source_record_id=counterpart.id).one()
            db.add(
                DedupCandidate(
                    space_id=document.space_id,
                    source_record_id=source.id,
                    candidate_kind="transfer",
                    existing_source_record_id=counterpart.id,
                    existing_operation_id=link.operation_id,
                    confidence="possible",
                )
            )
            pending = True
    return pending


def process_statement_document(document_id: uuid.UUID, space_id: uuid.UUID) -> str:
    with session_scope(space_id) as db:
        document = _document(db, space_id=space_id, document_id=document_id)
        if document.status in {"confirmed", "deleted"}:
            return document.status
        document.status = "processing"
        run = ParseRun(space_id=space_id, document_id=document.id, status="running")
        db.add(run)
        db.flush()
        try:
            if not all((document.dek_wrapped, document.dek_wrap_nonce, document.content_nonce)):
                raise AppError(
                    "Document key material is missing",
                    code="IMPORT_DECRYPT_FAILED",
                    status_code=409,
                )
            assert document.dek_wrapped is not None
            assert document.dek_wrap_nonce is not None
            assert document.content_nonce is not None
            raw = decrypt_file(
                ciphertext=get_blob_store().get(document.object_key),
                content_nonce=document.content_nonce,
                dek_wrapped=document.dek_wrapped,
                wrap_nonce=document.dek_wrap_nonce,
            )
            kind = magic_kind(raw)
            if kind is None:
                raise AppError(
                    "Unsupported document content", code="IMPORT_TYPE_INVALID", status_code=415
                )
            adapter = detect_adapter(raw, kind)
            draft = adapter.parse(raw)
            run.adapter_id = adapter.adapter_id
            run.parser_version = draft.parser_version
            run.draft = _draft_json(draft)
            run.status = "succeeded"
            document.adapter_id = adapter.adapter_id
            document.account_fingerprint = draft.account_fingerprint
            document.active_parse_run_id = run.id
            document.reconciliation = {
                "currency": draft.currency,
                "opening_balance_kopecks": draft.opening_balance_kopecks,
                "closing_balance_kopecks": draft.closing_balance_kopecks,
                "full": draft.opening_balance_kopecks is not None
                and draft.closing_balance_kopecks is not None,
                "confirmed_without_full_reconciliation": False,
            }
            if document.reconciliation["full"]:
                signed_total = sum(
                    row.amount_kopecks if row.direction == "in" else -row.amount_kopecks
                    for row in draft.rows
                )
                computed = int(draft.opening_balance_kopecks or 0) + signed_total
                document.reconciliation["computed_closing_kopecks"] = computed
                document.reconciliation["matched"] = computed == draft.closing_balance_kopecks
            if draft.account_fingerprint and document.account_id is None:
                matches = (
                    db.query(Account)
                    .filter_by(space_id=space_id, fingerprint=draft.account_fingerprint)
                    .all()
                )
                if len(matches) == 1:
                    document.account_id = matches[0].id
            for row in draft.rows:
                db.add(
                    _source_from_row(
                        space_id=space_id, document_id=document.id, run_id=run.id, row=row
                    )
                )
            db.flush()
            has_candidates = _build_candidates(db, document=document, run=run)
            critical = (
                db.query(SourceRecord.id).filter_by(parse_run_id=run.id, critical=True).first()
            )
            document.needs_account_mapping = document.account_id is None
            needs_manual_reconciliation = not document.reconciliation["full"]
            document.status = (
                "review_required"
                if critical
                or document.needs_account_mapping
                or needs_manual_reconciliation
                or has_candidates
                or document.reconciliation.get("matched") is False
                else "ready"
            )
        except AppError as exc:
            run.status = "failed"
            run.error_code = exc.code
            document.status = "failed"
            document.error_code = exc.code
        except Exception:
            run.status = "failed"
            run.error_code = "IMPORT_PARSE_FAILED"
            document.status = "failed"
            document.error_code = "IMPORT_PARSE_FAILED"
        return document.status


def list_documents(db: Session, *, space_id: uuid.UUID) -> list[StatementDocument]:
    return (
        db.query(StatementDocument)
        .filter_by(space_id=space_id)
        .order_by(StatementDocument.created_at.desc())
        .all()
    )


def document_detail(db: Session, *, space_id: uuid.UUID, document_id: uuid.UUID) -> dict:
    document = _document(db, space_id=space_id, document_id=document_id)
    records = []
    if document.active_parse_run_id:
        records = (
            db.query(SourceRecord)
            .filter_by(parse_run_id=document.active_parse_run_id)
            .order_by(SourceRecord.created_at)
            .all()
        )
    return {
        "id": document.id,
        "status": document.status,
        "adapter_id": document.adapter_id,
        "account_id": document.account_id,
        "needs_account_mapping": document.needs_account_mapping,
        "error_code": document.error_code,
        "reconciliation": document.reconciliation,
        "records": [
            {
                "id": item.id,
                "external_id": item.external_id,
                "occurred_on": item.occurred_on,
                "posted_on": item.posted_on,
                "amount_kopecks": item.amount_kopecks,
                "direction": item.direction,
                "description": item.description,
                "critical": item.critical,
                "warnings": item.field_warnings,
                "review_decision": item.review_decision,
                "duplicate_operation_id": item.duplicate_operation_id,
            }
            for item in records
        ],
    }


def decide_source_record(
    db: Session,
    *,
    space_id: uuid.UUID,
    document_id: uuid.UUID,
    source_record_id: uuid.UUID,
    decision: str,
    duplicate_operation_id: uuid.UUID | None,
    user: User,
) -> None:
    document = _document(db, space_id=space_id, document_id=document_id)
    source = (
        db.query(SourceRecord)
        .filter_by(
            id=source_record_id,
            space_id=space_id,
            parse_run_id=document.active_parse_run_id,
        )
        .one_or_none()
    )
    if source is None:
        raise not_found("IMPORT_SOURCE_RECORD_NOT_FOUND", "Import row not found")
    if decision not in {"create", "discard", "duplicate", "transfer"}:
        raise conflict("IMPORT_DECISION_INVALID", "Unsupported row decision")
    candidates = db.query(DedupCandidate).filter_by(source_record_id=source.id).all()
    matching = [item for item in candidates if item.candidate_kind == decision]
    if decision == "duplicate" and duplicate_operation_id is None and len(matching) == 1:
        duplicate_operation_id = matching[0].existing_operation_id
    if decision in {"duplicate", "transfer"} and len(matching) != 1:
        raise conflict("IMPORT_CANDIDATE_AMBIGUOUS", "A unique matching candidate is required")
    if decision == "duplicate":
        operation = (
            db.query(Operation)
            .filter_by(id=duplicate_operation_id, space_id=space_id)
            .one_or_none()
        )
        if operation is None:
            raise not_found("LEDGER_OPERATION_NOT_FOUND", "Duplicate operation not found")
    source.review_decision = decision
    source.duplicate_operation_id = duplicate_operation_id
    for candidate in candidates:
        if candidate not in matching:
            candidate.resolution = "is_new"
        elif decision == "duplicate":
            candidate.resolution = "is_duplicate"
        else:
            candidate.resolution = "accepted_transfer"
        candidate.decided_by_user_id = user.id
    if source.critical and decision in {"discard", "duplicate"}:
        source.critical = False
    unresolved = (
        db.query(SourceRecord.id)
        .filter_by(parse_run_id=document.active_parse_run_id, critical=True)
        .first()
    )
    pending_candidate = (
        db.query(DedupCandidate.id)
        .join(SourceRecord, SourceRecord.id == DedupCandidate.source_record_id)
        .filter(
            SourceRecord.parse_run_id == document.active_parse_run_id,
            DedupCandidate.resolution == "pending",
        )
        .first()
    )
    reconciliation = document.reconciliation or {}
    reconciled = reconciliation.get("full") and reconciliation.get("matched") is not False
    reconciled = reconciled or reconciliation.get("confirmed_without_full_reconciliation")
    if not unresolved and not pending_candidate and document.account_id and reconciled:
        document.status = "ready"


def set_review_confirmation(
    db: Session,
    *,
    space_id: uuid.UUID,
    document_id: uuid.UUID,
    account_id: uuid.UUID,
    confirmed_without_full_reconciliation: bool,
    reason: str | None,
) -> StatementDocument:
    document = _document(db, space_id=space_id, document_id=document_id)
    account = db.query(Account).filter_by(id=account_id, space_id=space_id).one_or_none()
    if account is None:
        raise not_found("LEDGER_ACCOUNT_NOT_FOUND", "Account not found")
    if confirmed_without_full_reconciliation and not reason:
        raise conflict("IMPORT_RECONCILIATION_REASON_REQUIRED", "A confirmation reason is required")
    document.account_id = account.id
    document.needs_account_mapping = False
    reconciliation = dict(document.reconciliation or {})
    reconciliation["confirmed_without_full_reconciliation"] = confirmed_without_full_reconciliation
    reconciliation["reason"] = reason
    document.reconciliation = reconciliation
    critical = (
        db.query(SourceRecord.id)
        .filter_by(parse_run_id=document.active_parse_run_id, critical=True)
        .first()
    )
    pending_candidate = (
        db.query(DedupCandidate.id)
        .join(SourceRecord, SourceRecord.id == DedupCandidate.source_record_id)
        .filter(
            SourceRecord.parse_run_id == document.active_parse_run_id,
            DedupCandidate.resolution == "pending",
        )
        .first()
    )
    if not critical and not pending_candidate and reconciliation.get("matched") is not False:
        document.status = "ready"
    return document


def confirm_document(
    db: Session, *, space_id: uuid.UUID, document_id: uuid.UUID, user: User
) -> StatementDocument:
    document = _document(db, space_id=space_id, document_id=document_id)
    db.refresh(document, with_for_update=True)
    if document.status == "confirmed":
        return document
    if document.status != "ready" or document.account_id is None:
        raise conflict("IMPORT_NOT_READY", "Import review is not complete")
    reconciliation = document.reconciliation or {}
    if not reconciliation.get("full") and not reconciliation.get(
        "confirmed_without_full_reconciliation"
    ):
        raise conflict("IMPORT_RECONCILIATION_REQUIRED", "Reconciliation must be confirmed")
    if reconciliation.get("full") and reconciliation.get("matched") is False:
        raise conflict("IMPORT_RECONCILIATION_MISMATCH", "Statement arithmetic does not reconcile")
    pending = (
        db.query(DedupCandidate.id)
        .join(SourceRecord, SourceRecord.id == DedupCandidate.source_record_id)
        .filter(
            SourceRecord.parse_run_id == document.active_parse_run_id,
            DedupCandidate.resolution == "pending",
        )
        .first()
    )
    if pending:
        raise conflict("IMPORT_DECISIONS_REQUIRED", "Duplicate or transfer decisions remain")
    records = db.query(SourceRecord).filter_by(parse_run_id=document.active_parse_run_id).all()
    if any(item.critical for item in records):
        raise conflict("IMPORT_FIELDS_UNRESOLVED", "Critical source fields remain unresolved")
    for source in records:
        if source.review_decision == "discard":
            continue
        if source.review_decision == "transfer":
            candidate = (
                db.query(DedupCandidate)
                .filter_by(
                    source_record_id=source.id,
                    candidate_kind="transfer",
                    resolution="accepted_transfer",
                )
                .one()
            )
            assert candidate.existing_source_record_id is not None
            counterpart = db.get(SourceRecord, candidate.existing_source_record_id)
            old_link = (
                db.query(SourceRecordLink)
                .filter_by(source_record_id=candidate.existing_source_record_id)
                .one()
            )
            old_operation = db.get(Operation, old_link.operation_id)
            if (
                counterpart is None
                or old_operation is None
                or old_operation.account_id is None
                or old_operation.type not in {"income", "expense"}
            ):
                raise conflict(
                    "IMPORT_TRANSFER_TARGET_MISSING",
                    "Transfer counterpart is unavailable",
                )
            other_links = (
                db.query(SourceRecordLink.id)
                .filter(
                    SourceRecordLink.operation_id == old_operation.id,
                    SourceRecordLink.id != old_link.id,
                )
                .first()
            )
            if other_links:
                raise conflict(
                    "IMPORT_TRANSFER_TARGET_AMBIGUOUS",
                    "Counterpart has multiple links",
                )
            ensure_period_open_for_date(db, space_id=space_id, day=old_operation.occurred_on)
            from app.budgeting.models import ExpectedIncomeMatch

            has_income_match = (
                db.query(ExpectedIncomeMatch.id).filter_by(operation_id=old_operation.id).first()
            )
            has_refund = (
                db.query(Operation.id)
                .filter_by(parent_operation_id=old_operation.id, status="confirmed")
                .first()
            )
            if has_income_match or has_refund:
                raise conflict(
                    "IMPORT_TRANSFER_TARGET_HAS_DEPENDENCIES",
                    "Unlink matches and refunds before converting this operation to a transfer",
                )
            candidate.replacement_snapshot = {
                "type": old_operation.type,
                "account_id": str(old_operation.account_id),
                "amount_kopecks": old_operation.amount_kopecks,
                "occurred_on": old_operation.occurred_on.isoformat(),
                "posted_on": old_operation.posted_on.isoformat()
                if old_operation.posted_on
                else None,
                "category_id": str(old_operation.category_id)
                if old_operation.category_id
                else None,
                "income_source_id": str(old_operation.income_source_id)
                if old_operation.income_source_id
                else None,
                "payee_id": str(old_operation.payee_id) if old_operation.payee_id else None,
                "description": old_operation.description,
                "request_key": old_operation.request_key,
                "link_kind": old_link.kind,
            }
            source_account_id = (
                document.account_id if source.direction == "out" else old_operation.account_id
            )
            target_account_id = (
                old_operation.account_id if source.direction == "out" else document.account_id
            )
            db.query(DedupCandidate).filter_by(existing_operation_id=old_operation.id).update(
                {DedupCandidate.existing_operation_id: None}
            )
            db.delete(old_link)
            db.delete(old_operation)
            db.flush()
            assert source.occurred_on is not None
            operation = create_transfer(
                db,
                space_id=space_id,
                user=user,
                source_account_id=source_account_id,
                target_account_id=target_account_id,
                amount_kopecks=source.amount_kopecks,
                occurred_on=source.occurred_on,
                posted_on=source.posted_on,
                description=source.description,
                request_key=f"import-transfer:{source.id}",
            )
            db.add_all(
                [
                    SourceRecordLink(
                        space_id=space_id,
                        source_record_id=source.id,
                        operation_id=operation.id,
                        kind="transfer",
                    ),
                    SourceRecordLink(
                        space_id=space_id,
                        source_record_id=counterpart.id,
                        operation_id=operation.id,
                        kind="transfer",
                    ),
                ]
            )
            continue
        if source.review_decision == "duplicate" and source.duplicate_operation_id:
            duplicate_operation = (
                db.query(Operation)
                .filter_by(id=source.duplicate_operation_id, space_id=space_id)
                .one_or_none()
            )
            if duplicate_operation is None:
                raise conflict(
                    "IMPORT_DUPLICATE_TARGET_MISSING",
                    "Duplicate target no longer exists",
                )
            db.add(
                SourceRecordLink(
                    space_id=space_id,
                    source_record_id=source.id,
                    operation_id=duplicate_operation.id,
                    kind="duplicate",
                )
            )
            continue
        existing_links = (
            db.query(SourceRecordLink)
            .join(SourceRecord, SourceRecord.id == SourceRecordLink.source_record_id)
            .filter(
                SourceRecord.space_id == space_id,
                SourceRecord.external_id == source.external_id,
                SourceRecord.external_id.is_not(None),
            )
            .all()
            if source.external_id
            else []
        )
        linked_operation = (
            db.get(Operation, existing_links[0].operation_id) if len(existing_links) == 1 else None
        )
        kind = "duplicate"
        if linked_operation is None:
            assert source.occurred_on is not None
            if source.direction == "in":
                linked_operation = create_income(
                    db,
                    space_id=space_id,
                    user=user,
                    account_id=document.account_id,
                    amount_kopecks=source.amount_kopecks,
                    occurred_on=source.occurred_on,
                    posted_on=source.posted_on,
                    description=source.description,
                    request_key=f"import:{source.id}",
                )
            else:
                linked_operation = create_expense(
                    db,
                    space_id=space_id,
                    user=user,
                    account_id=document.account_id,
                    amount_kopecks=source.amount_kopecks,
                    occurred_on=source.occurred_on,
                    posted_on=source.posted_on,
                    description=source.description,
                    request_key=f"import:{source.id}",
                )
            kind = "created"
        db.add(
            SourceRecordLink(
                space_id=space_id,
                source_record_id=source.id,
                operation_id=linked_operation.id,
                kind=kind,
            )
        )
    document.status = "confirmed"
    audit.record(
        db,
        event_type="import.confirmed",
        space_id=space_id,
        user_id=user.id,
        detail={"document_id": str(document.id), "records": len(records)},
    )
    return document


def prepare_reparse(
    db: Session, *, space_id: uuid.UUID, document_id: uuid.UUID, user: User
) -> StatementDocument:
    document = _document(db, space_id=space_id, document_id=document_id)
    if document.status == "confirmed":
        raise conflict(
            "IMPORT_REPARSE_CONFIRMED",
            "Revert the confirmed import before reparsing its source",
        )
    if document.status == "deleted":
        raise conflict("IMPORT_SOURCE_DELETED", "Deleted source files cannot be reparsed")
    if document.status in {"queued", "processing"}:
        return document
    document.status = "queued"
    document.error_code = None
    audit.record(
        db,
        event_type="import.reparse_queued",
        space_id=space_id,
        user_id=user.id,
        detail={"document_id": str(document.id)},
    )
    return document


def revert_document(
    db: Session, *, space_id: uuid.UUID, document_id: uuid.UUID, user: User
) -> StatementDocument:
    from app.budgeting.models import BudgetPeriod

    document = _document(db, space_id=space_id, document_id=document_id)
    if document.status != "confirmed":
        return document
    links = (
        db.query(SourceRecordLink)
        .join(SourceRecord, SourceRecord.id == SourceRecordLink.source_record_id)
        .filter(SourceRecord.parse_run_id == document.active_parse_run_id)
        .all()
    )
    transfer_candidates = (
        db.query(DedupCandidate)
        .join(SourceRecord, SourceRecord.id == DedupCandidate.source_record_id)
        .filter(
            SourceRecord.parse_run_id == document.active_parse_run_id,
            DedupCandidate.candidate_kind == "transfer",
            DedupCandidate.resolution == "accepted_transfer",
        )
        .all()
    )
    created = [db.get(Operation, link.operation_id) for link in links if link.kind == "created"]
    transfer_operations = [
        db.get(Operation, link.operation_id) for link in links if link.kind == "transfer"
    ]
    affected = {
        (operation.occurred_on.year, operation.occurred_on.month)
        for operation in created + transfer_operations
        if operation is not None
    }
    for candidate in transfer_candidates:
        candidate_snapshot = candidate.replacement_snapshot or {}
        if candidate_snapshot.get("occurred_on"):
            original_day = date.fromisoformat(candidate_snapshot["occurred_on"])
            affected.add((original_day.year, original_day.month))
    closed = (
        db.query(BudgetPeriod)
        .filter(
            BudgetPeriod.space_id == space_id,
            BudgetPeriod.status == "closed",
        )
        .all()
    )
    impacted = [item for item in closed if (item.year, item.month) in affected]
    if impacted:
        raise conflict(
            "IMPORT_REVERT_REQUIRES_REOPEN",
            "Affected budget periods must be reopened before reverting",
            details={"period_ids": [str(item.id) for item in impacted]},
        )
    created_ids = [
        operation.id for operation in created + transfer_operations if operation is not None
    ]
    dependent_refund = (
        db.query(Operation.id)
        .filter(Operation.parent_operation_id.in_(created_ids), Operation.status == "confirmed")
        .first()
        if created_ids
        else None
    )
    if dependent_refund:
        raise conflict(
            "IMPORT_REVERT_HAS_DEPENDENCIES",
            "Void dependent refunds before reverting this import",
        )
    handled_link_ids: set[uuid.UUID] = set()
    for candidate in transfer_candidates:
        snapshot = candidate.replacement_snapshot
        if not snapshot or candidate.existing_source_record_id is None:
            raise conflict(
                "IMPORT_REVERT_SNAPSHOT_MISSING",
                "Transfer replacement metadata is unavailable",
            )
        current_link = (
            db.query(SourceRecordLink)
            .filter_by(source_record_id=candidate.source_record_id, kind="transfer")
            .one()
        )
        transfer_operation = db.get(Operation, current_link.operation_id)
        if transfer_operation is None:
            raise conflict("IMPORT_REVERT_OPERATION_MISSING", "Transfer operation is unavailable")
        transfer_links = (
            db.query(SourceRecordLink)
            .filter_by(operation_id=transfer_operation.id, kind="transfer")
            .all()
        )
        handled_link_ids.update(link.id for link in transfer_links)
        for transfer_link in transfer_links:
            db.delete(transfer_link)
        db.delete(transfer_operation)
        db.flush()
        account_id = uuid.UUID(snapshot["account_id"])
        occurred_on = date.fromisoformat(snapshot["occurred_on"])
        posted_on = date.fromisoformat(snapshot["posted_on"]) if snapshot["posted_on"] else None
        if snapshot["type"] == "income":
            restored = create_income(
                db,
                space_id=space_id,
                user=user,
                account_id=account_id,
                amount_kopecks=int(snapshot["amount_kopecks"]),
                occurred_on=occurred_on,
                posted_on=posted_on,
                income_source_id=(
                    uuid.UUID(snapshot["income_source_id"])
                    if snapshot["income_source_id"]
                    else None
                ),
                description=snapshot["description"],
                request_key=snapshot["request_key"],
            )
        else:
            restored = create_expense(
                db,
                space_id=space_id,
                user=user,
                account_id=account_id,
                amount_kopecks=int(snapshot["amount_kopecks"]),
                occurred_on=occurred_on,
                posted_on=posted_on,
                category_id=(
                    uuid.UUID(snapshot["category_id"]) if snapshot["category_id"] else None
                ),
                payee_id=uuid.UUID(snapshot["payee_id"]) if snapshot["payee_id"] else None,
                description=snapshot["description"],
                request_key=snapshot["request_key"],
            )
        db.add(
            SourceRecordLink(
                space_id=space_id,
                source_record_id=candidate.existing_source_record_id,
                operation_id=restored.id,
                kind=snapshot["link_kind"],
            )
        )
    for link in links:
        if link.id in handled_link_ids:
            continue
        operation = db.get(Operation, link.operation_id)
        db.delete(link)
        if link.kind == "created" and operation is not None:
            db.delete(operation)
    document.status = "ready"
    audit.record(
        db,
        event_type="import.reverted",
        space_id=space_id,
        user_id=user.id,
        detail={"document_id": str(document.id)},
    )
    return document


def delete_source_file(
    db: Session, *, space_id: uuid.UUID, document_id: uuid.UUID, user: User
) -> StatementDocument:
    document = _document(db, space_id=space_id, document_id=document_id)
    document.dek_wrapped = None
    document.dek_wrap_nonce = None
    document.content_nonce = None
    document.status = "deleted"
    audit.record(
        db,
        event_type="import.source_deleted",
        space_id=space_id,
        user_id=user.id,
        detail={"document_id": str(document.id)},
    )
    return document