"""DMS plugin routes — folders, files, preview, Collabora, internal sharing, search, bulk."""

from __future__ import annotations

import uuid

from fastapi import (
    APIRouter,
    Depends,
    File,
    Form,
    HTTPException,
    Response,
    UploadFile,
    status,
)
from fastapi.responses import StreamingResponse
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.db import get_db
from app.core.storage import LocalStorage, get_storage_backend
from app.core.visibility import apply_visibility_filter, check_single_entity_access
from app.deps import get_current_user, require_permission

# BUG-018 God-Object-Split: Helper/Konstanten leben jetzt in common.py;
# Re-Exports sichern Import- und Patch-Kompatibilitaet
# (tests patchen app.plugins.builtins.dms.routes.MAX_FILE_SIZE fuer den Upload).
from app.plugins.builtins.dms.common import (  # noqa: F401
    ALLOWED_MIME_PREFIXES,
    BLOCKED_EXTENSIONS,
    CHUNK_SIZE,
    MAX_FILE_SIZE,
    OFFICE_EXTENSIONS,
    _file_storage_path,
    _get_file_extension,
    _is_blocked_filetype,
    _parse_uuid,
    _sanitize_filename,
    chunk_size,
)
from app.plugins.builtins.dms.folders_routes import router as folders_router
from app.plugins.builtins.dms.models import File as DmsFile
from app.plugins.builtins.dms.models import Folder
from app.plugins.builtins.dms.schemas import (
    FileMetadataResponse,
    FileUpdate,
)
from app.plugins.builtins.dms.search_bulk_routes import router as search_bulk_router
from app.plugins.builtins.dms.sharing_routes import router as sharing_router
from app.plugins.builtins.permissions.contracts import get_contract as get_perms_contract

# Get Permission model from the permissions contract
_perms_contract = get_perms_contract()
Permission = _perms_contract.Permission

router = APIRouter(prefix="/api/v1/dms", tags=["dms"])

# Office file extensions mapped to Collabora file types
@router.post("/files/upload", status_code=status.HTTP_201_CREATED, response_model=FileMetadataResponse, dependencies=[Depends(require_permission("dms:write"))])
async def upload_file(
    file: UploadFile = File(...),
    folder_id: str | None = Form(None),
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(get_current_user),
):
    """AC5: POST /api/v1/dms/files/upload → 201, file stored + metadata."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    user_id = uuid.UUID(current_user["user_id"])
    fid = _parse_uuid(folder_id, "folder_id") if folder_id else None

    # Rate limit — UPLOAD policy
    from app.core.rate_limit import RateLimitPolicy, check_rate_limit_policy
    await check_rate_limit_policy(
        f"rate:upload:dms:{tenant_id}:{user_id}",
        RateLimitPolicy.UPLOAD,
    )

    # Check for blocked file types
    if _is_blocked_filetype(file.filename or ""):
        raise HTTPException(
            400,
            detail={"detail": "File type not allowed", "code": "blocked_filetype"},
        )

    # MIME type validation: verify content_type against allowlist
    mime_type = file.content_type or "application/octet-stream"
    if not any(mime_type.startswith(prefix) for prefix in ALLOWED_MIME_PREFIXES):
        raise HTTPException(
            400,
            detail={"detail": f"MIME type '{mime_type}' not allowed", "code": "blocked_mimetype"},
        )

    # Validate folder exists if specified
    if fid is not None:
        folder_result = await db.execute(
            select(Folder).where(
                Folder.id == fid,
                Folder.tenant_id == tenant_id,
                Folder.deleted_at.is_(None),
            )
        )
        if folder_result.scalar_one_or_none() is None:
            raise HTTPException(404, detail={"detail": "Folder not found", "code": "not_found"})

    # Stream file to storage — avoid loading entire file into RAM
    import hashlib
    chunk_size = 1024 * 1024  # noqa: F811 (Original-Shadowing im Original auch so)
    sha256 = hashlib.sha256()
    file_size = 0

    async def chunk_stream():
        nonlocal file_size
        while True:
            chunk = await file.read(chunk_size)
            if not chunk:
                break
            file_size += len(chunk)
            if file_size > MAX_FILE_SIZE:
                raise HTTPException(
                    413, detail={"detail": "File too large (max 100MB)", "code": "file_too_large"}
                )
            sha256.update(chunk)
            yield chunk

    # ── Hook: dms.before_upload (Filter) — can modify filename ──
    from app.core.hooks import apply_filters
    upload_data = {
        "filename": file.filename or "unnamed",
        "mime_type": file.content_type or "application/octet-stream",
    }
    upload_data = await apply_filters("dms.before_upload", upload_data)

    # Create file record
    file_id = uuid.uuid4()
    storage_path = _file_storage_path(tenant_id, file_id)

    # Save file via storage backend (true streaming, no RAM accumulation)
    storage = get_storage_backend()
    await storage.save_stream(storage_path, chunk_stream())

    content_hash = sha256.hexdigest()

    mime_type = upload_data["mime_type"]

    # Tenant-local deduplication: check for existing file with same content_hash
    existing_q = await db.execute(
        select(DmsFile).where(
            DmsFile.tenant_id == tenant_id,
            DmsFile.content_hash == content_hash,
            DmsFile.deleted_at.is_(None),
        ).limit(1)
    )
    existing_file = existing_q.scalar_one_or_none()

    if existing_file:
        # Deduplicate: reuse existing file, remove the duplicate we just saved
        await storage.delete(storage_path)
        dms_file = existing_file
    else:
        dms_file = DmsFile(
            id=file_id,
            tenant_id=tenant_id,
            name=upload_data["filename"],
            folder_id=fid,
            uploaded_by=user_id,
            mime_type=mime_type,
            size_bytes=file_size,
            storage_path=storage_path,
            content_hash=content_hash,
        )
        db.add(dms_file)
        await db.flush()
        # Record history for new file only (D-PLUG)
        from app.services.entity_history_service import record_history
        await record_history(db, tenant_id, user_id, "dms_file", dms_file.id, "create", snapshot_after={
            "id": str(dms_file.id), "name": dms_file.name,
            "folder_id": str(dms_file.folder_id) if dms_file.folder_id else None,
            "mime_type": dms_file.mime_type, "size_bytes": dms_file.size_bytes,
        })

    # Lifecycle hook: dms.after_upload
    from app.core.hooks import do_action
    await do_action("dms.after_upload", {'id': str(dms_file.id), 'name': dms_file.name, 'folder_id': str(dms_file.folder_id) if dms_file.folder_id else None, 'mime_type': dms_file.mime_type, 'size_bytes': dms_file.size_bytes}, db=db, tenant_id=tenant_id, user_id=user_id)
    await do_action("dms_file.after_create", {'id': str(dms_file.id), 'name': dms_file.name, 'tenant_id': str(tenant_id)}, db=db, tenant_id=tenant_id, user_id=user_id)

    # Outbox event: file.created
    from app.core.outbox import enqueue_outbox_event
    await enqueue_outbox_event(db, tenant_id, 'file.created', {'file_id': str(dms_file.id), 'tenant_id': str(tenant_id), 'name': dms_file.name, 'mime_type': dms_file.mime_type, 'size_bytes': dms_file.size_bytes}, aggregate_type='dms_file', aggregate_id=dms_file.id)

    return {
        "id": str(dms_file.id),
        "name": dms_file.name,
        "folder_id": str(dms_file.folder_id) if dms_file.folder_id else None,
        "uploaded_by": str(dms_file.uploaded_by),
        "mime_type": dms_file.mime_type,
        "size_bytes": dms_file.size_bytes,
        "content_hash": dms_file.content_hash,
        "deleted_at": None,
        "created_at": dms_file.created_at.isoformat() if dms_file.created_at else None,
        "updated_at": dms_file.updated_at.isoformat() if dms_file.updated_at else None,
    }


@router.get("/files/{file_id}", dependencies=[Depends(require_permission("dms:read"))])
async def get_file(
    file_id: str,
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(get_current_user),
):
    """AC6: GET /api/v1/dms/files/{id} → 200 + file metadata."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    user_id = uuid.UUID(current_user["user_id"])
    is_system_admin = current_user.get("role") == "admin"
    fid = _parse_uuid(file_id, "file_id")

    result = await db.execute(
        select(DmsFile).where(
            DmsFile.id == fid,
            DmsFile.tenant_id == tenant_id,
            DmsFile.deleted_at.is_(None),
        )
    )
    dms_file = result.scalar_one_or_none()
    if dms_file is None:
        raise HTTPException(404, detail={"detail": "File not found", "code": "not_found"})

    if not await check_single_entity_access(db, "dms_file", fid, user_id, tenant_id, "read", is_system_admin):
        raise HTTPException(403, detail={"detail": "Access denied", "code": "forbidden"})

    return {
        "id": str(dms_file.id),
        "name": dms_file.name,
        "folder_id": str(dms_file.folder_id) if dms_file.folder_id else None,
        "uploaded_by": str(dms_file.uploaded_by),
        "mime_type": dms_file.mime_type,
        "size_bytes": dms_file.size_bytes,
        "deleted_at": None,
        "created_at": dms_file.created_at.isoformat() if dms_file.created_at else None,
        "updated_at": dms_file.updated_at.isoformat() if dms_file.updated_at else None,
    }


@router.get("/files", dependencies=[Depends(require_permission("dms:read"))])
async def list_all_files(
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(get_current_user),
):
    """List all non-deleted files for the current tenant."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    user_id = uuid.UUID(current_user["user_id"])
    is_system_admin = current_user.get("role") == "admin"

    query = select(DmsFile).where(
        DmsFile.tenant_id == tenant_id,
        DmsFile.deleted_at.is_(None),
    )
    query = await apply_visibility_filter(
        db, query, "dms_file", DmsFile, user_id, tenant_id, is_system_admin
    )
    result = await db.execute(query)
    files = result.scalars().all()

    return [
        {
            "id": str(f.id),
            "name": f.name,
            "folder_id": str(f.folder_id) if f.folder_id else None,
            "uploaded_by": str(f.uploaded_by),
            "mime_type": f.mime_type,
            "size_bytes": f.size_bytes,
            "deleted_at": None,
            "created_at": f.created_at.isoformat() if f.created_at else None,
            "updated_at": f.updated_at.isoformat() if f.updated_at else None,
        }
        for f in files
    ]


@router.get("/folders/{folder_id}/files", dependencies=[Depends(require_permission("dms:read"))])
async def list_files_in_folder(
    folder_id: str,
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(get_current_user),
):
    """List all non-deleted files in a specific folder (non-recursive)."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    user_id = uuid.UUID(current_user["user_id"])
    is_system_admin = current_user.get("role") == "admin"
    fid = _parse_uuid(folder_id, "folder_id")

    # Validate folder exists
    folder_result = await db.execute(
        select(Folder).where(
            Folder.id == fid,
            Folder.tenant_id == tenant_id,
            Folder.deleted_at.is_(None),
        )
    )
    if folder_result.scalar_one_or_none() is None:
        raise HTTPException(404, detail={"detail": "Folder not found", "code": "not_found"})

    query = select(DmsFile).where(
        DmsFile.tenant_id == tenant_id,
        DmsFile.folder_id == fid,
        DmsFile.deleted_at.is_(None),
    )
    query = await apply_visibility_filter(
        db, query, "dms_file", DmsFile, user_id, tenant_id, is_system_admin
    )
    result = await db.execute(query)
    files = result.scalars().all()

    return [
        {
            "id": str(f.id),
            "name": f.name,
            "folder_id": str(f.folder_id) if f.folder_id else None,
            "uploaded_by": str(f.uploaded_by),
            "mime_type": f.mime_type,
            "size_bytes": f.size_bytes,
            "deleted_at": None,
            "created_at": f.created_at.isoformat() if f.created_at else None,
            "updated_at": f.updated_at.isoformat() if f.updated_at else None,
        }
        for f in files
    ]


@router.patch("/files/{file_id}", dependencies=[Depends(require_permission("dms:write"))])
async def update_file(
    file_id: str,
    body: FileUpdate,
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(get_current_user),
):
    """AC7: PATCH /api/v1/dms/files/{id} → 200, rename/move."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    user_id = uuid.UUID(current_user["user_id"])
    is_system_admin = current_user.get("role") == "admin"
    fid = _parse_uuid(file_id, "file_id")

    result = await db.execute(
        select(DmsFile).where(
            DmsFile.id == fid,
            DmsFile.tenant_id == tenant_id,
            DmsFile.deleted_at.is_(None),
        )
    )
    dms_file = result.scalar_one_or_none()
    if dms_file is None:
        raise HTTPException(404, detail={"detail": "File not found", "code": "not_found"})

    if not await check_single_entity_access(db, "dms_file", fid, user_id, tenant_id, "write", is_system_admin):
        raise HTTPException(403, detail={"detail": "Access denied", "code": "forbidden"})

    # Lifecycle hook: dms.before_update
    from app.core.hooks import do_action
    await do_action("dms.before_update", body.model_dump(exclude_unset=True), db=db, tenant_id=tenant_id, user_id=user_id, file_id=file_id)

    data = body.model_dump(exclude_unset=True)

    # Capture snapshot before update (D-PLUG)
    snapshot_before = {
        "id": str(dms_file.id), "name": dms_file.name,
        "folder_id": str(dms_file.folder_id) if dms_file.folder_id else None,
        "mime_type": dms_file.mime_type, "size_bytes": dms_file.size_bytes,
    }

    if "name" in data and data["name"] is not None:
        dms_file.name = data["name"]

    if "folder_id" in data:
        new_folder = _parse_uuid(data["folder_id"], "folder_id") if data["folder_id"] else None
        if new_folder is not None:
            folder_result = await db.execute(
                select(Folder).where(
                    Folder.id == new_folder,
                    Folder.tenant_id == tenant_id,
                    Folder.deleted_at.is_(None),
                )
            )
            if folder_result.scalar_one_or_none() is None:
                raise HTTPException(404, detail={"detail": "Folder not found", "code": "not_found"})
        dms_file.folder_id = new_folder

    await db.flush()
    await db.refresh(dms_file)

    snapshot_after = {
        "id": str(dms_file.id), "name": dms_file.name,
        "folder_id": str(dms_file.folder_id) if dms_file.folder_id else None,
        "mime_type": dms_file.mime_type, "size_bytes": dms_file.size_bytes,
    }
    # Compute changes diff (D-PLUG)
    changes: dict = {}
    for key, new_val in snapshot_after.items():
        old_val = snapshot_before.get(key)
        if old_val != new_val:
            changes[key] = {"old": old_val, "new": new_val}
    # Record history (D-PLUG)
    from app.services.entity_history_service import record_history
    await record_history(db, tenant_id, user_id, "dms_file", dms_file.id, "update",
                         snapshot_before=snapshot_before, snapshot_after=snapshot_after, changes=changes or None)

    # Lifecycle hook: dms.after_update
    from app.core.hooks import do_action
    await do_action("dms.after_update", {'id': str(dms_file.id), 'name': dms_file.name}, db=db, tenant_id=tenant_id, user_id=user_id, file_id=file_id)
    await do_action("dms_file.after_update", {'id': str(dms_file.id), 'name': dms_file.name, 'tenant_id': str(tenant_id)}, db=db, tenant_id=tenant_id, user_id=user_id, file_id=file_id)

    return {
        "id": str(dms_file.id),
        "name": dms_file.name,
        "folder_id": str(dms_file.folder_id) if dms_file.folder_id else None,
        "uploaded_by": str(dms_file.uploaded_by),
        "mime_type": dms_file.mime_type,
        "size_bytes": dms_file.size_bytes,
        "deleted_at": None,
        "created_at": dms_file.created_at.isoformat() if dms_file.created_at else None,
        "updated_at": dms_file.updated_at.isoformat() if dms_file.updated_at else None,
    }


@router.delete("/files/{file_id}", status_code=status.HTTP_204_NO_CONTENT, dependencies=[Depends(require_permission("dms:delete"))])
async def delete_file(
    file_id: str,
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(get_current_user),
):
    """AC8: DELETE /api/v1/dms/files/{id} → 204, soft-delete."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    user_id = uuid.UUID(current_user["user_id"])
    is_system_admin = current_user.get("role") == "admin"
    fid = _parse_uuid(file_id, "file_id")

    result = await db.execute(
        select(DmsFile).where(
            DmsFile.id == fid,
            DmsFile.tenant_id == tenant_id,
            DmsFile.deleted_at.is_(None),
        )
    )
    dms_file = result.scalar_one_or_none()
    if dms_file is None:
        raise HTTPException(404, detail={"detail": "File not found", "code": "not_found"})

    if not await check_single_entity_access(db, "dms_file", fid, user_id, tenant_id, "delete", is_system_admin):
        raise HTTPException(403, detail={"detail": "Access denied", "code": "forbidden"})

    # Lifecycle hook: dms.before_delete
    from app.core.hooks import do_action
    await do_action("dms.before_delete", db=db, tenant_id=tenant_id, user_id=user_id, file_id=file_id)

    # Capture snapshot before delete (D-PLUG)
    snapshot_before = {
        "id": str(dms_file.id), "name": dms_file.name,
        "folder_id": str(dms_file.folder_id) if dms_file.folder_id else None,
        "mime_type": dms_file.mime_type, "size_bytes": dms_file.size_bytes,
    }

    from datetime import UTC, datetime

    dms_file.deleted_at = datetime.now(UTC)
    await db.flush()

    # Record history (D-PLUG)
    from app.services.entity_history_service import record_history
    await record_history(db, tenant_id, user_id, "dms_file", dms_file.id, "delete", snapshot_before=snapshot_before)

    # Lifecycle hook: dms.after_delete
    await do_action("dms.after_delete", db=db, tenant_id=tenant_id, user_id=user_id, file_id=file_id)
    await do_action("dms_file.after_delete", db=db, tenant_id=tenant_id, user_id=user_id, file_id=file_id)

    # Outbox event: file.deleted
    from app.core.outbox import enqueue_outbox_event
    await enqueue_outbox_event(db, tenant_id, 'file.deleted', {'file_id': str(fid), 'tenant_id': str(tenant_id)}, aggregate_type='dms_file', aggregate_id=fid)

    return Response(status_code=status.HTTP_204_NO_CONTENT)


@router.post("/files/{file_id}/restore", dependencies=[Depends(require_permission("dms:write"))])
async def restore_file(
    file_id: str,
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(get_current_user),
):
    """AC9: POST /api/v1/dms/files/{id}/restore → 200, restored from trash."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    user_id = uuid.UUID(current_user["user_id"])
    is_system_admin = current_user.get("role") == "admin"
    fid = _parse_uuid(file_id, "file_id")

    result = await db.execute(
        select(DmsFile).where(
            DmsFile.id == fid,
            DmsFile.tenant_id == tenant_id,
            DmsFile.deleted_at.is_not(None),
        )
    )
    dms_file = result.scalar_one_or_none()
    if dms_file is None:
        raise HTTPException(404, detail={"detail": "Deleted file not found", "code": "not_found"})

    if not await check_single_entity_access(db, "dms_file", fid, user_id, tenant_id, "write", is_system_admin):
        raise HTTPException(403, detail={"detail": "Access denied", "code": "forbidden"})

    # Lifecycle hook: dms.before_restore
    from app.core.hooks import do_action
    await do_action("dms.before_restore", db=db, tenant_id=tenant_id, user_id=user_id, file_id=file_id)

    dms_file.deleted_at = None
    await db.flush()
    await db.refresh(dms_file)

    # Lifecycle hook: dms.after_restore
    await do_action("dms.after_restore", {'id': str(dms_file.id), 'name': dms_file.name}, db=db, tenant_id=tenant_id, user_id=user_id, file_id=file_id)

    # Outbox event: file.restored
    from app.core.outbox import enqueue_outbox_event
    await enqueue_outbox_event(db, tenant_id, 'file.restored', {'file_id': str(fid), 'tenant_id': str(tenant_id)}, aggregate_type='dms_file', aggregate_id=fid)

    return {
        "id": str(dms_file.id),
        "name": dms_file.name,
        "folder_id": str(dms_file.folder_id) if dms_file.folder_id else None,
        "uploaded_by": str(dms_file.uploaded_by),
        "mime_type": dms_file.mime_type,
        "size_bytes": dms_file.size_bytes,
        "deleted_at": None,
        "created_at": dms_file.created_at.isoformat() if dms_file.created_at else None,
        "updated_at": dms_file.updated_at.isoformat() if dms_file.updated_at else None,
    }


# ─── Preview & Edit ───


@router.get("/files/{file_id}/preview", dependencies=[Depends(require_permission("dms:read"))])
async def preview_file(
    file_id: str,
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(get_current_user),
):
    """AC10: GET /api/v1/dms/files/{id}/preview → 200 + PDF stream."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    user_id = uuid.UUID(current_user["user_id"])
    is_system_admin = current_user.get("role") == "admin"
    fid = _parse_uuid(file_id, "file_id")

    result = await db.execute(
        select(DmsFile).where(
            DmsFile.id == fid,
            DmsFile.tenant_id == tenant_id,
            DmsFile.deleted_at.is_(None),
        )
    )
    dms_file = result.scalar_one_or_none()
    if dms_file is None:
        raise HTTPException(404, detail={"detail": "File not found", "code": "not_found"})

    if not await check_single_entity_access(db, "dms_file", fid, user_id, tenant_id, "read", is_system_admin):
        raise HTTPException(403, detail={"detail": "Access denied", "code": "forbidden"})

    if dms_file.mime_type != "application/pdf":
        raise HTTPException(
            400, detail={"detail": "Only PDF files can be previewed", "code": "not_pdf"}
        )

    storage = get_storage_backend()
    if not await storage.exists(dms_file.storage_path):
        raise HTTPException(
            404, detail={"detail": "File not found on disk", "code": "file_missing"}
        )

    # Stream file directly from storage without loading into RAM

    from fastapi.responses import FileResponse as FastApiFileResponse

    if isinstance(storage, LocalStorage):
        # LocalStorage: use FileResponse for automatic streaming
        full_path = storage._full_path(dms_file.storage_path)
        return FastApiFileResponse(
            path=full_path,
            media_type="application/pdf",
            headers={"Content-Disposition": f'inline; filename="{dms_file.name}"'},
        )
    else:
        # S3 or other: fall back to read (TODO: implement S3 streaming)
        content = await storage.read(dms_file.storage_path)
        def _stream():
            yield content
        return StreamingResponse(
            _stream(),
            media_type="application/pdf",
            headers={"Content-Disposition": f'inline; filename="{dms_file.name}"'},
        )


@router.get("/files/{file_id}/download", dependencies=[Depends(require_permission("dms:read"))])
async def download_file(
    file_id: str,
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(get_current_user),
):
    """Download any file type — streams directly from storage without loading into RAM."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    user_id = uuid.UUID(current_user["user_id"])
    is_admin = current_user.get("role") == "admin"
    fid = _parse_uuid(file_id, "file_id")

    result = await db.execute(
        select(DmsFile).where(
            DmsFile.id == fid,
            DmsFile.tenant_id == tenant_id,
            DmsFile.deleted_at.is_(None),
        )
    )
    dms_file = result.scalar_one_or_none()
    if dms_file is None:
        raise HTTPException(404, detail={"detail": "File not found", "code": "not_found"})

    if not await check_single_entity_access(db, "dms_file", fid, user_id, tenant_id, "read", is_admin):
        raise HTTPException(403, detail={"detail": "Access denied", "code": "forbidden"})

    storage = get_storage_backend()
    if not await storage.exists(dms_file.storage_path):
        raise HTTPException(404, detail={"detail": "File not found on disk", "code": "file_missing"})

    from fastapi.responses import FileResponse as FastApiFileResponse
    if isinstance(storage, LocalStorage):
        full_path = storage._full_path(dms_file.storage_path)
        return FastApiFileResponse(
            path=full_path,
            media_type=dms_file.mime_type or "application/octet-stream",
            filename=dms_file.name,
        )
    else:
        content = await storage.read(dms_file.storage_path)
        def _stream():
            yield content
        return StreamingResponse(
            _stream(),
            media_type=dms_file.mime_type or "application/octet-stream",
            headers={"Content-Disposition": f'attachment; filename="{dms_file.name}"'},
        )


# Sub-Router einbinden (BUG-018 Split): folders, sharing/collabora, search/bulk
router.include_router(folders_router)
router.include_router(sharing_router)
router.include_router(search_bulk_router)