"""DMS Edit-Session/Collabora & Sharing Routen — extrahiert aus routes.py (BUG-018)."""

from __future__ import annotations

import uuid

from fastapi import (
    APIRouter,
    Body,
    Depends,
    HTTPException,
    Response,
    status,
)
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.db import get_db
from app.core.visibility import check_single_entity_access
from app.deps import get_current_user, require_permission
from app.plugins.builtins.dms.common import (
    OFFICE_EXTENSIONS,
    _get_file_extension,
    _parse_uuid,
)
from app.plugins.builtins.dms.models import File as DmsFile
from app.plugins.builtins.dms.schemas import ShareRemoveRequest, ShareRequest
from app.plugins.builtins.permissions.contracts import get_contract as get_perms_contract

_perms_contract = get_perms_contract()
Permission = _perms_contract.Permission

router = APIRouter(tags=["dms"])

@router.post("/files/{file_id}/edit-session", dependencies=[Depends(require_permission("dms:write"))])
async def create_edit_session(
    file_id: str,
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(get_current_user),
):
    """AC11: POST /api/v1/dms/files/{id}/edit-session → 200 + Collabora config."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    user_id = current_user["user_id"]
    user_name = current_user.get("name", "Unknown")
    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"})

    ext = _get_file_extension(dms_file.name)
    if ext not in OFFICE_EXTENSIONS:
        raise HTTPException(
            400,
            detail={
                "detail": "Only Office files (docx, xlsx, pptx) are supported",
                "code": "not_office",
            },
        )

    file_type = OFFICE_EXTENSIONS[ext]
    download_url = f"/api/v1/dms/files/{fid}/preview"
    callback_url = f"/api/v1/dms/files/{fid}/callback"

    config = {
        "document": {
            "fileType": file_type,
            "key": str(uuid.uuid4()),
            "title": dms_file.name,
            "url": download_url,
        },
        "editorConfig": {
            "mode": "edit",
            "callbackUrl": callback_url,
            "user": {
                "id": user_id,
                "name": user_name,
            },
        },
    }

    return config


# ─── Internal Sharing ───


@router.post("/files/{file_id}/share", dependencies=[Depends(require_permission("dms:share"))])
async def share_file(
    file_id: str,
    body: ShareRequest,
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(get_current_user),
):
    """AC12: POST /api/v1/dms/files/{id}/share → 200, internal share created."""
    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")

    # Verify file exists
    file_result = await db.execute(
        select(DmsFile).where(
            DmsFile.id == fid,
            DmsFile.tenant_id == tenant_id,
            DmsFile.deleted_at.is_(None),
        )
    )
    if file_result.scalar_one_or_none() 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, "share", is_system_admin):
        raise HTTPException(403, detail={"detail": "Access denied", "code": "forbidden"})

    created_perms: list[dict] = []

    for uid_str in body.user_ids:
        uid = _parse_uuid(uid_str, "user_id")
        # Check if already exists
        existing = await db.execute(
            select(Permission).where(
                Permission.tenant_id == tenant_id,
                Permission.file_id == fid,
                Permission.user_id == uid,
                Permission.access_level == body.access_level,
            )
        )
        if existing.scalar_one_or_none() is None:
            perm = Permission(
                tenant_id=tenant_id,
                file_id=fid,
                user_id=uid,
                group_id=None,
                access_level=body.access_level,
            )
            db.add(perm)
            await db.flush()
            created_perms.append(
                {
                    "id": str(perm.id),
                    "file_id": str(fid),
                    "user_id": str(uid),
                    "group_id": None,
                    "access_level": body.access_level,
                }
            )

    for gid_str in body.group_ids:
        gid = _parse_uuid(gid_str, "group_id")
        existing = await db.execute(
            select(Permission).where(
                Permission.tenant_id == tenant_id,
                Permission.file_id == fid,
                Permission.group_id == gid,
                Permission.access_level == body.access_level,
            )
        )
        if existing.scalar_one_or_none() is None:
            perm = Permission(
                tenant_id=tenant_id,
                file_id=fid,
                user_id=uuid.UUID(current_user["user_id"]),
                group_id=gid,
                access_level=body.access_level,
            )
            db.add(perm)
            await db.flush()
            created_perms.append(
                {
                    "id": str(perm.id),
                    "file_id": str(fid),
                    "user_id": str(perm.user_id),
                    "group_id": str(gid),
                    "access_level": body.access_level,
                }
            )

    return {
        "file_id": str(fid),
        "shared_with": created_perms,
        "count": len(created_perms),
    }


@router.delete("/files/{file_id}/share", status_code=status.HTTP_204_NO_CONTENT, dependencies=[Depends(require_permission("dms:share"))])
async def remove_share(
    file_id: str,
    body: ShareRemoveRequest = Body(...),
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(get_current_user),
):
    """AC13: DELETE /api/v1/dms/files/{id}/share → 204, share removed."""
    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")

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

    if body.user_id:
        uid = _parse_uuid(body.user_id, "user_id")
        result = await db.execute(
            select(Permission).where(
                Permission.tenant_id == tenant_id,
                Permission.file_id == fid,
                Permission.user_id == uid,
            )
        )
        perms = result.scalars().all()
        for p in perms:
            await db.delete(p)

    if body.group_id:
        gid = _parse_uuid(body.group_id, "group_id")
        result = await db.execute(
            select(Permission).where(
                Permission.tenant_id == tenant_id,
                Permission.file_id == fid,
                Permission.group_id == gid,
            )
        )
        perms = result.scalars().all()
        for p in perms:
            await db.delete(p)

    await db.flush()
    return Response(status_code=status.HTTP_204_NO_CONTENT)


# ─── Search & Bulk ───