"""Universal entity permission routes — ACL management for ALL entities."""

from __future__ import annotations

import uuid

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

from app.core.db import get_db
from app.core.rate_limit import check_rate_limit
from app.deps import get_current_user, get_redis_dep, require_permission
from app.schemas.entity_permission import (
    EntityPermissionCreate,
    EntityPermissionUpdate,
)
from app.services import bulk_permission_service, entity_permission_service

router = APIRouter(prefix="/api/v1/permissions", tags=["entity-permissions"])

# Rate limits for permission changes (prevent abuse/DoS)
_PERM_RATE_LIMIT_MAX = 50  # max changes per minute
_PERM_RATE_LIMIT_WINDOW = 60  # 60 seconds


@router.get("/{entity_type}/{entity_id}")
async def list_entity_permissions(
    entity_type: str,
    entity_id: str,
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(get_current_user),
):
    """List all permission entries for a specific entity."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    try:
        items = await entity_permission_service.list_permissions(
            db, tenant_id, entity_type, entity_id
        )
    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e)) from e
    return {"items": items, "total": len(items)}


@router.post("/{entity_type}/{entity_id}", status_code=status.HTTP_201_CREATED)
async def create_entity_permission(
    entity_type: str,
    entity_id: str,
    body: EntityPermissionCreate,
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(get_current_user),
    redis = Depends(get_redis_dep),
):
    """Grant or update a permission on any entity for a user, group, role, or guest."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    user_id = uuid.UUID(current_user["user_id"])
    is_system_admin = current_user.get("is_system_admin", False)
    # Permission check: only owner/admin/system_admin can manage permissions
    if not is_system_admin:
        access = await entity_permission_service.get_effective_access(
            db, tenant_id, user_id, entity_type, uuid.UUID(entity_id)
        )
        if access not in ("owner", "admin", "delete"):
            raise HTTPException(status_code=403, detail="Sie benötigen Admin-Rechte auf diesen Datensatz, um Berechtigungen zu verwalten")
    # Rate limit: max 50 permission changes per minute per user
    await check_rate_limit(
        f"perm_change:{user_id}",
        _PERM_RATE_LIMIT_MAX,
        _PERM_RATE_LIMIT_WINDOW,
    )
    try:
        result = await entity_permission_service.create_permission(
            db,
            tenant_id,
            entity_type,
            entity_id,
            body.principal_type,
            body.principal_id,
            body.permission_level,
            body.expires_at,
            created_by=user_id,
            redis=redis,
        )
        return result
    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e)) from e


async def _check_entity_ownership(
    db: AsyncSession,
    tenant_id: uuid.UUID,
    user_id: uuid.UUID,
    entity_type: str,
    entity_id: str,
    is_system_admin: bool,
) -> None:
    """Verify that the current user owns the entity or is system admin.

    Raises 403 if the user is neither owner nor system admin.
    """
    if is_system_admin:
        return

    from sqlalchemy import select

    from app.services.entity_permission_service import ENTITY_MODELS

    model_info = ENTITY_MODELS.get(entity_type)
    if model_info is None:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail={"detail": f"Unknown entity type: {entity_type}", "code": "not_found"},
        )

    model = model_info["model"]
    try:
        eid = uuid.UUID(entity_id)
    except ValueError:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail={"detail": "Invalid entity_id", "code": "invalid_id"},
        ) from None

    result = await db.execute(
        select(model.owner_id).where(
            model.id == eid,
            model.tenant_id == tenant_id,
        )
    )
    row = result.first()
    if row is None:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail={"detail": "Entity not found", "code": "not_found"},
        )
    owner_id = row[0]
    if owner_id is not None and owner_id != user_id:
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail={"detail": "Only the entity owner or system admin can modify permissions", "code": "forbidden"},
        )


@router.put("/{entity_type}/{entity_id}/{permission_id}")
async def update_entity_permission(
    entity_type: str,
    entity_id: str,
    permission_id: str,
    body: EntityPermissionUpdate,
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(get_current_user),
):
    """Update an existing permission entry."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    user_id = uuid.UUID(current_user["user_id"])
    await check_rate_limit(
        f"perm_change:{user_id}",
        _PERM_RATE_LIMIT_MAX,
        _PERM_RATE_LIMIT_WINDOW,
    )
    # Ownership check: only owner or system admin can update permissions
    await _check_entity_ownership(
        db, tenant_id, user_id, entity_type, entity_id,
        current_user.get("is_system_admin", False),
    )
    try:
        return await entity_permission_service.update_permission(
            db,
            tenant_id,
            permission_id,
            body.permission_level,
            body.expires_at,
        )
    except ValueError as e:
        raise HTTPException(status_code=404, detail=str(e)) from e


@router.delete("/{entity_type}/{entity_id}/{permission_id}", status_code=status.HTTP_204_NO_CONTENT)
async def delete_entity_permission(
    entity_type: str,
    entity_id: str,
    permission_id: str,
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(get_current_user),
):
    """Revoke a permission entry."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    user_id = uuid.UUID(current_user["user_id"])
    await check_rate_limit(
        f"perm_change:{user_id}",
        _PERM_RATE_LIMIT_MAX,
        _PERM_RATE_LIMIT_WINDOW,
    )
    try:
        await entity_permission_service.delete_permission(db, tenant_id, permission_id)
    except ValueError as e:
        raise HTTPException(status_code=404, detail=str(e)) from e


@router.get("/{entity_type}/{entity_id}/access")
async def get_entity_access(
    entity_type: str,
    entity_id: str,
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(get_current_user),
):
    """Get effective access level for the current user on an entity."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    user_id = uuid.UUID(current_user["user_id"])
    access = await entity_permission_service.get_effective_access(
        db, tenant_id, user_id, entity_type, uuid.UUID(entity_id)
    )
    is_owner = access == "owner"
    is_shared = access not in ("none", "owner")
    return {
        "entity_type": entity_type,
        "entity_id": entity_id,
        "access_level": access,
        "is_owner": is_owner,
        "is_shared": is_shared,
    }


@router.get("/all")
async def list_all_permissions(
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(require_permission("settings:read")),
):
    """List ALL permission entries for the current tenant."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    items = await entity_permission_service.list_all_permissions(db, tenant_id)
    return {"items": items, "total": len(items)}


@router.get("/registry")
async def list_entity_registry(
    current_user: dict = Depends(get_current_user),
):
    """List all registered entity types that support permissions."""
    # Static list for now — will be dynamic from Permission Registry in Sprint 4
    entity_types = [
        {"entity_type": "contact", "label": "Kontakte", "table": "contacts"},
        {"entity_type": "contact_folder", "label": "Ordner", "table": "contact_folders"},
        {"entity_type": "address", "label": "Adressen", "table": "addresses"},
        {"entity_type": "attachment", "label": "Anhänge", "table": "attachments"},
        {"entity_type": "bank_account", "label": "Bankkonten", "table": "bank_accounts"},
        {"entity_type": "workflow", "label": "Workflows", "table": "workflows"},
        {"entity_type": "sequence", "label": "Sequenzen", "table": "sequences"},
        {"entity_type": "saved_filter", "label": "Gespeicherte Filter", "table": "saved_filters"},
        {"entity_type": "saved_view", "label": "Gespeicherte Ansichten", "table": "saved_views"},
        {"entity_type": "webhook", "label": "Webhooks", "table": "webhooks"},
        {"entity_type": "notification", "label": "Benachrichtigungen", "table": "notifications"},
        {"entity_type": "custom_field_definition", "label": "Custom Fields", "table": "custom_field_definitions"},
        {"entity_type": "ai_conversation", "label": "AI Konversationen", "table": "ai_conversations"},
    ]
    return {"items": entity_types, "total": len(entity_types)}


@router.post("/bulk", status_code=status.HTTP_201_CREATED)
async def bulk_share_permissions(
    body: dict,
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(require_permission("settings:write")),
):
    """Bulk share multiple entities with a principal."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    user_id = uuid.UUID(current_user["user_id"])
    try:
        result = await bulk_permission_service.bulk_share(
            db,
            tenant_id,
            body["entity_type"],
            body["entity_ids"],
            body["principal_type"],
            body["principal_id"],
            body["level"],
            created_by=user_id,
        )
        return result
    except (ValueError, KeyError) as e:
        raise HTTPException(status_code=400, detail=str(e)) from e


@router.post("/bulk/unshare", status_code=status.HTTP_200_OK)
async def bulk_unshare_permissions(
    body: dict,
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(require_permission("settings:write")),
):
    """Bulk remove permissions for a principal from multiple entities."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    try:
        result = await bulk_permission_service.bulk_unshare(
            db,
            tenant_id,
            body["entity_type"],
            body["entity_ids"],
            body["principal_type"],
            body["principal_id"],
        )
        return result
    except (ValueError, KeyError) as e:
        raise HTTPException(status_code=400, detail=str(e)) from e


@router.get("/analytics")
async def get_permission_analytics(
    db: AsyncSession = Depends(get_db),
    current_user: dict = Depends(require_permission("settings:read")),
):
    """Get permission analytics for the current tenant."""
    tenant_id = uuid.UUID(current_user["tenant_id"])
    try:
        result = await entity_permission_service.get_permission_analytics(db, tenant_id)
        return result
    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e)) from e