# app/modules/tenancy/services/admin_service.py
"""
Admin service for managing users and stores.

This module provides classes and functions for:
- User management and status control
- Store creation with owner user generation
- Store verification and activation
- Platform statistics

Note: Marketplace import job monitoring has been moved to the marketplace module.
"""

import logging
import secrets
import string
from datetime import UTC, datetime

from sqlalchemy import func, or_
from sqlalchemy.exc import SQLAlchemyError
from sqlalchemy.orm import Session, joinedload

from app.modules.tenancy.exceptions import (
    AdminOperationException,
    CannotModifySelfException,
    MerchantNotFoundException,
    StoreAlreadyExistsException,
    StoreNotFoundException,
    StoreValidationException,
    StoreVerificationException,
    UserAlreadyExistsException,
    UserCannotBeDeletedException,
    UserNotFoundException,
    UserRoleChangeException,
    UserStatusChangeException,
)
from app.modules.tenancy.models import Merchant, Platform, Role, Store, User
from app.modules.tenancy.schemas.store import StoreCreate
from middleware.auth import AuthManager

logger = logging.getLogger(__name__)


class AdminService:
    """Service class for admin operations following the application's service pattern."""

    # ============================================================================
    # USER MANAGEMENT
    # ============================================================================

    def get_all_users(self, db: Session, skip: int = 0, limit: int = 100) -> list[User]:
        """Get paginated list of all users."""
        try:
            return db.query(User).offset(skip).limit(limit).all()
        except SQLAlchemyError as e:
            logger.error(f"Failed to retrieve users: {str(e)}")
            raise AdminOperationException(
                operation="get_all_users", reason="Database query failed"
            )

    def toggle_user_status(
        self, db: Session, user_id: int, current_admin_id: int
    ) -> tuple[User, str]:
        """Toggle user active status."""
        user = self._get_user_by_id_or_raise(db, user_id)

        # Prevent self-modification
        if user.id == current_admin_id:
            raise CannotModifySelfException(user_id, "deactivate account")

        # Check if user is another admin
        if user.is_admin and user.id != current_admin_id:
            raise UserStatusChangeException(
                user_id=user_id,
                current_status="admin",
                attempted_action="toggle status",
                reason="Cannot modify another admin user",
            )

        try:
            original_status = user.is_active
            user.is_active = not user.is_active
            user.updated_at = datetime.now(UTC)
            db.flush()
            db.refresh(user)

            status_action = "activated" if user.is_active else "deactivated"
            message = f"User {user.username} has been {status_action}"

            logger.info(f"{message} by admin {current_admin_id}")
            return user, message

        except SQLAlchemyError as e:
            logger.error(f"Failed to toggle user {user_id} status: {str(e)}")
            raise UserStatusChangeException(
                user_id=user_id,
                current_status="active" if original_status else "inactive",
                attempted_action="toggle status",
                reason="Database update failed",
            )

    def list_users(
        self,
        db: Session,
        page: int = 1,
        per_page: int = 10,
        search: str | None = None,
        role: str | None = None,
        scope: str | None = None,
        is_active: bool | None = None,
    ) -> tuple[list[User], int, int]:
        """
        Get paginated list of users with filtering.

        Args:
            scope: Optional scope filter. 'merchant' returns users who are
                   merchant owners or store team members.

        Returns:
            Tuple of (users, total_count, total_pages)
        """
        import math

        from app.modules.tenancy.models import Merchant, StoreUser

        query = db.query(User)

        # Apply scope filter
        if scope == "merchant":
            owner_ids = db.query(Merchant.owner_user_id).distinct()
            team_ids = db.query(StoreUser.user_id).distinct()
            query = query.filter(User.id.in_(owner_ids.union(team_ids)))

        # Apply filters
        if search:
            search_term = f"%{search.lower()}%"
            query = query.filter(
                or_(
                    User.username.ilike(search_term),
                    User.email.ilike(search_term),
                    User.first_name.ilike(search_term),
                    User.last_name.ilike(search_term),
                )
            )

        if role:
            query = query.filter(User.role == role)

        if is_active is not None:
            query = query.filter(User.is_active == is_active)

        # Get total count
        total = query.count()
        pages = math.ceil(total / per_page) if total > 0 else 1

        # Apply pagination
        skip = (page - 1) * per_page
        users = (
            query.order_by(User.created_at.desc()).offset(skip).limit(per_page).all()
        )

        return users, total, pages

    def create_user(
        self,
        db: Session,
        email: str,
        username: str,
        password: str,
        first_name: str | None = None,
        last_name: str | None = None,
        role: str = "customer",
        current_admin_id: int | None = None,
    ) -> User:
        """
        Create a new user.

        Raises:
            UserAlreadyExistsException: If email or username already exists
        """
        # Check if email exists
        if db.query(User).filter(User.email == email).first():
            raise UserAlreadyExistsException("Email already registered", field="email")

        # Check if username exists
        if db.query(User).filter(User.username == username).first():
            raise UserAlreadyExistsException("Username already taken", field="username")

        # Create user
        auth_manager = AuthManager()
        user = User(
            email=email,
            username=username,
            hashed_password=auth_manager.hash_password(password),
            first_name=first_name,
            last_name=last_name,
            role=role,
            is_active=True,
        )
        db.add(user)
        db.flush()
        db.refresh(user)

        logger.info(f"Admin {current_admin_id} created user {user.username}")
        return user

    def get_user_details(self, db: Session, user_id: int) -> User:
        """
        Get user with relationships loaded.

        Raises:
            UserNotFoundException: If user not found
        """
        user = (
            db.query(User)
            .options(
                joinedload(User.owned_merchants), joinedload(User.store_memberships)
            )
            .filter(User.id == user_id)
            .first()
        )

        if not user:
            raise UserNotFoundException(str(user_id))

        return user

    def update_user(
        self,
        db: Session,
        user_id: int,
        current_admin_id: int,
        email: str | None = None,
        username: str | None = None,
        first_name: str | None = None,
        last_name: str | None = None,
        role: str | None = None,
        is_active: bool | None = None,
    ) -> User:
        """
        Update user information.

        Raises:
            UserNotFoundException: If user not found
            UserAlreadyExistsException: If email/username already taken
            UserRoleChangeException: If trying to change own admin role
        """
        user = self._get_user_by_id_or_raise(db, user_id)

        # Prevent changing own admin status
        if user.id == current_admin_id and role and role not in ("super_admin", "platform_admin"):
            raise UserRoleChangeException(
                user_id=user_id,
                current_role=user.role,
                target_role=role,
                reason="Cannot change your own admin role",
            )

        # Check email uniqueness if changing
        if email and email != user.email:
            if db.query(User).filter(User.email == email).first():
                raise UserAlreadyExistsException(
                    "Email already registered", field="email"
                )

        # Check username uniqueness if changing
        if username and username != user.username:
            if db.query(User).filter(User.username == username).first():
                raise UserAlreadyExistsException(
                    "Username already taken", field="username"
                )

        # Update fields
        if email is not None:
            user.email = email
        if username is not None:
            user.username = username
        if first_name is not None:
            user.first_name = first_name
        if last_name is not None:
            user.last_name = last_name
        if role is not None:
            user.role = role
        if is_active is not None:
            user.is_active = is_active

        user.updated_at = datetime.now(UTC)
        db.flush()
        db.refresh(user)

        logger.info(f"Admin {current_admin_id} updated user {user.username}")
        return user

    def delete_user(self, db: Session, user_id: int, current_admin_id: int) -> str:
        """
        Delete a user.

        Raises:
            UserNotFoundException: If user not found
            CannotModifySelfException: If trying to delete yourself
            UserCannotBeDeletedException: If user owns merchants
        """
        user = (
            db.query(User)
            .options(joinedload(User.owned_merchants))
            .filter(User.id == user_id)
            .first()
        )

        if not user:
            raise UserNotFoundException(str(user_id))

        # Prevent deleting yourself
        if user.id == current_admin_id:
            raise CannotModifySelfException(user_id, "delete account")

        # Prevent deleting users who own merchants
        if user.owned_merchants:
            raise UserCannotBeDeletedException(
                user_id=user_id,
                reason=f"User owns {len(user.owned_merchants)} merchant(ies). Transfer ownership first.",
                owned_count=len(user.owned_merchants),
            )

        from app.core.soft_delete import soft_delete

        username = user.username
        soft_delete(db, user, deleted_by_id=current_admin_id)

        logger.info(f"Admin {current_admin_id} deleted user {username}")
        return f"User {username} deleted successfully"

    def search_users(
        self,
        db: Session,
        query: str,
        limit: int = 10,
    ) -> list[dict]:
        """
        Search users by username or email.

        Used for autocomplete in ownership transfer.
        """
        search_term = f"%{query.lower()}%"
        users = (
            db.query(User)
            .filter(
                or_(User.username.ilike(search_term), User.email.ilike(search_term))
            )
            .limit(limit)
            .all()
        )

        return [
            {
                "id": user.id,
                "username": user.username,
                "email": user.email,
                "is_active": user.is_active,
            }
            for user in users
        ]

    # ============================================================================
    # STORE MANAGEMENT
    # ============================================================================

    def create_store(self, db: Session, store_data: StoreCreate) -> Store:
        """
        Create a store (storefront/brand) under an existing merchant.

        The store inherits owner and contact information from its parent merchant.

        Args:
            db: Database session
            store_data: Store creation data including merchant_id

        Returns:
            The created Store object with merchant relationship loaded

        Raises:
            ValidationException: If merchant not found or store code/subdomain exists
            AdminOperationException: If creation fails
        """
        try:
            # Validate merchant exists
            merchant = (
                db.query(Merchant).filter(Merchant.id == store_data.merchant_id).first()
            )
            if not merchant:
                raise MerchantNotFoundException(
                    store_data.merchant_id, identifier_type="id"
                )

            # Check if store code already exists
            existing_store = (
                db.query(Store)
                .filter(
                    func.upper(Store.store_code) == store_data.store_code.upper()
                )
                .first()
            )
            if existing_store:
                raise StoreAlreadyExistsException(store_data.store_code)

            # Check if subdomain already exists
            existing_subdomain = (
                db.query(Store)
                .filter(func.lower(Store.subdomain) == store_data.subdomain.lower())
                .first()
            )
            if existing_subdomain:
                raise StoreValidationException(
                    f"Subdomain '{store_data.subdomain}' is already taken",
                    field="subdomain",
                )

            # Create store linked to merchant
            store = Store(
                merchant_id=merchant.id,
                store_code=store_data.store_code.upper(),
                subdomain=store_data.subdomain.lower(),
                name=store_data.name,
                description=store_data.description,
                letzshop_csv_url_fr=store_data.letzshop_csv_url_fr,
                letzshop_csv_url_en=store_data.letzshop_csv_url_en,
                letzshop_csv_url_de=store_data.letzshop_csv_url_de,
                is_active=True,
                is_verified=False,  # Needs verification by admin
            )
            db.add(store)
            db.flush()  # Get store.id

            # Create default roles for store
            self._create_default_roles(db, store.id)

            # Assign store to platforms if provided
            if store_data.platform_ids:
                from app.modules.tenancy.models import StorePlatform

                for platform_id in store_data.platform_ids:
                    # Verify platform exists
                    platform = db.query(Platform).filter(Platform.id == platform_id).first()
                    if platform:
                        store_platform = StorePlatform(
                            store_id=store.id,
                            platform_id=platform_id,
                            is_active=True,
                        )
                        db.add(store_platform)  # noqa: PERF006
                        logger.debug(
                            f"Assigned store {store.store_code} to platform {platform.code}"
                        )

            db.flush()
            db.refresh(store)

            logger.info(
                f"Store {store.store_code} created under merchant {merchant.name} (ID: {merchant.id})"
            )

            return store

        except (StoreAlreadyExistsException, MerchantNotFoundException, StoreValidationException):
            raise
        except SQLAlchemyError as e:
            logger.error(f"Failed to create store: {str(e)}")
            raise AdminOperationException(
                operation="create_store",
                reason=f"Failed to create store: {str(e)}",
            )

    def get_all_stores(
        self,
        db: Session,
        skip: int = 0,
        limit: int = 100,
        search: str | None = None,
        is_active: bool | None = None,
        is_verified: bool | None = None,
        merchant_id: int | None = None,
        include_deleted: bool = False,
        only_deleted: bool = False,
    ) -> tuple[list[Store], int]:
        """Get paginated list of all stores with filtering."""
        try:
            # Eagerly load merchant relationship to avoid N+1 queries
            query = db.query(Store).options(joinedload(Store.merchant))

            # Soft-delete visibility
            if include_deleted or only_deleted:
                query = query.execution_options(include_deleted=True)
            if only_deleted:
                query = query.filter(Store.deleted_at.isnot(None))

            # Filter by merchant
            if merchant_id is not None:
                query = query.filter(Store.merchant_id == merchant_id)

            # Apply search filter
            if search:
                search_term = f"%{search}%"
                query = query.filter(
                    or_(
                        Store.name.ilike(search_term),
                        Store.store_code.ilike(search_term),
                        Store.subdomain.ilike(search_term),
                    )
                )

            # Apply status filters
            if is_active is not None:
                query = query.filter(Store.is_active == is_active)
            if is_verified is not None:
                query = query.filter(Store.is_verified == is_verified)

            # Get total count (without joinedload for performance)
            count_query = db.query(Store)
            if include_deleted or only_deleted:
                count_query = count_query.execution_options(include_deleted=True)
            if only_deleted:
                count_query = count_query.filter(Store.deleted_at.isnot(None))
            if merchant_id is not None:
                count_query = count_query.filter(Store.merchant_id == merchant_id)
            if search:
                search_term = f"%{search}%"
                count_query = count_query.filter(
                    or_(
                        Store.name.ilike(search_term),
                        Store.store_code.ilike(search_term),
                        Store.subdomain.ilike(search_term),
                    )
                )
            if is_active is not None:
                count_query = count_query.filter(Store.is_active == is_active)
            if is_verified is not None:
                count_query = count_query.filter(Store.is_verified == is_verified)
            total = count_query.count()

            # Get paginated results
            stores = query.offset(skip).limit(limit).all()

            return stores, total
        except SQLAlchemyError as e:
            logger.error(f"Failed to retrieve stores: {str(e)}")
            raise AdminOperationException(
                operation="get_all_stores", reason="Database query failed"
            )

    def get_store_by_id(self, db: Session, store_id: int) -> Store:
        """Get store by ID."""
        return self._get_store_by_id_or_raise(db, store_id)

    def verify_store(self, db: Session, store_id: int) -> tuple[Store, str]:
        """Toggle store verification status."""
        store = self._get_store_by_id_or_raise(db, store_id)

        try:
            original_status = store.is_verified
            store.is_verified = not store.is_verified
            store.updated_at = datetime.now(UTC)

            if store.is_verified:
                store.verified_at = datetime.now(UTC)

            db.flush()
            db.refresh(store)

            status_action = "verified" if store.is_verified else "unverified"
            message = f"Store {store.store_code} has been {status_action}"

            logger.info(message)
            return store, message

        except SQLAlchemyError as e:
            logger.error(f"Failed to verify store {store_id}: {str(e)}")
            raise StoreVerificationException(
                store_id=store_id,
                reason="Database update failed",
                current_verification_status=original_status,
            )

    def toggle_store_status(self, db: Session, store_id: int) -> tuple[Store, str]:
        """Toggle store active status."""
        store = self._get_store_by_id_or_raise(db, store_id)

        try:
            store.is_active = not store.is_active
            store.updated_at = datetime.now(UTC)
            db.flush()
            db.refresh(store)

            status_action = "activated" if store.is_active else "deactivated"
            message = f"Store {store.store_code} has been {status_action}"

            logger.info(message)
            return store, message

        except SQLAlchemyError as e:
            logger.error(f"Failed to toggle store {store_id} status: {str(e)}")
            raise AdminOperationException(
                operation="toggle_store_status",
                reason="Database update failed",
                target_type="store",
                target_id=str(store_id),
            )

    def delete_store(self, db: Session, store_id: int) -> str:
        """Delete store and all associated data."""
        store = self._get_store_by_id_or_raise(db, store_id)

        try:
            from app.core.soft_delete import soft_delete_cascade

            store_code = store.store_code

            soft_delete_cascade(db, store, deleted_by_id=None, cascade_rels=[
                ("products", []),
                ("customers", []),
                ("orders", []),
                ("store_users", []),
            ])

            logger.warning(f"Store {store_code} and all associated data deleted")
            return f"Store {store_code} successfully deleted"

        except SQLAlchemyError as e:
            logger.error(f"Failed to delete store {store_id}: {str(e)}")
            raise AdminOperationException(
                operation="delete_store", reason="Database deletion failed"
            )

    def update_store(
        self,
        db: Session,
        store_id: int,
        store_update,  # StoreUpdate schema
    ) -> Store:
        """
        Update store information (Admin only).

        Can update:
        - Store details (name, description, subdomain)
        - Business contact info (contact_email, phone, etc.)
        - Status (is_active, is_verified)

        Cannot update:
        - store_code (immutable)
        - merchant_id (store cannot be moved between merchants)

        Note: Ownership is managed at the Merchant level.
        Use merchant_service.transfer_ownership() for ownership changes.

        Args:
            db: Database session
            store_id: ID of store to update
            store_update: StoreUpdate schema with updated data

        Returns:
            Updated store object

        Raises:
            StoreNotFoundException: If store not found
            ValidationException: If subdomain already taken
        """
        store = self._get_store_by_id_or_raise(db, store_id)

        try:
            # Get update data
            update_data = store_update.model_dump(exclude_unset=True)

            # Handle reset_contact_to_merchant flag
            if update_data.pop("reset_contact_to_merchant", False):
                # Reset all contact fields to None (inherit from merchant)
                update_data["contact_email"] = None
                update_data["contact_phone"] = None
                update_data["website"] = None
                update_data["business_address"] = None
                update_data["tax_number"] = None

            # Convert empty strings to None for contact fields (empty = inherit)
            contact_fields = [
                "contact_email",
                "contact_phone",
                "website",
                "business_address",
                "tax_number",
            ]
            for field in contact_fields:
                if field in update_data and update_data[field] == "":
                    update_data[field] = None

            # Check subdomain uniqueness if changing
            if (
                "subdomain" in update_data
                and update_data["subdomain"] != store.subdomain
            ):
                existing = (
                    db.query(Store)
                    .filter(
                        Store.subdomain == update_data["subdomain"],
                        Store.id != store_id,
                    )
                    .first()
                )
                if existing:
                    raise StoreValidationException(
                        f"Subdomain '{update_data['subdomain']}' is already taken",
                        field="subdomain",
                    )

            # Update store fields
            for field, value in update_data.items():
                setattr(store, field, value)

            store.updated_at = datetime.now(UTC)

            db.flush()
            db.refresh(store)

            logger.info(
                f"Store {store_id} ({store.store_code}) updated by admin. "
                f"Fields updated: {', '.join(update_data.keys())}"
            )
            return store

        except StoreValidationException:
            raise
        except SQLAlchemyError as e:
            logger.error(f"Failed to update store {store_id}: {str(e)}")
            raise AdminOperationException(
                operation="update_store", reason=f"Database update failed: {str(e)}"
            )

    # NOTE: Store ownership transfer is now handled at the Merchant level.
    # Use merchant_service.transfer_ownership() instead.

    # NOTE: Marketplace import job operations have been moved to the marketplace module.
    # Use app.modules.marketplace routes for import job management.

    # ============================================================================
    # STATISTICS
    # ============================================================================

    def get_store_statistics(self, db: Session) -> dict:
        """
        Get store statistics for admin dashboard.

        Returns:
            Dict with total, verified, pending, and inactive counts.
        """
        try:
            total = db.query(Store).count()
            verified = db.query(Store).filter(Store.is_verified == True).count()  # noqa: E712
            active = db.query(Store).filter(Store.is_active == True).count()  # noqa: E712
            inactive = total - active
            pending = db.query(Store).filter(
                Store.is_active == True, Store.is_verified == False  # noqa: E712
            ).count()

            return {
                "total": total,
                "verified": verified,
                "pending": pending,
                "inactive": inactive,
            }
        except SQLAlchemyError as e:
            logger.error(f"Failed to get store statistics: {str(e)}")
            raise AdminOperationException(
                operation="get_store_statistics", reason="Database query failed"
            )

    def get_recent_stores(self, db: Session, limit: int = 5) -> list[dict]:
        """Get recently created stores."""
        try:
            stores = (
                db.query(Store).order_by(Store.created_at.desc()).limit(limit).all()
            )

            return [
                {
                    "id": v.id,
                    "store_code": v.store_code,
                    "name": v.name,
                    "subdomain": v.subdomain,
                    "is_active": v.is_active,
                    "is_verified": v.is_verified,
                    "created_at": v.created_at,
                }
                for v in stores
            ]
        except SQLAlchemyError as e:
            logger.error(f"Failed to get recent stores: {str(e)}")
            return []

    # NOTE: get_recent_import_jobs has been moved to the marketplace module

    # ============================================================================
    # PRIVATE HELPER METHODS
    # ============================================================================

    def get_user_by_id(self, db: Session, user_id: int) -> User | None:
        """
        Get user by ID.

        Public method for cross-module consumers that need to look up a user.
        Returns None if not found (does not raise).

        Args:
            db: Database session
            user_id: User ID

        Returns:
            User object or None
        """
        return db.query(User).filter(User.id == user_id).first()

    def get_user_by_email(self, db: Session, email: str) -> User | None:
        """Get user by email."""
        return db.query(User).filter(User.email == email).first()

    def get_user_by_username(self, db: Session, username: str) -> User | None:
        """Get user by username."""
        return db.query(User).filter(User.username == username).first()

    def _get_user_by_id_or_raise(self, db: Session, user_id: int) -> User:
        """Get user by ID or raise UserNotFoundException."""
        user = db.query(User).filter(User.id == user_id).first()
        if not user:
            raise UserNotFoundException(str(user_id))
        return user

    def _get_store_by_id_or_raise(self, db: Session, store_id: int) -> Store:
        """Get store by ID or raise StoreNotFoundException."""
        store = (
            db.query(Store)
            .options(joinedload(Store.merchant).joinedload(Merchant.owner))
            .filter(Store.id == store_id)
            .first()
        )
        if not store:
            raise StoreNotFoundException(str(store_id), identifier_type="id")
        return store

    def _generate_temp_password(self, length: int = 12) -> str:
        """Generate secure temporary password."""
        alphabet = string.ascii_letters + string.digits + "!@#$%^&*"
        return "".join(secrets.choice(alphabet) for _ in range(length))

    def _create_default_roles(self, db: Session, store_id: int):
        """Create default roles for a new store."""
        default_roles = [
            {"name": "Owner", "permissions": ["*"]},  # Full access
            {
                "name": "Manager",
                "permissions": [
                    "products.*",
                    "orders.*",
                    "customers.view",
                    "inventory.*",
                    "team.view",
                ],
            },
            {
                "name": "Editor",
                "permissions": [
                    "products.view",
                    "products.edit",
                    "orders.view",
                    "inventory.view",
                ],
            },
            {
                "name": "Viewer",
                "permissions": [
                    "products.view",
                    "orders.view",
                    "customers.view",
                    "inventory.view",
                ],
            },
        ]

        roles = [
            Role(
                store_id=store_id,
                name=role_data["name"],
                permissions=role_data["permissions"],
            )
            for role_data in default_roles
        ]
        db.add_all(roles)


    def get_user_statistics(self, db: Session) -> dict:
        """
        Get user statistics for dashboards.

        Returns:
            Dict with total_users, active_users, inactive_users, admin_users, activation_rate
        """
        from sqlalchemy import func

        total_users = db.query(func.count(User.id)).scalar() or 0
        active_users = (
            db.query(func.count(User.id))
            .filter(User.is_active == True)  # noqa: E712
            .scalar()
            or 0
        )
        inactive_users = total_users - active_users
        admin_users = (
            db.query(func.count(User.id))
            .filter(User.role.in_(["super_admin", "platform_admin"]))
            .scalar()
            or 0
        )

        return {
            "total_users": total_users,
            "active_users": active_users,
            "inactive_users": inactive_users,
            "admin_users": admin_users,
            "activation_rate": (
                (active_users / total_users * 100) if total_users > 0 else 0
            ),
        }


# Create service instance
admin_service = AdminService()