# services/inventory/app/repositories/stock_repository.py
"""
Stock Repository using Repository Pattern
"""

from typing import List, Optional, Dict, Any, Tuple
from uuid import UUID
from datetime import datetime, timedelta
from decimal import Decimal
from sqlalchemy import select, func, and_, or_, desc, asc, update
from sqlalchemy.ext.asyncio import AsyncSession
import structlog

from app.models.inventory import Stock, Ingredient
from app.schemas.inventory import StockCreate, StockUpdate
from shared.database.repository import BaseRepository
from shared.utils.batch_generator import BatchCountProvider

logger = structlog.get_logger()


class StockRepository(BaseRepository[Stock, StockCreate, StockUpdate], BatchCountProvider):
    """Repository for stock operations"""

    def __init__(self, session: AsyncSession):
        super().__init__(Stock, session)

    async def create_stock_entry(self, stock_data: StockCreate, tenant_id: UUID) -> Stock:
        """Create a new stock entry"""
        try:
            # Prepare data
            create_data = stock_data.model_dump()
            create_data['tenant_id'] = tenant_id

            # Ensure production_stage is properly converted to enum value
            if 'production_stage' in create_data:
                if hasattr(create_data['production_stage'], 'value'):
                    create_data['production_stage'] = create_data['production_stage'].value
                elif isinstance(create_data['production_stage'], str):
                    # If it's a string, ensure it's the correct enum value
                    from app.models.inventory import ProductionStage
                    try:
                        enum_obj = ProductionStage[create_data['production_stage']]
                        create_data['production_stage'] = enum_obj.value
                    except KeyError:
                        # If it's already the value, keep it as is
                        pass
            
            # Calculate available quantity
            available_qty = create_data['current_quantity'] - create_data.get('reserved_quantity', 0)
            create_data['available_quantity'] = max(0, available_qty)
            
            # Calculate total cost if unit cost provided
            if create_data.get('unit_cost') and create_data.get('current_quantity'):
                unit_cost = create_data['unit_cost']
                current_quantity = Decimal(str(create_data['current_quantity']))
                create_data['total_cost'] = unit_cost * current_quantity
            
            # Create record
            record = await self.create(create_data)
            logger.info(
                "Created stock entry", 
                stock_id=record.id,
                ingredient_id=record.ingredient_id,
                quantity=record.current_quantity,
                tenant_id=tenant_id
            )
            return record
            
        except Exception as e:
            logger.error("Failed to create stock entry", error=str(e), tenant_id=tenant_id)
            raise

    async def get_stock_by_ingredient(
        self, 
        tenant_id: UUID, 
        ingredient_id: UUID,
        include_unavailable: bool = False
    ) -> List[Stock]:
        """Get all stock entries for a specific ingredient"""
        try:
            query = select(self.model).where(
                and_(
                    self.model.tenant_id == tenant_id,
                    self.model.ingredient_id == ingredient_id
                )
            )
            
            if not include_unavailable:
                query = query.where(self.model.is_available == True)
                
            query = query.order_by(asc(self.model.expiration_date))
            
            result = await self.session.execute(query)
            return result.scalars().all()
            
        except Exception as e:
            logger.error("Failed to get stock by ingredient", error=str(e), ingredient_id=ingredient_id)
            raise

    async def get_total_stock_by_ingredient(self, tenant_id: UUID, ingredient_id: UUID) -> Dict[str, float]:
        """Get total stock quantities for an ingredient"""
        try:
            result = await self.session.execute(
                select(
                    func.coalesce(func.sum(Stock.current_quantity), 0).label('total_quantity'),
                    func.coalesce(func.sum(Stock.reserved_quantity), 0).label('total_reserved'),
                    func.coalesce(func.sum(Stock.available_quantity), 0).label('total_available')
                ).where(
                    and_(
                        Stock.tenant_id == tenant_id,
                        Stock.ingredient_id == ingredient_id,
                        Stock.is_available == True
                    )
                )
            )
            
            row = result.first()
            return {
                'total_quantity': float(row.total_quantity) if row.total_quantity else 0.0,
                'total_reserved': float(row.total_reserved) if row.total_reserved else 0.0,
                'total_available': float(row.total_available) if row.total_available else 0.0
            }
            
        except Exception as e:
            logger.error("Failed to get total stock", error=str(e), ingredient_id=ingredient_id)
            raise

    async def get_expiring_stock(
        self,
        tenant_id: UUID,
        days_ahead: int = 7
    ) -> List[Tuple[Stock, Ingredient]]:
        """Get stock items expiring within specified days using state-dependent expiration logic"""
        try:
            expiry_date = datetime.now() + timedelta(days=days_ahead)

            # Use final_expiration_date if available (for transformed products),
            # otherwise use regular expiration_date
            result = await self.session.execute(
                select(Stock, Ingredient)
                .join(Ingredient, Stock.ingredient_id == Ingredient.id)
                .where(
                    and_(
                        Stock.tenant_id == tenant_id,
                        Stock.is_available == True,
                        or_(
                            and_(
                                Stock.final_expiration_date.isnot(None),
                                Stock.final_expiration_date <= expiry_date
                            ),
                            and_(
                                Stock.final_expiration_date.is_(None),
                                Stock.expiration_date.isnot(None),
                                Stock.expiration_date <= expiry_date
                            )
                        )
                    )
                )
                .order_by(
                    asc(
                        func.coalesce(Stock.final_expiration_date, Stock.expiration_date)
                    )
                )
            )

            return result.all()

        except Exception as e:
            logger.error("Failed to get expiring stock", error=str(e), tenant_id=tenant_id)
            raise

    async def get_expired_stock(self, tenant_id: UUID) -> List[Tuple[Stock, Ingredient]]:
        """Get stock items that have expired using state-dependent expiration logic"""
        try:
            current_date = datetime.now()

            # Use final_expiration_date if available (for transformed products),
            # otherwise use regular expiration_date
            result = await self.session.execute(
                select(Stock, Ingredient)
                .join(Ingredient, Stock.ingredient_id == Ingredient.id)
                .where(
                    and_(
                        Stock.tenant_id == tenant_id,
                        Stock.is_available == True,
                        or_(
                            and_(
                                Stock.final_expiration_date.isnot(None),
                                Stock.final_expiration_date < current_date
                            ),
                            and_(
                                Stock.final_expiration_date.is_(None),
                                Stock.expiration_date.isnot(None),
                                Stock.expiration_date < current_date
                            )
                        )
                    )
                )
                .order_by(
                    desc(
                        func.coalesce(Stock.final_expiration_date, Stock.expiration_date)
                    )
                )
            )

            return result.all()

        except Exception as e:
            logger.error("Failed to get expired stock", error=str(e), tenant_id=tenant_id)
            raise

    async def reserve_stock(
        self,
        tenant_id: UUID,
        ingredient_id: UUID,
        quantity: float,
        fifo: bool = True
    ) -> List[Dict[str, Any]]:
        """Reserve stock using FIFO/LIFO method with state-dependent expiration"""
        try:
            # Order by appropriate expiration date based on transformation status
            effective_expiration = func.coalesce(Stock.final_expiration_date, Stock.expiration_date)
            order_clause = asc(effective_expiration) if fifo else desc(effective_expiration)

            result = await self.session.execute(
                select(Stock).where(
                    and_(
                        Stock.tenant_id == tenant_id,
                        Stock.ingredient_id == ingredient_id,
                        Stock.is_available == True,
                        Stock.available_quantity > 0
                    )
                ).order_by(order_clause)
            )
            
            stock_items = result.scalars().all()
            reservations = []
            remaining_qty = quantity
            
            for stock_item in stock_items:
                if remaining_qty <= 0:
                    break
                
                available = stock_item.available_quantity
                to_reserve = min(remaining_qty, available)
                
                # Update stock reservation
                new_reserved = stock_item.reserved_quantity + to_reserve
                new_available = stock_item.current_quantity - new_reserved
                
                await self.session.execute(
                    update(Stock)
                    .where(Stock.id == stock_item.id)
                    .values(
                        reserved_quantity=new_reserved,
                        available_quantity=new_available
                    )
                )
                
                reservations.append({
                    'stock_id': stock_item.id,
                    'reserved_quantity': to_reserve,
                    'batch_number': stock_item.batch_number,
                    'expiration_date': stock_item.expiration_date
                })
                
                remaining_qty -= to_reserve
            
            if remaining_qty > 0:
                logger.warning(
                    "Insufficient stock for reservation", 
                    ingredient_id=ingredient_id,
                    requested=quantity,
                    unfulfilled=remaining_qty
                )
            
            return reservations
            
        except Exception as e:
            logger.error("Failed to reserve stock", error=str(e), ingredient_id=ingredient_id)
            raise

    async def release_stock_reservation(
        self, 
        stock_id: UUID, 
        quantity: float
    ) -> Optional[Stock]:
        """Release reserved stock"""
        try:
            stock_item = await self.get_by_id(stock_id)
            if not stock_item:
                return None
            
            # Calculate new quantities
            new_reserved = max(0, stock_item.reserved_quantity - quantity)
            new_available = stock_item.current_quantity - new_reserved
            
            # Update stock
            await self.session.execute(
                update(Stock)
                .where(Stock.id == stock_id)
                .values(
                    reserved_quantity=new_reserved,
                    available_quantity=new_available
                )
            )
            
            # Refresh and return updated stock
            await self.session.refresh(stock_item)
            return stock_item
            
        except Exception as e:
            logger.error("Failed to release stock reservation", error=str(e), stock_id=stock_id)
            raise

    async def consume_stock(
        self, 
        stock_id: UUID, 
        quantity: float,
        from_reserved: bool = True
    ) -> Optional[Stock]:
        """Consume stock (reduce current quantity)"""
        try:
            stock_item = await self.get_by_id(stock_id)
            if not stock_item:
                return None
            
            if from_reserved:
                # Reduce from reserved quantity
                new_reserved = max(0, stock_item.reserved_quantity - quantity)
                new_current = max(0, stock_item.current_quantity - quantity)
                new_available = new_current - new_reserved
            else:
                # Reduce from available quantity
                new_current = max(0, stock_item.current_quantity - quantity)
                new_available = max(0, stock_item.available_quantity - quantity)
                new_reserved = stock_item.reserved_quantity
            
            # Update stock
            await self.session.execute(
                update(Stock)
                .where(Stock.id == stock_id)
                .values(
                    current_quantity=new_current,
                    reserved_quantity=new_reserved,
                    available_quantity=new_available,
                    is_available=new_current > 0
                )
            )
            
            # Refresh and return updated stock
            await self.session.refresh(stock_item)
            return stock_item
            
        except Exception as e:
            logger.error("Failed to consume stock", error=str(e), stock_id=stock_id)
            raise

    async def get_stock_summary_by_tenant(self, tenant_id: UUID) -> Dict[str, Any]:
        """Get stock summary for tenant dashboard"""
        try:
            # Basic stock summary
            basic_result = await self.session.execute(
                select(
                    func.count(Stock.id).label('total_stock_items'),
                    func.coalesce(func.sum(Stock.total_cost), 0).label('total_stock_value'),
                    func.count(func.distinct(Stock.ingredient_id)).label('unique_ingredients')
                ).where(
                    and_(
                        Stock.tenant_id == tenant_id,
                        Stock.is_available == True
                    )
                )
            )
            basic_summary = basic_result.first()

            # Count expired items
            expired_result = await self.session.execute(
                select(func.count(Stock.id)).where(
                    and_(
                        Stock.tenant_id == tenant_id,
                        Stock.is_available == True,
                        Stock.expiration_date < datetime.now()
                    )
                )
            )
            expired_count = expired_result.scalar() or 0

            # Count expiring soon items
            expiring_result = await self.session.execute(
                select(func.count(Stock.id)).where(
                    and_(
                        Stock.tenant_id == tenant_id,
                        Stock.is_available == True,
                        Stock.expiration_date.isnot(None),
                        Stock.expiration_date <= datetime.now() + timedelta(days=7)
                    )
                )
            )
            expiring_count = expiring_result.scalar() or 0

            return {
                'total_stock_items': basic_summary.total_stock_items or 0,
                'total_stock_value': float(basic_summary.total_stock_value) if basic_summary.total_stock_value else 0.0,
                'unique_ingredients': basic_summary.unique_ingredients or 0,
                'expired_items': expired_count,
                'expiring_soon_items': expiring_count
            }

        except Exception as e:
            logger.error("Failed to get stock summary", error=str(e), tenant_id=tenant_id)
            raise

    async def mark_expired_stock(self, tenant_id: UUID) -> int:
        """Mark expired stock items as expired using state-dependent expiration logic"""
        try:
            current_date = datetime.now()

            # Mark items as expired based on final_expiration_date or expiration_date
            result = await self.session.execute(
                update(Stock)
                .where(
                    and_(
                        Stock.tenant_id == tenant_id,
                        Stock.is_expired == False,
                        or_(
                            and_(
                                Stock.final_expiration_date.isnot(None),
                                Stock.final_expiration_date < current_date
                            ),
                            and_(
                                Stock.final_expiration_date.is_(None),
                                Stock.expiration_date.isnot(None),
                                Stock.expiration_date < current_date
                            )
                        )
                    )
                )
                .values(is_expired=True, quality_status="expired")
            )

            expired_count = result.rowcount
            logger.info(f"Marked {expired_count} stock items as expired using state-dependent logic", tenant_id=tenant_id)

            return expired_count

        except Exception as e:
            logger.error("Failed to mark expired stock", error=str(e), tenant_id=tenant_id)
            raise

    async def get_stock_by_production_stage(
        self,
        tenant_id: UUID,
        production_stage: 'ProductionStage',
        ingredient_id: Optional[UUID] = None
    ) -> List['Stock']:
        """Get stock items by production stage"""
        try:
            conditions = [
                Stock.tenant_id == tenant_id,
                Stock.production_stage == production_stage,
                Stock.is_available == True
            ]

            if ingredient_id:
                conditions.append(Stock.ingredient_id == ingredient_id)

            result = await self.session.execute(
                select(Stock)
                .where(and_(*conditions))
                .order_by(asc(func.coalesce(Stock.final_expiration_date, Stock.expiration_date)))
            )

            return result.scalars().all()

        except Exception as e:
            logger.error("Failed to get stock by production stage", error=str(e), production_stage=production_stage)
            raise

    async def get_stock_entries(
        self,
        tenant_id: UUID,
        skip: int = 0,
        limit: int = 100,
        ingredient_id: Optional[UUID] = None,
        available_only: bool = True
    ) -> List[Stock]:
        """Get stock entries with filtering and pagination"""
        try:
            conditions = [Stock.tenant_id == tenant_id]

            if available_only:
                conditions.append(Stock.is_available == True)

            if ingredient_id:
                conditions.append(Stock.ingredient_id == ingredient_id)

            query = (
                select(Stock)
                .where(and_(*conditions))
                .order_by(desc(Stock.created_at))
                .offset(skip)
                .limit(limit)
            )

            result = await self.session.execute(query)
            return result.scalars().all()

        except Exception as e:
            logger.error("Failed to get stock entries", error=str(e), tenant_id=tenant_id)
            raise

    async def delete_by_ingredient(self, ingredient_id: UUID, tenant_id: UUID) -> int:
        """Delete all stock entries for a specific ingredient"""
        try:
            from sqlalchemy import delete

            stmt = delete(Stock).where(
                and_(
                    Stock.ingredient_id == ingredient_id,
                    Stock.tenant_id == tenant_id
                )
            )

            result = await self.session.execute(stmt)
            deleted_count = result.rowcount

            logger.info(
                "Deleted stock entries for ingredient",
                ingredient_id=str(ingredient_id),
                tenant_id=str(tenant_id),
                deleted_count=deleted_count
            )

            return deleted_count

        except Exception as e:
            logger.error(
                "Failed to delete stock entries for ingredient",
                error=str(e),
                ingredient_id=str(ingredient_id),
                tenant_id=str(tenant_id)
            )
            raise

    async def get_daily_batch_count(
        self,
        tenant_id: str,
        date_start: datetime,
        date_end: datetime,
        prefix: Optional[str] = None
    ) -> int:
        """Get the count of batches created today for the given tenant"""
        try:
            conditions = [
                Stock.tenant_id == tenant_id,
                Stock.created_at >= date_start,
                Stock.created_at <= date_end
            ]

            if prefix:
                conditions.append(Stock.batch_number.like(f"{prefix}-%"))

            stmt = select(func.count(Stock.id)).where(and_(*conditions))
            result = await self.session.execute(stmt)
            count = result.scalar() or 0

            logger.debug(
                "Retrieved daily batch count",
                tenant_id=tenant_id,
                prefix=prefix,
                count=count,
                date_start=date_start,
                date_end=date_end
            )

            return count

        except Exception as e:
            logger.error(
                "Failed to get daily batch count",
                error=str(e),
                tenant_id=tenant_id,
                prefix=prefix
            )
            raise

    async def get_expired_batches_for_processing(self, tenant_id: UUID) -> List[Tuple[Stock, Ingredient]]:
        """Get expired batches that haven't been processed yet (for automatic processing)"""
        try:
            current_date = datetime.now()

            # Find expired batches that are still available and not yet marked as expired
            result = await self.session.execute(
                select(Stock, Ingredient)
                .join(Ingredient, Stock.ingredient_id == Ingredient.id)
                .where(
                    and_(
                        Stock.tenant_id == tenant_id,
                        Stock.is_available == True,
                        Stock.is_expired == False,
                        Stock.current_quantity > 0,
                        or_(
                            and_(
                                Stock.final_expiration_date.isnot(None),
                                Stock.final_expiration_date <= current_date
                            ),
                            and_(
                                Stock.final_expiration_date.is_(None),
                                Stock.expiration_date.isnot(None),
                                Stock.expiration_date <= current_date
                            )
                        )
                    )
                )
                .order_by(
                    asc(func.coalesce(Stock.final_expiration_date, Stock.expiration_date))
                )
            )

            expired_batches = result.all()
            logger.info("Found expired batches for processing",
                       tenant_id=str(tenant_id),
                       count=len(expired_batches))

            return expired_batches

        except Exception as e:
            logger.error("Failed to get expired batches for processing",
                        error=str(e), tenant_id=tenant_id)
            raise

    async def mark_batch_as_expired(self, stock_id: UUID, tenant_id: UUID) -> bool:
        """Mark a specific batch as expired and unavailable"""
        try:
            result = await self.session.execute(
                update(Stock)
                .where(
                    and_(
                        Stock.id == stock_id,
                        Stock.tenant_id == tenant_id
                    )
                )
                .values(
                    is_expired=True,
                    is_available=False,
                    quality_status="expired",
                    updated_at=datetime.now()
                )
            )

            if result.rowcount > 0:
                logger.info("Marked batch as expired",
                           stock_id=str(stock_id),
                           tenant_id=str(tenant_id))
                return True
            else:
                logger.warning("No batch found to mark as expired",
                              stock_id=str(stock_id),
                              tenant_id=str(tenant_id))
                return False

        except Exception as e:
            logger.error("Failed to mark batch as expired",
                        error=str(e),
                        stock_id=str(stock_id),
                        tenant_id=str(tenant_id))
            raise

    async def update_stock_to_zero(self, stock_id: UUID, tenant_id: UUID) -> bool:
        """Update stock quantities to zero after moving to waste"""
        try:
            result = await self.session.execute(
                update(Stock)
                .where(
                    and_(
                        Stock.id == stock_id,
                        Stock.tenant_id == tenant_id
                    )
                )
                .values(
                    current_quantity=0,
                    available_quantity=0,
                    updated_at=datetime.now()
                )
            )

            if result.rowcount > 0:
                logger.info("Updated stock quantities to zero",
                           stock_id=str(stock_id),
                           tenant_id=str(tenant_id))
                return True
            else:
                logger.warning("No stock found to update to zero",
                              stock_id=str(stock_id),
                              tenant_id=str(tenant_id))
                return False

        except Exception as e:
            logger.error("Failed to update stock to zero",
                        error=str(e),
                        stock_id=str(stock_id),
                        tenant_id=str(tenant_id))
            raise