import logging
import os
from datetime import datetime as dt
from decimal import Decimal
from typing import List

from sqlmodel import Field, Session, SQLModel, create_engine, select, text, Relationship, func

from sqlite3 import IntegrityError

MODULE='shop'

DATE_FORMAT = '%Y-%m-%d'

def today():
    return dt.now().strftime(DATE_FORMAT)


logger = logging.getLogger(__name__)

class ItemStoreLink(SQLModel, table=True):
    item_id: int | None = Field(default=None, foreign_key="item.id", primary_key=True)
    store_id: int | None = Field(default=None, foreign_key="store.id", primary_key=True)


class Item(SQLModel, table=True):
    '''An item to shop for.'''
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(default=None, unique=True)
    price: Decimal | None = Field(decimal_places=2)
    stores: list["Store"] = Relationship(back_populates="shopping_list", link_model=ItemStoreLink)
    purchase_date: dt | None = Field(default=None)
    def __str__(self):
        return f'{self.name} (#{self.id})'

class ItemZone(SQLModel, table=True):
    '''Where an item is usually found.

    Matched only by loose text matching, since items come and go, over time.
    '''
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(default=None, unique=True)  # milk
    zone: str = Field(default=None, unique=False) # dairy section


class PreferStore(SQLModel, table=True):
    '''Tracks which store we are shopping at, at the moment.'''
    store_id: int | None = Field(default=None, foreign_key="store.id", primary_key=True)

class Store(SQLModel, table=True):
    '''A place to shop at.'''
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(default=None, unique=True)
    shopping_list: list["Item"] = Relationship(back_populates="stores", link_model=ItemStoreLink)
    # purchase_history: list["PurchaseRecord"] = Relationship(back_populates="store")
    def __str__(self):
        return f'{self.name} (#{self.id})'

    def get_pretty_shopping_list(self) -> List[str]:
        results = []
        results.append(f' ## {self.name}')
        items = self.shopping_list
        if not items:
            results.append(f'-- Nothing to shop for at {self.name} --')
        else:
            for item in items:
                if(item.purchase_date):
                    results.append(f' - [x] {item}')
                else:
                    results.append(f' - [ ] {item}')
        return results


class PurchaseRecord(SQLModel, table=True):
    '''Tracks when and where items were purchased.'''
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(default=None)
    price: Decimal | None = Field(decimal_places=2)
    store: str | None = Field(default=None)
    purchase_date: dt | None = Field(default=None)
    def __str__(self):
        date = self.purchase_date.strftime(DATE_FORMAT)
        return f'Bought {self.name} at {self.store} on {date}'

def _get_with_id(cls, item_id):
    return select(cls).where(cls.id == item_id)

def _get_with_name(cls, name):
    return select(cls).where(func.lower(cls.name) == func.lower(name))


class Data():
    def __init__(self, db_file=None):
        if not db_file:
            db_file = os.path.join(os.environ.get('MATRIX_DATA_DIR', ''), f'{MODULE}.db')

        self.file = db_file
        logger.debug(f'Shop bot is using db file {self.file}')
        self.engine = self.get_engine()
        self.last_store_id = None

    def _set_pref_store_id(self, store_id):
        with Session(self.engine) as session:
            prefs = session.exec(select(PreferStore)).all()
            for pref in prefs:
                session.delete(pref)
            pref = PreferStore()
            pref.store_id = store_id
            session.add(pref)
            session.commit()

    def _get_pref_store_id(self):
        with Session(self.engine) as session:
            pref = session.exec(select(PreferStore)).one()
            return pref.store_id

    def _add_with_name(self, cls, name):
        item_id = -1
        try:
            with Session(self.engine) as session:
                new = cls(name=name)
                session.add(new)
                session.commit()
                item_id = new.id
        except:
            # duplicate add
            # recover by returning the item_id
            item = session.exec(select(Item).where(Item.name == name)).first()
            item_id = item.id

        return item_id

    def add_store(self, name):
        store_id = self._add_with_name(Store, name)
        self._set_pref_store_id(store_id)
        return store_id
            
    def add_item(self, name):
        names = name.split(',')
        for name in names:
            item_id = self._add_with_name(Item, name.strip())
            store_id = self._get_pref_store_id()
            self.assign_store(item_id, store_id)
        return item_id

    def assign_last_store(self, item_id):
        store_id = self._get_pref_store_id()
        self.assign_store(item_id, store_id)
        return store_id

    def assign_zone(self, item_name, zone_name):
        item_id = -1
        with Session(self.engine) as session:
            try:
                new = ItemZone(name=item_name)
                new.zone = zone_name
                session.add(new)
                session.commit()
                item_id = new.id
            except:
                pass # Already assigned
        return item_id

    def assign_store(self, item_id, store_id):
        self._set_pref_store_id(store_id)

        with Session(self.engine) as session:
            store = session.exec(_get_with_id(Store, store_id)).first()
            item = session.exec(_get_with_id(Item, item_id)).first()
            try:
                item.stores.append(store)
                session.commit()
            except:
                pass # Already assigned
        return ['Success']

    def list_purchases(self, store_name):
        with Session(self.engine) as session:
            cmd = select(PurchaseRecord).where(func.lower(PurchaseRecord.store) == func.lower(store_name))
            records = session.exec(cmd).all()
            return records

    def purchase_items(self, item_ids):
        results = []
        with Session(self.engine) as session:
            # Mark items as purchased
            for item_id in item_ids.split(' '):
                item = session.exec(_get_with_id(Item, item_id)).first()
                if item:
                    item.purchase_date = dt.today()
                
                # Track purchase history (locally only!)
                # to generate recommended shopping lists
                record = PurchaseRecord()
                record.name = item.name
                record.price = item.price
                record.purchase_date = item.purchase_date

                shopping_at = self._get_pref_store_id() # We bought it here
                cmd = select(Store).where(Store.id == shopping_at)
                store = session.exec(cmd).one()
                record.store = store.name
                session.add(record)

                results.append(str(record))
                # results.append(str(item))

            session.commit()
        return results


    def clear_list(self, store_name, clear_all=False):
        results = []
        with Session(self.engine) as session:
            store = session.exec(_get_with_name(Store, store_name)).first()
            if not store:
                return [f'Store {store_name} not found.']

            for item in store.shopping_list:
                if clear_all or item.purchase_date:
                    session.delete(item)

            session.commit()
            results = store.get_pretty_shopping_list()
        return results

    def get_stores(self):
        with Session(self.engine) as session:
            cmd = select(Store)
            return session.exec(cmd).all()

    def get_unsorted_list(self):

        results = []
        with Session(self.engine) as session:
            cmd = select(Item).where(Item.stores == None)
            items = session.exec(cmd).all()

            if not items:
                return [f'No unsorted items!']
            return items

    def get_last_shopping_list(self) -> List[str]:
        store_id = self._get_pref_store_id()
        with Session(self.engine) as session:
            store = session.exec(_get_with_id(Store, store_id)).first()
            if store:
                return store.get_pretty_shopping_list()
        return [f'Last shopping list store not found.']

    def get_shopping_list(self, store_name) -> List[str]:
        retsults = []
        with Session(self.engine) as session:
            store = session.exec(_get_with_name(Store, store_name)).first()
            if not store:
                return [f'Store {store_name} not found.']
            results = store.get_pretty_shopping_list()
        self._set_pref_store_id(store.id)
        return results

    def remove_item(self, item_id):
        with Session(self.engine) as session:
            item = session.exec(_get_with_id(Item, item_id)).first()
            session.delete(item)
            session.commit()

    def remove_store(self, store_id):
        with Session(self.engine) as session:
            store = session.exec(_get_with_id(Store, store_id)).first()
            session.delete(store)
            session.commit()

    def get_engine(self):
        return create_engine(f"sqlite:///{self.file}")

    def setup(self):
        SQLModel.metadata.create_all(self.engine)
        return 'Success'