from pydantic import BaseModel
from sqlalchemy import create_engine, Column, and_
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker, Session, DeclarativeMeta
from typing import Literal, List, Any


class SqlalchemyConnect:
    def __init__(self, Base: declarative_base, host="127.0.0.1", user="", password="", db=""):
        self.Base = Base
        self.host = host
        self.user = user
        self.password = password
        self.db = db
        self.engine = self.init_engine()

    def init_engine(self):
        engine = create_engine(
            f"mysql+pymysql://{self.user}:{self.password}@{self.host}/{self.db}?charset=utf8mb4")
        return engine

    def get_db(self) -> sessionmaker:
        try:
            session = sessionmaker(autocommit=False, autoflush=False, bind=self.engine)
            db = session()
            yield db
        finally:
            db.close()

    def get_db_commit(self) -> sessionmaker:
        try:
            session = sessionmaker(autocommit=False, autoflush=False, bind=self.engine)
            db = session()
            yield db
            db.commit()
        finally:
            db.close()

    def get_db_i(self) -> Session:
        engine = create_engine(
            f"mysql+pymysql://{self.user}:{self.password}@{self.host}/{self.db}?charset=utf8mb4")
        session = sessionmaker(autocommit=False, autoflush=False, bind=engine)
        db = session()
        return db

    def init_database(self):
        self.Base.metadata.create_all(bind=self.engine)


# 通用查询接口

QueryType = Literal['=', '==', '>', '>=', '<', '<=', 'in', 'like', 'range']


class QueryParam(BaseModel):
    name: str
    type: QueryType
    value: Any


class QueryParams(BaseModel):
    param_list: List[QueryParam]
    page: int
    page_size: int


def query_common(db: Session, model, query_params: QueryParams):
    query = db.query(model)
    page = query_params.page
    page_size = query_params.page_size
    query = query_common_core(model, query, query_params.param_list)
    count = query.count()
    page_size = min(page_size, 100)
    query = query.offset((page - 1) * page_size).limit(page_size).all()
    return count, query


def query_common_core(model, query, param_list: List[QueryParam]):
    for item in param_list:
        name = item.name
        query_type = item.type
        value = item.value
        column: Column = getattr(model, name)
        if query_type in ['=', '==']:
            query = query.filter(column == value)
        if query_type == ">":
            query = query.filter(column > value)
        if query_type == "<":
            query = query.filter(column < value)
        if query_type == ">=":
            query = query.filter(column >= value)
        if query_type == "<=":
            query = query.filter(column <= value)
        if query_type == "in":
            query = query.filter(column.in_(value))
        if query_type == "like":
            query = query.filter(column.like(f'%{value}%'))
        if query_type == "range":
            query = query.filter(and_(column >= value[0], column <= value[1]))
    return query