from typing import Optional
import pandas as pd
import phoenixdb
from mindsdb_sql_parser import parse_sql
from mindsdb.utilities.render.sqlalchemy_render import SqlalchemyRender
from mindsdb.integrations.libs.base import DatabaseHandler
from pyphoenix.sqlalchemy_phoenix import PhoenixDialect
from mindsdb_sql_parser.ast.base import ASTNode
from mindsdb.utilities import log
from mindsdb.integrations.libs.response import (
    HandlerStatusResponse as StatusResponse,
    HandlerResponse as Response,
    RESPONSE_TYPE
)

logger = log.getLogger(__name__)


class LindormHandler(DatabaseHandler):
    """
    This handler handles connection and execution of the Apache Phoenix statements.
    """

    name = 'lindorm'

    def __init__(self, name: str, connection_data: Optional[dict], **kwargs):
        """
        Initialize the handler.
        Args:
            name (str): name of particular handler instance
            connection_data (dict): parameters for connecting to the database
            **kwargs: arbitrary keyword arguments.
        """
        super().__init__(name)
        self.parser = parse_sql
        self.dialect = 'phoenix'
        optional_parameters = ['autocommit', 'lindorm_user', 'lindorm_password']
        for parameter in optional_parameters:
            if parameter not in connection_data:
                connection_data[parameter] = None

        self.connection_data = connection_data
        self.kwargs = kwargs

        self.connection = None
        self.is_connected = False

    def __del__(self):
        if self.is_connected is True:
            self.disconnect()

    def connect(self) -> StatusResponse:
        """
        Set up the connection required by the handler.
        Returns:
            HandlerStatusResponse
        """

        if self.is_connected is True:
            return self.connection

        lindorm_connection_data = {'lindorm_user': self.connection_data['lindorm_user'], 'lindorm_password': self.connection_data['lindorm_password']}

        self.connection = phoenixdb.connect(
            url=self.connection_data['url'],
            autocommit=self.connection_data['autocommit'],
            **lindorm_connection_data
        )
        self.is_connected = True

        return self.connection

    def disconnect(self):
        """ Close any existing connections

        Should switch self.is_connected.
        """

        if self.is_connected is False:
            return

        self.connection.close()
        self.is_connected = False
        return self.is_connected

    def check_connection(self) -> StatusResponse:
        """
        Check connection to the handler.
        Returns:
            HandlerStatusResponse
        """

        response = StatusResponse(False)
        need_to_close = self.is_connected is False

        try:
            self.connect()
            response.success = True
        except Exception as e:
            logger.error(f'Error connecting to the Phoenix Query Server, {e}!')
            response.error_message = str(e)
        finally:
            if response.success is True and need_to_close:
                self.disconnect()
            if response.success is False and self.is_connected is True:
                self.is_connected = False

        return response

    def native_query(self, query: str) -> StatusResponse:
        """
        Receive raw query and act upon it somehow.
        Args:
            query (str): query in native format
        Returns:
            HandlerResponse
        """

        need_to_close = self.is_connected is False

        connection = self.connect()
        cursor = connection.cursor()

        try:
            cursor.execute(query)
            result = cursor.fetchall()
            if result:
                response = Response(
                    RESPONSE_TYPE.TABLE,
                    data_frame=pd.DataFrame(
                        result,
                        columns=[x[0] for x in cursor.description]
                    )
                )
            else:
                connection.commit()
                response = Response(RESPONSE_TYPE.OK)
        except Exception as e:
            logger.error(f'Error running query: {query} on the Lindorm Query Server!')
            response = Response(
                RESPONSE_TYPE.ERROR,
                error_message=str(e)
            )

        cursor.close()
        if need_to_close is True:
            self.disconnect()

        return response

    def query(self, query: ASTNode) -> StatusResponse:
        """
        Receive query as AST (abstract syntax tree) and act upon it somehow.
        Args:
            query (ASTNode): sql query represented as AST. May be any kind
                of query: SELECT, INTSERT, DELETE, etc
        Returns:
            HandlerResponse
        """

        renderer = SqlalchemyRender(PhoenixDialect)
        query_str = renderer.get_string(query, with_failback=True)
        return self.native_query(query_str)

    def get_tables(self) -> StatusResponse:
        """
        Return list of entities that will be accessible as tables.
        Returns:
            HandlerResponse
        """

        query = """
            SELECT DISTINCT TABLE_NAME, TABLE_SCHEM FROM SYSTEM.CATALOG
        """
        result = self.native_query(query)
        df = result.data_frame
        df = df[df['TABLE_SCHEM'] != 'SYSTEM']
        df = df.drop('TABLE_SCHEM', axis=1)
        result.data_frame = df.rename(columns={df.columns[0]: 'table_name'})
        return result

    def get_columns(self, table_name: str) -> StatusResponse:
        """
        Returns a list of entity columns.
        Args:
            table_name (str): name of one of tables returned by self.get_tables()
        Returns:
            HandlerResponse
        """

        need_to_close = self.is_connected is False

        connection = self.connect()
        cursor = connection.cursor()

        try:
            query = f"SELECT * from {table_name} LIMIT 5"
            cursor.execute(query)
            cursor.fetchall()

            response = Response(
                RESPONSE_TYPE.TABLE,
                data_frame=pd.DataFrame(
                    [(x[0], x[1]) for x in cursor.description],
                    columns=['column_name', 'data_type']
                )
            )

        except Exception as e:
            logger.error(f'Error running query: {query} on the Phoenix Query Server!')
            response = Response(
                RESPONSE_TYPE.ERROR,
                error_message=str(e)
            )

        cursor.close()
        if need_to_close is True:
            self.disconnect()

        return response
