import json
from datetime import datetime
from pathlib import Path

import mariadb
from sqlalchemy import create_engine, select, text, MetaData, join
from sqlalchemy.orm import DeclarativeBase, relationship, sessionmaker

from database.base import Base
from database.comic import Comic
from database.metadata import MetaDataTable, MetaDataColumn


class KontorDB:

    def __init__(self, db_config):
        self.db_conn = mariadb.connect(
            host=db_config['mariadb']['host'],
            port=db_config['mariadb']['port'],
            user=db_config['mariadb']['user'],
            password=db_config['mariadb']['password'],
            database=db_config['mariadb']['database']
        )
        connect_string = ('mariadb+mariadbconnector://{}:{}@{}:{}/{}'
        .format(
            db_config['mariadb']['user'],
            db_config['mariadb']['password'],
            db_config['mariadb']['host'],
            db_config['mariadb']['port'],
            db_config['mariadb']['database']))
        # engine = create_engine(connect_string, echo=True)
        engine = create_engine(connect_string)
        Base.metadata.create_all(bind=engine)
        __session__ = sessionmaker(bind=engine)
        self.session = __session__()

    def get_table_names(self) -> list:
        tables = self.session.query(MetaDataTable).all()
        result = [table.table_name for table in tables]
        return result

    def get_column_meta_data(self, table_name: str, view_only=True) -> dict:
        meta_data = {}
        order = 0
        if view_only:
            for (_, column) in (self.session.query(MetaDataTable, MetaDataColumn).
                    filter(MetaDataTable.id == MetaDataColumn.table_id).
                    filter(MetaDataTable.table_name == table_name).
                    filter(MetaDataColumn.is_shown == 1).all()):
                meta_data[order] = {'column': column.column_name, 'label': column.column_label,
                                    'order': column.column_order, 'ref_column': column.ref_column}
                order += 1
        else:
            for (_, column) in (self.session.query(MetaDataTable, MetaDataColumn).
                    filter(MetaDataTable.id == MetaDataColumn.table_id).
                    filter(MetaDataTable.table_name == table_name).all()):
                meta_data[order] = {
                    'column': column.column_name,
                    'order': column.column_order,
                    'ref_column': column.ref_column
                }
                order += 1
        return meta_data

    def get_filters(self, table_name):
        _filter_map = {}
        for (_, column) in (self.session.query(MetaDataTable, MetaDataColumn).
                filter(MetaDataTable.id == MetaDataColumn.table_id).
                filter(MetaDataTable.table_name == table_name).
                filter(MetaDataColumn.show_filter == 1).all()):
            _filter_map[column.column_name] = {'label': column.filter_label, 'widget': None}
        print(f"retrieved {len(_filter_map)} filters: {_filter_map}")
        return _filter_map

    def data(self, table, columns: dict, filters) -> list:
        data = []
        entries = []
        if len(filters) == 0:
            entries = self.session.query(table).all()
        else:
            entries = self.session.query(table).filter_by(**filters)
        for entry in entries:
            row = []
            for order in columns.keys():
                column_name = columns[order]['column']
                if str(column_name).endswith("_id"):
                    ref_table = column_name[:-3]
                    # print(f"{ref_table=}")
                    ref = getattr(entry, ref_table)
                    value = getattr(ref, "name")
                    # print(f"{value=}")
                    row.append(value)
                else:
                    row.append(getattr(entry, column_name))
            # print(repr(row))
            data.append(row)
        return data

    def get_data(self, table_name: str, columns: dict, where_clause: str) -> list:
        data = []
        cursor = self.db_conn.cursor()
        cursor.execute(self.get_statement(table_name, columns, where_clause))
        rows = cursor.fetchall()
        print(len(rows))
        for row in rows:
            # print(f"KontorDB.get_data: {row}")
            data.append(list(row))
        cursor.close()
        # print(f"KontorDB.getData: return {len(data)}")
        if table_name == 'comic' and len(where_clause) == 0:
            data.clear()
            comics = self.session.query(Comic).all()
            for item in comics:
                # print(item)
                row = []
                for order in columns.keys():
                    column_name = columns[order]['column']
                    if str(column_name).endswith("_id"):
                        ref_table = column_name[:-3]
                        # print(f"{ref_table=}")
                        ref = getattr(item, ref_table)
                        value = getattr(ref, "name")
                        # print(f"{value=}")
                        row.append(value)
                    else:
                        row.append(getattr(item, column_name))
                # print(repr(row))
                data.append(row)
        return data

    def get_statement(self, table: str, header: dict, where_clause):
        columns = ""
        for index, column in header.items():
            if index > 0:
                columns += ", "
            columns += column['column']
        if len(columns) == 0:
            columns = "*"
        statement = f"SELECT {columns} FROM {table} {where_clause}"
        print(f"{statement=}")
        return statement

    def export_db(self, export_type: str, export_file_name: str, export_table_list: list):
        print(f"export DB to {export_file_name} as {export_type}")
        db = {}
        for table in export_table_list:
            columns = self.get_column_meta_data(table, view_only=False)
            model = Base.model_lookup_by_table_name(table)
            rows = self.session.query(model).all()
            entries = []
            print(f"found {len(rows)} entries")
            print(f"found {len(columns)} columns")
            for row in rows:
                print(row)
                entry = {}
                for order in columns:
                    print(columns[order])
                    column_name = columns[order]['column']
                    print(f"get value {column_name} from {row} of table {table}")
                    try:
                        value = getattr(row, column_name)
                        if isinstance(value, datetime):
                            entry[column_name] = str(value)
                        else:
                            entry[column_name] = value
                    except AttributeError as error:
                        print("could not get value")
                entries.append(entry)
            db[table] = entries
        export_file = Path(export_file_name)
        match export_type:
            case "JSON":
                json_dump = json.dumps(db, indent=4)
                with open(export_file_name, "w") as dump_file:
                    dump_file.write(json_dump)
            case "YAML":
                export_file = Path(export_file_name)
            case "SQLite":
                export_file = Path(export_file_name)
            case _:
                print("unknown export type")
        if export_file.exists():
            print(f"{export_file} exists")