import json
import pymysql
import pandas as pd
from django.core.management.base import BaseCommand
from sqlalchemy import create_engine
from tqdm import tqdm  # Progress bar support

# Database connection details
db_config = {
    "host": "localhost",
    "user": "root",
    "password": "Kfsh&rc9788",
    "database": "car2db_20250701",
}

EXCLUDED_TABLES = {"car_serie", "car_generation"}  # Tables to exclude from direct dump


class Command(BaseCommand):
    help = "Merge car_serie with car_generation, include in final JSON dump with a progress bar."

    def handle(self, *args, **kwargs):
        try:
            self.stdout.write(self.style.SUCCESS("Connecting to database..."))
            # Create SQLAlchemy engine
            engine = create_engine(
                f"mysql+pymysql://{db_config['user']}:{db_config['password']}@{db_config['host']}/{db_config['database']}"
            )

            # Load car_generation table
            self.stdout.write(self.style.SUCCESS("Loading car_generation data..."))
            car_generation_query = "SELECT * FROM car_generation;"
            car_generation_df = pd.read_sql(car_generation_query, engine)

            # Load car_serie table
            self.stdout.write(self.style.SUCCESS("Loading car_serie data..."))
            car_serie_query = "SELECT * FROM car_serie;"
            car_serie_df = pd.read_sql(car_serie_query, engine)

            # Perform a LEFT JOIN to keep all car series and merge with car generations
            self.stdout.write(
                self.style.SUCCESS("Merging car_serie with car_generation...")
            )
            merged_df = pd.merge(
                car_serie_df, car_generation_df, on="id_car_generation", how="left"
            )

            # Select and rename the relevant columns
            final_df = merged_df.rename(
                columns={
                    "id_car_serie": "id_car_serie",
                    "id_car_model_x": "id_car_model",
                    "name_y": "generation_name",
                    "name_x": "serie_name",
                    "year_begin": "year_begin",
                    "year_end": "year_end",
                }
            )[
                [
                    "id_car_serie",
                    "id_car_model",
                    "generation_name",
                    "serie_name",
                    "year_begin",
                    "year_end",
                ]
            ]

            # Convert merged data to a JSON-ready format
            self.stdout.write(self.style.SUCCESS("Processing merged data..."))
            car_serie_json = list(
                tqdm(final_df.to_dict(orient="records"), desc="Processing car_serie")
            )

            # Export the full database including merged car_serie
            self.export_database_to_json(car_serie_json)

        except Exception as e:
            self.stdout.write(self.style.ERROR(f"Error: {e}"))

    def export_database_to_json(self, car_serie_data):
        """Export the entire MariaDB database to JSON, replacing car_serie with merged data"""
        try:
            self.stdout.write(self.style.SUCCESS("Exporting database to JSON..."))
            # Connect to the database using pymysql
            connection = pymysql.connect(**db_config)
            cursor = connection.cursor()

            # Fetch all table names
            cursor.execute("SHOW TABLES")
            tables = cursor.fetchall()

            # Function to fetch data from a table and convert it to JSON
            def table_to_json(table_name):
                table_cursor = connection.cursor(pymysql.cursors.DictCursor)
                table_cursor.execute(f"SELECT * FROM {table_name}")
                rows = table_cursor.fetchall()
                return rows

            # Export each table to JSON, excluding `car_serie` and `car_generation`
            database_json = {}
            self.stdout.write(self.style.SUCCESS("Processing database tables..."))
            for table in tqdm(tables, desc="Exporting tables"):
                table_name = table[0]
                if table_name not in EXCLUDED_TABLES:
                    database_json[table_name] = table_to_json(table_name)

            # Add the merged car_serie data to the final export
            database_json["car_serie"] = car_serie_data

            # Save the JSON to a file
            self.stdout.write(self.style.SUCCESS("Saving database_export.json..."))
            with open("database_export.json", "w", encoding="utf-8") as json_file:
                json.dump(database_json, json_file, indent=4, ensure_ascii=False)

            self.stdout.write(
                self.style.SUCCESS(
                    "✅ Database exported to JSON successfully! (Including merged car_serie)"
                )
            )

        except Exception as e:
            self.stdout.write(self.style.ERROR(f"Error exporting database: {e}"))
        finally:
            if connection:
                connection.close()