from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import sessionmaker, Session
from sqlalchemy.exc import SQLAlchemyError, InvalidRequestError
from database.db import engine, Base
from carga.procesos import (
    extraer_zip,
    identificar_zip,
    inspeccionar_txts,
    transformar_txts,
    verificar_registros_db,
    primera_carga,
    extraer_db,
    verificar_registros_obsoletos,
    terminar_carga,
    verificar_agregar_registros,
    restaurar_db,
    carga_error,
)

Base.prepare(engine)

def get_db():
    SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close() 

config = {
    "almacen_zips": "zip/",
    "almacen_txts": "txts/",
    "zips_procesados": "zips_procesados/",
}

carga_gtfs = APIRouter()

@carga_gtfs.get("/")
def root():
    return "Pagina Principal. Use /docs en la URL para probar la carga."

@carga_gtfs.post("/carga")
async def carga(db: Session = Depends(get_db)):
            zip_info = identificar_zip(db=db)
            zip_ruta = config["almacen_zips"] + zip_info.zip + ".zip"

            extraer_zip(zip=zip_info, zip_ruta=zip_ruta, db=db)

            inspeccionar_txts(zip=zip_info, almacen_txts=config["almacen_txts"], zip_ruta=zip_ruta, db=db)
            df_agency, df_calendar, df_routes, df_stop_times, df_stops, df_trips, df_shapes, df_shapes_reference = transformar_txts(
                zip=zip_info, db=db
            )

            (
            db_inicial_agency,
            db_inicial_routes,
            db_inicial_calendar,
            db_inicial_stops,
            db_inicial_shapes_reference,
            db_inicial_shapes,
            db_inicial_trips,
            db_inicial_stop_times,
            ) = extraer_db(engine=engine)

            bd_vacia = verificar_registros_db(db=db)

            if bd_vacia:
                primera_carga(
                    zip=zip_info,
                    db=db,
                    engine=engine,
                    df_agency=df_agency,
                    df_calendar=df_calendar,
                    df_routes=df_routes,
                    df_stop_times=df_stop_times,
                    df_stops=df_stops,
                    df_trips=df_trips,
                    df_shapes=df_shapes,
                    df_shapes_reference=df_shapes_reference,
                )
                
                terminar_carga(zip=zip_info, db=db, zips_procesados=config["zips_procesados"], directorio_txts=config["almacen_txts"])
                return "Terminó correctamente"
            else:
                try:
                    (
                        df_db_agency,
                        df_db_routes,
                        df_db_calendar,
                        df_db_stops,
                        df_db_shapes_reference,
                        df_db_shapes,
                        df_db_trips,
                        df_db_stop_times,
                    ) = extraer_db(engine=engine)

                    verificar_registros_obsoletos(
                        zip=zip_info,
                        df_agency=df_agency,
                        df_calendar=df_calendar,
                        df_routes=df_routes,
                        df_stop_times=df_stop_times,
                        df_stops=df_stops,
                        df_trips=df_trips,
                        df_shapes=df_shapes,
                        df_shapes_reference=df_shapes_reference,
                        df_db_agency=df_db_agency,
                        df_db_routes=df_db_routes,
                        df_db_calendar=df_db_calendar,
                        df_db_stops=df_db_stops,
                        df_db_shapes_reference=df_db_shapes_reference,
                        df_db_shapes=df_db_shapes,
                        df_db_trips=df_db_trips,
                        df_db_stop_times=df_db_stop_times,
                        db=db,
                    )

                    (
                        df_db_agency,
                        df_db_routes,
                        df_db_calendar,
                        df_db_stops,
                        df_db_shapes_reference,
                        df_db_shapes,
                        df_db_trips,
                        df_db_stop_times,
                    ) = extraer_db(engine=engine)

                    verificar_agregar_registros(
                        zip=zip_info,
                        df_agency=df_agency,
                        df_calendar=df_calendar,
                        df_routes=df_routes,
                        df_stop_times=df_stop_times,
                        df_stops=df_stops,
                        df_trips=df_trips,
                        df_shapes=df_shapes,
                        df_shapes_reference=df_shapes_reference,
                        df_db_agency=df_db_agency,
                        df_db_routes=df_db_routes,
                        df_db_calendar=df_db_calendar,
                        df_db_stops=df_db_stops,
                        df_db_shapes_reference=df_db_shapes_reference,
                        df_db_shapes=df_db_shapes,
                        df_db_trips=df_db_trips,
                        df_db_stop_times=df_db_stop_times,
                        db=db,
                    )

                    terminar_carga(zip=zip_info, db=db, zips_procesados=config["zips_procesados"], directorio_txts=config["almacen_txts"])
                    return "La carga termino con exito."
            

                except SQLAlchemyError as e:

                    restaurar_db(db)

                    primera_carga(
                        zip=zip_info,
                        db=db,
                        engine=engine,
                        df_agency=db_inicial_agency,
                        df_calendar=db_inicial_calendar,
                        df_routes=db_inicial_routes,
                        df_stop_times=db_inicial_stop_times,
                        df_stops=db_inicial_stops,
                        df_trips=db_inicial_trips,
                        df_shapes=db_inicial_shapes,
                        df_shapes_reference=db_inicial_shapes_reference,
                    )

                    carga_error(zip=zip_info, db=db, zips_procesados=config["zips_procesados"], directorio_txts=config["almacen_txts"])
                    raise HTTPException(status_code=500, detail=f"Error durante la carga: {str(e)}")
                
                except Exception as e:
                    restaurar_db(db)

                    primera_carga(
                        zip=zip_info,
                        db=db,
                        engine=engine,
                        df_agency=db_inicial_agency,
                        df_calendar=db_inicial_calendar,
                        df_routes=db_inicial_routes,
                        df_stop_times=db_inicial_stop_times,
                        df_stops=db_inicial_stops,
                        df_trips=db_inicial_trips,
                        df_shapes=db_inicial_shapes,
                        df_shapes_reference=db_inicial_shapes_reference,
                    )
                    
                    carga_error(zip=zip_info, db=db, zips_procesados=config["zips_procesados"], directorio_txts=config["almacen_txts"])
                    raise HTTPException(status_code=500, detail=f"Error durante la carga: {str(e)}")