#!/usr/bin/env python3

from os import environ
from pathlib import Path

from psycopg2 import connect
from psycopg2._psycopg import cursor
from psycopg2 import Error
from psycopg2 import errorcodes


# verify if the installation
# exit code 0 -> no database update is necessary
# exit code 1 -> database update is necessary


def check_file():
    db_app_version_file = Path("./config/db_app_version.txt")
    if not db_app_version_file.exists():
        exit(1)
    if not db_app_version_file.is_file():
        exit(1)
    if not db_app_version_file.read_text().strip(" ").strip("\n") == environ["APP_VERSION"]:
        exit(1)


def check_database():
    connection = connect(
        user = environ["PGDB_USER"],
        password = environ["PGDB_PASSWORD"],
        host = environ["PGDB_HOST"],
        port = environ["PGDB_PORT"],
        database = environ["PGDB_DB"]
    ) 
    cur = connection.cursor()
    try:
        # check application version in db
        cur.execute("""
            select value from application_info
            where key = 'app_version';
        """)
        appinfo_result = list(cur.fetchone())[0]
        if appinfo_result == None:
            cur.close()
            connection.close()
            exit(1)
        if appinfo_result != environ["APP_VERSION"]:
            cur.close()
            connection.close()
            exit(1)
        # check rows in app_global
        required_rows = [
            "global_message",
            "admin_info"
        ]
        cur.execute("""
            select name from app_global;
        """)
        table_global_result = list(cur.fetchall())
        cur.close()
        connection.close()
        existing_rows = [list(row)[0] for row in table_global_result]
        for r in required_rows:
            if not r in existing_rows:
                exit(1)
    except Error:
        cur.close()
        connection.close()
        exit(1)
    except Exception as e:
        print(f"An exception occured: {e}")
        cur.close()
        connection.close()
        exit(1)


if __name__ == "__main__":
    check_file()
    check_database()
    exit(0)