// Copyright (C) 2024 Wibo Kuipers
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

use crate::core::method_types::Check;
use crate::core::utils::errors::AlphaDBError;
use crate::core::utils::globals::CONFIG_TABLE_NAME;
use mysql::{prelude::*, PooledConn};
use thiserror::Error;

#[derive(Error, Debug)]
pub enum CheckError {
    #[error(transparent)]
    AlphaDbError(#[from] AlphaDBError),

    #[error(transparent)]
    MySqlError(#[from] mysql::Error),
}

/// **Check**
///
/// Check if the database is initialized and get the current version
///
/// # Arguments
/// * `db_name` - The name of the database to check
/// * `connection` - Active connection pool to the database
///
/// # Returns
/// * `Result<Check, CheckError>` - Check struct containing initialization status and version
///
/// # Errors
/// * Returns `CheckError` if there are any database or AlphaDB errors
pub fn check(db_name: &str, connection: &mut PooledConn) -> Result<Check, CheckError> {
    let mut check = false;
    let mut version: Option<String> = None;

    // Check if the configuration table exists
    let table_check: Option<String> = connection.exec_first(
        "SELECT table_name FROM information_schema.tables WHERE table_schema = ? AND table_name = ?",
        (&db_name, CONFIG_TABLE_NAME),
    )?;

    if !table_check.is_none() {
        let fetched: Option<String> = connection.exec_first(format!("SELECT version FROM {} where db = ?", CONFIG_TABLE_NAME), (db_name,))?;

        if fetched.is_some() {
            version = fetched;
        }
    }

    // Check true means database is redy for use
    if table_check.is_some() && version.is_some() {
        check = true;
    }

    Ok(Check { check, version })
}
