//! Database Driver for MySQL
//!
//! Use of this driver requires enabling the `mysql` feature.
//!
//! Contains database-specific query data
//! Uses the [Mysql](https://crates.io/crates/mysql) crate for
//! interfacing with the database
use super::*;

use std::any::Any;
use std::cell::RefCell;
use my::{Pool};

/// The struct implementing the `DatabaseDriver` trait
#[derive(Debug)]
pub struct MySQLDriver {
    connection: RefCell<Option<Pool>>,
}

impl MySQLDriver {
    /// Create a MySQLDriver driver
    pub fn new(dsn: &str) -> Self {
        let mut driver =  MySQLDriver {
            connection: RefCell::new(None)
        };

        driver.connect(dsn);

        driver
    }

    fn test_new() -> Self {
        MySQLDriver {
            connection: RefCell::new(None)
        }
    }

    fn connect(&mut self, dsn: &str) {
        let connection = Pool::new(dsn).unwrap();

        self.connection = RefCell::new(Some(connection));
    }
}

impl DatabaseDriver for MySQLDriver {
    /// Get which characters are used to delimit identifiers
    /// such as tables, and columns
    fn _quotes(&self) -> (char, char) {
        ('`', '`')
    }

    fn query(&self, sql: &str) -> Result<Box<dyn Any>, Box<dyn Any>> {
        unimplemented!();
    }

    fn limit(&self, sql: &str, limit: Option<usize>, offset: Option<usize>) -> String {
        if limit.is_none() {
            return sql.to_string();
        }

        // Limit and Offset are defined
        if offset.is_some() {
            return format!("{} LIMIT {}.{}", sql, offset.unwrap(), limit.unwrap());
        }

        // Limit is defined
        format!("{} LIMIT {}", sql, limit.unwrap())
    }

    fn explain(&self, sql: &str) -> String {
        format!("EXPLAIN EXTENDED {}", sql)
    }

    fn random(&self) -> String {
        String::from(" RAND() DESC")
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_quote_identifier_backtick_quote() {
        let driver = MySQLDriver::test_new();

        assert_eq!(
            driver.quote_identifier("foo, bar, baz"),
            "`foo`,`bar`,`baz`"
        );
        assert_eq!(
            driver.quote_identifier("foo.bar, baz, fizz"),
            "`foo`.`bar`,`baz`,`fizz`"
        );
    }

    #[test]
    fn test_quote_identifiers_backtick_quote() {
        let driver = MySQLDriver::test_new();

        assert_eq!(
            driver.quote_identifiers(vec![
                "\tfoo. bar".to_string(),
                "baz".to_string(),
                "fizz.\n\tbuzz.baz".to_string(),
            ]),
            vec![
                "`foo`.`bar`".to_string(),
                "`baz`".to_string(),
                "`fizz`.`buzz`.`baz`".to_string(),
            ]
        );
    }
}