use log::debug;
use rusqlite::{params, Connection, OptionalExtension};
use std::error::Error;

/// Struct for each query line
#[derive(Debug)]
pub struct TweetToToot {
    pub tweet_id: u64,
    pub toot_id: u64,
}

/// if None is passed, read the last tweet from DB
/// if a tweet_id is passed, read this particular tweet from DB
pub fn read_state(
    conn: &Connection,
    s: Option<u64>,
) -> Result<Option<TweetToToot>, Box<dyn Error>> {
    debug!("Reading tweet_id {:?}", s);
    let query: String = match s {
        Some(i) => format!("SELECT * FROM tweet_to_toot WHERE toot_id = {i}"),
        None => "SELECT * FROM tweet_to_toot ORDER BY toot_id DESC LIMIT 1".to_string(),
    };

    let mut stmt = conn.prepare(&query)?;

    let t = stmt
        .query_row([], |row| {
            Ok(TweetToToot {
                tweet_id: row.get("tweet_id")?,
                toot_id: row.get("toot_id")?,
            })
        })
        .optional()?;

    Ok(t)
}

/// Writes last treated tweet id and toot id to the db
#[allow(dead_code)]
pub fn write_state(conn: &Connection, t: TweetToToot) -> Result<(), Box<dyn Error>> {
    debug!("Write struct {:?}", t);
    conn.execute(
        "INSERT INTO tweet_to_toot (tweet_id, toot_id) VALUES (?1, ?2)",
        params![t.tweet_id, t.toot_id],
    )?;

    Ok(())
}

/// Initiates the DB from path
pub fn init_db(d: &str) -> Result<(), Box<dyn Error>> {
    debug!("Initializing DB for Scootaloo");
    let conn = Connection::open(d)?;

    conn.execute(
        "CREATE TABLE IF NOT EXISTS tweet_to_toot (
            tweet_id            INTEGER,
            toot_id             INTEGER PRIMARY KEY
            )",
        [],
    )?;

    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::{fs::remove_file, path::Path};

    #[test]
    fn test_init_db() {
        let d = "/tmp/test_init_db.sqlite";

        init_db(d).unwrap();

        // check that file exist
        assert!(Path::new(d).exists());

        // open said file
        let conn = Connection::open(d).unwrap();
        conn.execute("SELECT * from tweet_to_toot;", []).unwrap();

        remove_file(d).unwrap();
    }

    #[test]
    fn test_init_init_db() {
        // init_db fn should be idempotent so let’s test that
        let d = "/tmp/test_init_init_db.sqlite";

        init_db(d).unwrap();

        let conn = Connection::open(d).unwrap();

        conn.execute(
            "INSERT INTO tweet_to_toot (tweet_id, toot_id)
            VALUES
            (100, 1001);",
            [],
        )
        .unwrap();

        init_db(d).unwrap();

        remove_file(d).unwrap();
    }

    #[test]
    fn test_write_state() {
        let d = "/tmp/test_write_state.sqlite";

        init_db(d).unwrap();

        let conn = Connection::open(d).unwrap();

        let t_in = TweetToToot {
            tweet_id: 123456789,
            toot_id: 987654321,
        };

        write_state(&conn, t_in).unwrap();

        let mut stmt = conn.prepare("SELECT * FROM tweet_to_toot;").unwrap();

        let t_out = stmt
            .query_row([], |row| {
                Ok(TweetToToot {
                    tweet_id: row.get("tweet_id").unwrap(),
                    toot_id: row.get("toot_id").unwrap(),
                })
            })
            .unwrap();

        assert_eq!(t_out.tweet_id, 123456789);
        assert_eq!(t_out.toot_id, 987654321);

        remove_file(d).unwrap();
    }

    #[test]
    fn test_none_to_tweet_id_read_state() {
        let d = "/tmp/test_none_to_tweet_id_read_state.sqlite";

        init_db(d).unwrap();

        let conn = Connection::open(d).unwrap();

        conn.execute(
            "INSERT INTO tweet_to_toot (tweet_id, toot_id)
            VALUES
            (101, 1001),
            (102, 1002);",
            [],
        )
        .unwrap();

        let t_out = read_state(&conn, None).unwrap().unwrap();

        remove_file(d).unwrap();

        assert_eq!(t_out.tweet_id, 102);
        assert_eq!(t_out.toot_id, 1002);
    }

    #[test]
    fn test_none_to_none_read_state() {
        let d = "/tmp/test_none_to_none_read_state.sqlite";

        init_db(d).unwrap();

        let conn = Connection::open(d).unwrap();

        let t_out = read_state(&conn, None).unwrap();

        remove_file(d).unwrap();

        assert!(t_out.is_none());
    }

    #[test]
    fn test_tweet_id_to_none_read_state() {
        let d = "/tmp/test_tweet_id_to_none_read_state.sqlite";

        init_db(d).unwrap();

        let conn = Connection::open(d).unwrap();

        conn.execute(
            "INSERT INTO tweet_to_toot (tweet_id, toot_id)
            VALUES
            (100, 1000);",
            [],
        )
        .unwrap();

        let t_out = read_state(&conn, Some(1200)).unwrap();

        remove_file(d).unwrap();

        assert!(t_out.is_none());
    }

    #[test]
    fn test_tweet_id_to_tweet_id_read_state() {
        let d = "/tmp/test_tweet_id_to_tweet_id_read_state.sqlite";

        init_db(d).unwrap();

        let conn = Connection::open(d).unwrap();

        conn.execute(
            "INSERT INTO tweet_to_toot (tweet_id, toot_id)
            VALUES
            (100, 1000);",
            [],
        )
        .unwrap();

        let t_out = read_state(&conn, Some(1000)).unwrap().unwrap();

        remove_file(d).unwrap();

        assert_eq!(t_out.tweet_id, 100);
        assert_eq!(t_out.toot_id, 1000);
    }
}