use anyhow::Result;
use rusqlite::fallible_iterator::FallibleIterator;

use crate::database::{DBExecutable, QueryResult};

#[derive(PartialEq, Debug)]
struct User {
    name: Option<String>,
    email: String,
}

impl User {
    fn new(email: &str) -> Self {
        Self {
            name: None,
            email: String::from(email),
        }
    }

    fn insert(&self) -> UserQuery<'_> {
        let name = self.name.as_deref();
        UserQuery::Insert(name, self.email.as_str())
    }

    fn delete(&self) -> UserQuery<'_> {
        UserQuery::Delete(&self.email)
    }

    fn query_by_email(&self) -> UserQuery<'_> {
        UserQuery::QueryByEmail(&self.email)
    }

    fn query_all<'a>() -> UserQuery<'a> {
        UserQuery::QueryAll
    }
}

enum UserQuery<'a> {
    Insert(Option<&'a str>, &'a str),
    Delete(&'a str),
    QueryByEmail(&'a str),
    QueryAll,
}

impl DBExecutable for UserQuery<'_> {
    type T = User;
    fn execute(&self, tx: &rusqlite::Transaction) -> Result<QueryResult<Self::T>> {
        match self {
            UserQuery::Insert(_, _) => self.db_insert(tx),
            UserQuery::Delete(_) => self.db_delete(tx),
            UserQuery::QueryByEmail(_) => self.db_query_by_email(tx),
            UserQuery::QueryAll => self.db_query_all(tx),
        }
    }
}

impl UserQuery<'_> {
    fn db_insert(&self, tx: &rusqlite::Transaction<'_>) -> Result<QueryResult<User>> {
        let (name, email) = if let UserQuery::Insert(name, email) = self {
            (name, email)
        } else {
            unreachable!("this should only be called by a UserQuery::Insert")
        };

        if let Some(name) = name {
            let q = "INSERT INTO user (name, email) VALUES (?, ?)";
            tx.execute(q, [name, email])?;
            return Ok(QueryResult::Empty);
        }

        let q = "INSERT INTO user (email) VALUES (?)";
        tx.execute(q, [email])?;
        Ok(QueryResult::Empty)
    }

    fn db_delete(&self, tx: &rusqlite::Transaction<'_>) -> Result<QueryResult<User>> {
        let email = if let UserQuery::Delete(email) = self {
            email
        } else {
            unreachable!("this should only be called by a UserQuery::Delete")
        };

        let q = "DELETE FROM user WHERE email = ?";
        tx.execute(q, [email])?;
        Ok(QueryResult::Empty)
    }

    fn db_query_by_email(&self, tx: &rusqlite::Transaction<'_>) -> Result<QueryResult<User>> {
        let email = if let UserQuery::QueryByEmail(email) = self {
            email
        } else {
            unreachable!("this should only be called by a UserQuery::QueryByEmail")
        };

        let q = "SELECT * FROM user WHERE email LIKE ?";
        let mut stmt = tx.prepare(q)?;
        let ris = stmt
            .query([email])?
            .map(|row| {
                Ok(User {
                    name: row.get(1).unwrap(),
                    email: row.get(2).unwrap(),
                })
            })
            .collect()?;
        Ok(QueryResult::Vec(ris))
    }

    fn db_query_all(&self, tx: &rusqlite::Transaction<'_>) -> Result<QueryResult<User>> {
        let q = "SELECT * FROM user";
        let mut stmt = tx.prepare(q)?;
        let ris = stmt
            .query(())?
            .map(|row| {
                Ok(User {
                    name: row.get(1).unwrap(),
                    email: row.get(2).unwrap(),
                })
            })
            .collect()?;
        Ok(QueryResult::Vec(ris))
    }
}

#[derive(Debug, PartialEq)]
struct List {
    address: String,
    desc: Option<String>,
}

impl List {
    fn new(name: &str) -> Self {
        List {
            address: String::from(name),
            desc: None,
        }
    }

    fn insert(&self) -> ListQuery<'_> {
        ListQuery::Insert(&self.address, self.desc.as_deref())
    }

    fn delete(&self) -> ListQuery<'_> {
        ListQuery::Delete(&self.address)
    }

    fn query_all<'a>() -> ListQuery<'a> {
        ListQuery::QueryAll
    }
}

enum ListQuery<'a> {
    Insert(&'a str, Option<&'a str>),
    Delete(&'a str),
    QueryByAddress(&'a str),
    QueryAll,
}

impl DBExecutable for ListQuery<'_> {
    type T = List;

    fn execute(&self, tx: &rusqlite::Transaction) -> Result<QueryResult<Self::T>> {
        match self {
            ListQuery::Insert(_, _) => self.db_insert(tx),
            ListQuery::Delete(_) => self.db_delete(tx),
            ListQuery::QueryByAddress(_) => self.db_query_by_address(tx),
            ListQuery::QueryAll => self.db_query_all(tx),
        }
    }
}

impl ListQuery<'_> {
    fn db_insert(&self, tx: &rusqlite::Transaction) -> Result<QueryResult<List>> {
        let (name, desc) = if let ListQuery::Insert(name, desc) = self {
            (name, desc)
        } else {
            unreachable!("this should only be called by ListQuery::Insert");
        };

        if let Some(desc) = desc {
            let q = "INSERT INTO list (name, description) VALUES (?, ?)";
            tx.execute(q, [name, desc])?;
        } else {
            let q = "INSERT INTO list (name) VALUES (?)";
            tx.execute(q, [name])?;
        }
        Ok(QueryResult::Empty)
    }

    fn db_delete(&self, tx: &rusqlite::Transaction) -> Result<QueryResult<List>> {
        let name = if let ListQuery::Delete(name) = self {
            name
        } else {
            unreachable!("this should only be called by ListQuery::Delete")
        };

        let q = "DELETE FROM list WHERE name = ?";
        tx.execute(q, [name])?;
        Ok(QueryResult::Empty)
    }

    fn db_query_by_address(&self, tx: &rusqlite::Transaction) -> Result<QueryResult<List>> {
        let name = if let ListQuery::QueryByAddress(name) = self {
            name
        } else {
            unreachable!("this should only be called by ListQuery::QueryByName")
        };

        let q = "SELECT * FROM list WHERE name = ?";
        let mut stmt = tx.prepare(q)?;
        let ris = stmt
            .query([name])?
            .map(|row| {
                Ok(List {
                    address: row.get(1).unwrap(),
                    desc: row.get(2).unwrap(),
                })
            })
            .collect()?;
        Ok(QueryResult::Vec(ris))
    }

    fn db_query_all(&self, tx: &rusqlite::Transaction) -> Result<QueryResult<List>> {
        let q = "SELECT * FROM list";
        let mut stmt = tx.prepare(q)?;
        let ris = stmt
            .query(())?
            .map(|row| {
                Ok(List {
                    address: row.get(1).unwrap(),
                    desc: row.get(2).unwrap(),
                })
            })
            .collect()?;
        Ok(QueryResult::Vec(ris))
    }
}

#[cfg(test)]
mod tests {
    use anyhow::Result;

    use crate::{
        database::{DB_NAME, Database},
        list::{List, User},
    };

    fn setup() -> Result<Database> {
        std::fs::create_dir("test")?;
        Database::new(&format!("test/{}", DB_NAME))
    }

    fn cleanup() -> Result<()> {
        std::fs::remove_dir_all("test")?;
        Ok(())
    }

    #[test]
    fn user_insert_wo_name() {
        let mut database = setup().expect("Failed setup");

        let user = User {
            name: None,
            email: String::from("mroik@poul.org"),
        };
        database.execute(user.insert()).expect("Failed insert");
        let user2 = database
            .execute(user.query_by_email())
            .expect("Failed query");
        match user2 {
            crate::database::QueryResult::Empty => assert!(false),
            crate::database::QueryResult::Vec(items) => {
                assert_eq!(items.len(), 1);
                assert_eq!(items[0], user);
            }
        }

        drop(database);
        cleanup().expect("Failed cleanup");
    }

    #[test]
    fn user_insert_with_name() {
        let mut database = setup().expect("Failed setup");

        let user = User {
            name: Some(String::from("Mirko Faina")),
            email: String::from("mroik@poul.org"),
        };
        database.execute(user.insert()).expect("Failed insert");
        let user2 = database
            .execute(user.query_by_email())
            .expect("Failed query");
        match &user2 {
            crate::database::QueryResult::Empty => assert!(false),
            crate::database::QueryResult::Vec(items) => {
                assert_eq!(items.len(), 1);
                assert_eq!(items[0], user);
            }
        }

        drop(database);
        cleanup().expect("Failed cleanup");
    }

    #[test]
    fn user_insert_twice() {
        let mut database = setup().expect("Failed setup");

        let user = User {
            name: Some(String::from("Mirko Faina")),
            email: String::from("mroik@poul.org"),
        };
        database.execute(user.insert()).expect("Failed insert");
        let ris = database.execute(user.insert());
        assert!(ris.is_err());

        drop(database);
        cleanup().expect("Failed cleanup");
    }

    #[test]
    fn user_delete() {
        let mut database = setup().expect("Failed setup");

        let user = User {
            name: Some(String::from("Mirko Faina")),
            email: String::from("mroik@poul.org"),
        };
        database.execute(user.insert()).expect("Failed insert");
        database.execute(user.delete()).expect("Failed delete");

        let ris = database
            .execute(User::query_all())
            .expect("Failed query all");
        match ris {
            crate::database::QueryResult::Empty => assert!(false),
            crate::database::QueryResult::Vec(items) => assert!(items.is_empty()),
        }

        drop(database);
        cleanup().expect("Failed cleanup");
    }

    #[test]
    fn list_insert_wo_desc() {
        let mut database = setup().expect("failed setup");

        let list = List {
            address: String::from("poul"),
            desc: None,
        };
        database.execute(list.insert()).expect("failed insert");
        let ris = database.execute(List::query_all()).expect("failed query");
        match ris {
            crate::database::QueryResult::Empty => assert!(false),
            crate::database::QueryResult::Vec(items) => {
                assert_eq!(items.len(), 1);
                assert_eq!(items[0], list);
            }
        }

        cleanup().expect("failed cleanup");
    }

    #[test]
    fn list_insert_with_desc() {
        let mut database = setup().expect("failed setup");

        let list = List {
            address: String::from("poul"),
            desc: Some(String::from("The mailing list of the POuL")),
        };
        database.execute(list.insert()).expect("failed insert");
        let ris = database.execute(List::query_all()).expect("failed query");
        match ris {
            crate::database::QueryResult::Empty => assert!(false),
            crate::database::QueryResult::Vec(items) => {
                assert_eq!(items.len(), 1);
                assert_eq!(items[0], list);
            }
        }

        drop(database);
        cleanup().expect("failed cleanup");
    }

    #[test]
    fn list_insert_twice() {
        let mut database = setup().expect("failed setup");

        let list = List {
            address: String::from("poul"),
            desc: Some(String::from("The mailing list of the POuL")),
        };
        database.execute(list.insert()).expect("failed insert");
        assert!(database.execute(list.insert()).is_err());

        drop(database);
        cleanup().expect("failed cleanup");
    }

    #[test]
    fn list_delete() {
        let mut database = setup().expect("failed setup");

        let list = List {
            address: String::from("poul"),
            desc: Some(String::from("The mailing list of the POuL")),
        };
        database.execute(list.insert()).expect("failed insert");
        database.execute(list.delete()).expect("failed delete");

        let ris = database
            .execute(List::query_all())
            .expect("Failed query all");
        match ris {
            crate::database::QueryResult::Empty => assert!(false),
            crate::database::QueryResult::Vec(items) => assert!(items.is_empty()),
        }

        drop(database);
        cleanup().expect("failed cleanup");
    }
}