use std::string::String;

use argon2::{
    password_hash::{rand_core::OsRng, PasswordHash, PasswordHasher, PasswordVerifier, SaltString},
    Argon2,
};

fn get_argon2<'k>() -> Argon2<'k> {
    Argon2::new(
        argon2::Algorithm::Argon2id,
        argon2::Version::V0x13,
        argon2::Params::new(
            4_096, // 4 MB. The code run on raspberry pi zero, the default memory is too high.
            4,     // Number of iteration.
            2,     // Degree of parallelism.
            None,
        )
        .unwrap(),
    )
}

pub fn hash(password: &str) -> Result<String, Box<dyn std::error::Error>> {
    let salt = SaltString::generate(&mut OsRng);
    let argon2 = get_argon2();
    argon2
        .hash_password(password.as_bytes(), &salt)
        .map(|h| h.to_string())
        .map_err(|e| e.into())
}

pub fn verify_password(
    password: &str,
    hashed_password: &str,
) -> Result<bool, Box<dyn std::error::Error>> {
    let argon2 = get_argon2();
    let parsed_hash = PasswordHash::new(hashed_password)?;
    Ok(argon2
        .verify_password(password.as_bytes(), &parsed_hash)
        .is_ok())
}

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

    #[test]
    fn simple_case() -> Result<(), Box<dyn std::error::Error>> {
        let password = "12345";
        let hash = hash(password)?;
        println!("hash: {}", &hash);
        assert!(verify_password(password, &hash)?);
        assert!(!verify_password("54321", &hash)?);
        Ok(())
    }

    #[test]
    fn password_with_special_characters() -> Result<(), Box<dyn std::error::Error>> {
        let password = "éà ä_\\😺🎮🇨🇭";
        let hash = hash(password)?;
        println!("hash: {}", &hash);
        assert!(verify_password(password, &hash)?);
        Ok(())
    }
}