use thiserror::Error;

pub mod charset;
pub mod entropy;
pub mod passphrase;

pub const MIN_LENGTH: usize = 4;
pub const MAX_LENGTH: usize = 128;
pub const MIN_WORDS: usize = 3;
pub const MAX_WORDS: usize = 12;
pub const RETRY_LIMIT: usize = 1000;

#[derive(Debug, Error, PartialEq, Eq)]
pub enum GenError {
    #[error("length {got} is out of range {min}..={max}")]
    InvalidLength { got: usize, min: usize, max: usize },
    #[error("at least one character class must be enabled")]
    NoCharacterClass,
    #[error("word count {got} is out of range {min}..={max}")]
    InvalidWordCount { got: usize, min: usize, max: usize },
    #[error("could not satisfy character class constraints after {0} attempts")]
    RetryLimitExceeded(usize),
}

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

    #[test]
    fn errors_render_readable_messages() {
        let err = GenError::InvalidLength {
            got: 2,
            min: MIN_LENGTH,
            max: MAX_LENGTH,
        };
        assert_eq!(err.to_string(), "length 2 is out of range 4..=128");
        assert_eq!(
            GenError::NoCharacterClass.to_string(),
            "at least one character class must be enabled"
        );
    }
}