aria-kit 0.6.0

//! Who a stretch of speech is attributed to.

use std::fmt;

use super::SpeakerName;

const ANONYMOUS_PREFIX: &str = "Speaker ";

/// An enrolled person, or a voice nobody enrolled, numbered in the order it
/// was first heard.
///
/// An enrolled name is never spelled like an anonymous one, so the text a
/// transcript or a client shows names one speaker.
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum Label {
    Enrolled(SpeakerName),
    Anonymous(u32),
}

impl Label {
    pub fn enrolled(&self) -> Option<&SpeakerName> {
        match self {
            Self::Enrolled(name) => Some(name),
            Self::Anonymous(_) => None,
        }
    }
}

impl fmt::Display for Label {
    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Self::Enrolled(name) => write!(formatter, "{name}"),
            Self::Anonymous(number) => write!(formatter, "{ANONYMOUS_PREFIX}{number}"),
        }
    }
}

pub(super) fn reads_as_anonymous(name: &str) -> bool {
    name.strip_prefix(ANONYMOUS_PREFIX)
        .is_some_and(|number| number.parse::<u32>().is_ok())
}

/// Hands out anonymous speaker numbers from 1, never reusing one: a number
/// retired by a merge leaves a gap rather than renaming a label somebody
/// already read.
#[derive(Debug, Default)]
pub(crate) struct AnonymousNumbering {
    issued: u32,
}

impl AnonymousNumbering {
    pub(crate) fn issue(&mut self) -> Label {
        self.issued += 1;
        Label::Anonymous(self.issued)
    }
}

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

    #[test]
    fn a_label_renders_as_a_name_or_a_numbered_speaker() {
        let alex = Label::Enrolled(SpeakerName::new("alex").expect("a usable name"));
        assert_eq!(alex.to_string(), "alex");
        assert_eq!(Label::Anonymous(3).to_string(), "Speaker 3");
    }
}