use std::path::Path;
use std::str::FromStr;

use once_cell::sync::Lazy;
use regex::Regex;

use crate::common::{Codepoint, CodepointIter, UcdFile, UcdFileByCodepoint};
use crate::error::Error;

/// A single row in the `Jamo.txt` file.
///
/// The `Jamo.txt` file defines the `Jamo_Short_Name` property.
#[derive(Clone, Debug, Default, Eq, PartialEq)]
pub struct JamoShortName {
    /// The codepoint corresponding to this row.
    pub codepoint: Codepoint,
    /// The actual "Jamo Short Name." This string contains at most 3 bytes and
    /// may be empty.
    pub name: String,
}

impl UcdFile for JamoShortName {
    fn relative_file_path() -> &'static Path {
        Path::new("Jamo.txt")
    }
}

impl UcdFileByCodepoint for JamoShortName {
    fn codepoints(&self) -> CodepointIter {
        self.codepoint.into_iter()
    }
}

impl FromStr for JamoShortName {
    type Err = Error;

    fn from_str(line: &str) -> Result<JamoShortName, Error> {
        static PARTS: Lazy<Regex> = Lazy::new(|| {
            Regex::new(
                r"(?x)
                ^
                (?P<codepoint>[A-Z0-9]+);
                \s*
                (?P<name>[A-Z]*)
                ",
            )
            .unwrap()
        });

        let caps = match PARTS.captures(line.trim()) {
            Some(caps) => caps,
            None => return err!("invalid Jamo_Short_name line"),
        };
        Ok(JamoShortName {
            codepoint: caps["codepoint"].parse()?,
            name: caps.name("name").unwrap().as_str().to_string(),
        })
    }
}

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

    #[test]
    fn parse1() {
        let line = "1164; YAE # HANGUL JUNGSEONG YAE\n";
        let row: JamoShortName = line.parse().unwrap();
        assert_eq!(row.codepoint, 0x1164);
        assert_eq!(row.name, "YAE");
    }

    #[test]
    fn parse2() {
        let line = "110B;     # HANGUL CHOSEONG IEUNG\n";
        let row: JamoShortName = line.parse().unwrap();
        assert_eq!(row.codepoint, 0x110B);
        assert_eq!(row.name, "");
    }
}