pub mod compiler;
pub mod error;
pub mod runtime;

use std::str::FromStr;

pub use error::{Error, Result};
use runtime::VMFlag;

pub const JAVA_BIN_VM: &str = "java";
pub const JAVA_BIN_COMPILER: &str = "javac";

pub const JAVA_EXT_SOURCE: &str = "java";
pub const JAVA_EXT_CLASS: &str = "class";

pub const F_JAVA_VERSION: &str = ".java-version";

/// Uses the java binary to parse its stdout for version information.
///
/// This is non-caching.
pub fn get_javac_ver() -> Result<semver::Version> {
    // TODO: Consider making this pull the version info from javac instead?

    /*
     * $ java --version
     *      openjdk 21.0.9 2025-10-21
     *      OpenJDK Runtime Environment (build 21.0.9+10)
     *      OpenJDK 64-Bit Server VM (build 21.0.9+10, mixed mode, sharing)
     */

    Ok(semver::Version::from_str(
        get_java_version_info()?
            .lines()
            .nth(0)
            .ok_or(Error::EmptyStdout)?
            .split_ascii_whitespace()
            .nth(1)
            .ok_or(Error::NthOutOfBounds)?,
    )?)
}

/// Calls the java binary, returning the complete stdout version information.
fn get_java_version_info() -> Result<String> {
    Ok(
        io::run_process(&[JAVA_BIN_VM, VMFlag::Version.to_string().as_str()])?
            .0
            .ok_or(Error::EmptyStdout)?,
    )
}