use std::process::Command;

use log::{debug, info};

use crate::{config::Config, errors::McError, minecraft::manifests::Version, platform::paths};

/// Build the full classpath
fn build_classpath(config: &Config, version: &Version) -> Result<String, McError> {
    let sep = if cfg!(windows) { ";" } else { ":" };
    let mut entries = Vec::new();

    for lib in &version.libraries {
        if let Some(artifact) = &lib.downloads.artifact {
            let path = paths::library_file(config, &artifact.path)?;
            entries.push(path.to_string_lossy().to_string());
        }
    }

    let client_jar = paths::client_jar(config, &version.id)?;
    entries.push(client_jar.to_string_lossy().to_string());
    Ok(entries.join(sep))
}

/// Launch Minecraft
pub fn launch(config: &Config, version: &Version) -> Result<(), McError> {
    let java = &config.java_path;
    let classpath = build_classpath(config, version)?;
    let natives_dir = paths::natives_dir(config, &version.id);

    if !natives_dir.exists() {
        return Err(McError::Runtime(format!(
            "Natives folder does not exist: {}",
            natives_dir.display()
        )));
    }

    info!("Launching Minecraft {}", version.id);
    debug!("Classpath: {}", classpath);
    debug!("Natives: {}", natives_dir.display());

    let status = Command::new(java)
        .arg(format!("-Xmx{}M", config.max_memory_mb))
        .arg(format!("-Djava.library.path={}", natives_dir.display()))
        .arg("-cp")
        .arg(classpath)
        .arg(&version.main_class)
        .arg("--username")
        .arg(&config.username)
        .arg("--version")
        .arg(&version.id)
        .arg("--gameDir")
        .arg(paths::minecraft_root(config))
        .arg("--assetsDir")
        .arg(paths::minecraft_root(config).join("assets"))
        .arg("--assetIndex")
        .arg(&version.id)
        .arg("--uuid")
        .arg(&config.uuid)
        .arg("--userProperties")
        .arg("{}")
        .arg("--accessToken")
        .arg("0")
        .arg("--userType")
        .arg("legacy")
        .args(&config.jvm_args)
        .status()?;

    if !status.success() {
        return Err(McError::Process("Minecraft exited with error".into()));
    }

    Ok(())
}