use log::{debug, info};
use tokio::{fs, io::AsyncWriteExt};

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

/// Download everything required to launch:
/// - client jar
/// - libraries
pub async fn download_all(config: &Config, version: &Version) -> Result<(), McError> {
    download_client(config, version).await?;
    download_libraries(config, &version.libraries).await?;
    Ok(())
}

async fn download_client(config: &Config, version: &Version) -> Result<(), McError> {
    let jar_path = paths::client_jar(config, &version.id)?;

    if jar_path.exists() {
        debug!("Client jar already exists");
        return Ok(());
    }

    info!("Downloading client {}", version.id);

    download_file(&version.downloads.client.url, &jar_path).await
}

async fn download_libraries(config: &Config, libraries: &[Library]) -> Result<(), McError> {
    for lib in libraries {
        let Some(artifact) = &lib.downloads.artifact else {
            continue;
        };

        let lib_path = paths::library_file(config, &artifact.path)?;

        if lib_path.exists() {
            continue;
        }

        info!("Downloading library {}", artifact.path);
        download_file(&artifact.url, &lib_path).await?;
    }

    Ok(())
}

/* ---------------- helper ---------------- */

async fn download_file(url: &str, path: &std::path::Path) -> Result<(), McError> {
    if let Some(parent) = path.parent() {
        fs::create_dir_all(parent).await?;
    }

    let response = reqwest::get(url).await?;
    let bytes = response.bytes().await?;

    let mut file = fs::File::create(path).await?;
    file.write_all(&bytes).await?;

    Ok(())
}