use octocrab::models::{InstallationRepositories, InstallationToken};
use octocrab::params::apps::CreateInstallationAccessToken;
use octocrab::Octocrab;
use url::Url;

#[tokio::main]
async fn main() -> octocrab::Result<()> {
    let app_id = read_env_var("GITHUB_APP_ID");
    let app_private_key = read_env_var("GITHUB_APP_PRIVATE_KEY");
    let key = jsonwebtoken::EncodingKey::from_rsa_pem(app_private_key.as_bytes()).unwrap();

    let token = octocrab::auth::create_jwt(app_id.parse::<u64>().unwrap().into(), &key).unwrap();

    let octocrab = Octocrab::builder().personal_token(token).build()?;

    let installations = octocrab
        .apps()
        .installations()
        .send()
        .await
        .unwrap()
        .take_items();

    let mut create_access_token = CreateInstallationAccessToken::default();
    create_access_token.repositories = vec!["octocrab".to_string()];

    // By design, tokens are not forwarded to urls that contain an authority. This means we need to
    // extract the path from the url and use it to make the request.
    let access_token_url =
        Url::parse(installations[0].access_tokens_url.as_ref().unwrap()).unwrap();

    let access: InstallationToken = octocrab
        .post(access_token_url.path(), Some(&create_access_token))
        .await
        .unwrap();

    let octocrab = octocrab::OctocrabBuilder::new()
        .personal_token(access.token)
        .build()
        .unwrap();

    let installed_repos: InstallationRepositories = octocrab
        .get("/installation/repositories", None::<&()>)
        .await
        .unwrap();
    let _repos = installed_repos.repositories;

    Ok(())
}

fn read_env_var(var_name: &str) -> String {
    let err = format!("Missing environment variable: {var_name}");
    std::env::var(var_name).expect(&err)
}