use std::{io::Write, fs::File};

use reqwest::Client;

use futures_util::StreamExt;

use crate::{get_current_list, config::Cfg, db::get_dl_links};

pub async fn download(config: Cfg) -> Result<(), Box<dyn std::error::Error>> {
    let list = get_current_list(config.clone())?;

    let links = get_dl_links(config.clone(), list)?;

    download_links(config, links).await?;

    Ok(())
}

async fn download_links(config: Cfg, links: Vec<String>) -> Result<String, Box<dyn std::error::Error>> {

    let dl_path = String::from(&config.downloads);

    for link in links {
        let filename = link.split('/').last().unwrap();
        let dl_path_file = format!("{}/{}", config.downloads, filename);
        println!("Downloading {}", link);

        let res = Client::new()
            .get(String::from(&link))
            .send()
            .await
            .or(Err(format!("Failed to GET from '{}'", &link)))?;
        
        // download chunks
        let mut file = File::create(String::from(&dl_path_file)).or(Err(format!("Failed to create file '{}'", dl_path_file)))?;
        let mut stream = res.bytes_stream();

        while let Some(item) = stream.next().await {
            let chunk = item.or(Err("Error while downloading file"))?;
            file.write_all(&chunk)
                .or(Err("Error while writing to file"))?;
        }
    }

    Ok(dl_path)
}