use anyhow::{anyhow, Result};
use futures_util::StreamExt;
use indicatif::{ProgressBar, ProgressStyle};
use reqwest::Client;
use std::{cmp::min, fs::File, io::Write};

pub async fn open_or_download(url: &str, path: &str) -> Result<Vec<u8>> {
    // Download file if it doesn't exist
    if !tokio::fs::try_exists(path).await? {
        download_file(url, path).await?;
    } else {
        println!("{} found", path);
    }
    Ok(tokio::fs::read(path).await?)
}

async fn download_file(url: &str, path: &str) -> Result<()> {
    // Reqwest setup
    let res = Client::new().get(url).send().await?;
    let total_size = res.content_length().unwrap();

    // Indicatif setup
    let pb = ProgressBar::new(total_size);
    pb.set_style(ProgressStyle::default_bar()
	    .template("{msg}\n{spinner:.green} [{elapsed_precise}] [{wide_bar:.cyan/blue}] {bytes}/{total_bytes} ({bytes_per_sec}, {eta})")?
	    .progress_chars("#>-"));
    pb.set_message(format!("Downloading {}", url));

    let mut file = File::create(path)?;
    let mut downloaded: u64 = 0;
    let mut stream = res.bytes_stream();

    while let Some(item) = stream.next().await {
        let chunk = item?;
        file.write_all(&chunk)?;
        let new = min(downloaded + (chunk.len() as u64), total_size);
        downloaded = new;
        pb.set_position(new);
    }

    pb.finish_with_message(format!("Downloaded {} to {}", url, path));
    Ok(())
}

pub async fn save_decklist(filepath: &str, decklist: Vec<String>) -> Result<()> {
    let mut file =
        File::create(filepath).or(Err(anyhow!("Failed to create file '{}'", filepath)))?;

    let contents = decklist
        .iter()
        .map(|line| format!("1 {}\n", line))
        .collect::<Vec<_>>()
        .join("");

    file.write_all(contents.as_bytes())?;

    println!("Decklist saved to {}", filepath);
    Ok(())
}