use mastodon_async::entities::visibility::Visibility;
use mastodon_async::helpers::toml as masto_toml;
use mastodon_async::prelude::*;
use mastodon_async::{helpers::cli, Result};
use reqwest;
use serde::Deserialize;
use std::collections::HashSet;
use std::io::Cursor;
use std::io::Write;
use std::process::Command;
use toml;

const CONFIG_FILENAME: &str = "config.toml";

#[derive(Deserialize)]
struct Config {
  bot: Bot,
  files: Files,
  errors: Errors,
}

#[derive(Deserialize)]
struct Bot {
  name: String,
  instance: String,
  bio: String,
}

#[derive(Deserialize)]
struct Files {
  posted: String,
  urls: String,
  tempfile: String,
}

#[derive(Deserialize)]
struct Errors {
  out_of_images: String,
}

/// Parses the given filename to a config struct
fn parse_config(filename: &str) -> Config {
  let toml_file = std::fs::read_to_string(filename)
    .expect("No config file, consider getting the original one and modifing it");
  toml::from_str(&toml_file).expect("Malformed config file, check the original one for reference")
}

#[tokio::main] // requires `features = ["mt"]
async fn main() -> Result<()> {
  let config: Config = parse_config(CONFIG_FILENAME);
  let mastodon = if let Ok(data) = masto_toml::from_file("mastodon-data.toml") {
    Mastodon::from(data)
  } else {
    register(&config).await?
  };

  match get_next_url(&config) {
    Some(url) => {
      post_image(&mastodon, &url, &config).await;
      update_bio(&mastodon, &config).await;
    }
    None => post(&mastodon, &config.errors.out_of_images).await,
  };

  Ok(())
}

fn get_next_url(config: &Config) -> Option<String> {
  let binding = std::fs::read_to_string(&config.files.posted).expect("Posted file not found");
  let posted = binding.lines().collect::<HashSet<&str>>();
  let binding = std::fs::read_to_string(&config.files.urls).expect("Urls file not found");
  let urls = binding.lines().collect::<HashSet<&str>>();
  let urls = urls.difference(&posted).collect::<Vec<_>>();
  if urls.is_empty() {
    None
  } else {
    let mut file = std::fs::OpenOptions::new()
      .write(true)
      .append(true) // This is needed to append to file
      .open(&config.files.posted)
      .unwrap();
    write!(file, "{}\n", urls[0]).unwrap();
    Some(urls[0].to_string().clone())
  }
}

async fn post_image(account: &Mastodon, url: &String, config: &Config) {
  fetch_url(url.to_string(), &config.files.tempfile)
    .await
    .unwrap();
  let attachment = account
    .media(&config.files.tempfile, Some(url.to_string()))
    .await
    .expect("Attachment upload error");
  let attachment = account
    .wait_for_processing(attachment, Default::default())
    .await
    .expect("Attachment processing error");
  let status = StatusBuilder::new()
    .media_ids(&[attachment.id])
    .visibility(Visibility::Unlisted)
    .sensitive(true)
    .build()
    .unwrap();
  account.new_status(status).await.unwrap();
}

async fn update_bio(account: &Mastodon, config: &Config) {
  let binding = std::fs::read_to_string(&config.files.posted).expect("Posted file not found");
  let posted = binding.lines().collect::<HashSet<&str>>();
  let binding = std::fs::read_to_string(&config.files.urls).expect("Url file not found");
  let urls = binding.lines().collect::<HashSet<&str>>();
  let remaining = urls.difference(&posted).count();

  Command::new("curl")
    .args([
      "-X",
      "PATCH",
      &format!("{}/api/v1/accounts/update_credentials", config.bot.instance),
      "-H",
      &format!("Authorization:Bearer {}", account.data.token),
      "-d",
      &format!(
        "note={}\n\n{} new images remaining",
        config.bot.bio, remaining
      ),
    ])
    .spawn()
    .unwrap()
    .wait()
    .unwrap();
}

async fn post(account: &Mastodon, msg: &str) {
  let status = StatusBuilder::new()
    .visibility(Visibility::Direct)
    .status(msg)
    .build()
    .unwrap();
  account.new_status(status).await.unwrap();
}

async fn fetch_url(url: String, file_name: &String) -> Result<()> {
  let response = reqwest::get(url).await?;
  let mut file = std::fs::File::create(file_name)?;
  let mut content = Cursor::new(response.bytes().await?);
  std::io::copy(&mut content, &mut file)?;
  Ok(())
}

async fn register(config: &Config) -> Result<Mastodon> {
  let registration = Registration::new(&config.bot.instance)
    .client_name(&config.bot.name)
    .scopes(Scopes::write_all())
    .build()
    .await?;
  let mastodon = cli::authenticate(registration).await?;

  // Save app data for using on the next run.
  masto_toml::to_file(&mastodon.data, "mastodon-data.toml")?;

  Ok(mastodon)
}