//! Challenges and their common interface.
//!
//! This module is the core of the Wooly Vault application, as it defines the interface that all
//! challenges must implement, and contains the challenge modules themselves.

use anyhow::anyhow;
use async_trait::async_trait;
use libpt::log::{error, info};

use crate::config::Config;
use crate::vault::VaultRef;

pub mod c1;
pub mod c2;
pub mod c3;

#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub struct ChallengeDesc {
    title: String,
    hints: Vec<String>,
    solution: String,
    description: String,
}

impl ChallengeDesc {
    /// Returns a list of hints for the challenge.
    ///
    /// A hint is a short text to be given to the contestants in case the admin thinks they need
    /// it. The first hint is the most vague, afterwards the hints become more and more helpful.
    ///
    /// # Returns
    ///
    /// A vector of strings containing hints for the challenge.
    pub fn hints(&self) -> Vec<&str> {
        self.hints.iter().map(|a| a.as_ref()).collect()
    }
    /// Returns the solution to the challenge.
    ///
    /// A solution is a short description of what has to be done to solve the challenge and get the
    /// secret of the vault.
    ///
    /// # Returns
    ///
    /// A string containing the solution to the challenge.
    pub fn solution(&self) -> &str {
        &self.solution
    }
    /// Returns the description to the challenge.
    ///
    /// The description is usually a short introduction to the challenge, without giving anything
    /// of the solution away.
    ///
    /// # Returns
    ///
    /// A string containing the description to the challenge.
    pub fn description(&self) -> &str {
        &self.description
    }
    /// Returns the title to the challenge.
    ///
    /// The title is just a short name, usually consisting of one to 5 words.
    ///
    /// # Returns
    ///
    /// A string containing the title to the challenge.
    pub fn title(&self) -> &str {
        &self.title
    }
}

/// Defines the behavior of a challenge.
///
/// Any type that implements this trait can be served as a challenge in the Wooly Vault application.
#[async_trait]
pub trait Challenge
where
    Self: Sized + 'static,
    Self: Send,
    Self: Sync,
    Self: Clone,
    Self: std::fmt::Debug,
{
    /// Getter for the [vault](VaultRef).
    fn vault(&self) -> VaultRef;
    /// Getter for the [Config].
    fn config(&self) -> Config;
    /// Get the various texts for this challenge.
    fn text() -> ChallengeDesc;
    /// Creates a new instance of the challenge with the given configuration and vault.
    ///
    /// # Arguments
    ///
    /// * `config` - The configuration for the challenge.
    /// * `vault` - The vault that holds the secret for the challenge.
    ///
    /// # Returns
    ///
    /// A new instance of the challenge.
    fn new(config: Config, vault: VaultRef) -> Self;
    /// Starts the challenge and serves it to the contestants.
    ///
    /// This method is asynchronous and returns a result indicating whether the challenge was
    /// successful only after the challenge has ended.
    ///
    /// # Returns
    ///
    /// A result indicating whether the challenge was successfully served.
    ///
    /// # Errors
    ///
    /// Will error when the challenge errors, for example when the network adress cannot be bound.
    async fn serve(&self) -> anyhow::Result<()>;
    /// Serves a challenge and sets up the hint and monitoring service for the admin.
    ///
    /// This method not only serves the challenge, but it also sets up a small webservice for the
    /// admin of the challenge, where they can see the hints, the solution, and the winners.
    ///
    /// The admin interface will only be served when [Config::addr_admin] is set by the user.
    ///
    /// Challenges should not typically implement this themselves, if they want to customize the
    /// admin interface, define [admin_interface](Self::admin_interface).
    /// The admin interface is not part of the challenge and just for monitoring.
    ///
    /// # Returns
    ///
    /// A result indicating whether the challenge and the admin interface were successfully served.
    async fn start(&self) -> anyhow::Result<()> {
        let c = self.clone();
        tokio::spawn(async move {
            if let Err(e) = c.serve().await {
                error!("challenge {} has crashed! {e:#?}", Self::text().title());
            };
        });
        Ok(())
    }
}

/// Selects a challenge by index and serves it with the given configuration and vault.
///
/// # Arguments
///
/// * `index` - The index of the challenge to select.
/// * `config` - The configuration for the challenge.
/// * `vault` - The vault that holds the secret for the challenge.
///
/// # Returns
///
/// A result indicating whether the challenge has successfully ended.
///
/// # Errors
///
/// Returns an error if no challenge with the given index exists, or if the challenge that is being
/// served errors.
pub async fn select_and_start(index: u16, config: Config, vault: VaultRef) -> anyhow::Result<()> {
    info!("select+start");
    match index {
        1 => c1::C1::new(config, vault).start().await?,
        2 => c2::C2::new(config, vault).start().await?,
        3 => c3::C3::new(config, vault).start().await?,
        _ => {
            return Err(anyhow!(
                "no challenge with index {index} does currently exist"
            ))
        }
    }
    Ok(())
}