use crate::util::time;
use crate::{db::db, gui::message, gui::question, space_repetition, util::event::Events};
use anyhow::Result;
use rusqlite::Connection;
use std::io;
use termion::{raw::IntoRawMode, screen::AlternateScreen};
use tui::{backend::TermionBackend, Terminal};

pub fn start(conn: &Connection, deck_name: &String) -> Result<()> {
    let stdout = io::stdout().into_raw_mode()?;
    let stdout = AlternateScreen::from(stdout);
    let backend = TermionBackend::new(stdout);
    let mut terminal = Terminal::new(backend)?;

    let events = Events::new();

    let mut answers = 0;

    loop {
        let now = time::now()?;
        let title = title(deck_name, answers, db::count_available(&conn).unwrap_or(0));

        match db::next_ready(&conn) {
            Some(card) if card.ready <= now => {
                let difficulty = question::ask(&mut terminal, &events, &title, &card)?;
                answers += 1;
                db::update(
                    &conn,
                    &card.question,
                    &space_repetition::update(card.state, difficulty),
                )?;
            }
            Some(card) => {
                let message = format!(
                    "Prochaine carte disponible dans {}.",
                    time::pp_duration(card.ready - now)
                );
                let _ = message::show(&mut terminal, &events, &title, &message);
                break;
            }
            None => {
                let message = format!("Aucune carte n’est disponible. Votre deck est-il vide ?");
                let _ = message::show(&mut terminal, &events, &title, &message);
                break;
            }
        }
    }

    Ok(())
}

fn title(deck_name: &String, answers: i32, available_cards: i32) -> String {
    if answers == 0 && available_cards == 0 {
        deck_name.to_string()
    } else if available_cards == 0 {
        format!("{} ({} / {})", deck_name, answers, answers + available_cards)
    } else {
        format!("{} ({} / {})", deck_name, answers + 1, answers + available_cards)
    }
}