use crate::{Opt, RunMode};
use crate::result::{AppResult, AppError};
use crate::initialization::init_config;
use crate::config::{update_episode, update_config, Config};
use std::process::{Command};

pub fn run(opts: Opt) -> AppResult<()> {
    let mode = opts.mode.unwrap_or_else(|| RunMode::Play);
    match mode {
        RunMode::Init => {
            init_config()
        }
        RunMode::Play => {
            play()
        }
        RunMode::Prev => {
            update_episode(prev_episode)
        }
        RunMode::Next => {
            update_episode(next_episode)
        }
        RunMode::Update => {
            update_config()
        }
    }
}

pub fn prev_episode(current: usize) -> AppResult<usize> {
    if let Some(episode) = current.checked_sub(1) {
        Ok(episode)
    } else {
        Err(AppError::RuntimeError(
            String::from("Episode can't be less than zero.")
        ))
    }
}

pub fn next_episode(current: usize) -> AppResult<usize> {
    if let Some(episode) = current.checked_add(1) {
        Ok(episode)
    } else {
        Err(AppError::RuntimeError(
            String::from("Reached usize limit. Sorry.")
        ))
    }
}

pub fn play() -> AppResult<()> {
    let conf = Config::read()?;
    let mut episode = conf.get_current_episode()?;
    while !episode.is_empty() {
        let mut child = Command::new("sh")
            .arg("-c")
            .arg(conf.command.replace("{}", episode.as_str()))
            .spawn()?;
        child.wait()?;
        update_episode(next_episode)?;
        let conf = Config::read()?;
        episode = conf.get_current_episode()?;
    }
    Ok(())
}