//! Logic to define and parse a configuration from command line arguments.
use clap::Parser;
use colored::Color;
/// Contains all the arguments parsed from the command line.
/// 
/// # Fields
///
/// - `titles_path`: Specifies the path to the ASCII text files directory. If not provided, assumes the directory is in the current directory.
/// - `art_path`: Specifies the path to the ASCII image files directory. If not provided, assumes the directory is in the current directory.
/// - `banner_path`: Specifies the path to the ASCII banner file. If not provided, assumes the file is in the current directory.
/// - `color`: Specifies the color to output the terminal header as. If not provided, outputs as normal.
///
/// # Examples
/// ```
/// use clap::Parser;
/// use term_header::config;
///
/// let args = config::Args::parse();
///
/// assert_eq!(args.titles_path, "./titles/");
/// assert_eq!(args.art_path, "./art/");
/// assert_eq!(args.banner_path, "./banner.txt");
/// assert_eq!(args.color, None);
/// ```
#[derive(Parser, Debug)]
#[command(
    name = "term-header",
    author = "r0r-5chach", 
    version = "1.0", 
    about = "A program that generates ASCII art terminal headers.
color can cause unexpected behaviour when used with terminal themes.",
    long_about = None)]
pub struct Args {
    /// The path to the ASCII text files directory
    #[arg(short, long, default_value = "./titles/")]
    pub titles_path: String,

    /// The path to the ASCII image files directory
    #[arg(short, long, default_value = "./art/")]
    pub art_path: String,
    
    /// The path to the ASCII banner
    #[arg(short, long, default_value = "./banner.txt")]
    pub banner_path: String,
    
    /// The color the text should be outputed as (Terminal themes can cause unexpected behaviour)
    #[arg(short, long, default_value = None)]
    pub color: Option<Color>,
}
/// Contains the configuration for the program.
/// 
/// # Fields
/// - `title_file`: The contents of the randomly selected ASCII text file.
/// - `art_file`: The contents of the randomly selected ASCII image file.
/// - `banner_file`: The contents of the randomly selected ASCII banner file.
///
pub struct Config {
    pub title_file: String,
    pub art_file: String,
    pub banner_file: String,
    pub color: Option<Color>,
}
impl Config {
    /// Returns a new configuration parsed from the [Args] parsed from the command line.
    pub fn new(args: Args) -> Self { //TODO: Add examples using tempdir to create a dir
        let title_file = rand_file_from_path(args.titles_path);
        let art_file = rand_file_from_path(args.art_path);
        let banner_file = args.banner_path;
        let color = args.color;

        Self {
            title_file,
            art_file,
            banner_file,
            color,
        }
    }
}

fn get_file_count(dir: &str) -> usize {
    use std::fs;

    let files = match  fs::read_dir(&dir) {
        Ok(files) => files,
        Err(_) => path_not_found_error(&dir),
    };

    files.count()
}

fn rand_file_from_path(path: String) -> String {
    use rand::Rng;

    let mut rng = rand::thread_rng();
    let mut file = path.clone();
    
    let file_count = get_file_count(&path);
    
    match file_count {
        count if count < 2 => file.push_str("1"),
        _ => file.push_str(&rng.gen_range(1..get_file_count(&path)).to_string()),
    }
    file.push_str(".txt");

    file.to_string()
}

fn path_not_found_error(path: &str) -> ! {
    eprintln!("This path does not exist: {}", path);
    std::process::exit(1);
}