tenkan 0.1.6

use std::{
    collections::HashMap,
    fs::{File, OpenOptions},
    io::{BufRead, BufReader, Error, Write},
};

pub const TENKAN_DEFAULT_HEADER: &'static str = "tenkan.h";
pub const ENV_FILE_DEFAULT_NAME: &'static str = ".env";
const HELP_MESSAGE: &'static str = r#"
usage:

tenkan 
tenkan <header_name>
tenkan <header_name> <.env_path>
"#;

/// This function exits if provided .env file is invalid!
pub fn read_env_file(file_name: &str) -> Result<HashMap<String, String>, Error> {
    let f = File::open(file_name).unwrap_or_else(|_| {
        eprintln!(
            "⛔ Environment file {} could not be found, make sure it exits!",
            file_name
        );
        std::process::exit(1);
    });
    let f = BufReader::new(f);

    let env_map = f
        .lines()
        .map(|line| {
            let l = line.unwrap().trim().to_owned();
            let (key, value) = l.split_once('=').unwrap_or_else(|| {
                eprintln!("⛔ Invalid env var, exiting...");
                std::process::exit(1);
            });
            Ok((key.trim().to_owned(), value.trim().to_owned()))
        })
        .collect();

    env_map
}
/// Returns error if file creating or writing goes wrong
pub fn create_c_file(file_name: &str, env_map: &HashMap<String, String>) -> Result<(), Error> {
    let mut f = OpenOptions::new()
        .write(true)
        .create(true)
        .open(file_name.trim())?;
    f.write_all(
        format!(
            "/* automatically generated by tenkan {} */ \n",
            env!("CARGO_PKG_VERSION")
        )
        .as_bytes(),
    )?;
    for (key, value) in env_map {
        let env_var = format!("const char* {} = \"{}\";\n", key, value);
        f.write_all(env_var.as_bytes())?;
    }
    Ok(())
}

pub fn print_version() {
    println!("🛫 v{}", env!("CARGO_PKG_VERSION"));
}
pub fn print_help() {
    print!("{}", HELP_MESSAGE);
}