// src/program.rs

use flexi_logger::{init as log_init, LogConfig, LogRecord};
use time;
use std::process::exit;

fn app_format(record: &LogRecord) -> String {
    //2016-02-09 10:20:15,784 [myprog] INFO  src/myprog.rs - Processing update events
    let tm = time::at(time::get_time());
    let time: String = time::strftime("%Y-%m-%d %H:%M:%S,%f", &tm).unwrap();
    format!( "{} [{}] {:<5} {} - {}",
             &time[..time.len() - 6],
             record.location().module_path(),
             record.level(),
             record.location().file(),
             &record.args())
}

pub fn init<S: Into<String>>(spec: Option<S>) {
    let mut log_config = LogConfig::new();
    log_config.format = app_format;
    log_init(log_config, spec.map(|s| s.into())).unwrap();
}

pub fn exit_with_error(msg: String, code: i32) -> ! {
    error!("Exiting: {}", msg);
    exit(code);
}

// src/myprog.rs
#[macro_use]
extern crate clap;
#[macro_use]
extern crate log;
extern crate flexi_logger;
extern crate time;

use clap::{ArgMatches, App, Arg};

mod program;

fn myprog(args: ArgMatches) -> Result<(), (String, i32)> {
    Ok(())
}

fn main() {
	let args = App::new("My App")
		.version(crate_version!())
		.author("Jakub Pastuszek <jpastuszek@whatclinic.com>")
		.about("Does stuff")
		.arg(Arg::with_name("log-spec")
				.short("l")
				.long("log-sepc")
				.value_name("LOG_LEVEL_SPEC")
				.help("Logging level specification, e.g: myprog=info")
				.takes_value(true))
		.get_matches();

    program::init(args.value_of("log-spec"));

    myprog(args).unwrap_or_else(|(err, code)| program::exit_with_error(err, code));
}

// Cargo.toml
[package]
name = "myprog"
version = "0.1.0"
authors = ["Jakub Pastuszek <jpastuszek@gmail.com>"]

[[bin]]
name = "myprog"
path = "src/myprog.rs"

[dependencies]
clap = "~2.0"
log = "~0.3"
flexi_logger = "~0.3"
time = "~0.1"