use std::{
	str::FromStr,
};

type Result <T> = std::result::Result <T, crate::error::Error>;

pub struct Config {
	pub interval_secs: u64,
	pub prompt: String,
	
	// Open dev tools in a web browser and run `Math.random () * 2225`
	pub offset_secs: u64,
}

impl Default for Config {
	fn default () -> Self {
		Self {
			interval_secs: 2225,
			prompt: "Write a journal entry, then hit Tab, Enter to submit it.".into (),
			offset_secs: 0,
		}
	}
}

impl Config {
	pub fn from_args <I: Iterator <Item=String>> (mut args: I) -> Result <Self> {
		use crate::error::Error::{
			CannotParseArg,
			ParamNeedsArg,
		};
		
		let mut that = Self::default ();
		
		// Finally found the difference: https://stackoverflow.com/questions/1788923/parameter-vs-argument
		
		while let Some (arg) = args.next () {
			if arg == "--interval-secs" {
				let val = args.next ().ok_or (ParamNeedsArg ("--interval-secs"))?;
				let val = u64::from_str (&val).map_err (|_| CannotParseArg ("--interval-secs <u64>"))?;
				that.interval_secs = val;
			}
			else if arg == "--offset-secs" {
				let val = args.next ().ok_or (ParamNeedsArg ("--offset-secs"))?;
				let val = u64::from_str (&val).map_err (|_| CannotParseArg ("--offset-secs <u64>"))?;
				that.offset_secs = val;
			}
			else if arg == "--prompt" {
				let val = args.next ().ok_or (ParamNeedsArg ("--prompt"))?;
				that.prompt = val;
			}
		}
		
		Ok (that)
	}
}

#[cfg (test)]
mod test {
	#[test]
	fn parse () {
		
	}
}