use lexopt::ValueExt;

use crate::is_valid_name;
use std::collections::HashMap;

pub struct Subcommands {
	subcommands: HashMap<String, String>,
	pub script: String,
	pub inner_parser: lexopt::Parser,
}
impl Subcommands {
	pub fn parse(mut parser: lexopt::Parser) -> Result<Self, lexopt::Error> {
		use lexopt::prelude::*;
		use std::fs::File;
		use std::io::{BufReader, prelude::*};

		let script = parser.value()?.string()?;

		let mut subcommands: HashMap<String, String> = HashMap::new();

		let file = File::open(&script).map_err(|err| err.to_string())?;
		let reader = BufReader::new(file);

		for line in reader.lines() {
			let line = line.map_err(|err| err.to_string())?;

			//skip shebang
			if line.starts_with("#!") {
				continue;
			}

			if let Some(line) = line.strip_prefix("#=") {
				let (name, args) = line
					.split_once(' ')
					.ok_or("Invalid subcommand declaration")?;

				if !is_valid_name(name) {
					return Err("Invalid subcommand name: {name}".into());
				}

				subcommands.insert(name.to_string(), args.to_string());
			} else {
				break;
			}
		}

		Ok(Self {
			subcommands,
			script,
			inner_parser: parser,
		})
	}

	pub fn get_current_subcommand_args(&mut self) -> Result<(String, String), lexopt::Error> {
		let subcommand = self.inner_parser.value()?.string()?;

		self.subcommands
			.get(&subcommand)
			.map(|args| (subcommand, args.to_owned()))
			.ok_or("Unknown subcommand".into())
	}
}