use handlebars::Handlebars;
use lazy_static::lazy_static;

use common::error::*;

use crate::args::TaskArgs;

fn escape(s: &str) -> String {
	format!("'{}'", s.replace("'", "'\\''"))
}

#[derive(Debug)]
pub struct TemplateEngine {
	tpl: Handlebars<'static>,
	tpl_raw: Handlebars<'static>,
}

impl TemplateEngine {
	pub fn new() -> Self {
		let mut tpl = Handlebars::new();
		tpl.set_strict_mode(true);
		tpl.register_escape_fn(escape);

		let mut tpl_raw = Handlebars::new();
		tpl_raw.set_strict_mode(true);
		tpl_raw.register_escape_fn(handlebars::no_escape);

		TemplateEngine { tpl, tpl_raw }
	}

	pub fn eval_raw(&self, input: &str, args: &TaskArgs) -> Result<String> {
		self.tpl_raw
			.render_template(input, args)
			.map_err(Error::new)
	}

	pub fn eval(&self, input: &str, args: &TaskArgs) -> Result<String> {
		self.tpl.render_template(input, args).map_err(Error::new)
	}
}

lazy_static! {
	pub static ref ENGINE: TemplateEngine = TemplateEngine::new();
}