price_checker/src/parser.rs

pub mod amazon;
pub mod darty;
pub mod du_bruit_dans_la_cuisine;
pub mod fnac;
pub mod ldlc;

use crate::price_result::PriceResult;
use anyhow::{anyhow, Result};
use arraygen::Arraygen;
use scraper::Html;
use url::Url;

pub trait Parser {
	/// Create the parser
	fn new() -> Result<Self>
	where
		Self: Sized;
	/// Get the name
	fn name(&self) -> &'static str;
}

/// Trait needed to get price from a specific website
pub trait PriceParser: Parser {
	/// Indicate if it can parse this URL
	fn can_parse(&self, url: &Url) -> bool;
	/// Parse the html into a price
	fn parse_price(&self, html: &Html) -> Result<PriceResult>;
}

pub trait SearchParser: PriceParser {
	/// Return the search URL
	fn search_url(&self, name: &str) -> Url;
	/// Return the first occurence of result of the page if any
	fn search(&self, html: &Html) -> Result<Option<Url>>;
}

macro_rules! gen_list {
	( $([$module:ident::$name:ident : $($array:ident),*]),* ) => {
		#[derive(Arraygen, Debug)]
		#[gen_array(pub fn get_all: & dyn Parser)]
		#[gen_array(pub fn get_price: & dyn PriceParser)]
		#[gen_array(pub fn get_search: & dyn SearchParser)]
		pub struct List {
			$(
				#[in_array(get_all, $($array),* )]
				$module: $module::$name
			),*
		}


		impl List {
			/// Create the list
			pub fn new() -> Result<Self> {
				Ok(List {
					$(
						$module: $module::$name::new()?
					),*
				})
			}
		}

	};
}

gen_list!(
	[darty::Darty: get_price],
	[fnac::Fnac: get_price, get_search],
	[du_bruit_dans_la_cuisine::DuBruitDansLaCuisine: get_price],
	[ldlc::LDLC: get_price],
	[amazon::Amazon: get_price, get_search]
);

impl List {
	pub fn get_parser(&self, name: &str) -> Result<&dyn SearchParser> {
		Ok(*self
			.get_search()
			.iter()
			.find(|&&parser| parser.name().to_lowercase() == name.to_lowercase())
			.ok_or(anyhow!("Cannot find the parser {}", name))?)
	}
}

#[test]
fn test_parser_list() {
	let parser_list = List::new().unwrap();
	assert_eq!(parser_list.get_price().len(), 5);
	assert_eq!(parser_list.get_search().len(), 2);
}