Improve async multithreading for aggregation about websurfx HOT 3 CLOSED

//! This module provides the functionality to scrape and gathers all the results from the upstream
//! search engines and then removes duplicate results.

use std::{collections::HashMap, rc::Rc, time::Duration, vec};

use rand::Rng;

use super::{
    aggregation_models::{RawSearchResult, SearchResult, SearchResults},
    user_agent::{self, random_user_agent},
};

use crate::engines::{duckduckgo, engine_models::SearchEngine, searx};

/// A function that aggregates all the scraped results from the above upstream engines and
/// then removes duplicate results and if two results are found to be from two or more engines
/// then puts their names together to show the results are fetched from these upstream engines
/// and then removes all data from the HashMap and puts into a struct of all results aggregated
/// into a vector and also adds the query used into the struct this is neccessory because
/// otherwise the search bar in search remains empty if searched from the query url
///
/// # Example:
///
/// If you search from the url like `https://127.0.0.1/search?q=huston` then the search bar should
/// contain the word huston and not remain empty.
///
/// # Arguments
///
/// * `query` - Accepts a string to query with the above upstream search engines.
/// * `page` - Accepts an u32 page number.
/// * `random_delay` - Accepts a boolean value to add a random delay before making the request.
///
/// # Error
///
/// Returns an error a reqwest and scraping selector errors if any error occurs in the results
/// function in either `searx` or `duckduckgo` or both otherwise returns a `SearchResults struct`
/// containing appropriate values.
pub async fn aggregate(
    query: &str,
    page: u32,
    random_delay: bool,
    debug: bool,
) -> Result<SearchResults, Box<dyn std::error::Error>> {
    let user_agent: String = random_user_agent();
    let mut result_map: HashMap<String, RawSearchResult> = HashMap::new();

    // Add a random delay before making the request.
    if random_delay || !debug {
        let mut rng = rand::thread_rng();
        let delay_secs = rng.gen_range(1..10);
        std::thread::sleep(Duration::from_secs(delay_secs));
    }

    let engines: Vec<Box<dyn SearchEngine + Send + Sync>> =
        vec![Box::new(duckduckgo::Duckduckgo), Box::new(searx::Searx)];

    let mut tasks = Vec::with_capacity(engines.len());

    for engine in engines {
        tasks.push(tokio::spawn(async move {
            engine.results(query, page, &user_agent)
        }))
    }

    let initial: bool = true;
    for task in tasks {
        if initial {
            result_map.extend(task.await?);
            initial = false
        } else {
            task.into_iter().for_each(|(key, value)| {
                result_map
                    .entry(key)
                    .and_modify(|result| {
                        result.add_engines(value.clone().engine());
                    })
                    .or_insert_with(|| -> RawSearchResult {
                        RawSearchResult::new(
                            value.title.clone(),
                            value.visiting_url.clone(),
                            value.description.clone(),
                            value.engine.clone(),
                        )
                    });
            });
        }
    }

    Ok(SearchResults::new(
        result_map
            .into_iter()
            .map(|(key, value)| {
                SearchResult::new(
                    value.title,
                    value.visiting_url,
                    key,
                    value.description,
                    value.engine,
                )
            })
            .collect(),
        query.to_string(),
    ))
}