//! This module provides the functionality to handle different routes of the `websurfx`
//! meta search engine website and provide appropriate response to each route/page
//! when requested.

use std::fs::read_to_string;

use crate::{
    cache::cacher::RedisCache,
    config::parser::Config,
    handler::public_paths::get_public_path,
    results::{aggregation_models::SearchResults, aggregator::aggregate},
};
use actix_web::{get, web, HttpRequest, HttpResponse};
use handlebars::Handlebars;
use serde::Deserialize;

/// A named struct which deserializes all the user provided search parameters and stores them.
///
/// # Fields
///
/// * `q` - It stores the search parameter option `q` (or query in simple words)
/// of the search url.
/// * `page` - It stores the search parameter `page` (or pageno in simple words)
/// of the search url.
#[derive(Debug, Deserialize)]
struct SearchParams {
    q: Option<String>,
    page: Option<u32>,
}

/// Handles the route of index page or main page of the `websurfx` meta search engine website.
#[get("/")]
pub async fn index(
    hbs: web::Data<Handlebars<'_>>,
    config: web::Data<Config>,
) -> Result<HttpResponse, Box<dyn std::error::Error>> {
    let page_content: String = hbs.render("index", &config.style).unwrap();
    Ok(HttpResponse::Ok().body(page_content))
}

/// Handles the route of any other accessed route/page which is not provided by the
/// website essentially the 404 error page.
pub async fn not_found(
    hbs: web::Data<Handlebars<'_>>,
    config: web::Data<Config>,
) -> Result<HttpResponse, Box<dyn std::error::Error>> {
    let page_content: String = hbs.render("404", &config.style)?;

    Ok(HttpResponse::Ok()
        .content_type("text/html; charset=utf-8")
        .body(page_content))
}

/// Handles the route of search page of the `websurfx` meta search engine website and it takes
/// two search url parameters `q` and `page` where `page` parameter is optional.
///
/// # Example
///
/// ```bash
/// curl "http://127.0.0.1:8080/search?q=sweden&page=1"
/// ```
///
/// Or
///
/// ```bash
/// curl "http://127.0.0.1:8080/search?q=sweden"
/// ```
#[get("/search")]
pub async fn search(
    hbs: web::Data<Handlebars<'_>>,
    req: HttpRequest,
    config: web::Data<Config>,
) -> Result<HttpResponse, Box<dyn std::error::Error>> {
    let params = web::Query::<SearchParams>::from_query(req.query_string())?;

    match &params.q {
        Some(query) => {
            if query.trim().is_empty() {
                return Ok(HttpResponse::Found()
                    .insert_header(("location", "/"))
                    .finish());
            }
            let page = match &params.page {
                Some(page) => *page,
                None => 0,
            };

            let url = format!(
                "http://{}:{}/search?q={}&page={}",
                config.binding_ip, config.port, query, page
            );
            let results_json = get_results(url, &config, query, page).await?;
            let page_content: String = hbs.render("search", &results_json)?;
            Ok(HttpResponse::Ok().body(page_content))
        }
        None => Ok(HttpResponse::Found()
            .insert_header(("location", "/"))
            .finish()),
    }
}

/// Fetches the results for a query and page.
/// First checks the redis cache, if that fails it gets proper results
async fn get_results(
    url: String,
    config: &Config,
    query: &str,
    page: u32,
) -> Result<SearchResults, Box<dyn std::error::Error>> {
    //Initialize redis cache connection struct
    let mut redis_cache = RedisCache::new(config.redis_url.clone())?;
    // fetch the cached results json.
    let cached_results_json = redis_cache.get_cached_json(&url);
    // check if fetched results was indeed fetched or it was an error and if so
    // handle the data accordingly.
    match cached_results_json {
        Ok(results_json) => Ok(serde_json::from_str::<SearchResults>(&results_json).unwrap()),
        Err(_) => {
            let mut results_json: crate::results::aggregation_models::SearchResults =
                aggregate(query, page, config.aggregator.random_delay, config.debug).await?;
            results_json.add_style(config.style.clone());
            redis_cache.cache_results(serde_json::to_string(&results_json)?, &url)?;
            Ok(results_json)
        }
    }
}

/// Handles the route of robots.txt page of the `websurfx` meta search engine website.
#[get("/robots.txt")]
pub async fn robots_data(_req: HttpRequest) -> Result<HttpResponse, Box<dyn std::error::Error>> {
    let page_content: String = read_to_string(format!("{}/robots.txt", get_public_path()?))?;
    Ok(HttpResponse::Ok()
        .content_type("text/plain; charset=ascii")
        .body(page_content))
}

/// Handles the route of about page of the `websurfx` meta search engine website.
#[get("/about")]
pub async fn about(
    hbs: web::Data<Handlebars<'_>>,
    config: web::Data<Config>,
) -> Result<HttpResponse, Box<dyn std::error::Error>> {
    let page_content: String = hbs.render("about", &config.style)?;
    Ok(HttpResponse::Ok().body(page_content))
}

/// Handles the route of settings page of the `websurfx` meta search engine website.
#[get("/settings")]
pub async fn settings(
    hbs: web::Data<Handlebars<'_>>,
    config: web::Data<Config>,
) -> Result<HttpResponse, Box<dyn std::error::Error>> {
    let page_content: String = hbs.render("settings", &config.style)?;
    Ok(HttpResponse::Ok().body(page_content))
}