/*
 * asklyphe-frontend routes/search.rs
 * - http routes for web searching
 *
 * Copyright (C) 2025 Real Microsoft, LLC
 *
 * This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, version 3.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License along with this program. If not, see <https://www.gnu.org/licenses/>.
*/

use crate::routes::index::frontpage_error;
use crate::routes::{authenticate_user, Themes, UserInfo};
use crate::searchbot::{gather_image_results, gather_search_results};
use crate::unit_converter;
use crate::unit_converter::UnitConversion;
use crate::wikipedia::WikipediaSummary;
use crate::{wikipedia, Opts, ALPHA, BUILT_ON, GIT_COMMIT, VERSION, YEAR};
use askama::Template;
use asklyphe_common::nats;
use asklyphe_common::nats::bingservice::{
    BingServiceQuery, BingServiceRequest, BingServiceResponse,
};
use asklyphe_common::nats::comms;
use asklyphe_common::nats::searchservice::{
    SearchSrvcQuery, SearchSrvcRequest, SearchSrvcResponse,
};
use async_nats::jetstream;
use axum::extract::Query;
use axum::http::StatusCode;
use axum::response::{IntoResponse, Redirect};
use axum::Extension;
use axum_extra::extract::CookieJar;
use isahc::config::{IpVersion, RedirectPolicy};
use isahc::RequestExt;
use serde::Serialize;
use std::collections::{BTreeMap, BTreeSet, HashMap};
use std::ops::Deref;
use std::sync::Arc;
use std::time::Duration;
use tokio::sync::{Mutex, RwLock};
use tracing::error;

#[derive(Serialize)]
pub struct SearchResult {
    pub title: Option<String>,
    pub description: Option<String>,
    pub url: String,
    pub percentage: String,
    pub value: String,
    pub asklyphe: bool,
    pub bing: bool,
    pub google: bool,
}

#[derive(Serialize)]
pub struct ImageSearchResult {
    pub src: String,
    pub url: String,
    pub bing: bool,
    pub google: bool,
}

#[derive(Debug, Default)]
pub struct Complications {
    disabled: bool,
    wikipedia: Option<WikipediaSummary>,
    unit_converter: Option<UnitConversion>,
}

pub async fn search(
    jar: CookieJar,
    Query(params): Query<HashMap<String, String>>,
    Extension(nats): Extension<Arc<jetstream::Context>>,
    Extension(opts): Extension<Opts>,
) -> impl IntoResponse {
    let stype = params
        .get("stype")
        .unwrap_or(&"web".to_string())
        .to_string();
    if stype == "image" {
        return image_search(jar, Query(params), Extension(nats), Extension(opts))
            .await
            .into_response();
    }
    let use_javascript = params.get("js").unwrap_or(&"0".to_string()).to_string();
    if use_javascript != *"1" {
        search_nojs(jar, Query(params), Extension(nats), Extension(opts))
            .await
            .into_response()
    } else {
        search_js(jar, Query(params), Extension(nats), Extension(opts))
            .await
            .into_response()
    }
}

#[derive(Template)]
#[template(path = "search_js.html")]
struct SearchTemplateJavascript {
    info: UserInfo,
    error: Option<String>,
    complications: Complications,
    search_query: String,
    websearch_url: String,
    imagesearch_url: String,
    version: String,
    git_commit: String,
    built_on: String,
    year: String,
    alpha: bool,
    theme: Themes,
}

pub async fn search_js(
    jar: CookieJar,
    Query(params): Query<HashMap<String, String>>,
    Extension(nats): Extension<Arc<jetstream::Context>>,
    Extension(opts): Extension<Opts>,
) -> impl IntoResponse {
    fn error_response(query: String, info: UserInfo, error: &str) -> SearchTemplateJavascript {
        let theme = info.get_theme();
        let querystr = url_encoded_data::stringify(&[("q", query.as_str())]);
        SearchTemplateJavascript {
            info,
            error: Some(format!(
                "internal server error ({})! report to developers (:",
                error
            )),
            complications: Default::default(),
            search_query: query,
            websearch_url: format!("/ask?{querystr}&js=1"),
            imagesearch_url: format!("/ask?{querystr}&js=1&stype=image"),
            version: VERSION.to_string(),
            git_commit: GIT_COMMIT.to_string(),
            built_on: BUILT_ON.to_string(),
            year: YEAR.to_string(),
            alpha: ALPHA,
            theme,
        }
    }
    if let Some(token) = jar.get("token") {
        let token = token.value().to_string();
        let info = match authenticate_user(nats.clone(), token).await {
            Ok(i) => i,
            Err(e) => {
                return (
                    jar.remove("token"),
                    frontpage_error(e.as_str(), opts.auth_url.clone()),
                )
                    .into_response();
            }
        };
        let mut query = params.get("q").unwrap_or(&"Deez".to_string()).to_string();
        let og_query = query.clone();
        let mut complications = Complications::default();
        // todo: better way of specifying that user doesn't want complications
        if !query.contains("-complications") {
            let mut wikiquery = query.clone().to_lowercase();
            wikiquery.retain(|c| c.is_alphanumeric() || c.is_ascii_whitespace());
            wikiquery = wikiquery.replace(' ', "%20");
            // todo: proper url escaping
            let wikipedia_comp =
                tokio::spawn(async move { wikipedia::get_wikipedia_page(&wikiquery, 20).await });
            complications.wikipedia = wikipedia_comp.await.unwrap_or_default();

            let mut unit_query = query.clone().to_lowercase();
            unit_query = unit_query.replace("metre", "meter");
            let unit_comp = unit_converter::convert_unit(&unit_query);
            complications.unit_converter = unit_comp;
        } else {
            complications.disabled = true;
            query = query.replace("-complications", "");
        }

        let theme = info.get_theme();
        let querystr = url_encoded_data::stringify(&[("q", og_query.as_str())]);
        SearchTemplateJavascript {
            info,
            error: None,
            complications,
            search_query: og_query,
            websearch_url: format!("/ask?{querystr}&js=1"),
            imagesearch_url: format!("/ask?{querystr}&js=1&stype=image"),
            version: VERSION.to_string(),
            git_commit: GIT_COMMIT.to_string(),
            built_on: BUILT_ON.to_string(),
            year: YEAR.to_string(),
            alpha: ALPHA,
            theme,
        }
        .into_response()
    } else {
        Redirect::to("/").into_response()
    }
}

#[derive(Template)]
#[template(path = "search.html")]
pub struct SearchTemplate {
    pub info: UserInfo,
    pub error: Option<String>,
    pub note: Option<String>,
    pub complications: Complications,
    pub search_query: String,
    pub query_time: f64,
    pub page_rank_time: f64,
    pub max_relevance: String,
    pub search_results: Vec<SearchResult>,
    pub blocked: Vec<(String, String)>,
    pub websearch_url: String,
    pub imagesearch_url: String,
    pub version: String,
    pub git_commit: String,
    pub built_on: String,
    pub year: String,
    pub alpha: bool,
    pub theme: Themes,
}

pub async fn search_nojs(
    jar: CookieJar,
    Query(params): Query<HashMap<String, String>>,
    Extension(nats): Extension<Arc<jetstream::Context>>,
    Extension(opts): Extension<Opts>,
) -> impl IntoResponse {
    fn error_response(query: String, info: UserInfo, error: &str) -> SearchTemplate {
        let theme = info.get_theme();
        let querystr = url_encoded_data::stringify(&[("q", query.as_str())]);
        SearchTemplate {
            info,
            error: Some(format!(
                "internal server error ({})! report to developers (:",
                error
            )),
            note: None,
            complications: Default::default(),
            search_query: query,
            query_time: 0.0,
            page_rank_time: 0.0,
            max_relevance: "".to_string(),
            search_results: vec![],
            blocked: vec![],
            websearch_url: format!("/ask?{querystr}&js=0"),
            imagesearch_url: format!("/ask?{querystr}&js=0&stype=image"),
            version: VERSION.to_string(),
            git_commit: GIT_COMMIT.to_string(),
            built_on: BUILT_ON.to_string(),
            year: YEAR.to_string(),
            alpha: ALPHA,
            theme,
        }
    }
    if let Some(token) = jar.get("token") {
        let token = token.value().to_string();
        let info = match authenticate_user(nats.clone(), token).await {
            Ok(i) => i,
            Err(e) => {
                return (
                    jar.remove("token"),
                    frontpage_error(e.as_str(), opts.auth_url.clone()),
                )
                    .into_response();
            }
        };
        let mut query = params.get("q").unwrap_or(&"Deez".to_string()).to_string();
        let og_query = query.clone();
        let mut complications = Complications::default();
        // todo: better way of specifying that user doesn't want complications
        if !query.contains("-complications") {
            let mut wikiquery = query.clone().to_lowercase();
            wikiquery.retain(|c| c.is_alphanumeric() || c.is_ascii_whitespace());
            wikiquery = wikiquery.replace(' ', "%20");
            // todo: proper url escaping
            let wikipedia_comp =
                tokio::spawn(async move { wikipedia::get_wikipedia_page(&wikiquery, 20).await });
            complications.wikipedia = wikipedia_comp.await.unwrap_or_default();

            let mut unit_query = query.clone().to_lowercase();
            unit_query = unit_query.replace("metre", "meter");
            let unit_comp = unit_converter::convert_unit(&unit_query);
            complications.unit_converter = unit_comp;
        } else {
            complications.disabled = true;
            query = query.replace("-complications", "");
        }

        let engines = params
            .get("engines")
            .unwrap_or(&"asklyphe,bing,google".to_string())
            .to_string();
        let mut engines = engines
            .split(",")
            .map(|v| v.to_string())
            .collect::<Vec<String>>();
        if opts.emergency {
            // disable asklyphe backend
            engines.retain(|v| v != "asklyphe");
        }

        gather_search_results(nats, query.as_str(), info, complications, Some(engines))
            .await
            .into_response()
    } else {
        Redirect::to("/").into_response()
    }
}

#[derive(Serialize)]
struct BlockedResult {
    url: String,
    reason: String,
}

#[derive(Serialize)]
struct SearchJsonInner {
    #[serde(skip_serializing_if = "Option::is_none")]
    note: Option<String>,
    query_time: f64,
    page_rank_time: f64,
    max_relevance: String,
    search_results: Vec<SearchResult>,
    blocked: Vec<BlockedResult>,
}

#[derive(Serialize)]
struct SearchJson {
    #[serde(skip_serializing_if = "Option::is_none")]
    error: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    results: Option<SearchJsonInner>,
}

pub async fn search_json(
    jar: CookieJar,
    Query(params): Query<HashMap<String, String>>,
    Extension(nats): Extension<Arc<jetstream::Context>>,
    Extension(opts): Extension<Opts>,
) -> String {
    fn json(input: SearchJson) -> String {
        serde_json::to_string(&input).expect("failed to serialise!")
    }

    fn error_response(error: &str) -> String {
        json(SearchJson {
            error: Some(error.to_string()),
            results: None,
        })
    }
    if let Some(token) = jar.get("token") {
        let token = token.value().to_string();
        let info = match authenticate_user(nats.clone(), token).await {
            Ok(i) => i,
            Err(e) => {
                return error_response("not authenticated");
            }
        };
        let query = params.get("q").unwrap_or(&"Deez".to_string()).to_string();
        let engines = params
            .get("engines")
            .unwrap_or(&"asklyphe,bing,google".to_string())
            .to_string();
        let mut engines = engines
            .split(",")
            .map(|v| v.to_string())
            .collect::<Vec<String>>();
        if opts.emergency {
            // disable asklyphe backend
            engines.retain(|v| v != "asklyphe");
        }

        let result = gather_search_results(
            nats,
            query.as_str(),
            info,
            Complications::default(),
            Some(engines),
        )
        .await;

        json(SearchJson {
            error: None,
            results: Some(SearchJsonInner {
                note: result.note,
                query_time: result.query_time,
                page_rank_time: result.page_rank_time,
                max_relevance: result.max_relevance,
                search_results: result.search_results,
                blocked: result
                    .blocked
                    .into_iter()
                    .map(|(url, reason)| BlockedResult { url, reason })
                    .collect(),
            }),
        })
    } else {
        error_response("not authenticated")
    }
}

#[derive(Template)]
#[template(path = "image_search.html")]
pub struct ImageSearchTemplate {
    pub info: UserInfo,
    pub error: Option<String>,
    pub note: Option<String>,
    pub search_query: String,
    pub search_results: Vec<ImageSearchResult>,
    pub blocked: Vec<(String, String)>,
    pub websearch_url: String,
    pub imagesearch_url: String,
    pub version: String,
    pub git_commit: String,
    pub built_on: String,
    pub year: String,
    pub alpha: bool,
    pub theme: Themes,
}
pub async fn image_search(
    jar: CookieJar,
    Query(params): Query<HashMap<String, String>>,
    Extension(nats): Extension<Arc<jetstream::Context>>,
    Extension(opts): Extension<Opts>,
) -> impl IntoResponse {
    fn error_response(query: String, info: UserInfo, error: &str) -> ImageSearchTemplate {
        let theme = info.get_theme();
        let querystr = url_encoded_data::stringify(&[("q", query.as_str())]);
        ImageSearchTemplate {
            info,
            error: Some(format!(
                "internal server error ({})! report to developers (:",
                error
            )),
            note: None,
            search_query: query,
            search_results: vec![],
            blocked: vec![],
            websearch_url: format!("/ask?{querystr}&js=0"),
            imagesearch_url: format!("/ask?{querystr}&js=0&stype=image"),
            version: VERSION.to_string(),
            git_commit: GIT_COMMIT.to_string(),
            built_on: BUILT_ON.to_string(),
            year: YEAR.to_string(),
            alpha: ALPHA,
            theme,
        }
    }
    if let Some(token) = jar.get("token") {
        let token = token.value().to_string();
        let info = match authenticate_user(nats.clone(), token).await {
            Ok(i) => i,
            Err(e) => {
                return (
                    jar.remove("token"),
                    frontpage_error(e.as_str(), opts.auth_url.clone()),
                )
                    .into_response();
            }
        };
        let query = params.get("q").unwrap_or(&"Deez".to_string()).to_string();
        let js = params.get("js").unwrap_or(&"0".to_string()).to_string();
        let engines = params
            .get("engines")
            .unwrap_or(&"bing,google".to_string())
            .to_string();
        let engines = engines
            .split(",")
            .map(|v| v.to_string())
            .collect::<Vec<String>>();

        gather_image_results(nats, &query, info, Some(engines), js == "1")
            .await
            .into_response()
    } else {
        Redirect::to("/").into_response()
    }
}

pub async fn image_proxy(
    jar: CookieJar,
    Query(params): Query<HashMap<String, String>>,
    Extension(nats): Extension<Arc<jetstream::Context>>,
    Extension(opts): Extension<Opts>,
) -> impl IntoResponse {
    static PROXY_TOKEN_CACHE: RwLock<BTreeSet<String>> = RwLock::const_new(BTreeSet::new());
    static IMAGE_CACHE: RwLock<BTreeMap<String, Vec<u8>>> = RwLock::const_new(BTreeMap::new());
    const TOKEN_CACHE_TTL_MINS: u64 = 10;
    const IMAGE_CACHE_TTL_MINS: u64 = 10;
    if let Some(token) = jar.get("token") {
        let token = token.value().to_string();
        let mut authenticated = false;
        {
            let cache = PROXY_TOKEN_CACHE.read().await;
            authenticated = cache.contains(&token);
        }
        if !authenticated {
            let _info = match authenticate_user(nats.clone(), token.clone()).await {
                Ok(i) => i,
                Err(e) => {
                    return StatusCode::UNAUTHORIZED.into_response();
                }
            };
            {
                let mut cache = PROXY_TOKEN_CACHE.write().await;
                cache.insert(token.clone());
                tokio::spawn(async move {
                    tokio::time::sleep(Duration::from_secs(TOKEN_CACHE_TTL_MINS * 60)).await;
                    let mut cache = PROXY_TOKEN_CACHE.write().await;
                    cache.remove(&token);
                });
            }
            authenticated = true;
        }
        if !authenticated {
            return StatusCode::UNAUTHORIZED.into_response();
        }
        use isahc::prelude::*;
        let url = params.get("url");
        if url.is_none() {
            return StatusCode::BAD_REQUEST.into_response();
        }
        let mut url = url.unwrap().to_string();

        let mut host = url.split("://");
        let host = host.nth(1).unwrap_or(&url);
        // fixme: we really need a better solution
        const BLOCKED_HOSTS: &[&str] = &[
            "0",
            "10",
            "100.6",
            "100.7",
            "100.8",
            "100.9",
            "100.10",
            "100.11",
            "100.12",
            "127",
            "169.254",
            "172.1",
            "172.2",
            "172.30",
            "172.31",
            "192.168",
            "198.18",
            "198.19",
            "localhost",
        ];
        for blocked in BLOCKED_HOSTS {
            if host.starts_with(blocked) {
                return StatusCode::NO_CONTENT.into_response();
            }
        }

        if !(url.starts_with("http://") || url.starts_with("https://")) {
            url.insert_str(0, "http://");
        }
        // fixme: replace with actual smart encoding system
        url = url.replace(" ", "%20");

        {
            let cache = IMAGE_CACHE.read().await;
            if let Some(cached_image) = cache.get(&url).cloned() {
                return cached_image.into_response();
            }
        }

        let response = isahc::Request::get(url.clone())
            .ip_version(IpVersion::V4)
            .header("user-agent", "AskLyphe Image Proxy (+https://asklyphe.com)")
            .timeout(Duration::from_secs(10))
            .redirect_policy(RedirectPolicy::Limit(6))
            .body(())
            .unwrap()
            .send_async()
            .await;
        if response.is_err() {
            return StatusCode::NO_CONTENT.into_response();
        }
        let mut response = response.unwrap();
        let data = response.bytes().await;
        if data.is_err() {
            return StatusCode::NO_CONTENT.into_response();
        }
        let data = data.unwrap();
        const MAX_IMAGE_SIZE_IN_CACHE_MB: usize = 512;
        if !data.is_empty() && data.len() < MAX_IMAGE_SIZE_IN_CACHE_MB * 1024 * 1024 {
            let mut cache = IMAGE_CACHE.write().await;
            const MAX_CACHE_SIZE_GB: usize = 10;
            const MAX_CACHE_SIZE_MB: usize = MAX_CACHE_SIZE_GB * 1024 * 1024;
            const MAX_CACHE_ENTRIES: usize =
                MAX_CACHE_SIZE_MB / MAX_IMAGE_SIZE_IN_CACHE_MB;
            if cache.len() < MAX_CACHE_ENTRIES {
                cache.insert(url.clone(), data.clone());
                tokio::spawn(async move {
                    tokio::time::sleep(Duration::from_secs(IMAGE_CACHE_TTL_MINS * 60)).await;
                    let mut cache = IMAGE_CACHE.write().await;
                    cache.remove(&url);
                });
            }
        }
        data.into_response()
    } else {
        StatusCode::UNAUTHORIZED.into_response()
    }
}