/*
 * This is the echoip-slatecave templating engine.
 * It wraps around tera in is specialized for echoip-slatecave.
 */

use axum::{
	headers::HeaderValue,
	http::StatusCode,
	http::header::SET_COOKIE,
	response::Html,
	response::IntoResponse,
	response::Response,
	response::Json,
};
use axum_extra::extract::cookie::Cookie;
use axum_extra::extract::cookie;
use tera::Tera;
use toml::Table;

use crate::DigResult;
use crate::IpResult;
use crate::config::DnsResolverConfig;
use crate::settings::*;


/* The echoip view */

#[derive(serde::Serialize, Clone)]
#[serde(untagged)]
pub enum View {
	Asn { asn: u32 },
	Dig { query: String, result: DigResult },
	DnsResolver{ config: DnsResolverConfig },
	DnsResolverList,
	Index { result: IpResult, user_agent: Option<String> },
	Ip { result: IpResult },
	Message{ title: String, message: String },
	#[serde(rename="404")]
	NotFound,
}

impl View {
	pub fn template_name(&self) -> String {
		match self {
			View::Asn{..} => "asn",
			View::Dig{..} => "dig",
			View::DnsResolver{..} => "dns_resolver",
			View::DnsResolverList => "dns_resolver_list",
			View::Index{..} => "index",
			View::Ip{..} => "ip",
			View::Message{..} => "message",
			View::NotFound => "404",
		}.to_string()
	}
}

/* The engine itself */

#[derive(Clone)]
pub struct Engine {
	pub tera: Tera,
	pub template_config: Option<Table>,
}

impl Engine {
	pub async fn render_view(
		&self,
		settings: &QuerySettings,
		view: &View,
	) -> Response {
		let mut response = match settings.format {
			ResponseFormat::TextHtml | ResponseFormat::TextPlain => {
				let template_name = view.template_name();

				let mut context = tera::Context::new();
				context.insert("view", &template_name);
				//intented for shared macros
				context.insert("format", &settings.format.to_string());
				context.insert("language", &settings.lang);
				context.insert("dns_resolvers", &settings.available_dns_resolvers);
				context.insert("dns_resolver_id", &settings.dns_resolver_id);
				context.insert("data", &view);
				context.insert("extra", &self.template_config);

				match self.tera.render(&(template_name+&settings.format.to_file_extension()), &context) {
					Ok(text) =>
						match settings.format {
							ResponseFormat::TextHtml => Html(text).into_response(),
							_ => text.into_response(),
						}
					Err(e) => {
						println!("There was an error while rendering template {}: {e:?}", view.template_name());
						(
							StatusCode::INTERNAL_SERVER_ERROR,
						format!("Template error in {}, contact owner or see logs.\n", view.template_name())
						).into_response()
					}
				}
			}
			//TODO: Plain Text should have its own matcher
			ResponseFormat::ApplicationJson => {
				match view {
					View::Dig{result, ..} => {
						Json(result).into_response()
					},
					View::Index{result, ..} | View::Ip{result, ..} => {
						Json(result).into_response()
					},
					View::DnsResolverList => {
						Json(settings.available_dns_resolvers.clone()).into_response()
					},
					View::DnsResolver{ config } => {
						Json(config).into_response()
					}
					_ => Json(view).into_response(),
				}
			}
		};
		match view {
			View::NotFound => *response.status_mut() = StatusCode::NOT_FOUND,
			_ => {},
		}
		let cookie = Cookie::build("dns_resolver",settings.dns_resolver_id.clone())
			.path("/")
			.same_site(cookie::SameSite::Strict)
			.finish();
		if let Ok(header_value) = HeaderValue::from_str(&cookie.to_string()) {
			response.headers_mut().append(
				SET_COOKIE,
				header_value,
			);
		}
		response
	}
}