use axum::http::{HeaderMap, Response, StatusCode};
use axum_extra::extract::Query;
use serde::Deserialize;
use acrate_core::diesel::GroupedBy;
use acrate_core::diesel_async::{AsyncConnection, AsyncPgConnection};
use acrate_core::meta::{MetaAlias, MetaLink, MetaLinkProperty, MetaLinkTitle, MetaProperty};
use acrate_hostmeta::jrd::ResourceDescriptorLinkJRD;
use acrate_hostmeta::xrd::{ResourceDescriptorLinkXRD, ResourceDescriptorPropertyXRD, ResourceDescriptorTitleXRD};
use crate::config;

#[derive(Debug, Clone, Deserialize)]
pub struct WebfingerQuery {
	pub resource: Option<String>,
	
	#[serde(default)]
	pub rel: Vec<String>,
}

const WEBFINGER_DOC: &str = "/.well-known/webfinger";

#[axum::debug_handler]
pub async fn webfinger_handler(
	Query(WebfingerQuery {resource, rel}): Query<WebfingerQuery>,
	headers: HeaderMap,
) -> Result<Response<String>, StatusCode> {
	log::info!("Handling a WebFinger request!");
	
	let resource = resource.unwrap_or_else(|| "".to_string());
	log::debug!("Resource is: {resource:#?}");
	
	log::debug!("Rel is: {rel:#?}");
	
	let accept = headers.get("Accept")
		.map(|v| v.to_str())
		.filter(Result::is_ok)
		.map(|v| v.unwrap())
		.unwrap_or("application/json")
		.to_string();
	log::debug!("Accept is: {accept:#?}");
	
	let mut response = Response::new("".to_string());
	
	let mut conn = AsyncPgConnection::establish(config::ACRATE_WEBFINGER_DATABASE_URL())
		.await
		.map_err(|_| StatusCode::BAD_GATEWAY)?;
	
	let aliases = MetaAlias::query_matching(&mut conn, WEBFINGER_DOC, &resource)
		.await
		.map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
	
	let properties = MetaProperty::query_matching(&mut conn, WEBFINGER_DOC, &resource)
		.await
		.map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
	
	let links = MetaLink::query_matching(&mut conn, WEBFINGER_DOC, &resource)
		.await
		.map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
	
	let link_properties = MetaLinkProperty::query_by_link(&mut conn, &links)
		.await
		.map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?
		.grouped_by(&links);
	
	let link_titles = MetaLinkTitle::query_by_link(&mut conn, &links)
		.await
		.map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?
		.grouped_by(&links);
	
	let links_full: Vec<(MetaLink, Vec<MetaLinkProperty>, Vec<MetaLinkTitle>)> = links
		.into_iter()
		.zip(link_properties)
		.zip(link_titles)
		.map(|((link, properties), titles)| (link, properties, titles))
		.collect();
	
	{
		let headers = response.headers_mut();
		headers.insert(
			"Access-Control-Allow-Origin",
			"*".parse().unwrap()
		);
	}
	
	for mime in accept.split(",") {
		{
			let headers = response.headers_mut();
			headers.insert(
				"Content-Type",
				mime.parse().map_err(|_| StatusCode::BAD_REQUEST)?
			);
		}

		let (mime, _params) = match mime.trim().split_once(";") {
			Some((mime, params)) => (mime, Some(params)),
			None => (mime, None),
		};

		match mime {
			"*/*" | "application/json" | "application/jrd+json" => {
				let subject = Some(resource);
				
				let aliases = aliases
					.into_iter()
					.map(|alias| alias.alias)
					.collect();
				
				let properties = properties
					.into_iter()
					.map(|prop| (prop.rel, prop.value))
					.collect();
				
				let links = links_full
					.into_iter()
					.map(|(link, properties, titles)| ResourceDescriptorLinkJRD {
						rel: link.rel,
						r#type: link.type_,
						href: link.href,
						template: link.template,
						properties: properties
							.into_iter()
							.map(|property| (property.rel, property.value))
							.collect(),
						titles: titles
							.into_iter()
							.map(|title| (title.language, title.value))
							.collect(),
					})
					.collect::<Vec<ResourceDescriptorLinkJRD>>();
				
				let rd = acrate_hostmeta::jrd::ResourceDescriptorJRD {
					subject,
					aliases,
					properties,
					links,
				};
				
				let json = serde_json::to_string_pretty(&rd)
					.map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
				
				{
					let body = response.body_mut();
					body.push_str(&json);
				}
				
				return Ok(response)
			},
			"application/xml" | "application/xrd+xml" => {
				let subject = Some(resource);
				
				let aliases = aliases
					.into_iter()
					.map(|alias| alias.alias)
					.collect();
				
				let properties: Vec<ResourceDescriptorPropertyXRD> = properties
					.into_iter()
					.map(|prop| ResourceDescriptorPropertyXRD {
						rel: prop.rel,
						value: prop.value,
					})
					.collect();
				
				let links = links_full
					.into_iter()
					.map(|(link, properties, titles)| ResourceDescriptorLinkXRD {
						rel: link.rel,
						r#type: link.type_,
						href: link.href,
						template: link.template,
						properties: properties
							.into_iter()
							.map(|property| ResourceDescriptorPropertyXRD {
								rel: property.rel,
								value: property.value,
							})
							.collect(),
						titles: titles
							.into_iter()
							.map(|title| ResourceDescriptorTitleXRD {
								language: title.language,
								value: title.value,
							})
							.collect(),
					})
					.collect::<Vec<ResourceDescriptorLinkXRD>>();
				
				let rd = acrate_hostmeta::xrd::ResourceDescriptorXRD {
					subject,
					aliases,
					properties,
					links,
				};
				
				let xml = quick_xml::se::to_string(&rd)
					.map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
				
				{
					let body = response.body_mut();
					body.push_str("<?xml version='1.0' encoding='UTF-8'?>");
					body.push_str(&xml);
				}
				
				return Ok(response)
			},
			_ => {
				continue;
			}
		}
	}
	
	Err(StatusCode::NOT_ACCEPTABLE)
}