// need this for ructe
#![allow(clippy::needless_borrow)]

use actix_web::{
    body::BodyStream,
    http::{
        header::{CacheControl, CacheDirective, ContentType, LastModified, LOCATION},
        StatusCode,
    },
    web, App, HttpRequest, HttpResponse, HttpResponseBuilder, HttpServer, ResponseError,
};
use awc::Client;
use console_subscriber::ConsoleLayer;
use once_cell::sync::Lazy;
use opentelemetry::{
    sdk::{propagation::TraceContextPropagator, Resource},
    KeyValue,
};
use opentelemetry_otlp::WithExportConfig;
use std::{
    io::Cursor,
    net::SocketAddr,
    time::{Duration, SystemTime},
};
use structopt::StructOpt;
use tracing_actix_web::TracingLogger;
use tracing_awc::Tracing;
use tracing_error::{ErrorLayer, SpanTrace};
use tracing_log::LogTracer;
use tracing_subscriber::{
    filter::Targets, fmt::format::FmtSpan, layer::SubscriberExt, Layer, Registry,
};
use url::Url;

include!(concat!(env!("OUT_DIR"), "/templates.rs"));

const HOURS: u32 = 60 * 60;
const DAYS: u32 = 24 * HOURS;

#[derive(Clone, Debug, StructOpt)]
struct Config {
    #[structopt(
        short,
        long,
        env = "PICTRS_PROXY_ADDR",
        default_value = "0.0.0.0:8081",
        help = "The address and port the server binds to"
    )]
    addr: SocketAddr,

    #[structopt(
        short,
        long,
        env = "PICTRS_PROXY_UPSTREAM",
        default_value = "http://localhost:8080",
        help = "The url of the upstream pict-rs server"
    )]
    upstream: Url,

    #[structopt(
        short,
        long,
        env = "PICTRS_PROXY_DOMAIN",
        default_value = "http://localhost:8081",
        help = "The scheme, domain, and optional port of the pict-rs proxy server"
    )]
    domain: Url,

    #[structopt(
        short,
        long,
        env = "PICTRS_PROXY_OPENTELEMETRY_URL",
        help = "URL of OpenTelemetry Collector"
    )]
    opentelemetry_url: Option<Url>,
}

impl Config {
    fn upstream_upload_url(&self) -> String {
        let mut url = self.upstream.clone();
        url.set_path("image");

        url.to_string()
    }

    fn upstream_details_url(&self, name: &str) -> String {
        let mut url = self.upstream.clone();
        url.set_path(&format!("image/details/original/{}", name));

        url.to_string()
    }

    fn upstream_image_url(&self, name: &str) -> String {
        let mut url = self.upstream.clone();
        url.set_path(&format!("image/original/{}", name));

        url.to_string()
    }

    fn upstream_thumbnail_url(&self, size: u64, name: &str, filetype: FileType) -> String {
        let mut url = self.upstream.clone();
        url.set_path(&format!("image/process.{}", filetype.as_str()));
        url.set_query(Some(&format!("src={}&thumbnail={}", name, size)));

        url.to_string()
    }

    fn upstream_delete_url(&self, token: &str, name: &str) -> String {
        let mut url = self.upstream.clone();
        url.set_path(&format!("image/delete/{}/{}", token, name));

        url.to_string()
    }

    fn image_url(&self, name: &str) -> String {
        let mut url = self.domain.clone();
        url.set_path(&format!("image/{}", name));

        url.to_string()
    }

    fn thumbnail_url(&self, size: u64, name: &str, filetype: FileType) -> String {
        let mut url = self.domain.clone();
        url.set_path(&format!("thumb/{}/{}/{}", size, filetype.as_str(), name));

        url.to_string()
    }

    fn view_url(&self, size: Option<u64>, name: &str) -> String {
        let mut url = self.domain.clone();
        if let Some(size) = size {
            url.set_path(&format!("view/{}/{}", size, name));
        } else {
            url.set_path(&format!("view/{}", name));
        }

        url.to_string()
    }

    fn thumbnails_url(&self, name: &str) -> String {
        let mut url = self.domain.clone();
        url.set_path("/thumbnails");
        url.set_query(Some(&format!("image={}", name)));

        url.to_string()
    }

    fn delete_url(&self, token: &str, name: &str) -> String {
        let mut url = self.domain.clone();
        url.set_path("delete");
        url.set_query(Some(&format!("file={}&token={}", name, token)));

        url.to_string()
    }

    fn confirm_delete_url(&self, token: &str, name: &str) -> String {
        let mut url = self.domain.clone();
        url.set_path("delete");
        url.set_query(Some(&format!("file={}&token={}&confirm=true", name, token)));

        url.to_string()
    }
}

static CONFIG: Lazy<Config> = Lazy::new(Config::from_args);

#[derive(Debug, serde::Deserialize)]
enum FileType {
    #[serde(rename = "jpg")]
    Jpg,
    #[serde(rename = "webp")]
    Webp,
}

impl FileType {
    fn as_str(&self) -> &'static str {
        match self {
            Self::Jpg => "jpg",
            Self::Webp => "webp",
        }
    }
}

#[derive(Debug, serde::Deserialize)]
pub struct Images {
    msg: String,
    files: Option<Vec<Image>>,
}

impl Images {
    fn files(&self) -> Option<&[Image]> {
        self.files.as_ref().map(|v| v.as_ref())
    }

    fn msg(&self) -> &str {
        &self.msg
    }

    fn is_ok(&self) -> bool {
        self.files().is_some()
    }

    fn message(&self) -> &'static str {
        if self.is_ok() {
            "Images Uploaded"
        } else {
            "Image Upload Failed"
        }
    }
}

#[derive(Debug, serde::Deserialize)]
pub struct Details {
    content_type: String,
}

#[derive(Debug, serde::Deserialize)]
pub struct Image {
    file: String,
    delete_token: String,
    details: Details,
}

impl Image {
    fn filename(&self) -> &str {
        &self.file
    }

    fn is_video(&self) -> bool {
        self.details.content_type.starts_with("video")
    }

    fn mime(&self) -> &str {
        &self.details.content_type
    }

    fn link(&self) -> String {
        CONFIG.image_url(&self.file)
    }

    fn thumbnails(&self) -> String {
        CONFIG.thumbnails_url(&self.file)
    }

    fn view(&self, size: Option<u64>) -> String {
        CONFIG.view_url(size, &self.file)
    }

    fn thumb(&self, size: u64, filetype: FileType) -> String {
        CONFIG.thumbnail_url(size, &self.file, filetype)
    }

    fn delete(&self) -> String {
        CONFIG.delete_url(&self.delete_token, &self.file)
    }

    fn confirm_delete(&self) -> String {
        CONFIG.confirm_delete_url(&self.delete_token, &self.file)
    }
}

fn statics(file: &str) -> String {
    format!("/static/{}", file)
}

#[derive(Debug)]
struct Error {
    context: SpanTrace,
    kind: ErrorKind,
}

impl<T> From<T> for Error
where
    ErrorKind: From<T>,
{
    fn from(error: T) -> Self {
        Error {
            context: SpanTrace::capture(),
            kind: error.into(),
        }
    }
}

impl std::fmt::Display for Error {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        writeln!(f, "{}", self.kind)?;
        std::fmt::Display::fmt(&self.context, f)
    }
}

impl std::error::Error for Error {
    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
        self.kind.source()
    }
}

impl ResponseError for Error {
    fn status_code(&self) -> StatusCode {
        StatusCode::INTERNAL_SERVER_ERROR
    }

    fn error_response(&self) -> HttpResponse {
        match render(HttpResponse::build(self.status_code()), |cursor| {
            self::templates::error(cursor, &self.kind.to_string())
        }) {
            Ok(res) => res,
            Err(_) => HttpResponse::build(self.status_code())
                .content_type(mime::TEXT_PLAIN.essence_str())
                .body(self.kind.to_string()),
        }
    }
}

#[derive(Debug, thiserror::Error)]
enum ErrorKind {
    #[error("{0}")]
    Io(#[from] std::io::Error),

    #[error("{0}")]
    SendRequest(#[from] awc::error::SendRequestError),

    #[error("{0}")]
    JsonPayload(#[from] awc::error::JsonPayloadError),
}

#[tracing::instrument(name = "Upload")]
async fn index() -> Result<HttpResponse, Error> {
    render(HttpResponse::Ok(), |cursor| {
        self::templates::index(cursor, "/upload", "images[]")
    })
}

#[tracing::instrument(name = "Upload", skip(req, body, client))]
async fn upload(
    req: HttpRequest,
    body: web::Payload,
    client: web::Data<Client>,
) -> Result<HttpResponse, Error> {
    let client_request = client.request_from(CONFIG.upstream_upload_url(), req.head());

    let client_request = if let Some(addr) = req.head().peer_addr {
        client_request.append_header(("X-Forwarded-For", addr.to_string()))
    } else {
        client_request
    };

    let mut res = client_request.send_stream(body).await?;

    let images = res.json::<Images>().await?;

    render(HttpResponse::build(res.status()), |cursor| {
        self::templates::images(cursor, images)
    })
}

const THUMBNAIL_SIZES: &[u64] = &[40, 50, 80, 100, 200, 400, 800, 1200];

#[derive(Debug, serde::Deserialize)]
struct ThumbnailQuery {
    image: String,
}

#[tracing::instrument(name = "Thumbs", skip(client))]
async fn thumbs(
    query: web::Query<ThumbnailQuery>,
    client: web::Data<Client>,
) -> Result<HttpResponse, Error> {
    let file = query.into_inner().image;

    let url = CONFIG.upstream_details_url(&file);
    let mut res = client.get(url).send().await?;

    if res.status() == StatusCode::NOT_FOUND {
        return Ok(to_404());
    }

    let details: Details = res.json().await?;

    let image = Image {
        file,
        delete_token: String::new(),
        details,
    };

    render(HttpResponse::Ok(), |cursor| {
        self::templates::thumbnails(cursor, image, THUMBNAIL_SIZES)
    })
}

#[tracing::instrument(name = "Image", skip(req, client))]
async fn image(
    url: String,
    req: HttpRequest,
    client: web::Data<Client>,
) -> Result<HttpResponse, Error> {
    let client_request = client.request_from(url, req.head());
    let client_request = if let Some(addr) = req.head().peer_addr {
        client_request.insert_header(("X-Forwarded-For", addr.to_string()))
    } else {
        client_request
    };

    let res = client_request.no_decompress().send().await?;

    if res.status() == StatusCode::NOT_FOUND {
        return Ok(to_404());
    }

    let mut client_res = HttpResponse::build(res.status());

    for (name, value) in res.headers().iter().filter(|(h, _)| *h != "connection") {
        client_res.insert_header((name.clone(), value.clone()));
    }

    Ok(client_res.body(BodyStream::new(res)))
}

#[tracing::instrument(name = "View original", skip(client))]
async fn view_original(
    file: web::Path<String>,
    client: web::Data<Client>,
) -> Result<HttpResponse, Error> {
    let file = file.into_inner();

    let url = CONFIG.upstream_details_url(&file);
    let mut res = client.get(url).send().await?;

    if res.status() == StatusCode::NOT_FOUND {
        return Ok(to_404());
    }

    let details: Details = res.json().await?;

    let image = Image {
        file,
        delete_token: String::new(),
        details,
    };

    render(HttpResponse::Ok(), |cursor| {
        self::templates::view(cursor, image, None)
    })
}

#[tracing::instrument(name = "View", skip(client))]
async fn view(
    parts: web::Path<(u64, String)>,
    client: web::Data<Client>,
) -> Result<HttpResponse, Error> {
    let (size, file) = parts.into_inner();

    if !valid_thumbnail_size(size) {
        return Ok(to_404());
    }

    let url = CONFIG.upstream_details_url(&file);
    let mut res = client.get(url).send().await?;

    if res.status() == StatusCode::NOT_FOUND {
        return Ok(to_404());
    }

    let details: Details = res.json().await?;

    let image = Image {
        file,
        delete_token: String::new(),
        details,
    };

    render(HttpResponse::Ok(), |cursor| {
        self::templates::view(cursor, image, Some(size))
    })
}

#[tracing::instrument(name = "Thumbnail", skip(req, client))]
async fn thumbnail(
    parts: web::Path<(u64, FileType, String)>,
    req: HttpRequest,
    client: web::Data<Client>,
) -> Result<HttpResponse, Error> {
    let (size, filetype, file) = parts.into_inner();

    if valid_thumbnail_size(size) {
        let url = CONFIG.upstream_thumbnail_url(size, &file, filetype);

        return image(url, req, client).await;
    }

    Ok(to_404())
}

fn valid_thumbnail_size(size: u64) -> bool {
    THUMBNAIL_SIZES.contains(&size)
}

#[tracing::instrument(name = "Full resolution", skip(req, client))]
async fn full_res(
    filename: web::Path<String>,
    req: HttpRequest,
    client: web::Data<Client>,
) -> Result<HttpResponse, Error> {
    let url = CONFIG.upstream_image_url(&filename.into_inner());

    image(url, req, client).await
}

#[allow(clippy::async_yields_async)]
#[tracing::instrument(name = "Static files")]
async fn static_files(filename: web::Path<String>) -> HttpResponse {
    let filename = filename.into_inner();

    if let Some(data) = self::templates::statics::StaticFile::get(&filename) {
        return HttpResponse::Ok()
            .insert_header(LastModified(SystemTime::now().into()))
            .insert_header(CacheControl(vec![
                CacheDirective::Public,
                CacheDirective::MaxAge(365 * DAYS),
                CacheDirective::Extension("immutable".to_owned(), None),
            ]))
            .insert_header(ContentType(data.mime.clone()))
            .body(data.content);
    }

    to_404()
}

#[derive(Debug, serde::Deserialize)]
struct DeleteQuery {
    token: String,
    file: String,

    #[serde(default)]
    confirm: bool,
}

#[tracing::instrument(name = "Delete", skip(client))]
async fn delete(
    query: web::Query<DeleteQuery>,
    client: web::Data<Client>,
) -> Result<HttpResponse, Error> {
    let DeleteQuery {
        token,
        file,
        confirm,
    } = query.into_inner();

    let url = CONFIG.upstream_details_url(&file);
    let mut res = client.get(url).send().await?;

    if res.status() == StatusCode::NOT_FOUND {
        return Ok(to_404());
    }

    if confirm {
        let url = CONFIG.upstream_delete_url(&token, &file);
        client.delete(url).send().await?;

        render(HttpResponse::Ok(), |cursor| {
            self::templates::deleted(cursor, &file)
        })
    } else {
        let details: Details = res.json().await?;

        render(HttpResponse::Ok(), move |cursor| {
            self::templates::confirm_delete(
                cursor,
                &Image {
                    file,
                    delete_token: token,
                    details,
                },
            )
        })
    }
}

fn to_404() -> HttpResponse {
    HttpResponse::TemporaryRedirect()
        .insert_header((LOCATION, "/404"))
        .finish()
}

#[tracing::instrument(name = "Not Found")]
async fn not_found() -> Result<HttpResponse, Error> {
    render(HttpResponse::NotFound(), |cursor| {
        self::templates::not_found(cursor)
    })
}

async fn go_home() -> HttpResponse {
    HttpResponse::TemporaryRedirect()
        .insert_header((LOCATION, "/"))
        .finish()
}

#[tracing::instrument(name = "Render", skip(builder, f))]
fn render(
    mut builder: HttpResponseBuilder,
    f: impl FnOnce(&mut Cursor<&mut Vec<u8>>) -> Result<(), std::io::Error>,
) -> Result<HttpResponse, Error> {
    let min = {
        let mut bytes = vec![];
        (f)(&mut Cursor::new(&mut bytes))?;
        minify_html::minify(&bytes, &minify_html::Cfg::spec_compliant())
    };

    Ok(builder
        .content_type(mime::TEXT_HTML.essence_str())
        .body(min))
}

fn init_tracing(
    service_name: &'static str,
    opentelemetry_url: Option<&Url>,
) -> Result<(), anyhow::Error> {
    opentelemetry::global::set_text_map_propagator(TraceContextPropagator::new());

    LogTracer::init()?;

    let targets: Targets = std::env::var("RUST_LOG")
        .unwrap_or_else(|_| "info".into())
        .parse()?;

    let format_layer = tracing_subscriber::fmt::layer()
        .with_span_events(FmtSpan::NEW | FmtSpan::CLOSE)
        .with_filter(targets.clone());

    let console_layer = ConsoleLayer::builder()
        .with_default_env()
        .server_addr(([0, 0, 0, 0], 6669))
        .event_buffer_capacity(1024 * 1024)
        .spawn();

    let subscriber = Registry::default()
        .with(console_layer)
        .with(format_layer)
        .with(ErrorLayer::default());

    if let Some(url) = opentelemetry_url {
        let tracer =
            opentelemetry_otlp::new_pipeline()
                .tracing()
                .with_trace_config(opentelemetry::sdk::trace::config().with_resource(
                    Resource::new(vec![KeyValue::new("service.name", service_name)]),
                ))
                .with_exporter(
                    opentelemetry_otlp::new_exporter()
                        .tonic()
                        .with_endpoint(url.as_str()),
                )
                .install_batch(opentelemetry::runtime::Tokio)?;

        let otel_layer = tracing_opentelemetry::layer()
            .with_tracer(tracer)
            .with_filter(targets);

        let subscriber = subscriber.with(otel_layer);

        tracing::subscriber::set_global_default(subscriber)?;
    } else {
        tracing::subscriber::set_global_default(subscriber)?;
    }

    Ok(())
}

#[actix_rt::main]
async fn main() -> Result<(), anyhow::Error> {
    dotenv::dotenv().ok();

    init_tracing("pict-rs-proxy", CONFIG.opentelemetry_url.as_ref())?;

    HttpServer::new(move || {
        let client = Client::builder()
            .wrap(Tracing)
            .add_default_header(("User-Agent", "pict-rs-frontend, v0.1.0"))
            .timeout(Duration::from_secs(30))
            .finish();

        App::new()
            .app_data(web::Data::new(client))
            .wrap(TracingLogger::default())
            .service(web::resource("/").route(web::get().to(index)))
            .service(web::resource("/upload").route(web::post().to(upload)))
            .service(web::resource("/image/{filename}").route(web::get().to(full_res)))
            .service(web::resource("/thumbnails").route(web::get().to(thumbs)))
            .service(web::resource("/view/{size}/{filename}").route(web::get().to(view)))
            .service(web::resource("/view/{filename}").route(web::get().to(view_original)))
            .service(
                web::resource("/thumb/{size}/{filetype}/{filename}")
                    .route(web::get().to(thumbnail)),
            )
            .service(web::resource("/static/{filename}").route(web::get().to(static_files)))
            .service(web::resource("/delete").route(web::get().to(delete)))
            .service(web::resource("/404").route(web::get().to(not_found)))
            .default_service(web::get().to(go_home))
    })
    .bind(CONFIG.addr)?
    .run()
    .await?;

    Ok(())
}