/*
 * Copyright 2019-present ScyllaDB
 */

/*
 * SPDX-License-Identifier: AGPL-3.0-or-later
 */

#pragma once

#include "alternator/executor.hh"
#include <seastar/core/future.hh>
#include <seastar/core/condition-variable.hh>
#include <seastar/http/httpd.hh>
#include <seastar/net/tls.hh>
#include <optional>
#include "alternator/auth.hh"
#include "service/qos/service_level_controller.hh"
#include "utils/small_vector.hh"
#include "utils/updateable_value.hh"
#include <seastar/core/units.hh>

namespace alternator {

using chunked_content = rjson::chunked_content;

class server {
    static constexpr size_t content_length_limit = 16*MB;
    using alternator_callback = std::function<future<executor::request_return_type>(executor&, executor::client_state&,
            tracing::trace_state_ptr, service_permit, rjson::value, std::unique_ptr<http::request>)>;
    using alternator_callbacks_map = std::unordered_map<std::string_view, alternator_callback>;

    httpd::http_server _http_server;
    httpd::http_server _https_server;
    executor& _executor;
    service::storage_proxy& _proxy;
    gms::gossiper& _gossiper;
    auth::service& _auth_service;
    qos::service_level_controller& _sl_controller;

    key_cache _key_cache;
    bool _enforce_authorization;
    utils::small_vector<std::reference_wrapper<seastar::httpd::http_server>, 2> _enabled_servers;
    gate _pending_requests;
    // In some places we will need a CQL updateable_timeout_config object even
    // though it isn't really relevant for Alternator which defines its own
    // timeouts separately. We can create this object only once.
    updateable_timeout_config _timeout_config;

    alternator_callbacks_map _callbacks;

    semaphore* _memory_limiter;
    utils::updateable_value<uint32_t> _max_concurrent_requests;

    class json_parser {
        static constexpr size_t yieldable_parsing_threshold = 16*KB;
        chunked_content _raw_document;
        rjson::value _parsed_document;
        std::exception_ptr _current_exception;
        semaphore _parsing_sem{1};
        condition_variable _document_waiting;
        condition_variable _document_parsed;
        abort_source _as;
        future<> _run_parse_json_thread;
    public:
        json_parser();
        // Moving a chunked_content into parse() allows parse() to free each
        // chunk as soon as it is parsed, so when chunks are relatively small,
        // we don't need to store the sum of unparsed and parsed sizes.
        future<rjson::value> parse(chunked_content&& content);
        future<> stop();
    };
    json_parser _json_parser;

public:
    server(executor& executor, service::storage_proxy& proxy, gms::gossiper& gossiper, auth::service& service, qos::service_level_controller& sl_controller);

    future<> init(net::inet_address addr, std::optional<uint16_t> port, std::optional<uint16_t> https_port, std::optional<tls::credentials_builder> creds,
            bool enforce_authorization, semaphore* memory_limiter, utils::updateable_value<uint32_t> max_concurrent_requests);
    future<> stop();
private:
    void set_routes(seastar::httpd::routes& r);
    // If verification succeeds, returns the authenticated user's username
    future<std::string> verify_signature(const seastar::http::request&, const chunked_content&);
    future<executor::request_return_type> handle_api_request(std::unique_ptr<http::request> req);
};

}