#include <boost/asio/redirect_error.hpp>
#include <boost/asio/use_awaitable.hpp>
#include <ranczo-io/utils/http.hpp>

#include <boost/asio/ssl.hpp>
#include <boost/beast/core.hpp>
#include <boost/beast/http.hpp>
#include <boost/beast/ssl.hpp>
#include <boost/url.hpp>

#include <string_view>

namespace ranczo {

using tcp       = boost::asio::ip::tcp;
namespace asio  = boost::asio;
namespace beast = boost::beast;
namespace http  = beast::http;

using PmrCharAlloc  = std::pmr::polymorphic_allocator< char >;
using PmrFields     = http::basic_fields< PmrCharAlloc >;
using PmrStringBody = http::basic_string_body< char, std::char_traits< char >, PmrCharAlloc >;
using PmrFlatBuffer = boost::beast::basic_flat_buffer< PmrCharAlloc >;
using PmrResponse   = http::response< PmrStringBody, PmrFields >;
using PmrRequest    = http::request< PmrStringBody, PmrFields >;

expected< HttpGetClient::ParsedUrl > HttpGetClient::parse_url_generic(std::string_view url) {
    ParsedUrl out;
    namespace urls = boost::urls;

    auto r = urls::parse_uri(url);
    if(!r) {
        return unexpected(r.error());
    }

    urls::url_view u = *r;

    out.scheme = std::string(u.scheme());
    out.host   = std::string(u.host());

    // ścieżka
    out.target = std::string(u.encoded_path());
    if(out.target.empty())
        out.target = "/";

    // query (bez fragmentu)
    if(!u.encoded_query().empty()) {
        out.target += "?";
        out.target += std::string(u.encoded_query());
    }

    // port
    if(!u.port().empty()) {
        out.port = u.port_number();
    } else {
        if(out.scheme == "https")
            out.port = 443;
        else
            out.port = 80;
    }

    out.use_ssl = (out.scheme == "https");

    return out;
}

awaitable_expected< std::pmr::string > HttpGetClient::async_get(std::string_view url, std::pmr::memory_resource * mr) {
    BOOST_ASSERT(mr);
    namespace ssl = boost::asio::ssl;

    PmrCharAlloc alloc{mr};

    // 1. Parse URL
    auto parsed_exp = parse_url_generic(url);
    if(!parsed_exp) {
        co_return unexpected(parsed_exp.error());
    }
    auto parsed = *parsed_exp;

    beast::error_code ec;

    // 2. Resolver
    tcp::resolver resolver{executor()};
    auto results = co_await resolver.async_resolve(parsed.host, std::to_string(parsed.port), asio::redirect_error(asio::use_awaitable, ec));
    if(ec) {
        co_return unexpected(ec);
    }

    // 3. Request na PMR
    http::request< PmrStringBody, PmrFields > req{http::verb::get, parsed.target, 11, PmrStringBody::value_type{alloc}, PmrFields{alloc}};
    req.set(http::field::host, parsed.host);
    req.set(http::field::user_agent, "ranczo-http-client");

    // 4. Wspólne rzeczy dla HTTP/HTTPS
    PmrFlatBuffer buffer{alloc};
    PmrResponse res{std::piecewise_construct, std::make_tuple(PmrStringBody::value_type{alloc}), std::make_tuple(PmrFields{alloc})};

    if(!parsed.use_ssl) {
        // ---------------------- HTTP (bez TLS) ----------------------
        beast::tcp_stream stream{executor()};
        stream.expires_after(_timeout);

        co_await stream.async_connect(results, asio::redirect_error(asio::use_awaitable, ec));
        if(ec) {
            co_return unexpected(ec);
        }

        co_await http::async_write(stream, req, asio::redirect_error(asio::use_awaitable, ec));
        if(ec) {
            co_return unexpected(ec);
        }

        co_await http::async_read(stream, buffer, res, asio::redirect_error(asio::use_awaitable, ec));
        if(ec) {
            co_return unexpected(ec);
        }

        stream.socket().shutdown(tcp::socket::shutdown_both, ec);
        // błąd przy shutdown zwykle ignorujemy
    } else {
        // ---------------------- HTTPS (TLS) ----------------------
        ssl::context ctx{ssl::context::tls_client};

        // Uwaga: do prawdziwego użycia:
        //  - ctx.set_default_verify_paths();
        //  - ctx.set_verify_mode(ssl::verify_peer);
        // Tu dla testów najprościej wyłączyć weryfikację:
        ctx.set_verify_mode(ssl::verify_none);

        beast::ssl_stream< beast::tcp_stream > stream{executor_, ctx};

        auto & lowest = beast::get_lowest_layer(stream);
        lowest.expires_after(_timeout);

        co_await lowest.async_connect(results, asio::redirect_error(asio::use_awaitable, ec));
        if(ec) {
            co_return unexpected(ec);
        }

        // (opcjonalnie) SNI – przydatne dla częsci serwerów
        if(!SSL_set_tlsext_host_name(stream.native_handle(), parsed.host.c_str())) {
            ec = beast::error_code(static_cast< int >(::ERR_get_error()), asio::error::get_ssl_category());
            co_return unexpected(ec);
        }

        co_await stream.async_handshake(ssl::stream_base::client, asio::redirect_error(asio::use_awaitable, ec));
        if(ec) {
            co_return unexpected(ec);
        }

        co_await http::async_write(stream, req, asio::redirect_error(asio::use_awaitable, ec));
        if(ec) {
            co_return unexpected(ec);
        }

        co_await http::async_read(stream, buffer, res, asio::redirect_error(asio::use_awaitable, ec));
        if(ec) {
            co_return unexpected(ec);
        }

        // shutdown TLS
        co_await stream.async_shutdown(asio::redirect_error(asio::use_awaitable, ec));
        // tu też często dostaniesz EOF – można zignorować
    }

    // Opcjonalnie możesz sprawdzić status:
    // if (res.result() != http::status::ok) { ... }

    // Body korzysta z tego samego PMR
    std::pmr::string body{alloc};
    body = res.body(); // kopia na tym samym allocatorze (bez dużych kosztów w mr)

    co_return body;
}

} // namespace ranczo