//SPDX-License-Identifier: LGPL-3.0-only
//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®

// A server is only as good as its worst peer. This drives ListenerHTTP1
// with many concurrent clients and then with peers that behave badly —
// vanishing mid-request, sending garbage, opening and dropping connections,
// stalling forever — and requires that it keeps serving correctly
// throughout and still shuts down promptly at the end.

import Crafter.Network;
import std;
using namespace Crafter;

namespace {
    std::atomic<int> failures{0};

    void Check(bool condition, std::string_view what) {
        if (!condition) {
            std::println("FAIL: {}", what);
            failures.fetch_add(1);
        }
    }

    constexpr std::uint16_t port = 8095;

    // Raw socket, no HTTP client in the way, so the test can send things a
    // well-behaved client never would.
    void SendRaw(std::string_view bytes, bool waitForReply) {
        ClientTCP socket("localhost", port);
        if (!bytes.empty()) socket.Send(bytes.data(), static_cast<std::uint32_t>(bytes.size()));
        if (waitForReply) {
            try {
                (void)socket.RecieveSync();
            } catch (const std::exception&) {
                // A dropped connection is an acceptable answer to nonsense.
            }
        }
    }
}

int main() {
    std::unordered_map<std::string, std::function<HTTPResponse(const HTTPRequest&)>> routes;
    routes["/work"] = [](const HTTPRequest& request) {
        return CreateResponseHTTP("200", request.body.empty() ? std::string("empty") : request.body);
    };

    try {
        ListenerAsyncHTTP1 listener(port, std::move(routes));
        // Keep the stalled-peer case quick; the defaults are measured in
        // tens of seconds, which is right for a real server and wrong for a
        // test.
        listener.listener.requestTimeout = std::chrono::milliseconds(300);
        listener.listener.keepAliveTimeout = std::chrono::milliseconds(500);

        // ── Many clients at once, each reusing its own connection ──────
        constexpr int clientCount = 24;
        constexpr int requestsPerClient = 8;
        std::atomic<int> completed{0};
        std::vector<std::thread> clients;
        for (int i = 0; i < clientCount; ++i) {
            clients.emplace_back([i, &completed] {
                try {
                    ClientHTTP1 client("localhost", port);
                    for (int request = 0; request < requestsPerClient; ++request) {
                        const std::string payload = std::format("client-{}-request-{}", i, request);
                        HTTPResponse response = client.Send(
                            CreateRequestHTTP("POST", "/work", "localhost", payload));
                        Check(response.status == "200", "concurrent request status");
                        Check(response.body == payload, "concurrent request body matches its sender");
                        completed.fetch_add(1);
                    }
                } catch (const std::exception& error) {
                    std::println("client threw: {}", error.what());
                    failures.fetch_add(1);
                }
            });
        }
        for (auto& client : clients) client.join();
        Check(completed.load() == clientCount * requestsPerClient, "every concurrent request finished");
        Check(listener.listener.AcceptedCount() == clientCount,
              "each client used exactly one connection");

        // ── Peers that misbehave ──────────────────────────────────────
        SendRaw("", false);                                     // connect, say nothing, leave
        SendRaw("GET /work HTTP/1.1\r\nHost: x\r\n", false);     // headers cut short
        SendRaw("POST /work HTTP/1.1\r\nHost: x\r\nContent-Length: 100\r\n\r\nshort", false);
        SendRaw("not http at all\r\n\r\n", true);                // garbage start line
        SendRaw("GET / HTTP/1.1\r\nHost : x\r\n\r\n", true);     // smuggling-shaped header
        SendRaw(std::string("GET /") + std::string(16 * 1024, 'z') + " HTTP/1.1\r\n\r\n", true);

        // A peer that opens a request and then just sits there must be cut
        // loose by the request timeout rather than holding its thread.
        {
            ClientTCP stalled("localhost", port);
            const std::string partial = "POST /work HTTP/1.1\r\nHost: x\r\nContent-Length: 10\r\n\r\nab";
            stalled.Send(partial.data(), static_cast<std::uint32_t>(partial.size()));
            const auto start = std::chrono::steady_clock::now();
            try {
                (void)stalled.RecieveUntilCloseSync();
            } catch (const std::exception&) {}
            const auto elapsed = std::chrono::steady_clock::now() - start;
            Check(elapsed < std::chrono::seconds(5), "a stalled peer is timed out, not waited on");
        }

        // ── Still healthy afterwards ──────────────────────────────────
        ClientHTTP1 client("localhost", port);
        HTTPResponse response = client.Send(CreateRequestHTTP("POST", "/work", "localhost",
                                                              std::string("still here")));
        Check(response.status == "200", "the server survived the abuse");
        Check(response.body == "still here", "and still answers correctly");

        // Shutdown has to finish quickly even with connections open.
        const auto start = std::chrono::steady_clock::now();
        listener.Stop();
        const auto elapsed = std::chrono::steady_clock::now() - start;
        Check(elapsed < std::chrono::seconds(5), "Stop() returns promptly with a connection still open");
    } catch (const std::exception& error) {
        std::println("threw: {}", error.what());
        return 1;
    }

    if (failures.load() != 0) {
        std::println("{} check(s) failed", failures.load());
        return 1;
    }
    return 0;
}