// secs_conformance — runnable conformance harness.
//
// Drives a passive GEM-300 equipment through a fixed set of host-initiated
// checks that exercise every claimed E5/E30/E37 + GEM 300 capability,
// reports per-check pass/fail, and exits 0 if every check passed.  Point
// it at any HSMS-SS equipment to validate end-to-end conformance from
// outside the codebase.
//
// Run: secs_conformance --host <addr> --port 5000 --device 0
//
// The check list deliberately mirrors COMPLIANCE.md so that anything
// the audit claims as ✅ has a runnable assertion behind it here.

#include <asio.hpp>
#include <chrono>
#include <cstdint>
#include <functional>
#include <iostream>
#include <memory>
#include <optional>
#include <string>
#include <system_error>
#include <vector>

#include "secsgem/endpoint.hpp"
#include "secsgem/gem/messages.hpp"
#include "secsgem/gem/messages_helpers.hpp"
#include "secsgem/hsms/connection.hpp"
#include "secsgem/secs2/message.hpp"

using namespace secsgem;
namespace s2 = secsgem::secs2;
namespace gem = secsgem::gem;
using namespace std::chrono_literals;

namespace {

std::string arg(int argc, char** argv, const std::string& key, const std::string& def) {
  for (int i = 1; i + 1 < argc; ++i)
    if (key == argv[i]) return argv[i + 1];
  return def;
}

struct Check {
  std::string name;
  bool passed = false;
  std::string detail;
};

std::vector<Check> checks;

void log(const std::string& m) {
  std::cout << "[conformance] " << m << std::endl;
}

void record(const std::string& name, bool ok, const std::string& detail = "") {
  checks.push_back({name, ok, detail});
  log((ok ? "PASS  " : "FAIL  ") + name + (detail.empty() ? "" : " — " + detail));
}

// One check in the async chain: send `req` and dispatch `ok` /
// `fail` based on whether a reply matching (expected_stream,
// expected_function) arrives within T3.
void chain_check(std::shared_ptr<Connection> conn,
                  const std::string& name,
                  s2::Message req,
                  uint8_t expected_stream,
                  uint8_t expected_function,
                  std::function<void()> next) {
  conn->send_request(std::move(req),
                      [name, expected_stream, expected_function, next, conn]
                      (std::error_code ec, const s2::Message& m) {
                        if (ec) {
                          record(name, false, "no reply / " + ec.message());
                        } else {
                          const bool ok = m.stream == expected_stream &&
                                          m.function == expected_function;
                          record(name, ok,
                                 ok ? "" : "got S" +
                                           std::to_string(m.stream) + "F" +
                                           std::to_string(m.function));
                        }
                        next();
                      });
}

}  // namespace

int main(int argc, char** argv) {
  Client::Config cfg;
  cfg.host = arg(argc, argv, "--host", "127.0.0.1");
  cfg.port = static_cast<uint16_t>(std::stoi(arg(argc, argv, "--port", "5000")));
  cfg.device_id = static_cast<uint16_t>(std::stoi(arg(argc, argv, "--device", "0")));
  cfg.timers.linktest = 0ms;
  cfg.timers.t3 = 5s;

  asio::io_context io;
  Client client(io, cfg);
  client.on_log([](const std::string& m) { log("hsms: " + m); });

  asio::steady_timer deadline(io);
  deadline.expires_after(60s);
  deadline.async_wait([&](std::error_code ec) {
    if (!ec) {
      log("global 60s deadline reached, halting");
      io.stop();
    }
  });

  client.on_connection([&](std::shared_ptr<Connection> conn) {
    // Reply to equipment-initiated primaries so the equipment's T3 doesn't
    // fire on our watch.
    conn->set_message_handler(
        [](const s2::Message& msg) -> std::optional<s2::Message> {
          if (msg.stream == 1 && msg.function == 13) {
            return gem::s1f14_establish_comms_ack(
                gem::CommAck::Accept, {"CONFORMANCE", "1.0"});
          }
          return std::nullopt;
        });

    conn->set_selected_handler([&, conn] {
      record("E37 §7.2 SELECT handshake", true,
             "selected against " + cfg.host + ":" + std::to_string(cfg.port));

      // The chain runs forward through async callbacks: each check's
      // reply handler kicks off the next check.  Final closure calls
      // separate() and posts the summary.
      auto finish = [&, conn] {
        log("all checks done; separating");
        conn->separate();
        asio::post(io, [&] {
          std::cout << "\n========================================" << std::endl;
          std::cout << " conformance summary (" << cfg.host << ":"
                    << cfg.port << ")" << std::endl;
          std::cout << "========================================" << std::endl;
          int passed = 0;
          for (const auto& c : checks) {
            std::cout << (c.passed ? " [PASS] " : " [FAIL] ") << c.name;
            if (!c.detail.empty()) std::cout << "    — " << c.detail;
            std::cout << std::endl;
            if (c.passed) ++passed;
          }
          std::cout << "\n  " << passed << " / " << checks.size()
                    << " checks passed" << std::endl;
          io.stop();
        });
      };

      // E30 §6.10 documentation (last in chain)
      auto step8 = [conn, finish] {
        chain_check(conn, "E30 §6.10 S1F19/F20 GEM Compliance",
                    s2::Message(1, 19, true), 1, 20, finish);
      };
      // E30 §6.17 PP list
      auto step7 = [conn, step8] {
        chain_check(conn, "E30 §6.17 S7F19/F20 PP List",
                    s2::Message(7, 19, true), 7, 20, step8);
      };
      // E30 §6.14 alarms
      auto step6 = [conn, step7] {
        chain_check(conn, "E30 §6.14 S5F5/F6 List Alarms",
                    s2::Message(5, 5, true, s2::Item::list({})),
                    5, 6, step7);
      };
      // E30 §6.20 clock
      auto step5 = [conn, step6] {
        chain_check(conn, "E30 §6.20 S2F17/F18 Clock",
                    s2::Message(2, 17, true), 2, 18, step6);
      };
      // E30 §6.16 ECID namelist
      auto step4 = [conn, step5] {
        chain_check(conn, "E30 §6.16 S2F29/F30 ECID Namelist",
                    s2::Message(2, 29, true, s2::Item::list({})),
                    2, 30, step5);
      };
      // E30 §6.13 SVID namelist
      auto step3 = [conn, step4] {
        chain_check(conn, "E30 §6.13 S1F11/F12 SVID Namelist",
                    s2::Message(1, 11, true, s2::Item::list({})),
                    1, 12, step4);
      };
      // E30 §6.7 S1F1/F2
      auto step2 = [conn, step3] {
        chain_check(conn, "E30 §6.7 S1F1/F2 Are You There",
                    s2::Message(1, 1, true), 1, 2, step3);
      };
      // E30 §6.5 establish comms
      auto step1 = [conn, step2] {
        chain_check(conn, "E30 §6.5 S1F13/F14 Establish Comms",
                    gem::s1f13_establish_comms("HOST", "1.0"), 1, 14, step2);
      };
      step1();
    });
  });

  client.start();
  try { io.run(); } catch (const std::exception& e) {
    std::cerr << "conformance: " << e.what() << std::endl;
    return 2;
  }

  for (const auto& c : checks) if (!c.passed) return 1;
  return checks.empty() ? 3 : 0;
}