#include "config.hpp"
#include "connection.hpp"
#include "connection_handler.hpp"
#include "http_handler.hpp"
#include "perfetto_categories.hpp"
#include "server.hpp"
#include <atomic>
#include <csignal>
#include <fcntl.h>
#include <iostream>
#include <netdb.h>
#include <netinet/tcp.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#include <vector>

PERFETTO_TRACK_EVENT_STATIC_STORAGE();

// Global server instance for signal handler access
static Server *g_server = nullptr;

void signal_handler(int sig) {
  if (sig == SIGTERM || sig == SIGINT) {
    if (g_server) {
      g_server->shutdown();
    }
  }
}

std::vector<int> create_listen_sockets(const weaseldb::Config &config) {
  std::vector<int> listen_fds;

  // Check if unix socket path is specified
  if (!config.server.unix_socket_path.empty()) {
    // Create unix socket
    int sfd = socket(AF_UNIX, SOCK_STREAM, 0);
    if (sfd == -1) {
      perror("socket");
      throw std::runtime_error("Failed to create unix socket");
    }

    // Remove existing socket file if it exists
    unlink(config.server.unix_socket_path.c_str());

    struct sockaddr_un addr;
    memset(&addr, 0, sizeof(addr));
    addr.sun_family = AF_UNIX;

    if (config.server.unix_socket_path.length() >= sizeof(addr.sun_path)) {
      close(sfd);
      throw std::runtime_error("Unix socket path too long");
    }

    strncpy(addr.sun_path, config.server.unix_socket_path.c_str(),
            sizeof(addr.sun_path) - 1);

    if (bind(sfd, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
      perror("bind");
      close(sfd);
      throw std::runtime_error("Failed to bind unix socket");
    }

    if (listen(sfd, SOMAXCONN) == -1) {
      perror("listen");
      close(sfd);
      throw std::runtime_error("Failed to listen on unix socket");
    }

    listen_fds.push_back(sfd);
    return listen_fds;
  }

  // TCP socket creation
  struct addrinfo hints;
  struct addrinfo *result, *rp;
  int s;

  memset(&hints, 0, sizeof(hints));
  hints.ai_family = AF_UNSPEC;     /* Allow IPv4 or IPv6 */
  hints.ai_socktype = SOCK_STREAM; /* stream socket */
  hints.ai_flags = AI_PASSIVE;     /* For wildcard IP address */
  hints.ai_protocol = 0;           /* Any protocol */
  hints.ai_canonname = nullptr;
  hints.ai_addr = nullptr;
  hints.ai_next = nullptr;

  s = getaddrinfo(config.server.bind_address.c_str(),
                  std::to_string(config.server.port).c_str(), &hints, &result);
  if (s != 0) {
    fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(s));
    throw std::runtime_error("Failed to resolve bind address");
  }

  int sfd = -1;
  for (rp = result; rp != nullptr; rp = rp->ai_next) {
    sfd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
    if (sfd == -1) {
      continue;
    }

    int val = 1;
    if (setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val)) == -1) {
      perror("setsockopt SO_REUSEADDR");
      close(sfd);
      continue;
    }

    // Enable TCP_NODELAY for low latency (only for TCP sockets)
    if (rp->ai_family == AF_INET || rp->ai_family == AF_INET6) {
      if (setsockopt(sfd, IPPROTO_TCP, TCP_NODELAY, &val, sizeof(val)) == -1) {
        perror("setsockopt TCP_NODELAY");
        close(sfd);
        continue;
      }
    }

    if (bind(sfd, rp->ai_addr, rp->ai_addrlen) == 0) {
      break; /* Success */
    }

    close(sfd);
    sfd = -1;
  }

  freeaddrinfo(result);

  if (rp == nullptr || sfd == -1) {
    throw std::runtime_error("Could not bind to any address");
  }

  if (listen(sfd, SOMAXCONN) == -1) {
    perror("listen");
    close(sfd);
    throw std::runtime_error("Failed to listen on socket");
  }

  listen_fds.push_back(sfd);
  return listen_fds;
}

void print_help(const char *program_name) {
  std::cout << "WeaselDB - High-performance write-side database component\n\n";
  std::cout << "Usage: " << program_name << " [OPTIONS]\n\n";
  std::cout << "Options:\n";
  std::cout << "  --config <file>    Path to TOML configuration file (default: "
               "config.toml)\n";
  std::cout << "  --help             Show this help message and exit\n";
  std::cout << "  -h                 Show this help message and exit\n\n";
  std::cout << "Examples:\n";
  std::cout << "  " << program_name
            << "                    # Use default config.toml\n";
  std::cout << "  " << program_name
            << " --config my.toml   # Use custom config file\n";
  std::cout << "  " << program_name
            << " --help             # Show this help\n\n";
  std::cout << "For configuration documentation, see config.md\n";
}

int main(int argc, char *argv[]) {
#if ENABLE_PERFETTO
  perfetto::TracingInitArgs args;
  args.backends |= perfetto::kSystemBackend;
  perfetto::Tracing::Initialize(args);
  perfetto::TrackEvent::Register();
#endif

  std::string config_file = "config.toml";

  // Parse command line arguments
  for (int i = 1; i < argc; i++) {
    std::string arg = argv[i];

    if (arg == "--help" || arg == "-h") {
      print_help(argv[0]);
      return 0;
    } else if (arg == "--config") {
      if (i + 1 >= argc) {
        std::cerr << "Error: --config requires a filename argument\n";
        print_help(argv[0]);
        return 1;
      }
      config_file = argv[++i];
    } else if (arg.starts_with("--config=")) {
      config_file = arg.substr(9);
    } else {
      // For backward compatibility, treat lone argument as config file
      if (argc == 2) {
        config_file = arg;
      } else {
        std::cerr << "Error: Unknown argument '" << arg << "'\n";
        print_help(argv[0]);
        return 1;
      }
    }
  }

  auto config = weaseldb::ConfigParser::load_from_file(config_file);

  if (!config) {
    std::cerr << "Failed to load config from: " << config_file << std::endl;
    std::cerr << "Using default configuration..." << std::endl;
    config = weaseldb::Config{};
  }

  std::cout << "Configuration loaded successfully:" << std::endl;
  if (!config->server.unix_socket_path.empty()) {
    std::cout << "Unix socket path: " << config->server.unix_socket_path
              << std::endl;
  } else {
    std::cout << "Server bind address: " << config->server.bind_address
              << std::endl;
    std::cout << "Server port: " << config->server.port << std::endl;
  }
  std::cout << "Max request size: " << config->server.max_request_size_bytes
            << " bytes" << std::endl;
  std::cout << "I/O threads: " << config->server.io_threads << std::endl;
  std::cout << "Epoll instances: " << config->server.epoll_instances
            << std::endl;
  std::cout << "Event batch size: " << config->server.event_batch_size
            << std::endl;
  std::cout << "Max connections: " << config->server.max_connections
            << std::endl;
  std::cout << "Read buffer size: " << config->server.read_buffer_size
            << " bytes" << std::endl;
  std::cout << "Min request ID length: " << config->commit.min_request_id_length
            << std::endl;
  std::cout << "Request ID retention: "
            << config->commit.request_id_retention_hours.count() << " hours"
            << std::endl;
  std::cout << "Subscription buffer size: "
            << config->subscription.max_buffer_size_bytes << " bytes"
            << std::endl;
  std::cout << "Keepalive interval: "
            << config->subscription.keepalive_interval.count() << " seconds"
            << std::endl;

  // Create listen sockets
  std::vector<int> listen_fds;
  try {
    listen_fds = create_listen_sockets(*config);
  } catch (const std::exception &e) {
    std::cerr << "Failed to create listen sockets: " << e.what() << std::endl;
    return 1;
  }

  // Create handler and server
  HttpHandler http_handler;
  auto server = Server::create(*config, http_handler, listen_fds);
  g_server = server.get();

  // Setup signal handling
  signal(SIGPIPE, SIG_IGN);
  signal(SIGTERM, signal_handler);
  signal(SIGINT, signal_handler);

  std::cout << "Starting WeaselDB HTTP server..." << std::endl;
  server->run();
  std::cout << "Server shutdown complete." << std::endl;

  return 0;
}