// webchat.c - A basic TCP server with INET and Unix socket support
// Compile: gcc -std=c99 -o webchat webchat.c
// Usage: ./webchat -p 8080  or  ./webchat -u /tmp/mysocket

#include <arpa/inet.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <openssl/sha.h>
#include <openssl/hmac.h>
#include <openssl/crypto.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/epoll.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/uio.h>
#include <sys/un.h>
#include <time.h>
#include <unistd.h>

#include "config.h"

#include "util/defs.h"
#include "util/arenastr.c"
#include "util/strmanip.c"

#define DEFAULT_DB "fanr.sqlite"

enum{
  listen_backlog=10,
  bwt_expiry_time_secs = 60 * 60,
  quieter_logs = true,
};

static int srv_close_and_fail(int sock){
  close(sock);
  return -1;
}

static int create_inet_socket(int port) {
  int sock = socket(AF_INET, SOCK_STREAM, 0);
  if (sock < 0) {
    perror("socket");
    return -1;
  }

  int opt = 1;
  if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) < 0) {
    perror("setsockopt");
    return srv_close_and_fail(sock);
  }

  struct sockaddr_in addr = {0};
  addr.sin_family = AF_INET;
  addr.sin_addr.s_addr = INADDR_ANY;
  addr.sin_port = htons(port);

  if (bind(sock, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
    perror("bind");
    return srv_close_and_fail(sock);
  }

  if (listen(sock, listen_backlog) < 0) {
    perror("listen");
    return srv_close_and_fail(sock);
  }

  log("Listening on TCP port %d (fd:%d)\n", port, sock);
  return sock;
}

static int create_unix_socket(str path) {
  MAKE_ARENA(a, 256);

  char *path_cstr = str_to_cstr(&a, path);
  if (!path_cstr) {
    fprintf(stderr, "Failed to convert path to C string\n");
    return -1;
  }

  // Unlink existing socket file
  unlink(path_cstr);

  int sock = socket(AF_UNIX, SOCK_STREAM, 0);
  if (sock < 0) {
    perror("socket");
    return -1;
  }

  struct sockaddr_un addr = {0};
  addr.sun_family = AF_UNIX;
  strncpy(addr.sun_path, path_cstr, sizeof(addr.sun_path) - 1);

  if (bind(sock, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
    perror("bind");
    return srv_close_and_fail(sock);
  }

  // Set permissions
  if (chmod(path_cstr, 0777) < 0) {
    perror("chmod");
    return srv_close_and_fail(sock);
  }

  if (listen(sock, listen_backlog) < 0) {
    perror("listen");
    return srv_close_and_fail(sock);
  }

  log("Listening on Unix socket: %s (fd:%d)\n", path_cstr, sock);
  return sock;
}

static void print_usage(const char *prog) {
  fprintf(stderr,
    "fanr webchat server\n"
    "usage: %s [options]\n"
    "options:\n"
    "  -p <port>      TCP port to listen on\n"
    "  -u <path>      Unix socket path (overrides -p)\n"
    "  -d <path>      SQLite database path (default: fanr.sqlite)\n"
    "  -h, --help     Show this help\n"
    "examples:\n"
    "  %s -p 12345\n"
    "  %s -u /tmp/webchat.sock\n"
    "  %s -p 8080 -d /var/lib/webchat/chat.db\n",
    prog, prog, prog, prog);
}

#include "util/rw.c"
#include "util/monotime.c"
#include "util/blisp_parser.c"
#include "util/b64.c"
#include "util/passwordhash.c"
#include "util/bwt.c"
#include "util/ulid.c"
#include "util/dbapi.c"
#include "util/httpmulti.c"
#include "wssys.c"
#include "secret.key"

#include "client.c"
#include "http.c"
#include "netloop.c"

typedef struct cliargs cliargs;
struct cliargs{
  char const *port_str;
  char const *usock_path;
  char const *db_name;
};

static cliargs parse_argv(int argc, char *argv[]){
  cliargs a = {.db_name=DEFAULT_DB};

  for (int i = 1; i < argc; i++) {
    if (strcmp(argv[i], "-p") == 0 && i + 1 < argc) {
      a.port_str = argv[++i];
    } else if (strcmp(argv[i], "-u") == 0 && i + 1 < argc) {
      a.usock_path = argv[++i];
    } else if (strcmp(argv[i], "-d") == 0 && i + 1 < argc) {
      a.db_name = argv[++i];
    } else if (strcmp(argv[i], "-h") == 0 || strcmp(argv[i], "--help") == 0) {
      print_usage(argv[0]);
      exit(0);
    } else {
      fprintf(stderr, "Unknown option: %s\n", argv[i]);
      print_usage(argv[0]);
      exit(1);
    }
  }

  if (!a.port_str && !a.usock_path) {
    fprintf(stderr, "Error: Either -p or -u is required\n");
    print_usage(argv[0]);
    exit(1);
  }

  return a;
}

int main(int argc, char *argv[]) {
  signal(SIGPIPE, SIG_IGN);
  cliargs args = parse_argv(argc, argv);
  log("Web Chat server starting. (database: %s)\n", args.db_name);

  init_realtime_monotonic_offset();

  int listen_fd = -1;
  if (args.usock_path) {
    str path = str_from_cstr(args.usock_path);
    if (path.len == 0) {
      fprintf(stderr, "Invalid path\n");
      return 1;
    }
    listen_fd = create_unix_socket(path);
  } else if (args.port_str) {
    int port = atoi(args.port_str);
    if (port <= 0 || port > 65535) {
      fprintf(stderr, "Invalid port: %s\n", args.port_str);
      return 1;
    }
    listen_fd = create_inet_socket(port);
  }
  if (listen_fd < 0) diesys("failed to create listening socket");

  unless(db_init(args.db_name)) diesys("Failed to initialise database [%s] [err: %s]", args.db_name, db_errmsg());

  event_loop(listen_fd);

  close(listen_fd);
  db_close();
  return 0;
}