#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>
#include <nginx.h>


static void ngx_worker_process_cycle(ngx_cycle_t *cycle, void *data);
static ngx_int_t ngx_add_inherited_sockets(ngx_cycle_t *cycle, char **envp);
static void ngx_exec_new_binary(ngx_cycle_t *cycle, char *const *argv);
static ngx_int_t ngx_core_module_init(ngx_cycle_t *cycle);


typedef struct {
     ngx_str_t  user;
     int        daemon;
     int        single;
     ngx_str_t  pid;
} ngx_core_conf_t;


static ngx_str_t  core_name = ngx_string("core");

static ngx_command_t  ngx_core_commands[] = {

    { ngx_string("user"),
      NGX_MAIN_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_core_str_slot,
      0,
      offsetof(ngx_core_conf_t, user),
      NULL },

    { ngx_string("daemon"),
      NGX_MAIN_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_core_flag_slot,
      0,
      offsetof(ngx_core_conf_t, daemon),
      NULL },

    { ngx_string("single_process"),
      NGX_MAIN_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_core_flag_slot,
      0,
      offsetof(ngx_core_conf_t, single),
      NULL },

      ngx_null_command
};


ngx_module_t  ngx_core_module = {
    NGX_MODULE,
    &core_name,                            /* module context */
    ngx_core_commands,                     /* module directives */
    NGX_CORE_MODULE,                       /* module type */
    ngx_core_module_init,                  /* init module */
    NULL                                   /* init child */
};


ngx_int_t              ngx_max_module;


/* STUB */
uid_t      user;

u_int ngx_connection_counter;

ngx_int_t  ngx_master;
ngx_int_t  ngx_single;


ngx_int_t  ngx_respawn;
ngx_int_t  ngx_terminate;
ngx_int_t  ngx_quit;
ngx_int_t  ngx_reconfigure;
ngx_int_t  ngx_reopen;
ngx_int_t  ngx_change_binary;


int main(int argc, char *const *argv, char **envp)
{
    struct timeval     tv;
    ngx_fd_t           fd;
    ngx_int_t          i;
    ngx_err_t          err;
    ngx_log_t         *log;
    ngx_cycle_t       *cycle, init_cycle;
    ngx_open_file_t   *file;
    ngx_core_conf_t   *ccf;
#if !(WIN32)
    size_t             len;
    char               pid[/* STUB */ 10];
    ngx_file_t         pidfile;
    struct passwd     *pwd;
#endif

#if __FreeBSD__
    ngx_debug_init();
#endif

    /* TODO */ ngx_max_sockets = -1;

    ngx_time_init();
#if (HAVE_PCRE)
    ngx_regex_init();
#endif

    log = ngx_log_init_errlog();

    /* init_cycle->log is required for signal handlers */

    ngx_memzero(&init_cycle, sizeof(ngx_cycle_t));
    init_cycle.log = log;
    ngx_cycle = &init_cycle;

    if (ngx_os_init(log) == NGX_ERROR) {
        return 1;
    }

    ngx_max_module = 0;
    for (i = 0; ngx_modules[i]; i++) {
        ngx_modules[i]->index = ngx_max_module++;
    }

    if (!(init_cycle.pool = ngx_create_pool(1024, log))) {
        return 1;
    }

    if (ngx_add_inherited_sockets(&init_cycle, envp) == NGX_ERROR) {
        return 1;
    }

    cycle = ngx_init_cycle(&init_cycle);
    if (cycle == NULL) {
        return 1;
    }

    ngx_cycle = cycle;

    ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);

    if (ccf->single == 1) {
        ngx_master = 0;
        ngx_single = 1;

    } else {
        ngx_master = 1;
        ngx_single = 0;
    }

#if !(WIN32)

    /* STUB */
    if (ccf->user.len) {
        pwd = getpwnam(ccf->user.data);
        if (pwd == NULL) {
            ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                          "getpwnam(%s) failed", ccf->user);
            return 1;
        }

        user = pwd->pw_uid;
    }
    /* */

    if (ccf->daemon != 0) {
        if (ngx_daemon(cycle->log) == NGX_ERROR) {
            return 1;
        }
    }

    if (dup2(cycle->log->file->fd, STDERR_FILENO) == -1) {
        ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                      "dup2(STDERR) failed");
        return 1;
    }

    if (ccf->pid.len == 0) {
        ccf->pid.len = sizeof(NGINX_PID) - 1;
        ccf->pid.data = NGINX_PID;
    }

    len = ngx_snprintf(pid, /* STUB */ 10, PID_T_FMT, ngx_getpid());
    ngx_memzero(&pidfile, sizeof(ngx_file_t));
    pidfile.name = ccf->pid;

    pidfile.fd = ngx_open_file(pidfile.name.data, NGX_FILE_RDWR,
                               NGX_FILE_CREATE_OR_OPEN);

    if (pidfile.fd == NGX_INVALID_FILE) {
        ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                      ngx_open_file_n " \"%s\" failed", pidfile.name.data);
        return 1;
    }

    if (ngx_write_file(&pidfile, pid, len, 0) == NGX_ERROR) {
        return 1;
    }

    if (ngx_close_file(pidfile.fd) == NGX_FILE_ERROR) {
        ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
                      ngx_close_file_n " \"%s\" failed", pidfile.name.data);
    }

#endif

    /* a life cycle */

    for ( ;; ) {
        ngx_log_debug0(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "new cycle");

        if (ngx_master) {
            ngx_spawn_process(cycle, ngx_worker_process_cycle, NULL,
                              "worker process", NGX_PROCESS_RESPAWN);

        } else {
            ngx_init_temp_number();

            for (i = 0; ngx_modules[i]; i++) {
                if (ngx_modules[i]->init_process) {
                    if (ngx_modules[i]->init_process(cycle) == NGX_ERROR) {
                        /* fatal */
                        exit(1);
                    }
                }
            }
        }

#if 0
        reconfigure = 0;
        reopen = 0;
#endif

        /* a cycle with the same configuration */

        for ( ;; ) {

            /* an event loop */

            for ( ;; ) {

                err = 0;

                if (ngx_single) {
                    ngx_log_debug0(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                                   "worker cycle");

                    ngx_process_events(cycle->log);

                } else {
                    ngx_set_errno(0);
                    ngx_msleep(1000);
                    err = ngx_errno;

                    ngx_gettimeofday(&tv);
                    ngx_time_update(tv.tv_sec);

                    if (err) {
                        ngx_log_debug0(NGX_LOG_DEBUG_EVENT, cycle->log, err,
                                       "sleep() exited");
                    }
                }

                if (ngx_quit || ngx_terminate) {
#if !(WIN32)
                    if (ngx_delete_file(pidfile.name.data) == NGX_FILE_ERROR) {
                        ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
                                      ngx_delete_file_n " \"%s\" failed",
                                      pidfile.name.data);
                    }
#endif

                    ngx_log_error(NGX_LOG_INFO, cycle->log, 0, "exiting");

                    if (ngx_master) {
                        ngx_signal_processes(cycle,
                                        ngx_signal_value(NGX_SHUTDOWN_SIGNAL));

                        /* TODO: wait workers */

                        ngx_msleep(1000);

                        ngx_gettimeofday(&tv);
                        ngx_time_update(tv.tv_sec);
                    }

                    ngx_log_error(NGX_LOG_INFO, cycle->log, 0, "exit");
                    exit(0);
                }

                if (err == NGX_EINTR) {
                    ngx_respawn_processes(cycle);
                }

                if (ngx_change_binary) {
                    ngx_change_binary = 0;
                    ngx_log_error(NGX_LOG_INFO, cycle->log, 0,
                                  "changing binary");
                    ngx_exec_new_binary(cycle, argv);
                    /* TODO: quit workers */
                }

                if (ngx_reconfigure) {
                    ngx_log_error(NGX_LOG_INFO, cycle->log, 0, "reconfiguring");
                    break;
                }

                if (ngx_reopen) {
                    ngx_log_error(NGX_LOG_INFO, cycle->log, 0,
                                  "reopening logs");
                    ngx_reopen_files(cycle);
                    ngx_reopen = 0;
                }

            }

            cycle = ngx_init_cycle(cycle);
            if (cycle == NULL) {
                cycle = (ngx_cycle_t *) ngx_cycle;
                continue;
            }

            ngx_cycle = cycle;
            ngx_reconfigure = 0;
            break;
        }
    }
}


static void ngx_worker_process_cycle(ngx_cycle_t *cycle, void *data)
{
    ngx_int_t         i;
    ngx_listening_t  *ls;

    if (user) {
        if (setuid(user) == -1) {
            ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
                          "setuid() failed");
            /* fatal */
            exit(1);
        }
    }

    ngx_init_temp_number();

    /*
     * disable deleting previous events for the listening sockets because
     * in the worker processes there are no events at all at this point
     */ 
    ls = cycle->listening.elts;
    for (i = 0; i < cycle->listening.nelts; i++) {
        ls[i].remain = 0;
    }

    for (i = 0; ngx_modules[i]; i++) {
        if (ngx_modules[i]->init_process) {
            if (ngx_modules[i]->init_process(cycle) == NGX_ERROR) {
                /* fatal */
                exit(1);
            }
        }
    }

    /* TODO: threads: start ngx_worker_thread_cycle() */

    for ( ;; ) {
        ngx_log_debug0(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "worker cycle");

        ngx_process_events(cycle->log);

        if (ngx_terminate) {
            ngx_log_error(NGX_LOG_INFO, cycle->log, 0, "exiting");
            exit(0);
        }

        if (ngx_quit) {
            ngx_log_error(NGX_LOG_INFO, cycle->log, 0,
                          "gracefully shutdowning");
            break;
        }

        if (ngx_reopen) {
            ngx_log_error(NGX_LOG_INFO, cycle->log, 0, "reopen logs");
            ngx_reopen_files(cycle);
            ngx_reopen = 0;
        }
    }

    ngx_close_listening_sockets(cycle);

    for ( ;; ) {
        if (ngx_event_timer_rbtree == &ngx_event_timer_sentinel) {
            ngx_log_error(NGX_LOG_INFO, cycle->log, 0, "exiting");
            exit(0);
        }

        ngx_log_debug0(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "worker cycle");

        ngx_process_events(cycle->log);
    }
}


static ngx_int_t ngx_add_inherited_sockets(ngx_cycle_t *cycle, char **envp)
{
    char                *p, *v;
    ngx_socket_t         s;
    ngx_listening_t     *ls;

    for ( /* void */ ; *envp; envp++) {
        if (ngx_strncmp(*envp, NGINX_VAR, NGINX_VAR_LEN) != 0) {
            continue;
        }

        ngx_log_error(NGX_LOG_INFO, cycle->log, 0,
                      "using inherited sockets from \"%s\"", *envp);

        ngx_init_array(cycle->listening, cycle->pool,
                       10, sizeof(ngx_listening_t), NGX_ERROR);

        for (p = *envp + NGINX_VAR_LEN, v = p; *p; p++) {
            if (*p == ':' || *p == ';') {
                s = ngx_atoi(v, p - v);
                if (s == NGX_ERROR) {
                    ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
                                  "invalid socket number \"%s\" "
                                  "in NGINX enviroment variable, "
                                  "ignoring the rest of the variable", v);
                    break;
                }
                v = p + 1;

                if (!(ls = ngx_push_array(&cycle->listening))) {
                    return NGX_ERROR;
                }

                ls->fd = s;
            }
        }

        return ngx_set_inherited_sockets(cycle);
    }

    return NGX_OK;
}


static void ngx_exec_new_binary(ngx_cycle_t *cycle, char *const *argv)
{
    char             *env[2], *var, *p;
    ngx_int_t         i;
    ngx_exec_ctx_t    ctx;
    ngx_listening_t  *ls;

    ctx.path = argv[0];
    ctx.name = "new binary process";
    ctx.argv = argv;

    var = ngx_alloc(NGINX_VAR_LEN
                            + cycle->listening.nelts * (NGX_INT32_LEN + 1) + 1,
                    cycle->log);

    p = ngx_cpymem(var, NGINX_VAR, NGINX_VAR_LEN);

    ls = cycle->listening.elts;
    for (i = 0; i < cycle->listening.nelts; i++) {
        p += ngx_snprintf(p, NGX_INT32_LEN + 2, "%u;", ls[i].fd);
    }

    env[0] = var;
    env[1] = NULL;
    ctx.envp = (char *const *) &env;

    ngx_exec(cycle, &ctx);

    ngx_free(var);
}


static ngx_int_t ngx_core_module_init(ngx_cycle_t *cycle)
{
    ngx_core_conf_t  *ccf;

    /*
     * ngx_core_module has a special init procedure: it is called by
     * ngx_init_cycle() before the configuration file parsing to create
     * ngx_core_module configuration and to set its default parameters
     */

    if (((void **)(cycle->conf_ctx))[ngx_core_module.index] != NULL) {
        return NGX_OK;
    }

    if (!(ccf = ngx_pcalloc(cycle->pool, sizeof(ngx_core_conf_t)))) {
        return NGX_ERROR;
    }
    /* set by pcalloc()
     *
     * ccf->pid = NULL;
     */
    ccf->daemon = -1;
    ccf->single = -1;

    ((void **)(cycle->conf_ctx))[ngx_core_module.index] = ccf;

    return NGX_OK;
}