/*
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * https://opensource.org/license/bsd-3-clause
 *
 * Copyright (C) 2011, 2012, 2013 Citrix Systems
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if !defined(TURN_NO_HIREDIS)

#include "hiredis_libevent2.h"
#include "ns_turn_utils.h"

#include <event2/buffer.h>
#include <event2/bufferevent.h>

#include <hiredis/async.h>
#include <hiredis/hiredis.h>
#if defined(TURN_HAVE_HIREDIS_SSL)
#include <hiredis/hiredis_ssl.h>
#endif

//////////////// Libevent context ///////////////////////

struct redisLibeventEvents {
  redisAsyncContext *context;
  int invalid;
  int allocated;
  struct event_base *base;
  struct event *rev, *wev;
  int rev_set, wev_set;
  char *ip;
  int port;
  char *user;
  char *pwd;
  int db;
  void *ssl_ctx; /* redisSSLContext*, or NULL for a plaintext connection */
};

/* Initiate TLS on a freshly created async context. Returns 0 on success (or
   when no TLS is configured), -1 on failure. The handshake itself completes
   asynchronously through the normal read/write events. */
static int redis_le_init_ssl(struct redisLibeventEvents *e, redisAsyncContext *ac) {
  if (!e || !e->ssl_ctx) {
    return 0;
  }
#if defined(TURN_HAVE_HIREDIS_SSL)
  if (redisInitiateSSLWithContext(&ac->c, (redisSSLContext *)e->ssl_ctx) != REDIS_OK) {
    TURN_LOG_FUNC(TURN_LOG_LEVEL_ERROR, "%s: Redis TLS init failed: %s\n", __FUNCTION__, ac->c.errstr);
    return -1;
  }
  return 0;
#else
  (void)ac;
  TURN_LOG_FUNC(TURN_LOG_LEVEL_ERROR, "%s: Redis TLS requested but hiredis_ssl support is not compiled in\n",
                __FUNCTION__);
  return -1;
#endif
}

///////////// Messages ////////////////////////////

struct redis_message {
  char arg[513];
};

/////////////////// forward declarations ///////////////

static void redis_reconnect(struct redisLibeventEvents *e);

//////////////////////////////////////////////////////////

static int redis_le_valid(struct redisLibeventEvents *e) { return (e && !(e->invalid) && (e->context)); }

/////////////////// Callbacks ////////////////////////////

static void redisLibeventReadEvent(evutil_socket_t fd, short event, void *arg) {
  ((void)fd);
  ((void)event);
  struct redisLibeventEvents *e = (struct redisLibeventEvents *)arg;
  if (redis_le_valid(e)) {
    {
      char buf[8];
      int len = 0;
      do {
        len = recv(fd, buf, sizeof(buf), MSG_PEEK);
      } while ((len < 0) && socket_eintr());
      if (len < 1) {
        e->invalid = 1;
        TURN_LOG_FUNC(TURN_LOG_LEVEL_ERROR, "%s: Redis connection broken: e=0x%p\n", __FUNCTION__, e);
      }
    }
    if (redis_le_valid(e)) {
      redisAsyncHandleRead(e->context);
    }
  } else {
    redis_reconnect(e);
  }
}

static void redisLibeventWriteEvent(evutil_socket_t fd, short event, void *arg) {
  ((void)fd);
  ((void)event);
  struct redisLibeventEvents *e = (struct redisLibeventEvents *)arg;
  if (redis_le_valid(e)) {
    redisAsyncHandleWrite(e->context);
  }
}

static void redisLibeventAddRead(void *privdata) {
  struct redisLibeventEvents *e = (struct redisLibeventEvents *)privdata;
  if (e && (e->rev) && !(e->rev_set)) {
    event_add(e->rev, NULL);
    e->rev_set = 1;
  }
}

static void redisLibeventDelRead(void *privdata) {
  struct redisLibeventEvents *e = (struct redisLibeventEvents *)privdata;
  if (e && e->rev && e->rev_set) {
    event_del(e->rev);
    e->rev_set = 0;
  }
}

static void redisLibeventAddWrite(void *privdata) {
  struct redisLibeventEvents *e = (struct redisLibeventEvents *)privdata;
  if (e && (e->wev) && !(e->wev_set)) {
    event_add(e->wev, NULL);
    e->wev_set = 1;
  }
}

static void redisLibeventDelWrite(void *privdata) {
  struct redisLibeventEvents *e = (struct redisLibeventEvents *)privdata;
  if (e && e->wev && e->wev_set) {
    event_del(e->wev);
    e->wev_set = 0;
  }
}

static void redisLibeventCleanup(void *privdata) {

  if (privdata) {

    struct redisLibeventEvents *e = (struct redisLibeventEvents *)privdata;
    if (e->allocated) {
      if (e->rev) {
        if (e->rev_set) {
          event_del(e->rev);
        }
        event_free(e->rev);
        e->rev = NULL;
      }
      e->rev_set = 0;
      if (e->wev) {
        if (e->wev_set) {
          event_del(e->wev);
        }
        event_free(e->wev);
        e->wev = NULL;
      }
      e->wev_set = 0;
      e->context = NULL;
    }
  }
}

///////////////////////// Send-receive ///////////////////////////

int is_redis_asyncconn_good(redis_context_handle rch) {
  if (rch) {
    struct redisLibeventEvents *e = (struct redisLibeventEvents *)rch;
    if (redis_le_valid(e)) {
      return 1;
    }
  }
  return 0;
}

void send_message_to_redis(redis_context_handle rch, const char *command, const char *key, const char *format, ...) {
  if (!rch) {
    return;
  } else {

    struct redisLibeventEvents *e = (struct redisLibeventEvents *)rch;

    if (!redis_le_valid(e)) {
      redis_reconnect(e);
    }

    if (!redis_le_valid(e)) {
      ;
    } else {

      redisAsyncContext *ac = e->context;

      struct redis_message rm;

      va_list args;
      va_start(args, format);
      vsnprintf(rm.arg, sizeof(rm.arg) - 1, format, args);
      va_end(args);
      rm.arg[sizeof(rm.arg) - 1] = 0;

      if ((redisAsyncCommand(ac, NULL, e, "%s %s %s", command, key, rm.arg) != REDIS_OK)) {
        e->invalid = 1;
        TURN_LOG_FUNC(TURN_LOG_LEVEL_ERROR, "%s: Redis connection broken: ac=0x%p, e=0x%p\n", __FUNCTION__, ac, e);
      }
    }
  }
}

///////////////////////// Attach /////////////////////////////////

redis_context_handle redisLibeventAttach(struct event_base *base, char *ip0, int port0, char *user, char *pwd, int db,
                                         void *ssl_ctx) {

  char ip[256];
  if (ip0 && ip0[0]) {
    STRCPY(ip, ip0);
  } else {
    strncpy(ip, "127.0.0.1", sizeof(ip));
  }

  int port = DEFAULT_REDIS_PORT;
  if (port0 > 0) {
    port = port0;
  }

  redisAsyncContext *ac = redisAsyncConnect(ip, port);
  if (!ac) {
    fprintf(stderr, "Error: redisAsyncConnect returned NULL\n");
    return NULL;
  } else if (ac->err) {
    fprintf(stderr, "Error: %s:%s\n", ac->errstr, ac->c.errstr);
    return NULL;
  }

  /* Create container for context and r/w events */
  struct redisLibeventEvents *e = (struct redisLibeventEvents *)calloc(1, sizeof(struct redisLibeventEvents));
  if (!e) {
    return NULL;
  }

  e->allocated = 1;
  e->context = ac;
  e->base = base;
  e->ip = strdup(ip);
  e->port = port;
  if (user) {
    e->user = strdup(user);
  }
  if (pwd) {
    e->pwd = strdup(pwd);
  }
  e->db = db;
  e->ssl_ctx = ssl_ctx;

  /* Upgrade to TLS before any command (AUTH/SELECT) is queued. */
  if (redis_le_init_ssl(e, ac) < 0) {
    redisAsyncFree(ac);
    e->context = NULL;
    free(e->ip);
    free(e->user);
    free(e->pwd);
    free(e);
    return NULL;
  }

  /* Register functions to start/stop listening for events */
  ac->ev.addRead = redisLibeventAddRead;
  ac->ev.delRead = redisLibeventDelRead;
  ac->ev.addWrite = redisLibeventAddWrite;
  ac->ev.delWrite = redisLibeventDelWrite;
  ac->ev.cleanup = redisLibeventCleanup;

  ac->ev.data = e;

  /* Initialize and install read/write events */
  e->rev = event_new(e->base, e->context->c.fd, EV_READ | EV_PERSIST, redisLibeventReadEvent, e);

  e->wev = event_new(e->base, e->context->c.fd, EV_WRITE, redisLibeventWriteEvent, e);

  if (e->rev == NULL || e->wev == NULL) {
    free(e);
    return NULL;
  }

  event_add(e->wev, NULL);
  e->wev_set = 1;

  // Authentication
  if (redis_le_valid(e) && pwd && strlen(pwd)) {
    if (user && strlen(user)) {
      if (redisAsyncCommand(ac, NULL, e, "AUTH %s %s", e->user, e->pwd) != REDIS_OK) {
        e->invalid = 1;
      }
    } else {
      if (redisAsyncCommand(ac, NULL, e, "AUTH %s", e->pwd) != REDIS_OK) {
        e->invalid = 1;
      }
    }
  }

  if (redis_le_valid(e)) {
    if (redisAsyncCommand(ac, NULL, e, "SELECT %d", db) != REDIS_OK) {
      e->invalid = 1;
    }
  }

  return (redis_context_handle)e;
}

static void redis_reconnect(struct redisLibeventEvents *e) {
  if (!e || !(e->allocated)) {
    return;
  }

  if (e->rev) {
    if (e->rev_set) {
      event_del(e->rev);
    }
    event_free(e->rev);
    e->rev = NULL;
  }
  e->rev_set = 0;

  if (e->wev) {
    if (e->wev_set) {
      event_del(e->wev);
    }
    event_free(e->wev);
    e->wev = NULL;
  }
  e->wev_set = 0;

  redisAsyncContext *ac = NULL;

  if (e->context) {
    redisAsyncFree(e->context);
    e->context = NULL;
  }

  ac = redisAsyncConnect(e->ip, e->port);
  if (!ac) {
    return;
  }

  e->context = ac;

  /* Re-upgrade to TLS before any command is queued on the new context. */
  if (redis_le_init_ssl(e, ac) < 0) {
    redisAsyncFree(ac);
    e->context = NULL;
    return;
  }

  /* Register functions to start/stop listening for events */
  ac->ev.addRead = redisLibeventAddRead;
  ac->ev.delRead = redisLibeventDelRead;
  ac->ev.addWrite = redisLibeventAddWrite;
  ac->ev.delWrite = redisLibeventDelWrite;
  ac->ev.cleanup = redisLibeventCleanup;

  ac->ev.data = e;

  /* Initialize and install read/write events */
  e->rev = event_new(e->base, e->context->c.fd, EV_READ, redisLibeventReadEvent, e);

  e->wev = event_new(e->base, e->context->c.fd, EV_WRITE, redisLibeventWriteEvent, e);

  if (e->rev == NULL || e->wev == NULL) {
    return;
  }

  event_add(e->wev, NULL);
  e->wev_set = 1;
  e->invalid = 0;

  // Authentication
  if (redis_le_valid(e) && e->pwd && strlen(e->pwd)) {
    if (e->user && strlen(e->user)) {
      if (redisAsyncCommand(ac, NULL, e, "AUTH %s %s", e->user, e->pwd) != REDIS_OK) {
        e->invalid = 1;
      }
    } else {
      if (redisAsyncCommand(ac, NULL, e, "AUTH %s", e->pwd) != REDIS_OK) {
        e->invalid = 1;
      }
    }
  }

  if (redis_le_valid(e)) {
    if (redisAsyncCommand(ac, NULL, e, "SELECT %d", e->db) != REDIS_OK) {
      e->invalid = 1;
    }
  }

  if (redis_le_valid(e)) {
    TURN_LOG_FUNC(TURN_LOG_LEVEL_INFO, "%s: Re-connected to redis, async\n", __FUNCTION__);
  }
}

/////////////////////////////////////////////////////////

#endif
/* TURN_NO_HIREDIS */
