/*
 * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The OpenAirInterface Software Alliance licenses this file to You under
 * the OAI Public License, Version 1.1  (the "License"); you may not use this file
 * except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.openairinterface.org/?page_id=698
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *-------------------------------------------------------------------------------
 * For more information about the OpenAirInterface (OAI) Software Alliance:
 *      contact@openairinterface.org
 */

/**
 * @file antenna-control-mplane.c
 * @brief Implementation of O-RAN WG4 M-Plane compliant antenna control
 * 
 * This implements NETCONF-based antenna muting using the actual O-RAN
 * YANG models (o-ran-uplane-conf.yang) and the MPLANE-TRX-CONTROL feature.
 */

#include "antenna-control-mplane.h"
#include "ru-mplane-api.h"
#include "xml/get-xml.h"
#include "common/utils/assertions.h"

// Forward declaration - actual function in config-mplane.c
extern bool edit_val_commmit_rpc(ru_session_t *ru_session, const char *content);

// Forward declaration - actual function in get-mplane.c
extern bool get_mplane(ru_session_t *ru_session, char **answer);

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <libyang/libyang.h>
#include <nc_client.h>

const char *antenna_ctrl_result_str(antenna_ctrl_result_t result)
{
  switch (result) {
    case ANTENNA_CTRL_SUCCESS:
      return "Success";
    case ANTENNA_CTRL_ERR_NO_SESSION:
      return "No active NETCONF session";
    case ANTENNA_CTRL_ERR_FEATURE_NOT_SUPPORTED:
      return "MPLANE-TRX-CONTROL feature not supported by RU";
    case ANTENNA_CTRL_ERR_INVALID_ARRAY_NAME:
      return "Invalid array name";
    case ANTENNA_CTRL_ERR_INVALID_MASK:
      return "Invalid antenna bitmask";
    case ANTENNA_CTRL_ERR_NETCONF_FAILED:
      return "NETCONF RPC failed";
    case ANTENNA_CTRL_ERR_VALIDATION_FAILED:
      return "Configuration validation failed";
    case ANTENNA_CTRL_ERR_COMMIT_FAILED:
      return "Configuration commit failed";
    default:
      return "Unknown error";
  }
}

/**
 * @brief Convert antenna bitmask to O-RAN binary format
 * 
 * O-RAN uses binary type in YANG which is base64 encoded in XML.
 * For simplicity, we encode the bitmask as hex bytes.
 * 
 * Per O-RAN spec: "The antenna mask contains as many binary values as
 * number of array elements associated with respective tx or rx-array.
 * Value of '1' indicates antenna element shall be kept active and
 * value of '0' indicates antenna element should be turned inactive."
 */
static char *bitmask_to_base64(uint8_t bitmask, uint8_t num_antennas)
{
  // For up to 8 antennas, we need 1 byte
  // Base64 encoding of 1 byte = 4 characters + null terminator
  char *result = malloc(8);
  if (result == NULL) return NULL;
  
  // Mask to only include configured antennas
  uint8_t valid_mask = (1 << num_antennas) - 1;
  uint8_t masked_value = bitmask & valid_mask;
  
  // Simple base64 encoding for single byte
  // Input: masked_value (8 bits) -> padded to 6+6+4 bits for base64
  static const char b64chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  
  // Encode single byte with padding
  result[0] = b64chars[(masked_value >> 2) & 0x3F];
  result[1] = b64chars[(masked_value << 4) & 0x30];
  result[2] = '=';
  result[3] = '=';
  result[4] = '\0';
  
  return result;
}

/**
 * @brief Decode base64 to antenna bitmask
 */
static uint8_t base64_to_bitmask(const char *b64_str)
{
  if (b64_str == NULL || strlen(b64_str) < 2) return 0xFF;
  
  static const char b64chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  
  // Find index of first two base64 characters
  const char *p1 = strchr(b64chars, b64_str[0]);
  const char *p2 = strchr(b64chars, b64_str[1]);
  
  if (p1 == NULL || p2 == NULL) return 0xFF;
  
  uint8_t val1 = (uint8_t)(p1 - b64chars);
  uint8_t val2 = (uint8_t)(p2 - b64chars);
  
  // Reconstruct byte
  return (val1 << 2) | (val2 >> 4);
}

bool mplane_create_antenna_mask_xml(ru_session_t *ru_session,
                                     bool is_tx,
                                     const char *array_name,
                                     uint8_t antenna_bitmask,
                                     uint8_t num_antennas,
                                     char **xml_content)
{
  if (ru_session == NULL || ru_session->ctx == NULL || array_name == NULL || xml_content == NULL) {
    return false;
  }

  *xml_content = NULL;
  LY_ERR ret = LY_SUCCESS;
  struct lyd_node *root = NULL;
  
  // Create root node for o-ran-uplane-conf
  ret = lyd_new_path(NULL, (struct ly_ctx *)ru_session->ctx, 
                     "/o-ran-uplane-conf:user-plane-configuration", NULL, 0, &root);
  if (ret != LY_SUCCESS) {
    MP_LOG_W("Failed to create root user-plane-configuration node.\n");
    return false;
  }
  
  // Create the antenna mask configuration
  const char *list_name = is_tx ? "tx-array-antenna-mask-config" : "rx-array-antenna-mask-config";
  struct lyd_node *mask_node = NULL;
  
  ret = lyd_new_list(root, NULL, list_name, 0, &mask_node, array_name);
  if (ret != LY_SUCCESS) {
    MP_LOG_W("Failed to create %s list node for array '%s'.\n", list_name, array_name);
    lyd_free_tree(root);
    return false;
  }
  
  // Convert bitmask to base64 for YANG binary type
  char *b64_mask = bitmask_to_base64(antenna_bitmask, num_antennas);
  if (b64_mask == NULL) {
    MP_LOG_W("Failed to encode antenna bitmask.\n");
    lyd_free_tree(root);
    return false;
  }
  
  // Add antenna-bitmask leaf
  ret = lyd_new_term(mask_node, NULL, "antenna-bitmask", b64_mask, 0, NULL);
  free(b64_mask);
  
  if (ret != LY_SUCCESS) {
    MP_LOG_W("Failed to create antenna-bitmask node.\n");
    lyd_free_tree(root);
    return false;
  }
  
  // Print to XML
  // Note: LYD_PRINT_SIBLINGS in libyang v2.1+, LYD_PRINT_WITHSIBLINGS in older v2, LYP_WITHSIBLINGS in v1
#ifdef MPLANE_V1
  lyd_print_mem(xml_content, root, LYD_XML, LYP_WITHSIBLINGS);
#elif defined MPLANE_V2
  #ifdef LYD_PRINT_SIBLINGS
  lyd_print_mem(xml_content, root, LYD_XML, LYD_PRINT_SIBLINGS);
  #else
  lyd_print_mem(xml_content, root, LYD_XML, LYD_PRINT_WITHSIBLINGS);
  #endif
#endif
  lyd_free_tree(root);
  
  if (*xml_content == NULL) {
    MP_LOG_W("Failed to generate XML content.\n");
    return false;
  }
  
  MP_LOG_I("Generated %s antenna mask XML for array '%s', mask=0x%02X\n",
           is_tx ? "TX" : "RX", array_name, antenna_bitmask);
  
  return true;
}

antenna_ctrl_result_t mplane_set_tx_antenna_mask(ru_session_t *ru_session,
                                                  const char *array_name,
                                                  uint8_t antenna_bitmask,
                                                  uint8_t num_antennas)
{
  if (ru_session == NULL || ru_session->session == NULL) {
    return ANTENNA_CTRL_ERR_NO_SESSION;
  }
  
  if (array_name == NULL || strlen(array_name) == 0) {
    return ANTENNA_CTRL_ERR_INVALID_ARRAY_NAME;
  }
  
  if (num_antennas == 0 || num_antennas > 8) {
    return ANTENNA_CTRL_ERR_INVALID_MASK;
  }
  
  // Generate XML for antenna mask configuration
  char *xml_content = NULL;
  if (!mplane_create_antenna_mask_xml(ru_session, true, array_name, 
                                       antenna_bitmask, num_antennas, &xml_content)) {
    return ANTENNA_CTRL_ERR_NETCONF_FAILED;
  }
  
  MP_LOG_I("Setting TX antenna mask via NETCONF:\n%s\n", xml_content);
  
  // Use existing M-Plane infrastructure to send edit-config, validate, commit
  bool success = edit_val_commmit_rpc(ru_session, xml_content);
  free(xml_content);
  
  if (!success) {
    MP_LOG_W("Failed to configure TX antenna mask for array '%s'\n", array_name);
    return ANTENNA_CTRL_ERR_COMMIT_FAILED;
  }
  
  MP_LOG_I("Successfully configured TX antenna mask 0x%02X for array '%s'\n",
           antenna_bitmask, array_name);
  
  return ANTENNA_CTRL_SUCCESS;
}

antenna_ctrl_result_t mplane_set_rx_antenna_mask(ru_session_t *ru_session,
                                                  const char *array_name,
                                                  uint8_t antenna_bitmask,
                                                  uint8_t num_antennas)
{
  if (ru_session == NULL || ru_session->session == NULL) {
    return ANTENNA_CTRL_ERR_NO_SESSION;
  }
  
  if (array_name == NULL || strlen(array_name) == 0) {
    return ANTENNA_CTRL_ERR_INVALID_ARRAY_NAME;
  }
  
  if (num_antennas == 0 || num_antennas > 8) {
    return ANTENNA_CTRL_ERR_INVALID_MASK;
  }
  
  // Generate XML for antenna mask configuration
  char *xml_content = NULL;
  if (!mplane_create_antenna_mask_xml(ru_session, false, array_name,
                                       antenna_bitmask, num_antennas, &xml_content)) {
    return ANTENNA_CTRL_ERR_NETCONF_FAILED;
  }
  
  MP_LOG_I("Setting RX antenna mask via NETCONF:\n%s\n", xml_content);
  
  // Use existing M-Plane infrastructure to send edit-config, validate, commit
  bool success = edit_val_commmit_rpc(ru_session, xml_content);
  free(xml_content);
  
  if (!success) {
    MP_LOG_W("Failed to configure RX antenna mask for array '%s'\n", array_name);
    return ANTENNA_CTRL_ERR_COMMIT_FAILED;
  }
  
  MP_LOG_I("Successfully configured RX antenna mask 0x%02X for array '%s'\n",
           antenna_bitmask, array_name);
  
  return ANTENNA_CTRL_SUCCESS;
}

antenna_ctrl_result_t mplane_get_tx_antenna_mask(ru_session_t *ru_session,
                                                  const char *array_name,
                                                  uint8_t *antenna_bitmask)
{
  if (ru_session == NULL || ru_session->session == NULL) {
    return ANTENNA_CTRL_ERR_NO_SESSION;
  }
  
  if (array_name == NULL || antenna_bitmask == NULL) {
    return ANTENNA_CTRL_ERR_INVALID_ARRAY_NAME;
  }
  
  // Get operational datastore
  char *operational_ds = NULL;
  if (!get_mplane(ru_session, &operational_ds)) {
    return ANTENNA_CTRL_ERR_NETCONF_FAILED;
  }
  
  // Build XPath to find the antenna mask for this array
  char xpath[256];
  snprintf(xpath, sizeof(xpath), 
           "tx-array-antenna-mask-config[array-name='%s']/antenna-bitmask", 
           array_name);
  
  // Extract the value from XML response
  char *mask_b64 = get_ru_xml_node(operational_ds, "antenna-bitmask");
  free(operational_ds);
  
  if (mask_b64 == NULL) {
    // No mask configured, assume all active
    *antenna_bitmask = 0xFF;
    return ANTENNA_CTRL_SUCCESS;
  }
  
  *antenna_bitmask = base64_to_bitmask(mask_b64);
  free(mask_b64);
  
  MP_LOG_I("Retrieved TX antenna mask 0x%02X for array '%s'\n",
           *antenna_bitmask, array_name);
  
  return ANTENNA_CTRL_SUCCESS;
}

antenna_ctrl_result_t mplane_get_rx_antenna_mask(ru_session_t *ru_session,
                                                  const char *array_name,
                                                  uint8_t *antenna_bitmask)
{
  if (ru_session == NULL || ru_session->session == NULL) {
    return ANTENNA_CTRL_ERR_NO_SESSION;
  }
  
  if (array_name == NULL || antenna_bitmask == NULL) {
    return ANTENNA_CTRL_ERR_INVALID_ARRAY_NAME;
  }
  
  // Get operational datastore
  char *operational_ds = NULL;
  if (!get_mplane(ru_session, &operational_ds)) {
    return ANTENNA_CTRL_ERR_NETCONF_FAILED;
  }
  
  // Extract the value from XML response (simplified - real impl would use XPath)
  char *mask_b64 = get_ru_xml_node(operational_ds, "antenna-bitmask");
  free(operational_ds);
  
  if (mask_b64 == NULL) {
    // No mask configured, assume all active
    *antenna_bitmask = 0xFF;
    return ANTENNA_CTRL_SUCCESS;
  }
  
  *antenna_bitmask = base64_to_bitmask(mask_b64);
  free(mask_b64);
  
  MP_LOG_I("Retrieved RX antenna mask 0x%02X for array '%s'\n",
           *antenna_bitmask, array_name);
  
  return ANTENNA_CTRL_SUCCESS;
}

bool mplane_supports_trx_control(ru_session_t *ru_session)
{
  if (ru_session == NULL || ru_session->session == NULL) {
    return false;
  }
  
  // Check if MPLANE-TRX-CONTROL feature is advertised in RU capabilities
  // This is done by checking the server capabilities from the hello exchange
  // or by querying the YANG library
  
  struct nc_session *session = (struct nc_session *)ru_session->session;
  const char * const *caps = nc_session_get_cpblts(session);
  
  if (caps == NULL) {
    return false;
  }
  
  // Look for o-ran-uplane-conf module with MPLANE-TRX-CONTROL feature
  for (int i = 0; caps[i] != NULL; i++) {
    if (strstr(caps[i], "o-ran-uplane-conf") != NULL) {
      // Module is supported, assume feature is enabled
      // A more complete implementation would query module features
      MP_LOG_I("RU supports o-ran-uplane-conf module (MPLANE-TRX-CONTROL)\n");
      return true;
    }
  }
  
  MP_LOG_W("RU does not advertise o-ran-uplane-conf module\n");
  return false;
}