/******************************************************************************
 *
 *  Copyright (C) 2011-2012 Broadcom Corporation
 *  Copyright (C) 2013 ST Microelectronics S.A.
 *
 *  Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
 *
 *  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.
 *
 *  Modified by ST Microelectronics S.A. (- changed configuration filename)
 *                                       (- changed getValue and GetStrValue)
 *
 *
 ******************************************************************************/
#include <stdio.h>
#include <list>
#include <string>
#include <vector>
#include <log/log.h>
#include "android_logmsg.h"
#include <sys/stat.h>
const char alternative_config_path[] = "";
const char* transport_config_paths[] = {"/odm/etc/", "/vendor/etc/", "/etc/"};

const int transport_config_path_size =
    (sizeof(transport_config_paths) / sizeof(transport_config_paths[0]));
#define config_name "libnfc-st.conf"
#define extra_config_base "libnfc-st-"
#define extra_config_ext ".conf"
#define IsStringValue 0x80000000

using namespace ::std;

class CNfcParam : public string {
 public:
  CNfcParam();
  CNfcParam(const char* name, const string& value);
  CNfcParam(const char* name, unsigned long value);
  virtual ~CNfcParam();
  unsigned long numValue() const { return m_numValue; }
  const char* str_value() const { return m_str_value.c_str(); }
  size_t str_len() const { return m_str_value.length(); }

 private:
  string m_str_value;
  unsigned long m_numValue;
};

class CNfcConfig : public vector<const CNfcParam*> {
 public:
  virtual ~CNfcConfig();
  static CNfcConfig& GetInstance();
  friend void readOptionalConfig(const char* optional);

  bool getValue(const char* name, char* pValue, size_t& len) const;
  bool getValue(const char* name, unsigned long& rValue) const;
  bool getValue(const char* name, unsigned short& rValue) const;
  const CNfcParam* find(const char* p_name) const;
  void clean();

 private:
  CNfcConfig();
  bool readConfig(const char* name, bool bResetContent);
  void moveFromList();
  void moveToList();
  void add(const CNfcParam* pParam);
  list<const CNfcParam*> m_list;
  bool mValidFile;

  unsigned long state;

  inline bool Is(unsigned long f) { return (state & f) == f; }
  inline void Set(unsigned long f) { state |= f; }
  inline void Reset(unsigned long f) { state &= ~f; }
};

/*******************************************************************************
**
** Function:    isPrintable()
**
** Description: determine if 'c' is printable
**
** Returns:     1, if printable, otherwise 0
**
*******************************************************************************/
inline bool isPrintable(char c) {
  return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') ||
         (c >= '0' && c <= '9') || c == '/' || c == '_' || c == '-' || c == '.';
}

/*******************************************************************************
**
** Function:    isDigit()
**
** Description: determine if 'c' is numeral digit
**
** Returns:     true, if numerical digit
**
*******************************************************************************/
inline bool isDigit(char c, int base) {
  if ('0' <= c && c <= '9') return true;
  if (base == 16) {
    if (('A' <= c && c <= 'F') || ('a' <= c && c <= 'f')) return true;
  }
  return false;
}

/*******************************************************************************
**
** Function:    getDigitValue()
**
** Description: return numerical value of a decimal or hex char
**
** Returns:     numerical value if decimal or hex char, otherwise 0
**
*******************************************************************************/
inline int getDigitValue(char c, int base) {
  if ('0' <= c && c <= '9') return c - '0';
  if (base == 16) {
    if ('A' <= c && c <= 'F')
      return c - 'A' + 10;
    else if ('a' <= c && c <= 'f')
      return c - 'a' + 10;
  }
  return 0;
}

/*******************************************************************************
**
** Function:    findConfigFile()
**
** Description: find config file among transport_config_paths**
**
** Returns:     none
**
*******************************************************************************/
void findConfigFile(const string& configName,
                                                string& filePath) {
  for (int i = 0; i < transport_config_path_size - 1; i++) {
    filePath.assign(transport_config_paths[i]);
    filePath += configName;
    struct stat file_stat;
    if (stat(filePath.c_str(), &file_stat) == 0 && S_ISREG(file_stat.st_mode)) {
      return;
    }
  }
  filePath.assign(transport_config_paths[transport_config_path_size - 1]);
  filePath += configName;
}

/*******************************************************************************
**
** Function:    CNfcConfig::readConfig()
**
** Description: read Config settings and parse them into a linked list
**              move the element from linked list to a array at the end
**
** Returns:     1, if there are any config data, 0 otherwise
**
*******************************************************************************/
bool CNfcConfig::readConfig(const char* name, bool bResetContent) {
  enum {
    BEGIN_LINE = 1,
    TOKEN,
    STR_VALUE,
    NUM_VALUE,
    BEGIN_HEX,
    BEGIN_QUOTE,
    END_LINE
  };

  FILE* fd = NULL;
  string token;
  string strValue;
  unsigned long numValue = 0;
  CNfcParam* pParam = NULL;
  int i = 0;
  int base = 0;
  char c = 0;

  state = BEGIN_LINE;
  /* open config file, read it into a buffer */
  if ((fd = fopen(name, "rb")) == NULL) {
      STLOG_HAL_W("%s Cannot open config file %s\n", __func__, name);
    if (bResetContent) {
        STLOG_HAL_W("%s Using default value for all settings\n", __func__);
      mValidFile = false;
    }
    return false;
  }
  STLOG_HAL_D("%s Opened %s config %s\n", __func__,
        (bResetContent ? "base" : "optional"), name);

  mValidFile = true;
  if (size() > 0) {
    if (bResetContent)
      clean();
    else
      moveToList();
  }

  while (!feof(fd) && fread(&c, 1, 1, fd) == 1) {
    switch (state & 0xff) {
      case BEGIN_LINE:
        if (c == '#')
          state = END_LINE;
        else if (isPrintable(c)) {
          i = 0;
          token.erase();
          strValue.erase();
          state = TOKEN;
          token.push_back(c);
        }
        break;
      case TOKEN:
        if (c == '=') {
          token.push_back('\0');
          state = BEGIN_QUOTE;
        } else if (isPrintable(c))
          token.push_back(c);
        else
          state = END_LINE;
        break;
      case BEGIN_QUOTE:
        if (c == '"') {
          state = STR_VALUE;
          base = 0;
        } else if (c == '0')
          state = BEGIN_HEX;
        else if (isDigit(c, 10)) {
          state = NUM_VALUE;
          base = 10;
          numValue = getDigitValue(c, base);
          i = 0;
        } else if (c == '{') {
          state = NUM_VALUE;
          base = 16;
          i = 0;
          Set(IsStringValue);
        } else
          state = END_LINE;
        break;
      case BEGIN_HEX:
        if (c == 'x' || c == 'X') {
          state = NUM_VALUE;
          base = 16;
          numValue = 0;
          i = 0;
          break;
        } else if (isDigit(c, 10)) {
          state = NUM_VALUE;
          base = 10;
          numValue = getDigitValue(c, base);
          i=0;
          break;
        } else if (c != '\n' && c != '\r') {
          state = END_LINE;
          break;
        }
        [[fallthrough]]; // fall through to numValue to handle numValue

      case NUM_VALUE:
        if (isDigit(c, base)) {
          numValue *= base;
          numValue += getDigitValue(c, base);
          ++i;
        } else if (base == 16 &&
                   (c == ':' || c == '-' || c == ' ' || c == '}')) {
          if (i > 0) {
            int n = (i + 1) / 2;
            while (n-- > 0) {
              unsigned char c = (numValue >> (n * 8)) & 0xFF;
              strValue.push_back(c);
            }
          }
          Set(IsStringValue);
          numValue = 0;
          i = 0;
        } else {
          if (c == '\n' || c == '\r')
            state = BEGIN_LINE;
          else
            state = END_LINE;
          if (Is(IsStringValue) && base == 16 && i > 0) {
            int n = (i + 1) / 2;
            while (n-- > 0) strValue.push_back(((numValue >> (n * 8)) & 0xFF));
          }
          if (strValue.length() > 0)
            pParam = new CNfcParam(token.c_str(), strValue);
          else
            pParam = new CNfcParam(token.c_str(), numValue);
          add(pParam);
          strValue.erase();
          numValue = 0;
        }
        break;
      case STR_VALUE:
        if (c == '"') {
          strValue.push_back('\0');
          state = END_LINE;
          pParam = new CNfcParam(token.c_str(), strValue);
          add(pParam);
        } else if (isPrintable(c))
          strValue.push_back(c);
        break;
      case END_LINE:
        if (c == '\n' || c == '\r') state = BEGIN_LINE;
        break;
      default:
        break;
    }
  }

  fclose(fd);

  moveFromList();
  return size() > 0;
}

/*******************************************************************************
**
** Function:    CNfcConfig::CNfcConfig()
**
** Description: class constructor
**
** Returns:     none
**
*******************************************************************************/
CNfcConfig::CNfcConfig() : mValidFile(true) {}

/*******************************************************************************
**
** Function:    CNfcConfig::~CNfcConfig()
**
** Description: class destructor
**
** Returns:     none
**
*******************************************************************************/
CNfcConfig::~CNfcConfig() {}

/*******************************************************************************
**
** Function:    CNfcConfig::GetInstance()
**
** Description: get class singleton object
**
** Returns:     none
**
*******************************************************************************/
CNfcConfig& CNfcConfig::GetInstance() {
  static CNfcConfig theInstance;

  if (theInstance.size() == 0 && theInstance.mValidFile) {
    string strPath;
    if (alternative_config_path[0] != '\0') {
      strPath.assign(alternative_config_path);
      strPath += config_name;
      theInstance.readConfig(strPath.c_str(), true);
      if (!theInstance.empty()) {
        return theInstance;
      }
    }
    findConfigFile(config_name, strPath);
    theInstance.readConfig(strPath.c_str(), true);
  }

  return theInstance;
}

/*******************************************************************************
**
** Function:    CNfcConfig::getValue()
**
** Description: get a string value of a setting
**
** Returns:     true if setting exists
**              false if setting does not exist
**
*******************************************************************************/
bool CNfcConfig::getValue(const char* name, char* pValue, size_t& len) const {
  const CNfcParam* pParam = find(name);
  if (pParam == NULL || pValue== NULL) return false;

  if (pParam->str_len() > 0) {
    memset(pValue, 0, len);
    if (len > pParam->str_len()) len = pParam->str_len();
    memcpy(pValue, pParam->str_value(), len);
    return true;
  }
  return false;
}

/*******************************************************************************
**
** Function:    CNfcConfig::getValue()
**
** Description: get a long numerical value of a setting
**
** Returns:     true if setting exists
**              false if setting does not exist
**
*******************************************************************************/
bool CNfcConfig::getValue(const char* name, unsigned long& rValue) const {
  const CNfcParam* pParam = find(name);
  if (pParam == NULL) return false;

  if (pParam->str_len() == 0) {
    rValue = static_cast<unsigned long>(pParam->numValue());
    return true;
  }
  return false;
}

/*******************************************************************************
**
** Function:    CNfcConfig::getValue()
**
** Description: get a short numerical value of a setting
**
** Returns:     true if setting exists
**              false if setting does not exist
**
*******************************************************************************/
bool CNfcConfig::getValue(const char* name, unsigned short& rValue) const {
  const CNfcParam* pParam = find(name);
  if (pParam == NULL) return false;

  if (pParam->str_len() == 0) {
    rValue = static_cast<unsigned short>(pParam->numValue());
    return true;
  }
  return false;
}

/*******************************************************************************
**
** Function:    CNfcConfig::find()
**
** Description: search if a setting exist in the setting array
**
** Returns:     pointer to the setting object
**
*******************************************************************************/
const CNfcParam* CNfcConfig::find(const char* p_name) const {
  if (size() == 0) return NULL;

  for (const_iterator it = begin(), itEnd = end(); it != itEnd; ++it) {
    if (**it < p_name)
      continue;
    else if (**it == p_name) {
      if ((*it)->str_len() > 0) {
        STLOG_HAL_D("%s found %s=%s\n", __func__, p_name, (*it)->str_value());
      } else {
        STLOG_HAL_D("%s found %s=(0x%lX)\n", __func__, p_name, (*it)->numValue());
      }
      return *it;
    } else
      break;
  }
  return NULL;
}

/*******************************************************************************
**
** Function:    CNfcConfig::clean()
**
** Description: reset the setting array
**
** Returns:     none
**
*******************************************************************************/
void CNfcConfig::clean() {
  if (size() == 0) return;

  for (iterator it = begin(), itEnd = end(); it != itEnd; ++it) delete *it;
  clear();
}

/*******************************************************************************
**
** Function:    CNfcConfig::Add()
**
** Description: add a setting object to the list
**
** Returns:     none
**
*******************************************************************************/
void CNfcConfig::add(const CNfcParam* pParam) {
  if (m_list.size() == 0) {
    m_list.push_back(pParam);
    return;
  }
  for (list<const CNfcParam *>::iterator it = m_list.begin(),
                                         itEnd = m_list.end();
       it != itEnd; ++it) {
    if (**it < pParam->c_str()) continue;
    m_list.insert(it, pParam);
    return;
  }
  m_list.push_back(pParam);
}

/*******************************************************************************
**
** Function:    CNfcConfig::moveFromList()
**
** Description: move the setting object from list to array
**
** Returns:     none
**
*******************************************************************************/
void CNfcConfig::moveFromList() {
  if (m_list.size() == 0) return;

  for (list<const CNfcParam *>::iterator it = m_list.begin(),
                                         itEnd = m_list.end();
       it != itEnd; ++it)
    push_back(*it);
  m_list.clear();
}

/*******************************************************************************
**
** Function:    CNfcConfig::moveToList()
**
** Description: move the setting object from array to list
**
** Returns:     none
**
*******************************************************************************/
void CNfcConfig::moveToList() {
  if (m_list.size() != 0) m_list.clear();

  for (iterator it = begin(), itEnd = end(); it != itEnd; ++it)
    m_list.push_back(*it);
  clear();
}

/*******************************************************************************
**
** Function:    CNfcParam::CNfcParam()
**
** Description: class constructor
**
** Returns:     none
**
*******************************************************************************/
CNfcParam::CNfcParam() : m_numValue(0) {}

/*******************************************************************************
**
** Function:    CNfcParam::~CNfcParam()
**
** Description: class destructor
**
** Returns:     none
**
*******************************************************************************/
CNfcParam::~CNfcParam() {}

/*******************************************************************************
**
** Function:    CNfcParam::CNfcParam()
**
** Description: class copy constructor
**
** Returns:     none
**
*******************************************************************************/
CNfcParam::CNfcParam(const char* name, const string& value)
    : string(name), m_str_value(value), m_numValue(0) {}

/*******************************************************************************
**
** Function:    CNfcParam::CNfcParam()
**
** Description: class copy constructor
**
** Returns:     none
**
*******************************************************************************/
CNfcParam::CNfcParam(const char* name, unsigned long value)
    : string(name), m_numValue(value) {}

/*******************************************************************************
**
** Function:    GetStrValue
**
** Description: API function for getting a string value of a setting
**
** Returns:     True if found, otherwise False.
**
*******************************************************************************/
extern "C" int GetStrValue(const char* name, char* pValue, unsigned long l) {
  size_t len = l;
  CNfcConfig& rConfig = CNfcConfig::GetInstance();

  return rConfig.getValue(name, pValue, len);
}

/*******************************************************************************
**
** Function:    GetNumValue
**
** Description: API function for getting a numerical value of a setting
**
** Returns:     True if found, otherwise False.
**
*******************************************************************************/
extern "C" int GetNumValue(const char* name, void* pValue, unsigned long len) {
  if (!pValue) return false;

  CNfcConfig& rConfig = CNfcConfig::GetInstance();
  const CNfcParam* pParam = rConfig.find(name);

  if (pParam == NULL) return false;
  unsigned long v = pParam->numValue();
  if (v == 0 && pParam->str_len() > 0 && pParam->str_len() < 4) {
    const unsigned char* p = (const unsigned char*)pParam->str_value();
    for (size_t i = 0; i < pParam->str_len(); ++i) {
      v *= 256;
      v += *p++;
    }
  }
  switch (len) {
    case sizeof(unsigned long):
      *(static_cast<unsigned long*>(pValue)) = (unsigned long)v;
      break;
    case sizeof(unsigned short):
      *(static_cast<unsigned short*>(pValue)) = (unsigned short)v;
      break;
    case sizeof(unsigned char):
      *(static_cast<unsigned char*>(pValue)) = (unsigned char)v;
      break;
    default:
      return false;
  }
  return true;
}

/*******************************************************************************
**
** Function:    resetConfig
**
** Description: reset settings array
**
** Returns:     none
**
*******************************************************************************/
extern void resetConfig() {
  CNfcConfig& rConfig = CNfcConfig::GetInstance();

  rConfig.clean();
}

/*******************************************************************************
**
** Function:    readOptionalConfig()
**
** Description: read Config settings from an optional conf file
**
** Returns:     none
**
*******************************************************************************/
void readOptionalConfig(const char* extra) {
  string strPath;
  string configName(extra_config_base);
  configName += extra;
  configName += extra_config_ext;

  if (alternative_config_path[0] != '\0') {
    strPath.assign(alternative_config_path);
    strPath += configName;
  } else {
    findConfigFile(configName, strPath);
  }

  CNfcConfig::GetInstance().readConfig(strPath.c_str(), false);
}