/************************************************************************************
   Copyright (C) 2014,2020 MariaDB Corporation AB
   
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.
   
   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.
   
   You should have received a copy of the GNU Library General Public
   License along with this library; if not see <http://www.gnu.org/licenses>
   or write to the Free Software Foundation, Inc., 
   51 Franklin St., Fifth Floor, Boston, MA 02110, USA
*************************************************************************************/


/* MariaDB ODBC driver helper functions for platforms other than windows(so far) */

/* NOTE If you change something in this program, please consider if other platform's version 
        of the function you are changing, needs to be changed accordingly */

#include <ma_odbc.h>
#include <stdarg.h>
#include "ma_conv_charset.h"

extern MARIADB_CHARSET_INFO *DmUnicodeCs;
extern Client_Charset utf8;

char LogFile[256];


void InitializeCriticalSection(CRITICAL_SECTION *cs)
{
  pthread_mutexattr_t attr;

  pthread_mutexattr_init(&attr);
  pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
  pthread_mutex_init(cs, &attr);
}

int DSNPrompt_Lookup(MADB_Prompt *prompt, const char * SetupLibName)
{
  return MADB_PROMPT_NOT_SUPPORTED;
}


int DSNPrompt_Free  (MADB_Prompt *prompt)
{
  prompt->LibraryHandle= NULL;

  return 0;
}

/* Mimicking of VS' _snprintf */
int _snprintf(char *buffer, size_t count, const char *format, ...)
{
    va_list list;
    va_start(list, format);
    int result= vsnprintf(buffer, count, format, list);

    va_end(list);

    /* _snprintf returns negative number if buffer is not big enough */
    if (result > count)
    {
      return count - result - 1;
    }
    return result;
}


int strcpy_s(char *dest, size_t buffer_size, const char *src)
{
  size_t src_len;

  if (dest == NULL)
  {
    return EINVAL;
  }

  if (src == NULL)
  {
    *dest= '\0';
    return EINVAL;
  }

  src_len= strlen(src);

  if (buffer_size < src_len + 1)
  {
    *dest= 0;
    return ERANGE;
  }

  memcpy((void*)dest, (void*)src, src_len + 1);

  return 0;
}


const char* GetDefaultLogDir()
{
  const char *DefaultLogDir="/tmp";
  char *tmp= getenv("HOME");

  if (tmp)
  {
    DefaultLogDir= tmp;
  }

  _snprintf(LogFile, sizeof(LogFile), "%s/maodbc.log", DefaultLogDir);

  return LogFile;
}


/* CharLen < 0 - treat as NTS */
SQLINTEGER SqlwcsOctetLen(const SQLWCHAR *str, SQLINTEGER *CharLen)
{
  SQLINTEGER result= 0, inChars= *CharLen;

  if (str)
  {
    while (inChars > 0 || (inChars < 0 && *str))
    {
      result+= DmUnicodeCs->mb_charlen(*str);
      --inChars;
      str+= DmUnicodeCs->mb_charlen(*str)/sizeof(SQLWCHAR);
    }
  }

  if (*CharLen < 0)
  {
    *CharLen-= inChars;
  }
  return result;
}


SQLWCHAR *MADB_ConvertToWchar(const char *Ptr, SQLLEN PtrLength, Client_Charset* cc)
{
  SQLWCHAR *WStr= NULL;
  size_t Length= 0;

  if (!Ptr)
    return WStr;

  if (PtrLength == SQL_NTS)
  {
    PtrLength= -1;
    /* To copy terminating null as well */
    Length= 1;
  }

  if (!cc || !cc->CodePage)
    cc= &utf8;

  Length+= MbstrOctetLen(Ptr, &PtrLength, cc->cs_info);

  if ((WStr= (SQLWCHAR *)MADB_CALLOC(sizeof(SQLWCHAR) * (PtrLength + 1))))
  {
    size_t wstr_octet_len= sizeof(SQLWCHAR) * (PtrLength + 1);
    /* TODO: Need error processing. i.e. if MADB_ConvertString returns -1 */
    MADB_ConvertString(Ptr, &Length, cc->cs_info, (char*)WStr, &wstr_octet_len, DmUnicodeCs, NULL);
  }

  return WStr;
}


/* {{{ MADB_ConvertFromWChar */
char *MADB_ConvertFromWChar(const SQLWCHAR *Ptr, SQLINTEGER PtrLength, SQLULEN *Length, Client_Charset *cc,
                            BOOL *Error)
{
  char *AscStr;
  size_t AscLen= PtrLength, PtrOctetLen;
  BOOL dummyError= 0;
  
  if (Error)
  {
    *Error= 0;
  }
  else
  {
    Error= &dummyError;
  }

  if (cc == NULL || cc->CodePage < 1)
  {
    cc= &utf8;
  }

  if (PtrLength == SQL_NTS)
  {
    /*-1 - to calculate length as of nts */
    SQLINTEGER InCharLen= -1;
    PtrOctetLen= SqlwcsOctetLen(Ptr, &InCharLen);
    /* Allocating +1 character for terminating symbol */
    AscLen= (InCharLen+1)*cc->cs_info->char_maxlen;
  }
  else
  {
    /* PtrLength is in characters. MADB_ConvertString(iconv) needs bytes */
    PtrOctetLen= SqlwcsOctetLen(Ptr, &PtrLength);
    AscLen= PtrLength*cc->cs_info->char_maxlen;
  }

  if (!(AscStr = (char *)MADB_CALLOC(AscLen)))
    return NULL;

  AscLen= MADB_ConvertString((char*)Ptr, &PtrOctetLen, DmUnicodeCs, AscStr, &AscLen, cc->cs_info, Error);

  if (AscLen != (size_t)-1)
  {
    if (PtrLength == -1 && AscLen > 0)
    {
      --AscLen;
    }
  }
  else
  {
    MADB_FREE(AscStr);
    AscLen= 0;
  }
  if (Length)
    *Length= (SQLINTEGER)AscLen;

  return AscStr;
}
/* }}} */

/* {{{ MADB_ConvertAnsi2Unicode
       @AnsiLength[in]    - number of bytes to copy, negative if AnsiString is Null terminated and the terminating blank has to be copied
       @UnicodeLength[in] - size of output buffer in chars, that effectively mean in SQLWCHAR units
       @LengthIndicator[out] - number of available characters not counting terminating null(unless it was included in AnsiLength, and IsNull
                            is FALSE) 
       @IsNull[in]        - whether to copy terminating blank. The value has to be 1 or 0(TRUE/FALSE)
                            If AnsiString is negative, its value is neglected(null is copied)
       @returns 1 in case of error, 0 otherwise */
int MADB_ConvertAnsi2Unicode(Client_Charset *cc, const char *AnsiString, SQLLEN AnsiLength, 
                             SQLWCHAR *UnicodeString, SQLLEN UnicodeLength, 
                             SQLLEN *LengthIndicator, BOOL IsNull, MADB_Error *Error)
{
  SQLINTEGER  RequiredLength;
  SQLWCHAR   *Tmp= UnicodeString;
  int         rc= 0, error;
  size_t      SrcOctetLen, DestOctetLen;

  if (LengthIndicator)
    *LengthIndicator= 0;

  if (Error)
    MADB_CLEAR_ERROR(Error);

  if (!AnsiLength || UnicodeLength < 0)
  {
    if (Error)
      MADB_SetError(Error, MADB_ERR_HY090, NULL, 0);
    return 1;
  }

  if (AnsiLength == SQL_NTS || AnsiLength == -1)
  {
    IsNull= 1;
    AnsiLength= strlen(AnsiString);
  }

  /* calculate required length */
  RequiredLength= MbstrCharLen(AnsiString, AnsiLength, cc->cs_info) + IsNull;

  /* Set LengthIndicator */
  if (LengthIndicator)
    *LengthIndicator= RequiredLength - IsNull;
  /* No buffer length, no need to copy - got length and run */
  if (!UnicodeLength)
    return 0;

  if (RequiredLength > UnicodeLength)
  {
    Tmp= (SQLWCHAR *)malloc(RequiredLength * sizeof(SQLWCHAR));
    if (Tmp == NULL)
    {
      if (Error)
      {
        MADB_SetError(Error, MADB_ERR_HY001, NULL, 0);
      }
      return 1;
    }
  }
  else
  {
    RequiredLength= UnicodeLength;
  }

  SrcOctetLen= AnsiLength + IsNull;
  DestOctetLen= sizeof(SQLWCHAR) * RequiredLength;

  RequiredLength= MADB_ConvertString(AnsiString, &SrcOctetLen, cc->cs_info, 
                                        (char*)Tmp, &DestOctetLen, DmUnicodeCs, &error);

  if (RequiredLength < 1)
  {
    if (Error)
      MADB_SetError(Error, MADB_ERR_HY000, "Ansi to Unicode conversion error occurred", error);
    rc= 1;
    goto end;
  }

  if (LengthIndicator)
    *LengthIndicator= SqlwcsCharLen(Tmp, RequiredLength);

  /* Truncation */
  if (Tmp != UnicodeString)
  {
    memcpy((void*)UnicodeString, (void*)Tmp, (UnicodeLength-1)*sizeof(SQLWCHAR));
    *(UnicodeString + UnicodeLength - 1)= 0;

    if (Error)
      MADB_SetError(Error, MADB_ERR_01004, NULL, 0);
  }
end:
  if (Tmp != UnicodeString)
    free(Tmp);
  return rc;
}
/* }}} */

/* {{{ MADB_ConvertAnsi2Unicode
       @returns number of characters available at Src */
SQLLEN MADB_SetString(Client_Charset* cc, void *Dest, SQLULEN DestLength,
                      const char *Src, SQLLEN SrcLength/*bytes*/, MADB_Error *Error)
{
  SQLLEN Length= 0;

  if (SrcLength == SQL_NTS)
  {
    if (Src != NULL)
    {
      /* Thinking about utf8 - Should be probably len in characters */
      SrcLength= strlen(Src);
    }
    else
    {
      SrcLength= 0;
    }
  }

  /* Not enough space */
  if (!DestLength || !Dest)
  {
    if (Dest)
      MADB_SetError(Error, MADB_ERR_01004, NULL, 0);
    if (!cc)
      return SrcLength;
    else
    {
      Length= MbstrCharLen(Src, SrcLength, cc->cs_info);

      /* In case of !DestLength || !Dest(application didn't give buffer and probably wants to know required length)
       * we most probably have empty Src, and Length will be equal 0 in this case.
       * Taking source length as character length. MultiByteToWideChar on windows does that for us */
      return Length == 0 && SrcLength > 0 ? SrcLength : Length;
    }
  }

  if (!SrcLength || !Src || !strlen(Src))
  {
    memset((char *)Dest, 0, cc ? sizeof(SQLWCHAR) : sizeof(SQLCHAR));
    return 0;
  }

  if (!cc)
  {
    strncpy_s((char *)Dest, DestLength, Src ? Src : "", _TRUNCATE);
    /* strncpy does not write null at the end */
    *((char *)Dest + MIN(SrcLength, DestLength - 1))= '\0';

    if (Error && SrcLength >= DestLength)
      MADB_SetError(Error, MADB_ERR_01004, NULL, 0);
    return SrcLength;
  }
  else
  {
    MADB_ConvertAnsi2Unicode(cc, Src, -1, (SQLWCHAR *)Dest, DestLength, &Length, TRUE, Error);
    return Length;
  }
}
/* }}} */


/* Stub - needed on windows only */
int GetSourceAnsiCs(Client_Charset *cc)
{
  CopyClientCharset(&utf8, cc);
  return cc->CodePage;
}

/* {{{ MADB_DSN_PossibleConnect(MADB_Dsn *) */
BOOL MADB_DSN_PossibleConnect(MADB_Dsn *Dsn)
{
  return Dsn->Socket || (Dsn->ServerName && Dsn->Port > 0 && Dsn->IsTcpIp);
}


/* Stub - atm it looks like we don't need to do anything here */
char* MADB_GetDefaultPluginsDir(char* Buffer, size_t Size)
{
  return NULL;
}