///////////////////////////////////////////////////////////////////////////////
// Original Name:        src/common/intl.cpp
// Original Purpose:     Internationalization and localisation for wxWidgets
// Original Author:      Vadim Zeitlin
// Modified by: Charlie Fenton for BOINC  13 June, 2013
// Created:     29/01/98
// Copyright:   (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////
//
// This file is part of BOINC.
// http://boinc.berkeley.edu
//
// Simplified string localization code for use in BOINC adapted from
// wxWidgets src/common/intl.cpp.
//
// For sample code to get preferred system language, see
// wxLocale::GetSystemLanguage() in wxWidgets src/common/intl.cpp
//
// Those portions of this code which are taken from wxWidgets are 
// Copyright:   (c) 1998 Vadim Zeitlin 
// and are covered by the wxWidgets license which can be found here: 
// <http://www.wxwidgets.org/about/licence3.txt>
//
// This code assumes all catalogs are encoded UTF-8
// (Note: wxstd.mo files are encoded ISO 8859-1 not UTF-8.)
//
// We recommended that you first call BOINCTranslationAddCatalog()
// for each desired catalog (*.mo) file for the user's preferred
// language, then for each desired catalog (*.mo) file for the
// user's second preferred language and (optionally) then for each
// desired catalog (*.mo) file for the user's third preferred
// language.  This will make it more likley that a translation 
// will be found in some language useful to the user.
//

#include <stdint.h>
#include <cstring>
#include <cstdio>
#include <cstdlib>
#include <sys/param.h>  // for MAXPATHLEN
#include <sys/stat.h>   // For stat()
#include <filesys.h>

#include "translate.h"

static const uint32_t MSGCATALOG_MAGIC    = 0x950412de;
static const uint32_t MSGCATALOG_MAGIC_SW = 0xde120495;

#define MAXCATALOGS 20
#define VERBOSE true

// an entry in the string table
struct MsgTableEntry {
    uint32_t    nLen;           // length of the string
    uint32_t    ofsString;      // pointer to the string
};

// header of a .mo file
struct MsgCatalogHeader {
    uint32_t    magic,          // offset +00:  magic id
                revision,       //        +04:  revision
                numStrings;     //        +08:  number of strings in the file
    uint32_t    ofsOrigTable,   //        +0C:  start of original string table
                ofsTransTable;  //        +10:  start of translated string table
    uint32_t    nHashSize,      //        +14:  hash table size
                ofsHashTable;   //        +18:  offset of hash table start
};


struct MsgCatalogData {
    uint8_t         *pData;             // Pointer to catalog data
    uint32_t        nSize;              // Amount of memory pointed to by pData.
    uint32_t        NumStrings;         // number of strings in this domain
    bool            bSwapped;           // wrong endianness?
    MsgTableEntry   *pOrigTable;        // pointer to original strings
    MsgTableEntry   *pTransTable;       // pointer to translated strings
    char            languageCode[32];   // language code (e.g., "it_IT")
    char            catalogName[128];   // catalog name (e.g., "BOINC-Setup")
};

static struct MsgCatalogData theCatalogData[MAXCATALOGS];

static uint32_t     numLoadedCatalogs = 0;

// swap the 2 halves of 32 bit integer if needed
static uint32_t Swap(uint32_t ui, bool bSwapped) {
      return bSwapped ? (ui << 24) | ((ui & 0xff00) << 8) |
                          ((ui >> 8) & 0xff00) | (ui >> 24)
                        : ui;
}


// load a catalog from disk
// open disk file and read in it's contents
//
// catalogsDir is the path to the locale directory in
// the BOINC Data directory (ending in "locale/").
//
// language code is the standad language code such
// as "fr" or "zh_CN".
//
// catalogName is the domain (the file name of the
// *.mo file without the .mo such as "BOINC-Manager").
//
// Returns true if successful.
//
static bool LoadCatalog(const char * catalogsDir,
                const char *languageCode,
                const char *catalogName
                ) {
    unsigned int j;
    char searchPath[MAXPATHLEN];
    struct stat sbuf;
    char temp[32];
    char *underscore;
    FILE * f;
    uint8_t *pData;
    uint32_t nSize;
    uint32_t NumStrings;
    bool  bSwapped;
    MsgTableEntry *pOrigTable;
    MsgTableEntry *pTransTable;
    MsgCatalogData *pCatalog;
    
#if VERBOSE
    fprintf(stderr, "Attempting to load catalog %s for language code %s\n",
            catalogName, languageCode);
#endif
    for (j=0; j<numLoadedCatalogs; ++j) {
        pCatalog = &(theCatalogData[j]);
        if (!strcmp(pCatalog->catalogName, catalogName)) {
            if (!strcmp(pCatalog->languageCode, languageCode)) {
                // Don't load a catalog twice for the same language
#if VERBOSE
                fprintf(stderr, "Ignoring Catalog %s for language code %s; it was already loaded\n",
                        catalogName, languageCode);
#endif
                return true;    // Already loaded
            }
            // Don't load more languages for this catalog
            // if we've already "loaded" it for English
            if (!strcmp(pCatalog->languageCode, "en")) {
#if VERBOSE
                fprintf(stderr, "Ignoring Catalog %s for language code %s; after English for same catalog\n",
                        catalogName, languageCode);
#endif
                return true;    // Already loaded
            }
        }
    }
    
    // Since the original strings are English, no 
    // translation is needed for language en.
    if (!strcmp("en", languageCode)) {
        pCatalog = &(theCatalogData[numLoadedCatalogs++]);
        strlcpy(pCatalog->languageCode, languageCode, sizeof(pCatalog->languageCode));
        strlcpy(pCatalog->catalogName, catalogName, sizeof(pCatalog->catalogName));
        return true;
    }
  
    strlcpy(searchPath, catalogsDir, sizeof(searchPath));
    strlcat(searchPath, languageCode, sizeof(searchPath));
    strlcat(searchPath, "/", sizeof(searchPath));
    strlcat(searchPath, catalogName, sizeof(searchPath));
    strlcat(searchPath, ".mo", sizeof(searchPath));
    if (stat(searchPath, &sbuf) != 0) {
        // Try just base locale name: for things like "fr_BE" (belgium
        // french) we should use "fr" if no belgium specific message 
        // catalogs exist
        strlcpy(temp, languageCode, sizeof(temp));
        underscore = strchr(temp, (int)'_');
        if (underscore == NULL) return false;
        *underscore = '\0';
        strlcpy(searchPath, catalogsDir, sizeof(searchPath));
        strlcat(searchPath, temp, sizeof(searchPath));
        strlcat(searchPath, "/", sizeof(searchPath));
        strlcat(searchPath, catalogName, sizeof(searchPath));
        strlcat(searchPath, ".mo", sizeof(searchPath));
        if (stat(searchPath, &sbuf) != 0) return false;
    }
    

    pData = (uint8_t*)malloc(sbuf.st_size);
    if (pData == NULL) return false;
    f = fopen(searchPath, "r");
    if (f == NULL) {
        free(pData);
        pData = NULL;
        return false;
    }
    nSize = fread(pData, 1, sbuf.st_size, f);
    fclose(f);
    if (nSize != sbuf.st_size) {
        free(pData);
        pData = NULL;
        return false;
    }
    
    // examine header
    bool bValid = nSize + (size_t)0 > sizeof(MsgCatalogHeader);

    MsgCatalogHeader *pHeader = (MsgCatalogHeader *)pData;
    if ( bValid ) {
    // we'll have to swap all the integers if it's true
    bSwapped = pHeader->magic == MSGCATALOG_MAGIC_SW;

    // check the magic number
    bValid = bSwapped || pHeader->magic == MSGCATALOG_MAGIC;
    }

    if ( !bValid ) {
        // it's either too short or has incorrect magic number
        free(pData);
        pData = NULL;
        return false;
    }

    // initialize
    NumStrings  = Swap(pHeader->numStrings, bSwapped);
    if (NumStrings <= 1) {
        // This file has no translations (is effectively 
        // empty) so don't load it for better efficiency.
#if VERBOSE
        fprintf(stderr, "File %s contains no translated strings!\n", searchPath);
#endif
        free(pData);
        pData = NULL;
        return true;    // Not an error
    }
    pOrigTable  = (MsgTableEntry *)(pData +
                   Swap(pHeader->ofsOrigTable, bSwapped));
    pTransTable = (MsgTableEntry *)(pData +
                   Swap(pHeader->ofsTransTable, bSwapped));


    // now parse catalog's header and try to extract catalog charset
    uint32_t ofsString = Swap(pOrigTable->ofsString, bSwapped);
    // this check could fail for a corrupt message catalog
    if ( ofsString + Swap(pOrigTable->nLen, bSwapped) <= nSize) {
        char *begin = strstr((char *)(pData + Swap(pTransTable->ofsString, bSwapped)),
                            "Content-Type: text/plain; charset="
                            );
        if (begin != NULL) {
            begin += 34; //strlen("Content-Type: text/plain; charset=")
            if (strncasecmp(begin, "utf-8", 5)) {
#if VERBOSE
                fprintf(stderr, "File %s is not utf-8!\n", searchPath);
#endif
                free(pData);
                pData = NULL;
                return false;
            }
        }
    }

    pCatalog = &(theCatalogData[numLoadedCatalogs++]);
    pCatalog->pData = pData;
    pCatalog->nSize = nSize;
    pCatalog->NumStrings = NumStrings;
    pCatalog->bSwapped = bSwapped;
    pCatalog->pOrigTable = pOrigTable;
    pCatalog->pTransTable = pTransTable;
    strlcpy(pCatalog->languageCode, languageCode, sizeof(pCatalog->languageCode));
    strlcpy(pCatalog->catalogName, catalogName, sizeof(pCatalog->catalogName));
#if VERBOSE
    fprintf(stderr, "Successfully loaded catalog %s for language code %s\n",
            catalogName, languageCode);
#endif
    return true;
}


// Searches through the catalogs in the order they were added
// until it finds a translation for the src string, and
// returns a ponter to the UTF-8 encoded localized string.
// Returns a pointer to the original string if no translation
// was found.
//
uint8_t * _(char *src) {
    unsigned int i, j;
    MsgCatalogData *pCatalog;
    
    for (j=0; j<numLoadedCatalogs; ++j) {
        pCatalog = &(theCatalogData[j]);
        
        // Since the original strings are English, no 
        // translation is needed for language en.
        if (!strcmp("en", pCatalog->languageCode)) {
            continue;   // Try next catalog
        }
        
        if (pCatalog->pData == NULL) continue;    // Should never happen
        for (i=0; i<pCatalog->NumStrings; ++i) {
            if (!strcmp((char *)pCatalog->pData + pCatalog->pOrigTable[i].ofsString, src)) {
                return (pCatalog->pData + pCatalog->pTransTable[i].ofsString);
            }
        }
    }

    return (uint8_t *)src;
}


// catalogsDir is the path to the locale directory in
// the BOINC Data directory (ending in "locale/").
//
// language code is the standad language code such
// as "fr" or "zh_CN".
//
// catalogName is the domain (the file name of the
// *.mo file without the .mo such as "BOINC-Manager").
//
// Returns true if successful.
//
bool BOINCTranslationAddCatalog(const char * catalogsDir,
                                const char *languageCode,
                                const char * catalogName
                                ) {
    bool success = false;
    DIRREF dirp;
    char filename[64];
    int retval;
    
    if (numLoadedCatalogs >= (MAXCATALOGS)) {
#if VERBOSE
        fprintf(stderr, "Trying to load too many catalogs\n");
#endif
        return false;
    }

    // Add a catalog for this exact language and region code
    success = LoadCatalog(catalogsDir, languageCode, catalogName);
    
    // Add catalogs for the same language code but different region codes
    dirp = dir_open(catalogsDir);
    if (dirp) {
        while (true) {
            retval = dir_scan(filename, dirp, sizeof(filename));
            if (retval) break;
            if (!strcmp(languageCode, filename)) continue;  // Already added above
            if (!strncmp(languageCode, filename, 2)) {  // First 2 characters match
                if (LoadCatalog(catalogsDir, filename, catalogName)) {
                    success = true;
                }
            }
        }
        
        dir_close(dirp);
    }
    
    return success;
}


void BOINCTranslationInit() {
    int i;
    MsgCatalogData *pCatalog;
    
    numLoadedCatalogs = 0;
    
    for (i=0; i<MAXCATALOGS; ++i) {
        pCatalog = &(theCatalogData[i]);
        pCatalog->pData = NULL;
        pCatalog->nSize = 0;
        pCatalog->NumStrings = 0;
        pCatalog->bSwapped = false;
        pCatalog->pOrigTable = NULL;
        pCatalog->pTransTable = NULL;
        pCatalog->languageCode[0] = '\0';
        pCatalog->catalogName[0] = '\0';
        
    }
}


void BOINCTranslationCleanup() {
    int i;
    MsgCatalogData *pCatalog;
    
    for (i=0; i<MAXCATALOGS; ++i) {
        pCatalog = &(theCatalogData[i]);
        if (pCatalog->pData) free(pCatalog->pData);
        pCatalog->pData = NULL;
        pCatalog->nSize = 0;
        pCatalog->NumStrings = 0;
        pCatalog->bSwapped = false;
        pCatalog->pOrigTable = NULL;
        pCatalog->pTransTable = NULL;
        pCatalog->languageCode[0] = '\0';
        pCatalog->catalogName[0] = '\0';
    }

    numLoadedCatalogs = 0;
}