/*
  LibRCC - module providing charset recoding for the specified language

  Copyright (C) 2005-2018 Suren A. Chilingaryan <csa@suren.me>

  This library is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License version 2.1 or later
  as published by the Free Software Foundation.

  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 Lesser General Public License 
  for more details.

  You should have received a copy of the GNU Lesser General Public License 
  along with this program; if not, write to the Free Software Foundation, Inc.,
  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

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

#include "../config.h"

#include "internal.h"
#include "fs.h"

static rcc_autocharset_id rccConfigDetectCharsetInternal(rcc_language_config config, rcc_class_id class_id, const char *buf, size_t len) {
    int err;
    rcc_context ctx;
    rcc_class_type class_type;
    rcc_autocharset_id autocharset_id;
    
    if ((!buf)||(!config)) return (rcc_autocharset_id)-1;
    
    ctx = config->ctx;

    err = rccConfigConfigure(config);
    if (err) return (rcc_autocharset_id)-1;
    
    class_type = rccGetClassType(ctx, class_id);
    if ((class_type != RCC_CLASS_FS)||((class_type == RCC_CLASS_FS)&&(rccGetOption(ctx, RCC_OPTION_AUTODETECT_FS_TITLES)))) {
	rccMutexLock(config->mutex);
	autocharset_id = rccEngineDetectCharset(&config->engine_ctx, buf, len);
	rccMutexUnLock(config->mutex);
	return autocharset_id;
    }
    
    return (rcc_autocharset_id)-1;
}


rcc_autocharset_id rccConfigDetectCharset(rcc_language_config config, rcc_class_id class_id, const char *buf, size_t len) {
    return rccConfigDetectCharsetInternal(config, class_id, buf, len);
}

rcc_string rccConfigSizedFrom(rcc_language_config config, rcc_class_id class_id, const char *buf, size_t len) {
    rcc_context ctx;
    rcc_class_type class_type;
    rcc_string result;
    rcc_option_value usedb4;
    rcc_autocharset_id charset_id;
    const char *charset;


    if (!config) return NULL;
    ctx = config->ctx;

    if (rccStringSizedCheck(buf, len)) return NULL;
    
    usedb4 = rccGetOption(ctx, RCC_OPTION_LEARNING_MODE);

    if (usedb4&RCC_OPTION_LEARNING_FLAG_USE) {
	result = rccDb4GetKey(ctx->db4ctx, buf, len);
	if (result) {
	     if (rccStringFixID(result, ctx)) free(result);
	     else return result;
	}
    }

    class_type = rccGetClassType(ctx, class_id);

    if (class_type == RCC_CLASS_KNOWN) charset_id = (rcc_autocharset_id)-1;
    else charset_id = rccConfigDetectCharset(config, class_id, buf, len);
    if (charset_id != (rcc_autocharset_id)-1)
	charset = rccConfigGetAutoCharsetName(config, charset_id);
    else
	charset = rccConfigGetCurrentCharsetName(config, class_id);
    
    if (charset) {
	result = rccSizedFromCharset(ctx, charset, buf, len);
	if (result) rccStringChangeID(result, rccGetLanguageByName(ctx, config->language->sn));
	return result;
    }
    
    return NULL;
}

/* The supplied config have priority over language tag in the buf! */
char *rccConfigSizedTo(rcc_language_config config, rcc_class_id class_id, rcc_const_string buf, size_t *rlen) {
    char *result;
    const char *charset;

    if (!config) return NULL;

    if ((rccGetClassType(config->ctx, class_id) == RCC_CLASS_FS)&&(rccGetOption(config->ctx, RCC_OPTION_AUTODETECT_FS_NAMES))) {
	result = rccFS5(config->ctx, config, class_id, rccStringGetString(buf));
	if (result) {
	    if (rlen) *rlen = strlen(result);
	    return result;
	}
    }

    charset = rccConfigGetCurrentCharsetName(config, class_id);

    if (charset)
	return rccSizedToCharset(config->ctx, charset, buf, rlen);
    
    return NULL;
}


char *rccConfigSizedRecode(rcc_language_config config, rcc_class_id from, rcc_class_id to, const char *buf, size_t len, size_t *rlen) {
    rcc_context ctx;
    rcc_class_type class_type;
    rcc_string result;
    rcc_option_value usedb4;
    rcc_autocharset_id charset_id;
    rcc_string stmp;
    const char *tocharset, *fromcharset;


    if (!config) return NULL;
    ctx = config->ctx;

    if (rccStringSizedCheck(buf, len)) return NULL;
    
    usedb4 = rccGetOption(ctx, RCC_OPTION_LEARNING_MODE);

    if (usedb4&RCC_OPTION_LEARNING_FLAG_USE) {
	stmp = rccDb4GetKey(ctx->db4ctx, buf, len);
	if (stmp) {
	     if (rccStringFixID(stmp, ctx)) free(stmp);
	     else {
		result = rccConfigSizedTo(config, to, stmp, rlen);
		free(stmp);
		return result;
	    }
	}
    }

    class_type = rccGetClassType(ctx, from);

    if (class_type == RCC_CLASS_KNOWN) charset_id = (rcc_autocharset_id)-1;
    else charset_id = rccConfigDetectCharset(config, from, buf, len);
    if (charset_id != (rcc_autocharset_id)-1)
	fromcharset = rccConfigGetAutoCharsetName(config, charset_id);
    else
	fromcharset = rccConfigGetCurrentCharsetName(config, from);
    
    tocharset = rccConfigGetCurrentCharsetName(config, to);
    
    if ((fromcharset)&&(tocharset))
	return rccSizedRecodeCharsets(ctx, fromcharset, tocharset, buf, len, rlen);

    return NULL;

}


char *rccConfigSizedRecodeToCharset(rcc_language_config config, rcc_class_id class_id, const char *charset, rcc_const_string buf, size_t len, size_t *rlen) {
    rcc_context ctx;
    rcc_class_type class_type;
    rcc_string result;
    rcc_option_value usedb4;
    rcc_autocharset_id charset_id;
    rcc_string stmp;
    const char *ocharset;


    if (!config) return NULL;
    ctx = config->ctx;

    if (rccStringSizedCheck(buf, len)) return NULL;
    
    usedb4 = rccGetOption(ctx, RCC_OPTION_LEARNING_MODE);

    if (usedb4&RCC_OPTION_LEARNING_FLAG_USE) {
	stmp = rccDb4GetKey(ctx->db4ctx, buf, len);
	if (stmp) {
	     if (rccStringFixID(stmp, ctx)) free(stmp);
	     else {
		result = rccSizedToCharset(ctx, charset, stmp, rlen);
		free(stmp);
	        return result;
	    }
	}
    }

    class_type = rccGetClassType(ctx, class_id);

    if (class_type == RCC_CLASS_KNOWN) charset_id = (rcc_autocharset_id)-1;
    else charset_id = rccConfigDetectCharset(config, class_id, buf, len);
    if (charset_id != (rcc_autocharset_id)-1)
	ocharset = rccConfigGetAutoCharsetName(config, charset_id);
    else
	ocharset = rccConfigGetCurrentCharsetName(config, class_id);
    
    if (ocharset)
	return rccSizedRecodeCharsets(ctx, ocharset, charset, buf, len, rlen);

    return NULL;
}

char *rccConfigSizedRecodeFromCharset(rcc_language_config config, rcc_class_id class_id, const char *charset, const char *buf, size_t len, size_t *rlen) {
    rcc_context ctx;
    const char *ocharset;

    if (!config) return NULL;
    ctx = config->ctx;

    ocharset = rccConfigGetCurrentCharsetName(config, class_id);

    if (ocharset)
	return rccSizedRecodeCharsets(ctx, charset, ocharset, buf, len, rlen);

    return NULL;
}