/*
**
** Copyright 2009, The Android Open Source Project
**
** 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.
*/

#include "dictionary.h"
#include "jni.h"

#include <assert.h>
#include <stdio.h>

// ----------------------------------------------------------------------------

using namespace latinime;

//
// helper function to throw an exception
//
static void throwException(JNIEnv *env, const char* ex, const char* fmt, int data) {
    if (jclass cls = env->FindClass(ex)) {
        char msg[1000];
        sprintf(msg, fmt, data);
        env->ThrowNew(cls, msg);
        env->DeleteLocalRef(cls);
    }
}

static jint latinime_BinaryDictionary_open(JNIEnv *env, jobject object, jobject dictDirectBuffer,
        jint typedLetterMultiplier, jint fullWordMultiplier, jint maxWordLength, jint maxWords,
        jint maxAlternatives) {
    void *dict = env->GetDirectBufferAddress(dictDirectBuffer);
    if (dict == NULL) {
        fprintf(stderr, "DICT: Dictionary buffer is null\n");
        return 0;
    }
    Dictionary *dictionary = new Dictionary(dict, typedLetterMultiplier, fullWordMultiplier,
            maxWordLength, maxWords, maxAlternatives);
    return (jint) dictionary;
}

static int latinime_BinaryDictionary_getSuggestions(JNIEnv *env, jobject object, jint dict,
        jintArray inputArray, jint arraySize, jcharArray outputArray, jintArray frequencyArray,
        jintArray nextLettersArray, jint nextLettersSize) {
    Dictionary *dictionary = (Dictionary*) dict;
    if (dictionary == NULL) return 0;

    int *frequencies = env->GetIntArrayElements(frequencyArray, NULL);
    int *inputCodes = env->GetIntArrayElements(inputArray, NULL);
    jchar *outputChars = env->GetCharArrayElements(outputArray, NULL);
    int *nextLetters = nextLettersArray != NULL ? env->GetIntArrayElements(nextLettersArray, NULL)
            : NULL;

    int count = dictionary->getSuggestions(inputCodes, arraySize, (unsigned short*) outputChars,
            frequencies, nextLetters, nextLettersSize);

    env->ReleaseIntArrayElements(frequencyArray, frequencies, 0);
    env->ReleaseIntArrayElements(inputArray, inputCodes, JNI_ABORT);
    env->ReleaseCharArrayElements(outputArray, outputChars, 0);
    if (nextLetters) {
        env->ReleaseIntArrayElements(nextLettersArray, nextLetters, 0);
    }

    return count;
}

static int latinime_BinaryDictionary_getBigrams(JNIEnv *env, jobject object, jint dict,
        jcharArray prevWordArray, jint prevWordLength, jintArray inputArray, jint inputArraySize,
        jcharArray outputArray, jintArray frequencyArray, jint maxWordLength, jint maxBigrams,
        jint maxAlternatives) {
    Dictionary *dictionary = (Dictionary*) dict;
    if (dictionary == NULL) return 0;

    jchar *prevWord = env->GetCharArrayElements(prevWordArray, NULL);
    int *inputCodes = env->GetIntArrayElements(inputArray, NULL);
    jchar *outputChars = env->GetCharArrayElements(outputArray, NULL);
    int *frequencies = env->GetIntArrayElements(frequencyArray, NULL);

    int count = dictionary->getBigrams((unsigned short*) prevWord, prevWordLength, inputCodes,
            inputArraySize, (unsigned short*) outputChars, frequencies, maxWordLength, maxBigrams,
            maxAlternatives);

    env->ReleaseCharArrayElements(prevWordArray, prevWord, JNI_ABORT);
    env->ReleaseIntArrayElements(inputArray, inputCodes, JNI_ABORT);
    env->ReleaseCharArrayElements(outputArray, outputChars, 0);
    env->ReleaseIntArrayElements(frequencyArray, frequencies, 0);

    return count;
}


static jboolean latinime_BinaryDictionary_isValidWord(JNIEnv *env, jobject object, jint dict,
        jcharArray wordArray, jint wordLength) {
    Dictionary *dictionary = (Dictionary*) dict;
    if (dictionary == NULL) return (jboolean) false;

    jchar *word = env->GetCharArrayElements(wordArray, NULL);
    jboolean result = dictionary->isValidWord((unsigned short*) word, wordLength);
    env->ReleaseCharArrayElements(wordArray, word, JNI_ABORT);

    return result;
}

static void latinime_BinaryDictionary_close(JNIEnv *env, jobject object, jint dict) {
    delete (Dictionary*) dict;
}

// ----------------------------------------------------------------------------

static JNINativeMethod gMethods[] = {
    {"openNative", "(Ljava/nio/ByteBuffer;IIIII)I", (void*)latinime_BinaryDictionary_open},
    {"closeNative", "(I)V", (void*)latinime_BinaryDictionary_close},
    {"getSuggestionsNative", "(I[II[C[I[II)I", (void*)latinime_BinaryDictionary_getSuggestions},
    {"isValidWordNative", "(I[CI)Z", (void*)latinime_BinaryDictionary_isValidWord},
    {"getBigramsNative", "(I[CI[II[C[IIII)I", (void*)latinime_BinaryDictionary_getBigrams}
};

static int registerNativeMethods(JNIEnv* env, const char* className, JNINativeMethod* gMethods,
        int numMethods) {
    jclass clazz;

    clazz = env->FindClass(className);
    if (clazz == NULL) {
        fprintf(stderr, "Native registration unable to find class '%s'\n", className);
        return JNI_FALSE;
    }
    if (env->RegisterNatives(clazz, gMethods, numMethods) < 0) {
        fprintf(stderr, "RegisterNatives failed for '%s'\n", className);
        return JNI_FALSE;
    }

    return JNI_TRUE;
}

static int registerNatives(JNIEnv *env) {
    const char* const kClassPathName = "com/android/inputmethod/latin/BinaryDictionary";
    return registerNativeMethods(env, kClassPathName, gMethods,
            sizeof(gMethods) / sizeof(gMethods[0]));
}

/*
 * Returns the JNI version on success, -1 on failure.
 */
jint JNI_OnLoad(JavaVM* vm, void* reserved) {
    JNIEnv* env = NULL;
    jint result = -1;

    if (vm->GetEnv((void**) &env, JNI_VERSION_1_4) != JNI_OK) {
        fprintf(stderr, "ERROR: GetEnv failed\n");
        goto bail;
    }
    assert(env != NULL);

    if (!registerNatives(env)) {
        fprintf(stderr, "ERROR: BinaryDictionary native registration failed\n");
        goto bail;
    }

    /* success -- return valid version number */
    result = JNI_VERSION_1_4;

bail:
    return result;
}