/*

 *  Copyright (c) 2014, Facebook, Inc.

 *  All rights reserved.

 *

 *  This source code is licensed under the BSD-style license found in the

 *  LICENSE file in the root directory of this source tree. An additional grant

 *  of patent rights can be found in the PATENTS file in the same directory.

 *

 */

/*

 * This header file defines miscellaneous utility classes.

 *

 * @author Tian Xia <tianx@fb.com>

 *

 *  this file is copied from 

 * https://github.com/facebook/mysql-5.6/blob/fb-mysql-5.6.35/fbson/FbsonUtil.h

 * and modified by Doris

 */

#ifndef JSONB_JSONBUTIL_H

#define JSONB_JSONBUTIL_H

#include "common/status.h"

#include "util/jsonb_document.h"

#include "util/jsonb_stream.h"

namespace doris {

#define OUT_BUF_SIZE 1024

/*

 * JsonbToJson converts an JsonbValue object to a JSON string.

 */

class JsonbToJson {

public:

    JsonbToJson() : os_(buffer_, OUT_BUF_SIZE) {}

    // get json string

    std::string to_json_string(const char* data, size_t size) {

        const JsonbDocument* pdoc;

        THROW_IF_ERROR(doris::JsonbDocument::checkAndCreateDocument(data, size, &pdoc));

        return to_json_string(pdoc->getValue());

    }

    std::string to_json_string(const JsonbValue* val) {

        os_.clear();

        os_.seekp(0);

        if (val) {

            intern_json(val);

        }

        os_.put(0);

        std::string json_string {os_.getBuffer()};

        return json_string;

    }

    static std::string jsonb_to_json_string(const char* data, size_t size) {

        JsonbToJson jsonb_to_json;

        return jsonb_to_json.to_json_string(data, size);

    }

private:

    // recursively convert JsonbValue

    void intern_json(const JsonbValue* val) {

        switch (val->type) {

        case JsonbType::T_Null: {

            os_.write("null", 4);

            break;

        }

        case JsonbType::T_True: {

            os_.write("true", 4);

            break;

        }

        case JsonbType::T_False: {

            os_.write("false", 5);

            break;

        }

        case JsonbType::T_Int8: {

            os_.write(val->unpack<JsonbInt8Val>()->val());

            break;

        }

        case JsonbType::T_Int16: {

            os_.write(val->unpack<JsonbInt16Val>()->val());

            break;

        }

        case JsonbType::T_Int32: {

            os_.write(val->unpack<JsonbInt32Val>()->val());

            break;

        }

        case JsonbType::T_Int64: {

            os_.write(val->unpack<JsonbInt64Val>()->val());

            break;

        }

        case JsonbType::T_Double: {

            os_.write(val->unpack<JsonbDoubleVal>()->val());

            break;

        }

        case JsonbType::T_Float: {

            os_.write(val->unpack<JsonbFloatVal>()->val());

            break;

        }

        case JsonbType::T_Int128: {

            os_.write(val->unpack<JsonbInt128Val>()->val());

            break;

        }

        case JsonbType::T_String: {

            string_to_json(val->unpack<JsonbStringVal>()->getBlob(),

                           val->unpack<JsonbStringVal>()->length());

            break;

        }

        case JsonbType::T_Binary: {

            os_.write("\"<BINARY>", 9);

            os_.write(val->unpack<JsonbBinaryVal>()->getBlob(),

                      val->unpack<JsonbBinaryVal>()->getBlobLen());

            os_.write("<BINARY>\"", 9);

            break;

        }

        case JsonbType::T_Object: {

            object_to_json(val->unpack<ObjectVal>());

            break;

        }

        case JsonbType::T_Array: {

            array_to_json(val->unpack<ArrayVal>());

            break;

        }

        case JsonbType::T_Decimal32: {

            const auto* decimal_val = val->unpack<JsonbDecimal32>();

            decimal_to_json(Decimal32 {decimal_val->val()}, decimal_val->precision,

                            decimal_val->scale);

            break;

        }

        case JsonbType::T_Decimal64: {

            const auto* decimal_val = val->unpack<JsonbDecimal64>();

            decimal_to_json(Decimal64 {decimal_val->val()}, decimal_val->precision,

                            decimal_val->scale);

            break;

        }

        case JsonbType::T_Decimal128: {

            const auto* decimal_val = val->unpack<JsonbDecimal128>();

            decimal_to_json(Decimal128V3 {decimal_val->val()}, decimal_val->precision,

                            decimal_val->scale);

            break;

        }

        case JsonbType::T_Decimal256: {

            const auto* decimal_val = val->unpack<JsonbDecimal256>();

            decimal_to_json(Decimal256 {decimal_val->val()}, decimal_val->precision,

                            decimal_val->scale);

            break;

        }

        default:

            break;

        }

    }

    void string_to_json(const char* str, size_t len) {

        os_.put('"');

        if (nullptr == str) {

            os_.put('"');

            return;

        }

        char char_buffer[16];

        for (const char* ptr = str; ptr != str + len && *ptr; ++ptr) {

            if ((unsigned char)*ptr > 31 && *ptr != '\"' && *ptr != '\\') {

                os_.put(*ptr);

            } else {

                os_.put('\\');

                unsigned char token;

                switch (token = *ptr) {

                case '\\':

                    os_.put('\\');

                    break;

                case '\"':

                    os_.put('\"');

                    break;

                case '\b':

                    os_.put('b');

                    break;

                case '\f':

                    os_.put('f');

                    break;

                case '\n':

                    os_.put('n');

                    break;

                case '\r':

                    os_.put('r');

                    break;

                case '\t':

                    os_.put('t');

                    break;

                default: {

                    int char_num = snprintf(char_buffer, sizeof(char_buffer), "u%04x", token);

                    os_.write(char_buffer, char_num);

                    break;

                }

                }

            }

        }

        os_.put('"');

    }

    // convert object

    void object_to_json(const ObjectVal* val) {

        os_.put('{');

        auto iter = val->begin();

        auto iter_fence = val->end();

        while (iter < iter_fence) {

            // write key

            if (iter->klen()) {

                string_to_json(iter->getKeyStr(), iter->klen());

            } else {

                // NOTE: we use sMaxKeyId to represent an empty key. see jsonb_writer.h

                if (iter->getKeyId() == JsonbKeyValue::sMaxKeyId) {

                    string_to_json(nullptr, 0);

                } else {

                    os_.write(iter->getKeyId());

                }

            }

            os_.put(':');

            // convert value

            intern_json(iter->value());

            ++iter;

            if (iter != iter_fence) {

                os_.put(',');

            }

        }

        assert(iter == iter_fence);

        os_.put('}');

    }

    // convert array to json

    void array_to_json(const ArrayVal* val) {

        os_.put('[');

        auto iter = val->begin();

        auto iter_fence = val->end();

        while (iter != iter_fence) {

            // convert value

            intern_json((const JsonbValue*)iter);

            ++iter;

            if (iter != iter_fence) {

                os_.put(',');

            }

        }

        assert(iter == iter_fence);

        os_.put(']');

    }

    template <JsonbDecimalType T>

    void decimal_to_json(const T& value, const uint32_t precision, const uint32_t scale);

    JsonbOutStream os_;

    char buffer_[OUT_BUF_SIZE];

};

} // namespace doris

#endif // JSONB_JSONBUTIL_H