/* json11

 *

 * json11 is a tiny JSON library for C++11, providing JSON parsing and serialization.

 *

 * The core object provided by the library is json11::Json. A Json object represents any JSON

 * value: null, bool, number (int or double), string (std::string), array (std::vector), or

 * object (std::map).

 *

 * Json objects act like values: they can be assigned, copied, moved, compared for equality or

 * order, etc. There are also helper methods Json::dump, to serialize a Json to a string, and

 * Json::parse (static) to parse a std::string as a Json object.

 *

 * Internally, the various types of Json object are represented by the JsonValue class

 * hierarchy.

 *

 * A note on numbers - JSON specifies the syntax of number formatting but not its semantics,

 * so some JSON implementations distinguish between integers and floating-point numbers, while

 * some don't. In json11, we choose the latter. Because some JSON implementations (namely

 * JavaScript itself) treat all numbers as the same type, distinguishing the two leads

 * to JSON that will be *silently* changed by a round-trip through those implementations.

 * Dangerous! To avoid that risk, json11 stores all numbers as double internally, but also

 * provides integer helpers.

 *

 * Fortunately, double-precision IEEE754 ('double') can precisely store any integer in the

 * range +/-2^53, which includes every 'int' on most systems. (Timestamps often use int64

 * or long long to avoid the Y2038K problem; a double storing microseconds since some epoch

 * will be exact for +/- 275 years.)

 */

/* Copyright (c) 2013 Dropbox, Inc.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#pragma once

#include <string>

#include <vector>

#include <map>

#include <memory>

#include <initializer_list>

#ifdef _MSC_VER

    #if _MSC_VER <= 1800 // VS 2013

        #ifndef noexcept

            #define noexcept throw()

        #endif

        #ifndef snprintf

            #define snprintf _snprintf_s

        #endif

    #endif

#endif

namespace json11 {

enum JsonParse {

    STANDARD, COMMENTS

};

class JsonValue;

class Json final {

public:

    // Types

    enum Type {

        NUL, NUMBER, BOOL, STRING, ARRAY, OBJECT

    };

    // Array and object typedefs

    typedef std::vector<Json> array;

    typedef std::map<std::string, Json> object;

    // Constructors for the various types of JSON value.

    Json() noexcept;                // NUL

    Json(std::nullptr_t) noexcept;  // NUL

    Json(double value);             // NUMBER

    Json(int value);                // NUMBER

    Json(bool value);               // BOOL

    Json(const std::string &value); // STRING

    Json(std::string &&value);      // STRING

    Json(const char * value);       // STRING

    Json(const array &values);      // ARRAY

    Json(array &&values);           // ARRAY

    Json(const object &values);     // OBJECT

    Json(object &&values);          // OBJECT

    // Implicit constructor: anything with a to_json() function.

    template <class T, class = decltype(&T::to_json)>

    Json(const T & t) : Json(t.to_json()) {}

    // Implicit constructor: map-like objects (std::map, std::unordered_map, etc)

    template <class M, typename std::enable_if<

        std::is_constructible<std::string, decltype(std::declval<M>().begin()->first)>::value

        && std::is_constructible<Json, decltype(std::declval<M>().begin()->second)>::value,

            int>::type = 0>

    Json(const M & m) : Json(object(m.begin(), m.end())) {}

    // Implicit constructor: vector-like objects (std::list, std::vector, std::set, etc)

    template <class V, typename std::enable_if<

        std::is_constructible<Json, decltype(*std::declval<V>().begin())>::value,

            int>::type = 0>

    Json(const V & v) : Json(array(v.begin(), v.end())) {}

    // This prevents Json(some_pointer) from accidentally producing a bool. Use

    // Json(bool(some_pointer)) if that behavior is desired.

    Json(void *) = delete;

    // Accessors

    Type type() const;

    bool is_null()   const { return type() == NUL; }

    bool is_number() const { return type() == NUMBER; }

    bool is_bool()   const { return type() == BOOL; }

    bool is_string() const { return type() == STRING; }

    bool is_array()  const { return type() == ARRAY; }

    bool is_object() const { return type() == OBJECT; }

    // Return the enclosed value if this is a number, 0 otherwise. Note that json11 does not

    // distinguish between integer and non-integer numbers - number_value() and int_value()

    // can both be applied to a NUMBER-typed object.

    double number_value() const;

    int int_value() const;

    // Return the enclosed value if this is a boolean, false otherwise.

    bool bool_value() const;

    // Return the enclosed string if this is a string, "" otherwise.

    const std::string &string_value() const;

    // Return the enclosed std::vector if this is an array, or an empty vector otherwise.

    const array &array_items() const;

    // Return the enclosed std::map if this is an object, or an empty map otherwise.

    const object &object_items() const;

    // Return a reference to arr[i] if this is an array, Json() otherwise.

    const Json & operator[](size_t i) const;

    // Return a reference to obj[key] if this is an object, Json() otherwise.

    const Json & operator[](const std::string &key) const;

    // Serialize.

    void dump(std::string &out) const;

    std::string dump() const {

        std::string out;

        dump(out);

        return out;

    }

    // Parse. If parse fails, return Json() and assign an error message to err.

    static Json parse(const std::string & in,

                      std::string & err,

                      JsonParse strategy = JsonParse::STANDARD);

    static Json parse(const char * in,

                      std::string & err,

                      JsonParse strategy = JsonParse::STANDARD) {

        if (in) {

            return parse(std::string(in), err, strategy);

        } else {

            err = "null input";

            return nullptr;

        }

    }

    // Parse multiple objects, concatenated or separated by whitespace

    static std::vector<Json> parse_multi(

        const std::string & in,

        std::string::size_type & parser_stop_pos,

        std::string & err,

        JsonParse strategy = JsonParse::STANDARD);

    static inline std::vector<Json> parse_multi(

        const std::string & in,

        std::string & err,

        JsonParse strategy = JsonParse::STANDARD) {

        std::string::size_type parser_stop_pos;

        return parse_multi(in, parser_stop_pos, err, strategy);

    }

    bool operator== (const Json &rhs) const;

    bool operator<  (const Json &rhs) const;

    bool operator!= (const Json &rhs) const { return !(*this == rhs); }

    bool operator<= (const Json &rhs) const { return !(rhs < *this); }

    bool operator>  (const Json &rhs) const { return  (rhs < *this); }

    bool operator>= (const Json &rhs) const { return !(*this < rhs); }

    /* has_shape(types, err)

     *

     * Return true if this is a JSON object and, for each item in types, has a field of

     * the given type. If not, return false and set err to a descriptive message.

     */

    typedef std::initializer_list<std::pair<std::string, Type>> shape;

    bool has_shape(const shape & types, std::string & err) const;

private:

    std::shared_ptr<JsonValue> m_ptr;

};

// Internal class hierarchy - JsonValue objects are not exposed to users of this API.

class JsonValue {

protected:

    friend class Json;

    friend class JsonInt;

    friend class JsonDouble;

    virtual Json::Type type() const = 0;

    virtual bool equals(const JsonValue * other) const = 0;

    virtual bool less(const JsonValue * other) const = 0;

    virtual void dump(std::string &out) const = 0;

    virtual double number_value() const;

    virtual int int_value() const;

    virtual bool bool_value() const;

    virtual const std::string &string_value() const;

    virtual const Json::array &array_items() const;

    virtual const Json &operator[](size_t i) const;

    virtual const Json::object &object_items() const;

    virtual const Json &operator[](const std::string &key) const;

    virtual ~JsonValue() {}

};

} // namespace json11