// Hello World example
// This example shows basic usage of DOM-style API.

#include "rapidjson/document.h" // rapidjson's DOM-style API
#include "rapidjson/prettywriter.h" // for stringify JSON
#include <cstdio>

using namespace rapidjson;
using namespace std;

int main(int, char*[]) {
 ////////////////////////////////////////////////////////////////////////////
 // 1. Parse a JSON text string to a document.

 const char json[] = " { \"hello\" : \"world\", \"t\" : true , \"f\" : false, \"n\": null, \"i\":123, \"pi\": 3.1416, \"a\":[1, 2, 3, 4] } ";
 printf("Original JSON:\n %s\n", json);

 Document document; // Default template parameter uses UTF8 and MemoryPoolAllocator.

#if 0
 // "normal" parsing, decode strings to new buffers. Can use other input stream via ParseStream().
 if (document.Parse(json).HasParseError())
 return 1;
#else
 // In-situ parsing, decode strings directly in the source string. Source must be string.
 char buffer[sizeof(json)];
 memcpy(buffer, json, sizeof(json));
 if (document.ParseInsitu(buffer).HasParseError())
 return 1;
#endif

 printf("\nParsing to document succeeded.\n");

 ////////////////////////////////////////////////////////////////////////////
 // 2. Access values in document. 

 printf("\nAccess values in document:\n");
 assert(document.IsObject()); // Document is a JSON value represents the root of DOM. Root can be either an object or array.

 assert(document.HasMember("hello"));
 assert(document["hello"].IsString());
 printf("hello = %s\n", document["hello"].GetString());

 // Since version 0.2, you can use single lookup to check the existing of member and its value:
 Value::MemberIterator hello = document.FindMember("hello");
 assert(hello != document.MemberEnd());
 assert(hello->value.IsString());
 assert(strcmp("world", hello->value.GetString()) == 0);
 (void)hello;

 assert(document["t"].IsBool()); // JSON true/false are bool. Can also uses more specific function IsTrue().
 printf("t = %s\n", document["t"].GetBool() ? "true" : "false");

 assert(document["f"].IsBool());
 printf("f = %s\n", document["f"].GetBool() ? "true" : "false");

 printf("n = %s\n", document["n"].IsNull() ? "null" : "?");

 assert(document["i"].IsNumber()); // Number is a JSON type, but C++ needs more specific type.
 assert(document["i"].IsInt()); // In this case, IsUint()/IsInt64()/IsUint64() also return true.
 printf("i = %d\n", document["i"].GetInt()); // Alternative (int)document["i"]

 assert(document["pi"].IsNumber());
 assert(document["pi"].IsDouble());
 printf("pi = %g\n", document["pi"].GetDouble());

 {
 const Value& a = document["a"]; // Using a reference for consecutive access is handy and faster.
 assert(a.IsArray());
 for (SizeType i = 0; i < a.Size(); i++) // rapidjson uses SizeType instead of size_t.
 printf("a[%d] = %d\n", i, a[i].GetInt());
 
 int y = a[0].GetInt();
 (void)y;

 // Iterating array with iterators
 printf("a = ");
 for (Value::ConstValueIterator itr = a.Begin(); itr != a.End(); ++itr)
 printf("%d ", itr->GetInt());
 printf("\n");
 }

 // Iterating object members
 static const char* kTypeNames[] = { "Null", "False", "True", "Object", "Array", "String", "Number" };
 for (Value::ConstMemberIterator itr = document.MemberBegin(); itr != document.MemberEnd(); ++itr)
 printf("Type of member %s is %s\n", itr->name.GetString(), kTypeNames[itr->value.GetType()]);

 ////////////////////////////////////////////////////////////////////////////
 // 3. Modify values in document.

 // Change i to a bigger number
 {
 uint64_t f20 = 1; // compute factorial of 20
 for (uint64_t j = 1; j <= 20; j++)
 f20 *= j;
 document["i"] = f20; // Alternate form: document["i"].SetUint64(f20)
 assert(!document["i"].IsInt()); // No longer can be cast as int or uint.
 }

 // Adding values to array.
 {
 Value& a = document["a"]; // This time we uses non-const reference.
 Document::AllocatorType& allocator = document.GetAllocator();
 for (int i = 5; i <= 10; i++)
 a.PushBack(i, allocator); // May look a bit strange, allocator is needed for potentially realloc. We normally uses the document's.

 // Fluent API
 a.PushBack("Lua", allocator).PushBack("Mio", allocator);
 }

 // Making string values.

 // This version of SetString() just store the pointer to the string.
 // So it is for literal and string that exists within value's life-cycle.
 {
 document["hello"] = "rapidjson"; // This will invoke strlen()
 // Faster version:
 // document["hello"].SetString("rapidjson", 9);
 }

 // This version of SetString() needs an allocator, which means it will allocate a new buffer and copy the the string into the buffer.
 Value author;
 {
 char buffer2[10];
 int len = sprintf(buffer2, "%s %s", "Milo", "Yip"); // synthetic example of dynamically created string.

 author.SetString(buffer2, static_cast<SizeType>(len), document.GetAllocator());
 // Shorter but slower version:
 // document["hello"].SetString(buffer, document.GetAllocator());

 // Constructor version: 
 // Value author(buffer, len, document.GetAllocator());
 // Value author(buffer, document.GetAllocator());
 memset(buffer2, 0, sizeof(buffer2)); // For demonstration purpose.
 }
 // Variable 'buffer' is unusable now but 'author' has already made a copy.
 document.AddMember("author", author, document.GetAllocator());

 assert(author.IsNull()); // Move semantic for assignment. After this variable is assigned as a member, the variable becomes null.

 ////////////////////////////////////////////////////////////////////////////
 // 4. Stringify JSON

 printf("\nModified JSON with reformatting:\n");
 StringBuffer sb;
 PrettyWriter<StringBuffer> writer(sb);
 document.Accept(writer); // Accept() traverses the DOM and generates Handler events.
 puts(sb.GetString());

 return 0;
}