#include "libutil/json.hh"

#include <cstring>
#include <iomanip>

namespace nix {

void toJSON(std::ostream& str, const char* start, const char* end) {
  str << '"';
  for (auto i = start; i != end; i++) {
    if (*i == '\"' || *i == '\\') {
      str << '\\' << *i;
    } else if (*i == '\n') {
      str << "\\n";
    } else if (*i == '\r') {
      str << "\\r";
    } else if (*i == '\t') {
      str << "\\t";
    } else if (*i >= 0 && *i < 32) {
      str << "\\u" << std::setfill('0') << std::setw(4) << std::hex
          << static_cast<uint16_t>(*i) << std::dec;
    } else {
      str << *i;
    }
  }
  str << '"';
}

void toJSON(std::ostream& str, const char* s) {
  if (s == nullptr) {
    str << "null";
  } else {
    toJSON(str, s, s + strlen(s));
  }
}

template <>
void toJSON<int>(std::ostream& str, const int& n) {
  str << n;
}
template <>
void toJSON<unsigned int>(std::ostream& str, const unsigned int& n) {
  str << n;
}
template <>
void toJSON<long>(std::ostream& str, const long& n) {
  str << n;
}
template <>
void toJSON<unsigned long>(std::ostream& str, const unsigned long& n) {
  str << n;
}
template <>
void toJSON<long long>(std::ostream& str, const long long& n) {
  str << n;
}
template <>
void toJSON<unsigned long long>(std::ostream& str,
                                const unsigned long long& n) {
  str << n;
}
template <>
void toJSON<float>(std::ostream& str, const float& n) {
  str << n;
}
template <>
void toJSON<double>(std::ostream& str, const double& n) {
  str << n;
}

template <>
void toJSON<std::string>(std::ostream& str, const std::string& s) {
  toJSON(str, s.c_str(), s.c_str() + s.size());
}

template <>
void toJSON<bool>(std::ostream& str, const bool& b) {
  str << (b ? "true" : "false");
}

template <>
void toJSON<std::nullptr_t>(std::ostream& str, const std::nullptr_t& b) {
  str << "null";
}

JSONWriter::JSONWriter(std::ostream& str, bool indent)
    : state(new JSONState(str, indent)) {
  state->stack++;
}

JSONWriter::JSONWriter(JSONState* state) : state(state) { state->stack++; }

JSONWriter::~JSONWriter() {
  if (state != nullptr) {
    assertActive();
    state->stack--;
    if (state->stack == 0) {
      delete state;
    }
  }
}

void JSONWriter::comma() {
  assertActive();
  if (first) {
    first = false;
  } else {
    state->str << ',';
  }
  if (state->indent) {
    indent();
  }
}

void JSONWriter::indent() {
  state->str << '\n' << std::string(state->depth * 2, ' ');
}

void JSONList::open() {
  state->depth++;
  state->str << '[';
}

JSONList::~JSONList() {
  state->depth--;
  if (state->indent && !first) {
    indent();
  }
  state->str << "]";
}

JSONList JSONList::list() {
  comma();
  return JSONList(state);
}

JSONObject JSONList::object() {
  comma();
  return JSONObject(state);
}

JSONPlaceholder JSONList::placeholder() {
  comma();
  return JSONPlaceholder(state);
}

void JSONObject::open() {
  state->depth++;
  state->str << '{';
}

JSONObject::~JSONObject() {
  if (state != nullptr) {
    state->depth--;
    if (state->indent && !first) {
      indent();
    }
    state->str << "}";
  }
}

void JSONObject::attr(const std::string& s) {
  comma();
  toJSON(state->str, s);
  state->str << ':';
  if (state->indent) {
    state->str << ' ';
  }
}

JSONList JSONObject::list(const std::string& name) {
  attr(name);
  return JSONList(state);
}

JSONObject JSONObject::object(const std::string& name) {
  attr(name);
  return JSONObject(state);
}

JSONPlaceholder JSONObject::placeholder(const std::string& name) {
  attr(name);
  return JSONPlaceholder(state);
}

JSONList JSONPlaceholder::list() {
  assertValid();
  first = false;
  return JSONList(state);
}

JSONObject JSONPlaceholder::object() {
  assertValid();
  first = false;
  return JSONObject(state);
}

}  // namespace nix