/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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.
 *
 * Contains some contributions under the Thrift Software License.
 * Please see doc/old-thrift-license.txt in the Thrift distribution for
 * details.
 */

#include <fstream>
#include <iostream>
#include <sstream>
#include <limits>

#include <stdlib.h>
#include <sys/stat.h>
#include <sstream>

#include "thrift/platform.h"
#include "thrift/generate/t_generator.h"

using std::map;
using std::ofstream;
using std::ostream;
using std::ostringstream;
using std::string;
using std::stringstream;
using std::vector;
using std::stack;

static const string endl = "\n";
static const string quot = "\"";
static const bool NO_INDENT = false;
static const bool FORCE_STRING = true;

class t_json_generator : public t_generator {
public:
  t_json_generator(t_program* program,
                   const std::map<std::string, std::string>& parsed_options,
                   const std::string& option_string)
    : t_generator(program) {
    (void)option_string;
    std::map<std::string, std::string>::const_iterator iter;

    should_merge_includes_ = false;
    for( iter = parsed_options.begin(); iter != parsed_options.end(); ++iter) {
      if( iter->first.compare("merge") == 0) {
        should_merge_includes_ = true;
      } else {
        throw "unknown option json:" + iter->first;
      }
    }

    out_dir_base_ = "gen-json";
  }

  ~t_json_generator() override = default;

  /**
  * Init and close methods
  */

  void init_generator() override;
  void close_generator() override;

  void generate_typedef(t_typedef* ttypedef) override;
  void generate_enum(t_enum* tenum) override;
  void generate_program() override;
  void generate_function(t_function* tfunc);
  void generate_field(t_field* field);

  void generate_service(t_service* tservice) override;
  void generate_struct(t_struct* tstruct) override;

private:
  bool should_merge_includes_;

  ofstream_with_content_based_conditional_update f_json_;
  std::stack<bool> comma_needed_;

  template <typename T>
  string number_to_string(T t) {
    std::ostringstream out;
    out.imbue(std::locale::classic());
    out.precision(std::numeric_limits<T>::digits10);
    out << t;
    return out.str();
  }

  template <typename T>
  void write_number(T n) {
    f_json_ << number_to_string(n);
  }

  string get_type_name(t_type* ttype);
  string get_qualified_name(t_type* ttype);

  void start_object(bool should_indent = true);
  void start_array();
  void end_object();
  void end_array();
  void write_comma_if_needed();
  void indicate_comma_needed();
  string escape_json_string(const string& input);
  string json_str(const string& str);
  void merge_includes(t_program*);

  void generate_constant(t_const* con);

  void write_type_spec_entry(const char* name, t_type* ttype);
  void write_type_spec_object(const char* name, t_type* ttype);
  void write_type_spec(t_type* ttype);
  void write_string(const string& value);
  void write_value(t_type* tvalue);
  void write_const_value(t_const_value* value, bool force_string = false);
  void write_key_and(string key);
  void write_key_and_string(string key, string val);
  void write_key_and_integer(string key, int val);
  void write_key_and_bool(string key, bool val);
};

void t_json_generator::init_generator() {
  MKDIR(get_out_dir().c_str());

  string f_json_name = get_out_dir() + program_->get_name() + ".json";
  f_json_.open(f_json_name.c_str());

  // Merge all included programs into this one so we can output one big file.
  if (should_merge_includes_) {
    merge_includes(program_);
  }
}

string t_json_generator::escape_json_string(const string& input) {
  std::ostringstream ss;
  for (char iter : input) {
    switch (iter) {
    case '\\':
      ss << "\\\\";
      break;
    case '"':
      ss << "\\\"";
      break;
    case '/':
      ss << "\\/";
      break;
    case '\b':
      ss << "\\b";
      break;
    case '\f':
      ss << "\\f";
      break;
    case '\n':
      ss << "\\n";
      break;
    case '\r':
      ss << "\\r";
      break;
    case '\t':
      ss << "\\t";
      break;
    default:
      ss << iter;
      break;
    }
  }
  return ss.str();
}

void t_json_generator::start_object(bool should_indent) {
  f_json_ << (should_indent ? indent() : "") << "{" << endl;
  indent_up();
  comma_needed_.push(false);
}

void t_json_generator::start_array() {
  f_json_ << "[" << endl;
  indent_up();
  comma_needed_.push(false);
}

void t_json_generator::write_comma_if_needed() {
  if (comma_needed_.top()) {
    f_json_ << "," << endl;
  }
}

void t_json_generator::indicate_comma_needed() {
  comma_needed_.pop();
  comma_needed_.push(true);
}

void t_json_generator::write_key_and(string key) {
  write_comma_if_needed();
  indent(f_json_) << json_str(key) << ": ";
  indicate_comma_needed();
}

void t_json_generator::write_key_and_integer(string key, int val) {
  write_comma_if_needed();
  indent(f_json_) << json_str(key) << ": " << number_to_string(val);
  indicate_comma_needed();
}

void t_json_generator::write_key_and_string(string key, string val) {
  write_comma_if_needed();
  indent(f_json_) << json_str(key) << ": " << json_str(val);
  indicate_comma_needed();
}

void t_json_generator::write_key_and_bool(string key, bool val) {
  write_comma_if_needed();
  indent(f_json_) << json_str(key) << ": " << (val ? "true" : "false");
  indicate_comma_needed();
}

void t_json_generator::end_object() {
  indent_down();
  f_json_ << endl << indent() << "}";
  comma_needed_.pop();
}

void t_json_generator::end_array() {
  indent_down();
  if (comma_needed_.top()) {
    f_json_ << endl;
  }
  indent(f_json_) << "]";
  comma_needed_.pop();
}

void t_json_generator::write_type_spec_object(const char* name, t_type* ttype) {
  ttype = ttype->get_true_type();
  if (ttype->is_struct() || ttype->is_xception() || ttype->is_container()) {
    write_key_and(name);
    start_object(NO_INDENT);
    write_key_and("typeId");
    write_type_spec(ttype);
    end_object();
  }
}

void t_json_generator::write_type_spec_entry(const char* name, t_type* ttype) {
  write_key_and(name);
  write_type_spec(ttype);
}

void t_json_generator::write_type_spec(t_type* ttype) {
  ttype = ttype->get_true_type();

  write_string(get_type_name(ttype));

  if (ttype->annotations_.size() > 0) {
    write_key_and("annotations");
    start_object();
    for (auto & annotation : ttype->annotations_) {
      write_key_and_string(annotation.first, annotation.second);
    }
    end_object();
  }

  if (ttype->is_struct() || ttype->is_xception()) {
    write_key_and_string("class", get_qualified_name(ttype));
  } else if (ttype->is_map()) {
    t_type* ktype = ((t_map*)ttype)->get_key_type();
    t_type* vtype = ((t_map*)ttype)->get_val_type();
    write_key_and_string("keyTypeId", get_type_name(ktype));
    write_key_and_string("valueTypeId", get_type_name(vtype));
    write_type_spec_object("keyType", ktype);
    write_type_spec_object("valueType", vtype);
  } else if (ttype->is_list()) {
    t_type* etype = ((t_list*)ttype)->get_elem_type();
    write_key_and_string("elemTypeId", get_type_name(etype));
    write_type_spec_object("elemType", etype);
  } else if (ttype->is_set()) {
    t_type* etype = ((t_set*)ttype)->get_elem_type();
    write_key_and_string("elemTypeId", get_type_name(etype));
    write_type_spec_object("elemType", etype);
  }
}

void t_json_generator::close_generator() {
  f_json_ << endl;
  f_json_.close();
}

void t_json_generator::merge_includes(t_program* program) {
  vector<t_program*> includes = program->get_includes();
  vector<t_program*>::iterator inc_iter;
  for (inc_iter = includes.begin(); inc_iter != includes.end(); ++inc_iter) {
    t_program* include = *inc_iter;
    // recurse in case we get crazy
    merge_includes(include);
    // merge enums
    vector<t_enum*> enums = include->get_enums();
    vector<t_enum*>::iterator en_iter;
    for (en_iter = enums.begin(); en_iter != enums.end(); ++en_iter) {
      program->add_enum(*en_iter);
    }
    // merge typedefs
    vector<t_typedef*> typedefs = include->get_typedefs();
    vector<t_typedef*>::iterator td_iter;
    for (td_iter = typedefs.begin(); td_iter != typedefs.end(); ++td_iter) {
      program->add_typedef(*td_iter);
    }
    // merge structs
    vector<t_struct*> objects = include->get_objects();
    vector<t_struct*>::iterator o_iter;
    for (o_iter = objects.begin(); o_iter != objects.end(); ++o_iter) {
      program->add_struct(*o_iter);
    }
    // merge constants
    vector<t_const*> consts = include->get_consts();
    vector<t_const*>::iterator c_iter;
    for (c_iter = consts.begin(); c_iter != consts.end(); ++c_iter) {
      program->add_const(*c_iter);
    }

    // merge services
    vector<t_service*> services = include->get_services();
    vector<t_service*>::iterator sv_iter;
    for (sv_iter = services.begin(); sv_iter != services.end(); ++sv_iter) {
      program->add_service(*sv_iter);
    }
  }
}

void t_json_generator::generate_program() {

  init_generator();

  start_object();
  write_key_and_string("name", program_->get_name());
  if (program_->has_doc()) {
    write_key_and_string("doc", program_->get_doc());
  }

  // When merging includes, the "namespaces" and "includes" sections
  // become ambiguous, so just skip them.
  if (!should_merge_includes_) {
    // Generate namespaces
    write_key_and("namespaces");
    start_object(NO_INDENT);
    const map<string, string>& namespaces = program_->get_namespaces();
    map<string, string>::const_iterator ns_it;
    for (ns_it = namespaces.begin(); ns_it != namespaces.end(); ++ns_it) {
      write_key_and_string(ns_it->first, ns_it->second);
      indicate_comma_needed();
    }
    end_object();

    // Generate includes
    write_key_and("includes");
    start_array();
    const vector<t_program*> includes = program_->get_includes();
    vector<t_program*>::const_iterator inc_it;
    for (inc_it = includes.begin(); inc_it != includes.end(); ++inc_it) {
      write_comma_if_needed();
      f_json_ << indent();
      write_string((*inc_it)->get_name());
      indicate_comma_needed();
    }
    end_array();
  }

  // Generate enums
  write_key_and("enums");
  start_array();
  vector<t_enum*> enums = program_->get_enums();
  vector<t_enum*>::iterator en_iter;
  for (en_iter = enums.begin(); en_iter != enums.end(); ++en_iter) {
    write_comma_if_needed();
    generate_enum(*en_iter);
    indicate_comma_needed();
  }
  end_array();

  // Generate typedefs
  write_key_and("typedefs");
  start_array();
  vector<t_typedef*> typedefs = program_->get_typedefs();
  vector<t_typedef*>::iterator td_iter;
  for (td_iter = typedefs.begin(); td_iter != typedefs.end(); ++td_iter) {
    write_comma_if_needed();
    generate_typedef(*td_iter);
    indicate_comma_needed();
  }
  end_array();

  // Generate structs, exceptions, and unions in declared order
  write_key_and("structs");
  start_array();
  vector<t_struct*> objects = program_->get_objects();
  vector<t_struct*>::iterator o_iter;
  for (o_iter = objects.begin(); o_iter != objects.end(); ++o_iter) {
    write_comma_if_needed();
    if ((*o_iter)->is_xception()) {
      generate_xception(*o_iter);
    } else {
      generate_struct(*o_iter);
    }
    indicate_comma_needed();
  }
  end_array();

  // Generate constants
  write_key_and("constants");
  start_array();
  vector<t_const*> consts = program_->get_consts();
  vector<t_const*>::iterator c_iter;
  for (c_iter = consts.begin(); c_iter != consts.end(); ++c_iter) {
    write_comma_if_needed();
    generate_constant(*c_iter);
    indicate_comma_needed();
  }
  end_array();

  // Generate services
  write_key_and("services");
  start_array();
  vector<t_service*> services = program_->get_services();
  vector<t_service*>::iterator sv_iter;
  for (sv_iter = services.begin(); sv_iter != services.end(); ++sv_iter) {
    write_comma_if_needed();
    generate_service(*sv_iter);
    indicate_comma_needed();
  }
  end_array();

  end_object();

  // Close the generator
  close_generator();
}

void t_json_generator::generate_typedef(t_typedef* ttypedef) {
  start_object();
  write_key_and_string("name", get_qualified_name(ttypedef));
  write_key_and_string("typeId", get_type_name(ttypedef->get_true_type()));
  write_type_spec_object("type", ttypedef->get_true_type());
  if (ttypedef->has_doc()) {
    write_key_and_string("doc", ttypedef->get_doc());
  }
  if (ttypedef->annotations_.size() > 0) {
    write_key_and("annotations");
    start_object();
    for (auto & annotation : ttypedef->annotations_) {
      write_key_and_string(annotation.first, annotation.second);
    }
    end_object();
  }
  end_object();
}

void t_json_generator::write_string(const string& value) {
  f_json_ << quot << escape_json_string(value) << quot;
}

void t_json_generator::write_const_value(t_const_value* value, bool should_force_string) {

  switch (value->get_type()) {

  case t_const_value::CV_IDENTIFIER:
  case t_const_value::CV_INTEGER:
    if (should_force_string) {
      write_string(number_to_string(value->get_integer()));
    } else {
      write_number(value->get_integer());
    }
    break;

  case t_const_value::CV_DOUBLE:
    if (should_force_string) {
      write_string(number_to_string(value->get_double()));
    } else {
      write_number(value->get_double());
    }
    break;

  case t_const_value::CV_STRING:
    write_string(value->get_string());
    break;

  case t_const_value::CV_LIST: {
    start_array();
    std::vector<t_const_value*> list = value->get_list();
    std::vector<t_const_value*>::iterator lit;
    for (lit = list.begin(); lit != list.end(); ++lit) {
      write_comma_if_needed();
      f_json_ << indent();
      write_const_value(*lit);
      indicate_comma_needed();
    }
    end_array();
    break;
  }

  case t_const_value::CV_MAP: {
    start_object(NO_INDENT);
    std::map<t_const_value*, t_const_value*, t_const_value::value_compare> map = value->get_map();
    std::map<t_const_value*, t_const_value*, t_const_value::value_compare>::iterator mit;
    for (mit = map.begin(); mit != map.end(); ++mit) {
      write_comma_if_needed();
      f_json_ << indent();
      // JSON objects only allow string keys
      write_const_value(mit->first, FORCE_STRING);
      f_json_ << ": ";
      write_const_value(mit->second);
      indicate_comma_needed();
    }
    end_object();
    break;
  }

  default:
    f_json_ << "null";
    break;
  }
}

string t_json_generator::json_str(const string& str) {
  return quot + escape_json_string(str) + quot;
}

void t_json_generator::generate_constant(t_const* con) {
  start_object();

  write_key_and_string("name", con->get_name());
  write_key_and_string("typeId", get_type_name(con->get_type()));
  write_type_spec_object("type", con->get_type());

  if (con->has_doc()) {
    write_key_and_string("doc", con->get_doc());
  }

  write_key_and("value");
  write_const_value(con->get_value());

  end_object();
}

void t_json_generator::generate_enum(t_enum* tenum) {
  start_object();

  write_key_and_string("name", tenum->get_name());

  if (tenum->has_doc()) {
    write_key_and_string("doc", tenum->get_doc());
  }

  if (tenum->annotations_.size() > 0) {
      write_key_and("annotations");
      start_object();
      for (auto & annotation : tenum->annotations_) {
        write_key_and_string(annotation.first, annotation.second);
      }
      end_object();
  }

  write_key_and("members");
  start_array();
  vector<t_enum_value*> values = tenum->get_constants();
  vector<t_enum_value*>::iterator val_iter;
  for (val_iter = values.begin(); val_iter != values.end(); ++val_iter) {
    write_comma_if_needed();
    t_enum_value* val = (*val_iter);
    start_object();
    write_key_and_string("name", val->get_name());
    write_key_and_integer("value", val->get_value());
    if (val->has_doc()) {
      write_key_and_string("doc", val->get_doc());
    }
    end_object();
    indicate_comma_needed();
  }
  end_array();

  end_object();
}

void t_json_generator::generate_struct(t_struct* tstruct) {
  start_object();

  write_key_and_string("name", tstruct->get_name());

  if (tstruct->has_doc()) {
    write_key_and_string("doc", tstruct->get_doc());
  }

  if (tstruct->annotations_.size() > 0) {
    write_key_and("annotations");
    start_object();
    for (auto & annotation : tstruct->annotations_) {
      write_key_and_string(annotation.first, annotation.second);
    }
    end_object();
  }

  write_key_and_bool("isException", tstruct->is_xception());

  write_key_and_bool("isUnion", tstruct->is_union());

  write_key_and("fields");
  start_array();
  vector<t_field*> members = tstruct->get_members();
  vector<t_field*>::iterator mem_iter;
  for (mem_iter = members.begin(); mem_iter != members.end(); mem_iter++) {
    write_comma_if_needed();
    generate_field(*mem_iter);
    indicate_comma_needed();
  }
  end_array();

  end_object();
}

void t_json_generator::generate_service(t_service* tservice) {
  start_object();

  write_key_and_string("name", get_qualified_name(tservice));

  if (tservice->get_extends()) {
    write_key_and_string("extends", get_qualified_name(tservice->get_extends()));
  }

  if (tservice->has_doc()) {
    write_key_and_string("doc", tservice->get_doc());
  }

  if (tservice->annotations_.size() > 0) {
    write_key_and("annotations");
    start_object();
    for (auto & annotation : tservice->annotations_) {
      write_key_and_string(annotation.first, annotation.second);
    }
    end_object();
  }

  write_key_and("functions");
  start_array();
  vector<t_function*> functions = tservice->get_functions();
  vector<t_function*>::iterator fn_iter = functions.begin();
  for (; fn_iter != functions.end(); fn_iter++) {
    write_comma_if_needed();
    generate_function(*fn_iter);
    indicate_comma_needed();
  }
  end_array();

  end_object();
}

void t_json_generator::generate_function(t_function* tfunc) {
  start_object();

  write_key_and_string("name", tfunc->get_name());

  write_key_and_string("returnTypeId", get_type_name(tfunc->get_returntype()));
  write_type_spec_object("returnType", tfunc->get_returntype());

  write_key_and_bool("oneway", tfunc->is_oneway());

  if (tfunc->has_doc()) {
    write_key_and_string("doc", tfunc->get_doc());
  }

  if (tfunc->annotations_.size() > 0) {
    write_key_and("annotations");
    start_object();
    for (auto & annotation : tfunc->annotations_) {
      write_key_and_string(annotation.first, annotation.second);
    }
    end_object();
  }

  write_key_and("arguments");
  start_array();
  vector<t_field*> members = tfunc->get_arglist()->get_members();
  vector<t_field*>::iterator mem_iter = members.begin();
  for (; mem_iter != members.end(); mem_iter++) {
    write_comma_if_needed();
    generate_field(*mem_iter);
    indicate_comma_needed();
  }
  end_array();

  write_key_and("exceptions");
  start_array();
  vector<t_field*> excepts = tfunc->get_xceptions()->get_members();
  vector<t_field*>::iterator ex_iter = excepts.begin();
  for (; ex_iter != excepts.end(); ex_iter++) {
    write_comma_if_needed();
    generate_field(*ex_iter);
    indicate_comma_needed();
  }
  end_array();

  end_object();
}

void t_json_generator::generate_field(t_field* field) {
  start_object();

  write_key_and_integer("key", field->get_key());
  write_key_and_string("name", field->get_name());
  write_key_and_string("typeId", get_type_name(field->get_type()));
  write_type_spec_object("type", field->get_type());

  if (field->has_doc()) {
    write_key_and_string("doc", field->get_doc());
  }

  if (field->annotations_.size() > 0) {
    write_key_and("annotations");
    start_object();
    for (auto & annotation : field->annotations_) {
      write_key_and_string(annotation.first, annotation.second);
    }
    end_object();
  }

  write_key_and("required");
  switch (field->get_req()) {
  case t_field::T_REQUIRED:
    write_string("required");
    break;
  case t_field::T_OPT_IN_REQ_OUT:
    write_string("req_out");
    break;
  default:
    write_string("optional");
    break;
  }

  if (field->get_value()) {
    write_key_and("default");
    write_const_value(field->get_value());
  }

  end_object();
}

string t_json_generator::get_type_name(t_type* ttype) {
  ttype = ttype->get_true_type();
  if (ttype->is_list()) {
    return "list";
  }
  if (ttype->is_set()) {
    return "set";
  }
  if (ttype->is_map()) {
    return "map";
  }
  if (ttype->is_enum()) {
    return "i32";
  }
  if (ttype->is_struct()) {
    return ((t_struct*)ttype)->is_union() ? "union" : "struct";
  }
  if (ttype->is_xception()) {
    return "exception";
  }
  if (ttype->is_base_type()) {
    t_base_type* tbasetype = (t_base_type*)ttype;
    return tbasetype->is_binary() ? "binary" : t_base_type::t_base_name(tbasetype->get_base());
  }

  return "(unknown)";
}

string t_json_generator::get_qualified_name(t_type* ttype) {
  if (should_merge_includes_ || ttype->get_program() == program_) {
    return ttype->get_name();
  }
  return ttype->get_program()->get_name() + "." + ttype->get_name();
}

THRIFT_REGISTER_GENERATOR(json,
                          "JSON",
                          "    merge:           Generate output with included files merged\n")
