/*
 * 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.
 */

#include <string>
#include <fstream>
#include <iostream>
#include <vector>
#include <map>
#include <list>

#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::ostringstream;
using std::pair;
using std::string;
using std::stringstream;
using std::vector;

static const string endl = "\n"; // avoid ostream << std::endl flushes

/**
 * Graphviz code generator
 */
class t_gv_generator : public t_generator {
public:
  t_gv_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;

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

    out_dir_base_ = "gen-gv";
  }

  /**
   * Init and end of generator
   */
  void init_generator() override;
  void close_generator() override;

  /**
   * Program-level generation functions
   */
  void generate_typedef(t_typedef* ttypedef) override;
  void generate_enum(t_enum* tenum) override;
  void generate_const(t_const* tconst) override;
  void generate_struct(t_struct* tstruct) override;
  void generate_service(t_service* tservice) override;

protected:
  /**
   * Helpers
   */
  void print_type(t_type* ttype, string struct_field_ref);
  void print_const_value(t_type* type, t_const_value* tvalue);

private:
  ofstream_with_content_based_conditional_update f_out_;
  std::list<string> edges;
  bool exception_arrows;
};

/**
 * Init generator:
 * - Adds some escaping for the Graphviz domain.
 * - Create output directory and open file for writting.
 * - Write the file header.
 */
void t_gv_generator::init_generator() {
  escape_['{'] = "\\{";
  escape_['}'] = "\\}";

  // Make output directory
  MKDIR(get_out_dir().c_str());
  string fname = get_out_dir() + program_->get_name() + ".gv";
  f_out_.open(fname.c_str());
  f_out_ << "digraph \"" << escape_string(program_name_) << "\" {" << endl;
  f_out_ << "node [style=filled, shape=record];" << endl;
  f_out_ << "edge [arrowsize=0.5];" << endl;
  f_out_ << "rankdir=LR" << endl;
}

/**
 * Closes generator:
 * - Print accumulated nodes connections.
 * - Print footnote.
 * - Closes file.
 */
void t_gv_generator::close_generator() {
  // Print edges
  std::list<string>::iterator iter = edges.begin();
  for (; iter != edges.end(); iter++) {
    f_out_ << (*iter) << endl;
  }

  // Print graph end } and close file
  f_out_ << "}" << endl;
  f_out_.close();
}

void t_gv_generator::generate_typedef(t_typedef* ttypedef) {
  string name = ttypedef->get_name();
  f_out_ << "node [fillcolor=azure];" << endl;
  f_out_ << name << " [label=\"";

  f_out_ << escape_string(name);
  f_out_ << " :: ";
  print_type(ttypedef->get_type(), name);

  f_out_ << "\"];" << endl;
}

void t_gv_generator::generate_enum(t_enum* tenum) {
  string name = tenum->get_name();
  f_out_ << "node [fillcolor=white];" << endl;
  f_out_ << name << " [label=\"enum " << escape_string(name);

  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) {
    f_out_ << '|' << (*val_iter)->get_name();
    f_out_ << " = ";
    f_out_ << (*val_iter)->get_value();
  }

  f_out_ << "\"];" << endl;
}

void t_gv_generator::generate_const(t_const* tconst) {
  string name = tconst->get_name();

  f_out_ << "node [fillcolor=aliceblue];" << endl;
  f_out_ << "const_" << name << " [label=\"";

  f_out_ << escape_string(name);
  f_out_ << " = ";
  print_const_value(tconst->get_type(), tconst->get_value());
  f_out_ << " :: ";
  print_type(tconst->get_type(), "const_" + name);

  f_out_ << "\"];" << endl;
}

void t_gv_generator::generate_struct(t_struct* tstruct) {
  string name = tstruct->get_name();

  if (tstruct->is_xception()) {
    f_out_ << "node [fillcolor=lightpink];" << endl;
    f_out_ << name << " [label=\"";
    f_out_ << "exception " << escape_string(name);
  } else if (tstruct->is_union()) {
    f_out_ << "node [fillcolor=lightcyan];" << endl;
    f_out_ << name << " [label=\"";
    f_out_ << "union " << escape_string(name);
  } else {
    f_out_ << "node [fillcolor=beige];" << endl;
    f_out_ << name << " [label=\"";
    f_out_ << "struct " << escape_string(name);
  }

  vector<t_field*> members = tstruct->get_members();
  vector<t_field*>::iterator mem_iter = members.begin();
  for (; mem_iter != members.end(); mem_iter++) {
    string field_name = (*mem_iter)->get_name();

    // print port (anchor reference)
    f_out_ << "|<field_" << field_name << '>';

    // field name :: field type
    f_out_ << (*mem_iter)->get_name();
    f_out_ << " :: ";
    print_type((*mem_iter)->get_type(), name + ":field_" + field_name);
  }

  f_out_ << "\"];" << endl;
}

void t_gv_generator::print_type(t_type* ttype, string struct_field_ref) {
  if (ttype->is_container()) {
    if (ttype->is_list()) {
      f_out_ << "list\\<";
      print_type(((t_list*)ttype)->get_elem_type(), struct_field_ref);
      f_out_ << "\\>";
    } else if (ttype->is_set()) {
      f_out_ << "set\\<";
      print_type(((t_set*)ttype)->get_elem_type(), struct_field_ref);
      f_out_ << "\\>";
    } else if (ttype->is_map()) {
      f_out_ << "map\\<";
      print_type(((t_map*)ttype)->get_key_type(), struct_field_ref);
      f_out_ << ", ";
      print_type(((t_map*)ttype)->get_val_type(), struct_field_ref);
      f_out_ << "\\>";
    }
  } else if (ttype->is_base_type()) {
    f_out_ << (ttype->is_binary() ? "binary" : ttype->get_name());
  } else {
    f_out_ << ttype->get_name();
    edges.push_back(struct_field_ref + " -> " + ttype->get_name());
  }
}

/**
 * Prints out an string representation of the provided constant value
 */
void t_gv_generator::print_const_value(t_type* type, t_const_value* tvalue) {
  bool first = true;
  switch (tvalue->get_type()) {
  case t_const_value::CV_INTEGER:
    f_out_ << tvalue->get_integer();
    break;
  case t_const_value::CV_DOUBLE:
    f_out_ << tvalue->get_double();
    break;
  case t_const_value::CV_STRING:
    f_out_ << "\\\"" << get_escaped_string(tvalue) << "\\\"";
    break;
  case t_const_value::CV_MAP: {
    f_out_ << "\\{ ";
    map<t_const_value*, t_const_value*, t_const_value::value_compare> map_elems = tvalue->get_map();
    map<t_const_value*, t_const_value*, t_const_value::value_compare>::iterator map_iter;
    for (map_iter = map_elems.begin(); map_iter != map_elems.end(); map_iter++) {
      if (!first) {
        f_out_ << ", ";
      }
      first = false;
      print_const_value(((t_map*)type)->get_key_type(), map_iter->first);
      f_out_ << " = ";
      print_const_value(((t_map*)type)->get_val_type(), map_iter->second);
    }
    f_out_ << " \\}";
  } break;
  case t_const_value::CV_LIST: {
    f_out_ << "\\{ ";
    vector<t_const_value*> list_elems = tvalue->get_list();
    ;
    vector<t_const_value*>::iterator list_iter;
    for (list_iter = list_elems.begin(); list_iter != list_elems.end(); list_iter++) {
      if (!first) {
        f_out_ << ", ";
      }
      first = false;
      if (type->is_list()) {
        print_const_value(((t_list*)type)->get_elem_type(), *list_iter);
      } else {
        print_const_value(((t_set*)type)->get_elem_type(), *list_iter);
      }
    }
    f_out_ << " \\}";
  } break;
  case t_const_value::CV_IDENTIFIER:
    f_out_ << escape_string(type->get_name()) << "."
           << escape_string(tvalue->get_identifier_name());
    break;
  default:
    f_out_ << "UNKNOWN";
    break;
  }
}

void t_gv_generator::generate_service(t_service* tservice) {
  string service_name = get_service_name(tservice);
  f_out_ << "subgraph cluster_" << service_name << " {" << endl;
  f_out_ << "node [fillcolor=bisque];" << endl;
  f_out_ << "style=dashed;" << endl;
  f_out_ << "label = \"" << escape_string(service_name) << " service\";" << endl;

  // TODO: service extends

  vector<t_function*> functions = tservice->get_functions();
  vector<t_function*>::iterator fn_iter = functions.begin();
  for (; fn_iter != functions.end(); fn_iter++) {
    string fn_name = (*fn_iter)->get_name();

    f_out_ << "function_" << service_name << fn_name;
    f_out_ << "[label=\"<return_type>function " << escape_string(fn_name);
    f_out_ << " :: ";
    print_type((*fn_iter)->get_returntype(), "function_" + service_name + fn_name + ":return_type");

    vector<t_field*> args = (*fn_iter)->get_arglist()->get_members();
    vector<t_field*>::iterator arg_iter = args.begin();
    for (; arg_iter != args.end(); arg_iter++) {
      f_out_ << "|<param_" << (*arg_iter)->get_name() << ">";
      f_out_ << (*arg_iter)->get_name();
      if ((*arg_iter)->get_value() != nullptr) {
        f_out_ << " = ";
        print_const_value((*arg_iter)->get_type(), (*arg_iter)->get_value());
      }
      f_out_ << " :: ";
      print_type((*arg_iter)->get_type(),
                 "function_" + service_name + fn_name + ":param_" + (*arg_iter)->get_name());
    }
    // end of node
    f_out_ << "\"];" << endl;

    // Exception edges
    if (exception_arrows) {
      vector<t_field*> excepts = (*fn_iter)->get_xceptions()->get_members();
      vector<t_field*>::iterator ex_iter = excepts.begin();
      for (; ex_iter != excepts.end(); ex_iter++) {
        edges.push_back("function_" + service_name + fn_name + " -> "
                        + (*ex_iter)->get_type()->get_name() + " [color=red]");
      }
    }
  }

  f_out_ << " }" << endl;
}

THRIFT_REGISTER_GENERATOR(
    gv,
    "Graphviz",
    "    exceptions:      Whether to draw arrows from functions to exception.\n")
