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// Generates a Python gRPC service interface out of Protobuf IDL.

#include <memory>
#include <string>

#include "src/compiler/python_generator.h"
#include <google/protobuf/compiler/code_generator.h>
#include <google/protobuf/compiler/plugin.h>
#include <google/protobuf/io/coded_stream.h>
#include <google/protobuf/io/zero_copy_stream.h>
#include <google/protobuf/descriptor.h>

using google::protobuf::FileDescriptor;
using google::protobuf::compiler::CodeGenerator;
using google::protobuf::compiler::GeneratorContext;
using google::protobuf::compiler::PluginMain;
using google::protobuf::io::CodedOutputStream;
using google::protobuf::io::ZeroCopyOutputStream;
using std::string;

class PythonGrpcGenerator : public CodeGenerator {
 public:
  PythonGrpcGenerator() {}
  ~PythonGrpcGenerator() override {}

  bool Generate(const FileDescriptor* file,
                const string& parameter,
                GeneratorContext* context,
                string* error) const override {
    // Get output file name.
    string file_name;
    static const int proto_suffix_length = 6;  // length of ".proto"
    if (file->name().size() > static_cast<size_t>(proto_suffix_length) &&
        file->name().find_last_of(".proto") == file->name().size() - 1) {
      file_name = file->name().substr(
          0, file->name().size() - proto_suffix_length) + "_pb2.py";
    } else {
      *error = "Invalid proto file name. Proto file must end with .proto";
      return false;
    }

    std::unique_ptr<ZeroCopyOutputStream> output(
        context->OpenForInsert(file_name, "module_scope"));
    CodedOutputStream coded_out(output.get());
    string code = grpc_python_generator::GetServices(file);
    coded_out.WriteRaw(code.data(), code.size());
    return true;
  }
};

int main(int argc, char* argv[]) {
  PythonGrpcGenerator generator;
  return PluginMain(argc, argv, &generator);
}