/*
 * Copyright (C) 2018 The Android Open Source Project
 *
 * Licensed 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 "tools/ftrace_proto_gen/ftrace_proto_gen.h"

#include <fcntl.h>
#include <sys/wait.h>
#include <unistd.h>
#include <algorithm>
#include <fstream>
#include <regex>

#include "perfetto/base/logging.h"
#include "perfetto/ext/base/file_utils.h"
#include "perfetto/ext/base/pipe.h"
#include "perfetto/ext/base/string_splitter.h"
#include "perfetto/ext/base/string_utils.h"

namespace perfetto {

using base::StartsWith;
using base::Contains;

std::string EventNameToProtoFieldName(const std::string& name) {
  return (name == "0") ? "zero" : name;
}

std::string EventNameToProtoName(const std::string& name) {
  return ToCamelCase(EventNameToProtoFieldName(name)) + "FtraceEvent";
}

std::vector<FtraceEventName> ReadWhitelist(const std::string& filename) {
  std::string line;
  std::vector<FtraceEventName> lines;

  std::ifstream fin(filename, std::ios::in);
  if (!fin) {
    fprintf(stderr, "failed to open whitelist %s\n", filename.c_str());
    return lines;
  }
  while (std::getline(fin, line)) {
    if (!StartsWith(line, "#"))
      lines.emplace_back(FtraceEventName(line));
  }
  return lines;
}

bool GenerateProto(const FtraceEvent& format, Proto* proto_out) {
  proto_out->name = EventNameToProtoName(format.name);
  proto_out->event_name = format.name;
  std::set<std::string> seen;
  // TODO(hjd): We should be cleverer about id assignment.
  uint32_t i = 1;
  for (const FtraceEvent::Field& field : format.fields) {
    std::string name = GetNameFromTypeAndName(field.type_and_name);
    // TODO(hjd): Handle dup names.
    // sa_handler is problematic because glib headers redefine it at the
    // preprocessor level. It's impossible to have a variable or a function
    // called sa_handler. On the good side, we realistically don't care about
    // this field, it's just easier to skip it.
    if (name == "" || seen.count(name) || name == "sa_handler" ||
        name == "errno")
      continue;
    seen.insert(name);
    ProtoType type = InferProtoType(field);
    // Check we managed to infer a type.
    if (type.type == ProtoType::INVALID)
      continue;
    Proto::Field protofield{std::move(type), name, i};
    proto_out->AddField(std::move(protofield));
    i++;
  }

  return true;
}

void GenerateFtraceEventProto(const std::vector<FtraceEventName>& raw_whitelist,
                              const std::set<std::string>& groups,
                              std::ostream* fout) {
  *fout << "// Autogenerated by:\n";
  *fout << std::string("// ") + __FILE__ + "\n";
  *fout << "// Do not edit.\n\n";
  *fout << R"(syntax = "proto2";)"
        << "\n";
  *fout << "option optimize_for = LITE_RUNTIME;\n\n";

  for (const std::string& group : groups) {
    *fout << R"(import "protos/perfetto/trace/ftrace/)" << group
          << R"(.proto";)"
          << "\n";
  }
  *fout << "import \"protos/perfetto/trace/ftrace/generic.proto\";\n";
  *fout << "\n";
  *fout << "package perfetto.protos;\n\n";
  *fout << R"(message FtraceEvent {
  // Nanoseconds since an epoch.
  // Epoch is configurable by writing into trace_clock.
  // By default this timestamp is CPU local.
  // TODO: Figure out a story for reconciling the various clocks.
  optional uint64 timestamp = 1;

  // Kernel pid (do not confuse with userspace pid aka tgid)
  optional uint32 pid = 2;

  oneof event {
)";

  int i = 3;
  for (const FtraceEventName& event : raw_whitelist) {
    if (!event.valid()) {
      *fout << "    // removed field with id " << i << ";\n";
      ++i;
      continue;
    }

    std::string field_name = EventNameToProtoFieldName(event.name());
    std::string type_name = EventNameToProtoName(event.name());

    // "    " (indent) + TypeName + " " + field_name + " = " + 123 + ";"
    if (4 + type_name.size() + 1 + field_name.size() + 3 + 3 + 1 <= 80) {
      // Everything fits in one line:
      *fout << "    " << type_name << " " << field_name << " = " << i << ";\n";
    } else if (4 + type_name.size() + 1 + field_name.size() + 2 <= 80) {
      // Everything fits except the field id:
      *fout << "    " << type_name << " " << field_name << " =\n        " << i
            << ";\n";
    } else {
      // Nothing fits:
      *fout << "    " << type_name << "\n        " << field_name << " = " << i
            << ";\n";
    }
    ++i;
    // We cannot depend on the proto file to get this number because
    // it would cause a dependency cycle between this generator and the
    // generated code.
    if (i == 327) {
      *fout << "    GenericFtraceEvent generic = " << i << ";\n";
      ++i;
    }
  }
  *fout << "  }\n";
  *fout << "}\n";
}

// Generates section of event_info.cc for a single event.
std::string SingleEventInfo(perfetto::Proto proto,
                            const std::string& group,
                            const uint32_t proto_field_id) {
  std::string s = "";
  s += "    event->name = \"" + proto.event_name + "\";\n";
  s += "    event->group = \"" + group + "\";\n";
  s += "    event->proto_field_id = " + std::to_string(proto_field_id) + ";\n";

  for (const auto& field : proto.SortedFields()) {
    s += "    event->fields.push_back(MakeField(\"" + field->name + "\", " +
         std::to_string(field->number) + ", ProtoSchemaType::k" +
         ToCamelCase(field->type.ToString()) + "));\n";
  }
  return s;
}

// This will generate the event_info.cc file for the whitelisted protos.
void GenerateEventInfo(const std::vector<std::string>& events_info,
                       std::ostream* fout) {
  std::string s = "// Autogenerated by:\n";
  s += std::string("// ") + __FILE__ + "\n";
  s += "// Do not edit.\n";
  s += R"(
#include "perfetto/protozero/proto_utils.h"
#include "src/traced/probes/ftrace/event_info.h"

namespace perfetto {

using protozero::proto_utils::ProtoSchemaType;

std::vector<Event> GetStaticEventInfo() {
  std::vector<Event> events;
)";

  for (const auto& event : events_info) {
    s += "\n";
    s += "  {\n";
    s += "    events.emplace_back(Event{});\n";
    s += "    Event* event = &events.back();\n";
    s += event;
    s += "  }\n";
  }

  s += R"(
  return events;
}

}  // namespace perfetto
)";

  *fout << s;
}

std::string ProtoHeader() {
  std::string s = "// Autogenerated by:\n";
  s += std::string("// ") + __FILE__ + "\n";
  s += "// Do not edit.\n";

  s += R"(
syntax = "proto2";
option optimize_for = LITE_RUNTIME;
package perfetto.protos;

)";
  return s;
}

}  // namespace perfetto