/*
 * Copyright (C) 2021 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 "src/trace_processor/plugins/create_view_function/create_view_function.h"

#include <cstddef>
#include <memory>
#include <string>
#include <utility>
#include <vector>

#include "perfetto/base/compiler.h"
#include "perfetto/base/status.h"
#include "perfetto/ext/base/status_macros.h"
#include "perfetto/ext/base/string_utils.h"
#include "perfetto/ext/base/string_view.h"
#include "perfetto/trace_processor/basic_types.h"
#include "src/trace_processor/containers/null_term_string_view.h"
#include "src/trace_processor/core/plugin/plugin.h"
#include "src/trace_processor/perfetto_sql/engine/perfetto_sql_connection.h"
#include "src/trace_processor/perfetto_sql/parser/function_util.h"
#include "src/trace_processor/sqlite/sql_source.h"
#include "src/trace_processor/sqlite/sqlite_utils.h"

namespace perfetto::trace_processor {

void CreateViewFunction::Step(sqlite3_context* ctx,
                              int argc,
                              sqlite3_value** argv) {
  PERFETTO_DCHECK(argc == 3);

  auto* connection = GetUserData(ctx);

  // Type check all the arguments.
  if (sqlite::value::Type(argv[0]) != sqlite::Type::kText) {
    return sqlite::utils::SetError(ctx,
                                   "CREATE_VIEW_FUNCTION: function prototype "
                                   "(first argument) must be string");
  }
  if (sqlite::value::Type(argv[1]) != sqlite::Type::kText) {
    return sqlite::utils::SetError(ctx,
                                   "CREATE_VIEW_FUNCTION: return prototype "
                                   "(second argument) must be string");
  }
  if (sqlite::value::Type(argv[2]) != sqlite::Type::kText) {
    return sqlite::utils::SetError(
        ctx,
        "CREATE_VIEW_FUNCTION: SQL definition (third argument) must be string");
  }

  // Extract the arguments from the value wrappers.
  const char* prototype_str = sqlite::value::Text(argv[0]);
  const char* return_prototype_str = sqlite::value::Text(argv[1]);
  const char* sql_defn_str = sqlite::value::Text(argv[2]);

  static constexpr char kSqlTemplate[] =
      R"""(CREATE OR REPLACE PERFETTO FUNCTION %s RETURNS TABLE(%s) AS %s;)""";

  base::StringView function_name;
  auto parse_status = ParseFunctionName(prototype_str, function_name);
  if (!parse_status.ok()) {
    return sqlite::utils::SetError(ctx, parse_status);
  }

  std::string function_name_str = function_name.ToStdString();

  NullTermStringView sql_defn(sql_defn_str);
  std::string formatted_sql(sql_defn.size() + 1024, '\0');
  size_t size = base::SprintfTrunc(formatted_sql.data(), formatted_sql.size(),
                                   kSqlTemplate, prototype_str,
                                   return_prototype_str, sql_defn_str);
  formatted_sql.resize(size);

  auto res = connection->Execute(
      SqlSource::FromTraceProcessorImplementation(std::move(formatted_sql)));
  if (!res.status().ok()) {
    return sqlite::utils::SetError(ctx, res.status());
  }

  // CREATE_VIEW_FUNCTION returns no value (void function)
  return sqlite::utils::ReturnVoidFromFunction(ctx);
}

namespace create_view_function {
namespace {

class CreateViewFunctionPlugin : public Plugin<CreateViewFunctionPlugin> {
 public:
  ~CreateViewFunctionPlugin() override;

  void RegisterFunctions(PerfettoSqlConnection* connection,
                         std::vector<FunctionRegistration>& out) override {
    out.push_back(MakeFunctionRegistration<CreateViewFunction>(connection));
  }
};

CreateViewFunctionPlugin::~CreateViewFunctionPlugin() = default;

}  // namespace

void RegisterPlugin() {
  static PluginRegistration reg(
      []() -> std::unique_ptr<PluginBase> {
        return std::make_unique<CreateViewFunctionPlugin>();
      },
      CreateViewFunctionPlugin::kPluginId,
      CreateViewFunctionPlugin::kDepIds.data(),
      CreateViewFunctionPlugin::kDepIds.size());
  base::ignore_result(reg);
}

}  // namespace create_view_function
}  // namespace perfetto::trace_processor
