// Copyright 2020 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef ZIRCON_SYSTEM_ULIB_ZBITL_TEST_TESTS_H_
#define ZIRCON_SYSTEM_ULIB_ZBITL_TEST_TESTS_H_

#include <lib/zbitl/json.h>
#include <lib/zbitl/view.h>

#include <string>
#include <type_traits>

#include <zxtest/zxtest.h>

#include "corpus.h"

#define ASSERT_IS_OK(result)                                              \
  do {                                                                    \
    const auto& result_ = result;                                         \
    ASSERT_TRUE(result_.is_ok(), "unexpected error: %.*s",                \
                static_cast<int>(result_.error_value().zbi_error.size()), \
                result_.error_value().zbi_error.data());                  \
  } while (0)

// Usage of StorageIo below is a default-constructible class that should look
// like
// * a namespace member of `storage_type`, giving the underlying storage type.
// * a means of creating a 'ZBI' of that type from a string representation:
//   ```
//  void Create(std::string_view, storage_type* zbi)
//   ```
// * a means of reading the payload of an item:
//   ```
//  void ReadPayload(const storage_type& zbi, const zbi_header_t& header, payload_type payload)
//   ```
// (where payload_type is that of the official storage traits associated with
// storage_type.)

template <typename StorageIo>
inline void TestDefaultConstructedView(bool expect_storage_error) {
  static_assert(std::is_default_constructible_v<typename StorageIo::storage_type>,
                "this test case only applies to default-constructible storage types");

  zbitl::View<typename StorageIo::storage_type> view;

  // This ensures that everything statically compiles when instantiating the
  // templates, even though the header/payloads are never used.
  for (auto [header, payload] : view) {
    EXPECT_EQ(header->flags, header->flags);
    EXPECT_TRUE(false, "should not be reached");
  }

  auto error = view.take_error();
  ASSERT_TRUE(error.is_error(), "no error when header cannot be read??");
  EXPECT_FALSE(error.error_value().zbi_error.empty(), "empty zbi_error string!!");
  if (expect_storage_error) {
    EXPECT_TRUE(error.error_value().storage_error.has_value());
  } else {
    EXPECT_FALSE(error.error_value().storage_error.has_value());
  }
}

template <typename StorageIo>
inline void TestEmptyZbi() {
  StorageIo io;

  typename StorageIo::storage_type zbi;
  ASSERT_NO_FATAL_FAILURES(
      io.Create({zbitl::test::kEmptyZbi, sizeof(zbitl::test::kEmptyZbi)}, &zbi));
  zbitl::View view(std::move(zbi));  // Yay deduction guides!

  ASSERT_IS_OK(view.container_header());

  EXPECT_EQ(view.end(), view.begin());

  for (auto [header, payload] : view) {
    EXPECT_EQ(header->type, header->type);
    EXPECT_TRUE(false, "should not be reached");
  }

  auto error = view.take_error();
  EXPECT_FALSE(error.is_error(), "%s at offset %#x",
               std::string(error.error_value().zbi_error).c_str(),  // No '\0'.
               error.error_value().item_offset);
}

template <typename StorageIo>
inline void TestSimpleZbi() {
  StorageIo io;

  typename StorageIo::storage_type zbi;
  ASSERT_NO_FATAL_FAILURES(
      io.Create({zbitl::test::kSimpleZbi, sizeof(zbitl::test::kSimpleZbi)}, &zbi));
  zbitl::View view(std::move(zbi));

  ASSERT_IS_OK(view.container_header());

  size_t num_items = 0;
  for (auto [header, payload] : view) {
    EXPECT_EQ(ZBI_TYPE_CMDLINE, header->type);

    std::string contents;
    ASSERT_NO_FATAL_FAILURES(io.ReadPayload(view.storage(), *header, payload, &contents));
    switch (num_items++) {
      case 0:
        EXPECT_STR_EQ("hello world", contents.c_str(), "payload: %s", contents.c_str());
        break;
    }
    const uint32_t flags = header->flags;
    EXPECT_TRUE(flags & ZBI_FLAG_VERSION, "flags: %#x", flags);
  }
  EXPECT_EQ(1, num_items);

  auto error = view.take_error();
  EXPECT_FALSE(error.is_error(), "%s at offset %#x",
               std::string(error.error_value().zbi_error).c_str(),  // No '\0'.
               error.error_value().item_offset);
}

template <typename StorageIo>
void TestBadCrcZbi() {
  StorageIo io;

  typename StorageIo::storage_type zbi;
  ASSERT_NO_FATAL_FAILURES(
      io.Create({zbitl::test::kBadCrcZbi, sizeof(zbitl::test::kBadCrcZbi)}, &zbi));
  zbitl::View<typename StorageIo::storage_type, zbitl::Checking::kCrc> view(std::move(zbi));

  ASSERT_IS_OK(view.container_header());

  for (auto [header, payload] : view) {
    EXPECT_EQ(header->type, header->type);
    EXPECT_TRUE(false, "should not be reached");
  }
  auto error = view.take_error();
  ASSERT_TRUE(error.is_error());
  // The error shouldn't be one of storage.
  EXPECT_FALSE(error.error_value().storage_error);
}

template <typename StorageIo>
void TestMutation() {
  StorageIo io;

  typename StorageIo::storage_type zbi;
  ASSERT_NO_FATAL_FAILURES(
      io.Create({zbitl::test::kSimpleZbi, sizeof(zbitl::test::kSimpleZbi)}, &zbi));
  zbitl::View view(std::move(zbi));

  ASSERT_IS_OK(view.container_header());

  size_t num_items = 0;
  for (auto it = view.begin(); it != view.end(); ++it) {
    auto [header, payload] = *it;

    EXPECT_EQ(ZBI_TYPE_CMDLINE, header->type);

    std::string contents;
    ASSERT_NO_FATAL_FAILURES(io.ReadPayload(view.storage(), *header, payload, &contents));
    switch (num_items++) {
      case 0:
        EXPECT_STR_EQ("hello world", contents.c_str());
        ASSERT_TRUE(it.Replace({.type = ZBI_TYPE_DISCARD}).is_ok());
        break;
    }
  }
  EXPECT_EQ(1, num_items);

  {
    auto error = view.take_error();
    EXPECT_FALSE(error.is_error(), "%s at offset %#x",
                 std::string(error.error_value().zbi_error).c_str(),  // No '\0'.
                 error.error_value().item_offset);
  }

  num_items = 0;
  for (auto [header, payload] : view) {
    EXPECT_EQ(ZBI_TYPE_DISCARD, header->type);

    std::string contents;
    ASSERT_NO_FATAL_FAILURES(io.ReadPayload(view.storage(), *header, payload, &contents));
    switch (num_items++) {
      case 0:
        EXPECT_STR_EQ("hello world", contents.c_str());
        break;
    }
  }
  EXPECT_EQ(1, num_items);

  {
    auto error = view.take_error();
    EXPECT_FALSE(error.is_error(), "%s at offset %#x",
                 std::string(error.error_value().zbi_error).c_str(),  // No '\0'.
                 error.error_value().item_offset);
  }
}

#endif  // ZIRCON_SYSTEM_ULIB_ZBITL_TEST_TESTS_H_