/* Copyright 2017-2018 ccls Authors

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 "test.h"

#include "clang_complete.hh"
#include "filesystem.hh"
#include "indexer.h"
#include "platform.h"
#include "serializer.h"
#include "utils.h"

#include <llvm/Config/llvm-config.h>
#include <llvm/ADT/StringRef.h>
using namespace llvm;

#include <rapidjson/document.h>
#include <rapidjson/prettywriter.h>
#include <rapidjson/stringbuffer.h>
#include <rapidjson/writer.h>

#include <fstream>
#include <stdio.h>
#include <stdlib.h>

// The 'diff' utility is available and we can use dprintf(3).
#if _POSIX_C_SOURCE >= 200809L
#include <sys/wait.h>
#include <unistd.h>
#endif

extern bool gTestOutputMode;

std::string ToString(const rapidjson::Document &document) {
  rapidjson::StringBuffer buffer;
  rapidjson::PrettyWriter<rapidjson::StringBuffer> writer(buffer);
  writer.SetFormatOptions(
      rapidjson::PrettyFormatOptions::kFormatSingleLineArray);
  writer.SetIndent(' ', 2);

  buffer.Clear();
  document.Accept(writer);
  return buffer.GetString();
}

struct TextReplacer {
  struct Replacement {
    std::string from;
    std::string to;
  };

  std::vector<Replacement> replacements;

  std::string Apply(const std::string &content) {
    std::string result = content;

    for (const Replacement &replacement : replacements) {
      while (true) {
        size_t idx = result.find(replacement.from);
        if (idx == std::string::npos)
          break;

        result.replace(result.begin() + idx,
                       result.begin() + idx + replacement.from.size(),
                       replacement.to);
      }
    }

    return result;
  }
};

void TrimInPlace(std::string &s) {
  auto f = [](char c) { return !isspace(c); };
  s.erase(s.begin(), std::find_if(s.begin(), s.end(), f));
  s.erase(std::find_if(s.rbegin(), s.rend(), f).base(), s.end());
}

void ParseTestExpectation(
    const std::string &filename,
    const std::vector<std::string> &lines_with_endings, TextReplacer *replacer,
    std::vector<std::string> *flags,
    std::unordered_map<std::string, std::string> *output_sections) {
  // Scan for EXTRA_FLAGS:
  {
    bool in_output = false;
    for (std::string line : lines_with_endings) {
      line = StringRef(line).trim().str();

      if (StartsWith(line, "EXTRA_FLAGS:")) {
        assert(!in_output && "multiple EXTRA_FLAGS sections");
        in_output = true;
        continue;
      }

      if (in_output && line.empty())
        break;

      if (in_output)
        flags->push_back(line);
    }
  }

  // Scan for OUTPUT:
  {
    std::string active_output_filename;
    std::string active_output_contents;

    bool in_output = false;
    for (std::string line_with_ending : lines_with_endings) {
      if (StartsWith(line_with_ending, "*/"))
        break;

      if (StartsWith(line_with_ending, "OUTPUT:")) {
        // Terminate the previous output section if we found a new one.
        if (in_output) {
          (*output_sections)[active_output_filename] = active_output_contents;
        }

        // Try to tokenize OUTPUT: based one whitespace. If there is more than
        // one token assume it is a filename.
        std::vector<std::string> tokens = SplitString(line_with_ending, " ");
        if (tokens.size() > 1) {
          active_output_filename = StringRef(tokens[1]).trim().str();
        } else {
          active_output_filename = filename;
        }
        active_output_contents = "";

        in_output = true;
      } else if (in_output) {
        active_output_contents += line_with_ending;
        active_output_contents.push_back('\n');
      }
    }

    if (in_output)
      (*output_sections)[active_output_filename] = active_output_contents;
  }
}

void UpdateTestExpectation(const std::string &filename,
                           const std::string &expectation,
                           const std::string &actual) {
  // Read the entire file into a string.
  std::ifstream in(filename);
  std::string str;
  str.assign(std::istreambuf_iterator<char>(in),
             std::istreambuf_iterator<char>());
  in.close();

  // Replace expectation
  auto it = str.find(expectation);
  assert(it != std::string::npos);
  str.replace(it, expectation.size(), actual);

  // Write it back out.
  WriteToFile(filename, str);
}

void DiffDocuments(std::string path, std::string path_section,
                   rapidjson::Document &expected, rapidjson::Document &actual) {
  std::string joined_actual_output = ToString(actual);
  std::string joined_expected_output = ToString(expected);
  printf("[FAILED] %s (section %s)\n", path.c_str(), path_section.c_str());

#if _POSIX_C_SOURCE >= 200809L
  char expected_file[] = "/tmp/ccls.expected.XXXXXX";
  char actual_file[] = "/tmp/ccls.actual.XXXXXX";
  int expected_fd = mkstemp(expected_file);
  int actual_fd = mkstemp(actual_file);
  dprintf(expected_fd, "%s", joined_expected_output.c_str());
  dprintf(actual_fd, "%s", joined_actual_output.c_str());
  close(expected_fd);
  close(actual_fd);
  pid_t child = fork();
  if (child == 0) {
    execlp("diff", "diff", "-U", "3", expected_file, actual_file, NULL);
    _Exit(127);
  } else {
    int status;
    waitpid(child, &status, 0);
    unlink(expected_file);
    unlink(actual_file);
    // 'diff' returns 0 or 1 if exitted normaly.
    if (WEXITSTATUS(status) <= 1)
      return;
  }
#endif
  std::vector<std::string> actual_output =
      SplitString(joined_actual_output, "\n");
  std::vector<std::string> expected_output =
      SplitString(joined_expected_output, "\n");

  printf("Expected output for %s (section %s)\n:%s\n", path.c_str(),
         path_section.c_str(), joined_expected_output.c_str());
  printf("Actual output for %s (section %s)\n:%s\n", path.c_str(),
         path_section.c_str(), joined_actual_output.c_str());
}

void VerifySerializeToFrom(IndexFile *file) {
  std::string expected = file->ToString();
  std::string serialized = ccls::Serialize(SerializeFormat::Json, *file);
  std::unique_ptr<IndexFile> result =
      ccls::Deserialize(SerializeFormat::Json, "--.cc", serialized, "<empty>",
                        std::nullopt /*expected_version*/);
  std::string actual = result->ToString();
  if (expected != actual) {
    fprintf(stderr, "Serialization failure\n");
    // assert(false);
  }
}

std::string FindExpectedOutputForFilename(
    std::string filename,
    const std::unordered_map<std::string, std::string> &expected) {
  for (const auto &entry : expected) {
    if (EndsWith(entry.first, filename))
      return entry.second;
  }

  fprintf(stderr, "Couldn't find expected output for %s\n", filename.c_str());
  getchar();
  getchar();
  return "{}";
}

IndexFile *
FindDbForPathEnding(const std::string &path,
                    const std::vector<std::unique_ptr<IndexFile>> &dbs) {
  for (auto &db : dbs) {
    if (EndsWith(db->path, path))
      return db.get();
  }
  return nullptr;
}

bool RunIndexTests(const std::string &filter_path, bool enable_update) {
  gTestOutputMode = true;
  std::string version = LLVM_VERSION_STRING;

  // Index tests change based on the version of clang used.
  static const char kRequiredClangVersion[] = "6.0.0";
  if (version != kRequiredClangVersion &&
      version.find("svn") == std::string::npos) {
    fprintf(stderr,
            "Index tests must be run using clang version %s, ccls is running "
            "with %s\n",
            kRequiredClangVersion, version.c_str());
    return false;
  }

  bool success = true;
  bool update_all = false;
  // FIXME: show diagnostics in STL/headers when running tests. At the moment
  // this can be done by constructing ClangIndex index(1, 1);
  CompletionManager completion(
      nullptr, nullptr, [&](std::string, std::vector<lsDiagnostic>) {},
      [](lsRequestId id) {});
  GetFilesInFolder(
      "index_tests", true /*recursive*/, true /*add_folder_to_path*/,
      [&](const std::string &path) {
        bool is_fail_allowed = false;

        if (EndsWithAny(path, {".m", ".mm"})) {
#ifndef __APPLE__
          return;
#endif

          // objective-c tests are often not updated right away. do not bring
          // down
          // CI if they fail.
          if (!enable_update)
            is_fail_allowed = true;
        }

        if (path.find(filter_path) == std::string::npos)
          return;

        if (!filter_path.empty())
          printf("Running %s\n", path.c_str());

        // Parse expected output from the test, parse it into JSON document.
        std::vector<std::string> lines_with_endings;
        {
          std::ifstream fin(path);
          for (std::string line; std::getline(fin, line);)
            lines_with_endings.push_back(line);
        }
        TextReplacer text_replacer;
        std::vector<std::string> flags;
        std::unordered_map<std::string, std::string> all_expected_output;
        ParseTestExpectation(path, lines_with_endings, &text_replacer, &flags,
                             &all_expected_output);

        // Build flags.
        flags.push_back("-resource-dir=" + GetDefaultResourceDirectory());
        flags.push_back(path);

        // Run test.
        g_config = new Config;
        VFS vfs;
        WorkingFiles wfiles;
        std::vector<const char *> cargs;
        for (auto &arg : flags)
          cargs.push_back(arg.c_str());
        auto dbs = ccls::idx::Index(&completion, &wfiles, &vfs, "", path, cargs, {});

        for (const auto &entry : all_expected_output) {
          const std::string &expected_path = entry.first;
          std::string expected_output = text_replacer.Apply(entry.second);

          // Get output from index operation.
          IndexFile *db = FindDbForPathEnding(expected_path, dbs);
          std::string actual_output = "{}";
          if (db) {
            VerifySerializeToFrom(db);
            actual_output = db->ToString();
          }
          actual_output = text_replacer.Apply(actual_output);

          // Compare output via rapidjson::Document to ignore any formatting
          // differences.
          rapidjson::Document actual;
          actual.Parse(actual_output.c_str());
          rapidjson::Document expected;
          expected.Parse(expected_output.c_str());

          if (actual == expected) {
            // std::cout << "[PASSED] " << path << std::endl;
          } else {
            if (!is_fail_allowed)
              success = false;
            DiffDocuments(path, expected_path, expected, actual);
            puts("\n");
            if (enable_update) {
              printf("[Enter to continue - type u to update test, a to update "
                     "all]");
              char c = 'u';
              if (!update_all) {
                c = getchar();
                getchar();
              }

              if (c == 'a')
                update_all = true;

              if (update_all || c == 'u') {
                // Note: we use |entry.second| instead of |expected_output|
                // because
                // |expected_output| has had text replacements applied.
                UpdateTestExpectation(path, entry.second,
                                      ToString(actual) + "\n");
              }
            }
          }
        }
      });

  return success;
}