// Copyright 2017-2020 The Verible 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.

// verilog_lint is a command-line utility to check Verilog syntax
// and style compliance for the given file.
//
// Example usage:
// verilog_lint files...

#include <algorithm>
#include <fstream>
#include <iostream>
#include <memory>
#include <sstream>  // IWYU pragma: keep  // for ostringstream
#include <string>   // for string, allocator, etc
#include <vector>

#include "absl/flags/flag.h"
#include "absl/status/status.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/string_view.h"
#include "common/analysis/lint_rule_status.h"
#include "common/analysis/violation_handler.h"
#include "common/util/enum_flags.h"
#include "common/util/init_command_line.h"
#include "common/util/iterator_range.h"
#include "common/util/logging.h"  // for operator<<, LOG, LogMessage, etc
#include "verilog/analysis/verilog_linter.h"
#include "verilog/analysis/verilog_linter_configuration.h"

// From least to most disruptive
enum class AutofixMode {
  kNo,                  // No Autofixes
  kPatchInteractive,    // Interactively choose fixes, generate patch
  kPatch,               // Emit a patch
  kInplaceInteractive,  // Interactively choose fixes, apply inplace
  kInplace,             // Automatically apply patch in-place.
  kGenerateWaiver,      // Generate waiver file for violations
};

static const verible::EnumNameMap<AutofixMode> &AutofixModeEnumStringMap() {
  static const verible::EnumNameMap<AutofixMode> kAutofixModeEnumStringMap({
      {"no", AutofixMode::kNo},
      {"patch-interactive", AutofixMode::kPatchInteractive},
      {"patch", AutofixMode::kPatch},
      {"inplace-interactive", AutofixMode::kInplaceInteractive},
      {"inplace", AutofixMode::kInplace},
      {"generate-waiver", AutofixMode::kGenerateWaiver},
  });
  return kAutofixModeEnumStringMap;
}

std::ostream &operator<<(std::ostream &stream, AutofixMode mode) {
  return AutofixModeEnumStringMap().Unparse(mode, stream);
}

std::string AbslUnparseFlag(const AutofixMode &mode) {
  std::ostringstream stream;
  AutofixModeEnumStringMap().Unparse(mode, stream);
  return stream.str();
}

bool AbslParseFlag(absl::string_view text, AutofixMode *mode,
                   std::string *error) {
  return AutofixModeEnumStringMap().Parse(text, mode, error, "--autofix value");
}

// LINT.IfChange

ABSL_FLAG(bool, check_syntax, true,
          "If true, check for lexical and syntax errors, otherwise ignore.");
ABSL_FLAG(bool, parse_fatal, true,
          "If true, exit nonzero if there are any syntax errors.");
ABSL_FLAG(bool, lint_fatal, true,
          "If true, exit nonzero if linter finds violations.");
ABSL_FLAG(std::string, help_rules, "",
          "[all|<rule-name>], print the description of one rule/all rules "
          "and exit immediately.");
ABSL_FLAG(
    bool, generate_markdown, false,
    "If true, print the description of every rule formatted for the "
    "Markdown and exit immediately. Intended for the output to be written "
    "to a snippet of Markdown.");
ABSL_FLAG(bool, print_rules_file, false,
          "Print the current set of lint rules in a format that can be used to "
          "create a lint rules configuration file (i.e. .rules.verible_lint) "
          "and exit immediately.");
ABSL_FLAG(bool, show_diagnostic_context, false,
          "prints an additional "
          "line on which the diagnostic was found,"
          "followed by a line with a position marker");
ABSL_FLAG(
    AutofixMode, autofix, AutofixMode::kNo,
    "autofix mode; one of "
    "[no|patch-interactive|patch|inplace-interactive|inplace|generate-waiver]");
ABSL_FLAG(std::string, autofix_output_file, "",
          "File to write a patch with autofixes to if "
          "--autofix=patch or --autofix=patch-interactive "
          "or a waiver file if --autofix=generate-waiver");

// LINT.ThenChange(README.md)

using verilog::LinterConfiguration;

// LintOneFile returns 0, 1, or 2
static const int kAutofixErrorExitStatus = 3;

int main(int argc, char **argv) {
  const auto usage =
      absl::StrCat("usage: ", argv[0], " [options] <file> [<file>...]");
  const auto args = verible::InitCommandLine(usage, &argc, &argv);

  std::string help_flag = absl::GetFlag(FLAGS_help_rules);
  if (!help_flag.empty()) {
    verilog::GetLintRuleDescriptionsHelpFlag(&std::cout, help_flag);
    return 0;
  }

  // In documentation generation mode, print documentation and exit immediately.
  bool generate_markdown_flag = absl::GetFlag(FLAGS_generate_markdown);
  if (generate_markdown_flag) {
    verilog::GetLintRuleDescriptionsMarkdown(&std::cout);
    return 0;
  }

  int exit_status = 0;

  AutofixMode autofix_mode = absl::GetFlag(FLAGS_autofix);
  const std::string autofix_output_file =
      absl::GetFlag(FLAGS_autofix_output_file);

  std::unique_ptr<std::ostream> stream_closer;
  std::ostream *autofix_output_stream = nullptr;

  if (autofix_mode == AutofixMode::kPatch ||
      autofix_mode == AutofixMode::kPatchInteractive ||
      autofix_mode == AutofixMode::kGenerateWaiver) {
    if (autofix_output_file.empty() || autofix_output_file == "-") {
      autofix_output_stream = &std::cout;
    } else {
      stream_closer.reset(new std::ofstream(autofix_output_file));
      if (stream_closer->good()) {
        autofix_output_stream = stream_closer.get();
      } else {
        LOG(ERROR) << "Failed to create/open output patch file: "
                   << autofix_output_file;
      }
    }
    if (!autofix_output_stream) {
      std::cerr << "--autofix=patch needs --autofix_output_file" << std::endl;
      autofix_mode = AutofixMode::kNo;
      exit_status = kAutofixErrorExitStatus;
    }
  } else if (!autofix_output_file.empty()) {
    std::cerr << "--autofix_output_file has no effect for --autofix="
              << autofix_mode << std::endl;
  }

  const verible::ViolationFixer::AnswerChooser applyAllFixes =
      [](const verible::LintViolation &,
         absl::string_view) -> verible::ViolationFixer::Answer {
    return {verible::ViolationFixer::AnswerChoice::kApplyAll, 0};
  };

  std::unique_ptr<verible::ViolationHandler> violation_handler;
  switch (autofix_mode) {
    case AutofixMode::kNo:
      violation_handler.reset(new verible::ViolationPrinter(&std::cerr));
      break;
    case AutofixMode::kPatchInteractive:
      CHECK(autofix_output_stream);
      violation_handler.reset(
          new verible::ViolationFixer(&std::cerr, autofix_output_stream));
      break;
    case AutofixMode::kPatch:
      CHECK(autofix_output_stream);
      violation_handler.reset(new verible::ViolationFixer(
          &std::cerr, autofix_output_stream, applyAllFixes));
      break;
    case AutofixMode::kInplaceInteractive:
      violation_handler.reset(new verible::ViolationFixer(&std::cerr, nullptr));
      break;
    case AutofixMode::kInplace:
      violation_handler.reset(
          new verible::ViolationFixer(&std::cerr, nullptr, applyAllFixes));
      break;
    case AutofixMode::kGenerateWaiver:
      violation_handler.reset(new verible::ViolationWaiverPrinter(
          &std::cerr, autofix_output_stream));
      break;
  }

  // In documentation generation mode, print lint rule file and exit
  // immediately.
  bool print_rules_file_flag = absl::GetFlag(FLAGS_print_rules_file);
  if (print_rules_file_flag) {
    auto config_status = verilog::LinterConfigurationFromFlags("");
    if (!config_status.ok()) {
      std::cerr << config_status.status().message() << std::endl;
      return 1;
    }
    const LinterConfiguration &config = *config_status;

    verilog::GetLintRuleFile(&std::cout, config);
    return 0;
  }

  // All positional arguments are file names.  Exclude program name.
  for (const absl::string_view filename :
       verible::make_range(args.begin() + 1, args.end())) {
    // Copy configuration, so that it can be locally modified per file.
    auto config_status = verilog::LinterConfigurationFromFlags(filename);
    if (!config_status.ok()) {
      std::cerr << config_status.status().message() << std::endl;
      exit_status = 1;
      continue;
    }
    const LinterConfiguration &config = *config_status;

    const int lint_status = verilog::LintOneFile(
        &std::cout, filename, config, violation_handler.get(),
        absl::GetFlag(FLAGS_check_syntax), absl::GetFlag(FLAGS_parse_fatal),
        absl::GetFlag(FLAGS_lint_fatal),
        absl::GetFlag(FLAGS_show_diagnostic_context));
    exit_status = std::max(lint_status, exit_status);
  }  // for each file

  return exit_status;
}