// Copyright 2019 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_TOOLS_FIDL_INCLUDE_FIDL_FINDINGS_H_
#define ZIRCON_TOOLS_FIDL_INCLUDE_FIDL_FINDINGS_H_

///////////////////////////////////////////////////////////////
// Even though this file is namespaced to "fidl::lint", it
// could be promoted to the "fidl" namespace in the future.
//
// findings.h and findings.cpp should not have any
// dependencies on the "Lint" process. They should be
// generic enough to be useful for capturing and reporting
// findings from other developer tools, such as fidlc.
///////////////////////////////////////////////////////////////

#include <list>
#include <optional>
#include <sstream>
#include <string>

#include <fidl/source_span.h>

namespace fidl {

// A suggested change to address a linter |Finding|, with a human language
// description of the suggestion, and one or more potential |Replacement|
// values for referenced parts of the source.
struct Suggestion {
 public:
  explicit Suggestion(std::string description) : description_(description) {}

  Suggestion(std::string description, std::string replacement)
      : description_(description), replacement_(replacement) {}

  // Enable move construction and assignment
  Suggestion(Suggestion&& rhs) = default;
  Suggestion& operator=(Suggestion&&) = default;

  // Enable copy and assign
  Suggestion(const Suggestion&) = default;
  Suggestion& operator=(const Suggestion&) = default;

  // Describes the suggestion in human terms.
  inline const std::string& description() const { return description_; }
  inline const std::optional<std::string>& replacement() const { return replacement_; }

 private:
  std::string description_;
  std::optional<std::string> replacement_;
};

class Finding {
 public:
  // Construct a Finding with an analyzer-specific subcategory string (for
  // example, fidl-lint's check-id), SourceSpan, and message
  Finding(SourceSpan span, std::string subcategory, std::string message)
      : span_(span), subcategory_(subcategory), message_(message) {}

  // move constructor
  Finding(Finding&& rhs) = default;

  // Construct a new Suggestion with its constructor arguments, and add it to
  // the Finding.
  template <typename... Args>
  Suggestion& SetSuggestion(Args&&... args) {
    suggestion_.emplace(std::forward<Args>(args)...);
    return suggestion_.value();
  }

  // Returns a reference to a portion of a |SourceFile|, with supporting
  // methods to get the relative location of the reference within the file
  // (line and column), and std::string_view (substring) representing the characters
  // from reference start to end.
  inline const SourceSpan& span() const { return span_; }

  // Subcategory of the result (for example, fidl-lint's check-id). Used
  // to construct a Comment category, as described in the Tricium protobuf:
  //
  //   Category of the result, encoded as a path with the analyzer name as the
  //   root, followed by an arbitrary number of subcategories, for example
  //   "ClangTidy/llvm-header-guard".
  //
  // https://chromium.googlesource.com/infra/infra/+/refs/heads/master/go/src/infra/tricium/api/v1/data.proto
  inline const std::string& subcategory() const { return subcategory_; }

  // The annotation, as a human consumable text string.
  inline const std::string& message() const { return message_; }

  // An optional |Suggestion| to correct the issue (potentially with
  // a suggested |Replacement|).
  inline const std::optional<Suggestion>& suggestion() const { return suggestion_; }

 private:
  SourceSpan span_;
  std::string subcategory_;
  std::string message_;
  std::optional<Suggestion> suggestion_;
};

// Some checks may require referencing past findings. |std::list| is
// required, to allow references to |Finding| objects, held while the
// |Findings| container is still being filled. A |std::vector| will
// not work because it will move items around, invalidating the
// references.
using Findings = std::list<Finding>;

}  // namespace fidl

#endif  // ZIRCON_TOOLS_FIDL_INCLUDE_FIDL_FINDINGS_H_