// Copyright 2020 The Chromium 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 TOOLS_GN_RUST_PROJECT_WRITER_HELPERS_H_
#define TOOLS_GN_RUST_PROJECT_WRITER_HELPERS_H_

#include <fstream>
#include <sstream>
#include <string>
#include <tuple>
#include <unordered_map>
#include <vector>

#include "build_settings.h"
#include "gn/source_file.h"
#include "gn/target.h"

// These are internal types and helper functions for RustProjectWriter that have
// been extracted for easier testability.

// Crate Index in the generated file
using CrateIndex = size_t;

using ConfigList = std::vector<std::string>;
using Dependency = std::pair<CrateIndex, std::string>;
using DependencyList = std::vector<Dependency>;

// This class represents a crate to be serialized out as part of the
// rust-project.json file.  This is used to separate the generating
// of the data that needs to be in the file, from the file itself.
class Crate {
 public:
  Crate(SourceFile root,
        CrateIndex index,
        std::string label,
        std::string edition)
      : root_(root), index_(index), label_(label), edition_(edition) {}

  ~Crate() = default;

  // Add a config item to the crate.
  void AddConfigItem(std::string cfg_item) { configs_.push_back(cfg_item); }

  // Add another crate as a dependency of this one.
  void AddDependency(CrateIndex index, std::string name) {
    deps_.push_back(std::make_pair(index, name));
  }

  // Returns the root file for the crate.
  SourceFile& root() { return root_; }

  // Returns the crate index.
  CrateIndex index() { return index_; };

  // Returns the displayable crate label.
  const std::string& label() { return label_; }

  // Returns the Rust Edition this crate uses.
  const std::string& edition() { return edition_; }

  // Return the set of config items for this crate.
  ConfigList& configs() { return configs_; }

  // Return the set of dependencies for this crate.
  DependencyList& dependencies() { return deps_; }

 private:
  SourceFile root_;
  CrateIndex index_;
  std::string label_;
  std::string edition_;
  ConfigList configs_;
  DependencyList deps_;
};

using CrateList = std::vector<Crate>;

// Mapping of a sysroot crate (path) to it's index in the crates list.
using SysrootCrateIndexMap = std::unordered_map<std::string_view, CrateIndex>;

// Mapping of a sysroot (path) to the mapping of each of the sysroot crates to
// their index in the crates list.
using SysrootIndexMap =
    std::unordered_map<std::string_view, SysrootCrateIndexMap>;

// Add all of the crates for a sysroot (path) to the rust_project ostream.
// Add the given sysroot to the project, if it hasn't already been added.
void AddSysroot(const BuildSettings* build_settings,
                const std::string_view sysroot,
                SysrootIndexMap& sysroot_lookup,
                CrateList& crate_list);

// Write the entire rust-project.json file contents into the given stream, based
// on the the given crates list.
void WriteCrates(const BuildSettings* build_settings,
                 CrateList& crate_list,
                 std::ostream& rust_project);

#endif  // TOOLS_GN_RUST_PROJECT_WRITER_HELPERS_H_