// Copyright 2011 Google Inc. All Rights Reserved.
//
// 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.

#ifndef NINJA_BUILD_H_
#define NINJA_BUILD_H_

#include <map>
#include <set>
#include <string>
#include <queue>
#include <vector>
#include <memory>
#include <cstdio>

#include "graph.h"  // XXX needed for DependencyScan; should rearrange.
#include "exit_status.h"
#include "metrics.h"
#include "util.h"  // int64_t

struct BuildLog;
struct BuildStatus;
struct DiskInterface;
struct Edge;
struct Node;
struct State;

/// Plan stores the state of a build plan: what we intend to build,
/// which steps we're ready to execute.
struct Plan {
  Plan();

  /// Add a target to our plan (including all its dependencies).
  /// Returns false if we don't need to build this target; may
  /// fill in |err| with an error message if there's a problem.
  bool AddTarget(Node* node, string* err);

  // Pop a ready edge off the queue of edges to build.
  // Returns NULL if there's no work to do.
  Edge* FindWork();

  /// Returns true if there's more work to be done.
  bool more_to_do() const { return wanted_edges_; }

  /// Dumps the current state of the plan.
  void Dump();

  /// Mark an edge as done building.  Used internally and by
  /// tests.
  void EdgeFinished(Edge* edge);

  /// Clean the given node during the build.
  void CleanNode(DependencyScan* scan, Node* node);

  /// Number of edges with commands to run.
  int command_edge_count() const { return command_edges_; }

private:
  bool AddSubTarget(Node* node, vector<Node*>* stack, string* err);
  bool CheckDependencyCycle(Node* node, vector<Node*>* stack, string* err);
  void NodeFinished(Node* node);

  /// Keep track of which edges we want to build in this plan.  If this map does
  /// not contain an entry for an edge, we do not want to build the entry or its
  /// dependents.  If an entry maps to false, we do not want to build it, but we
  /// might want to build one of its dependents.  If the entry maps to true, we
  /// want to build it.
  map<Edge*, bool> want_;

  set<Edge*> ready_;

  /// Total number of edges that have commands (not phony).
  int command_edges_;

  /// Total remaining number of wanted edges.
  int wanted_edges_;
};

/// CommandRunner is an interface that wraps running the build
/// subcommands.  This allows tests to abstract out running commands.
/// RealCommandRunner is an implementation that actually runs commands.
struct CommandRunner {
  virtual ~CommandRunner() {}
  virtual bool CanRunMore() = 0;
  virtual bool StartCommand(Edge* edge) = 0;
  /// Wait for a command to complete.
  virtual Edge* WaitForCommand(ExitStatus* status, string* output) = 0;
  virtual vector<Edge*> GetActiveEdges() { return vector<Edge*>(); }
  virtual void Abort() {}
};

/// Options (e.g. verbosity, parallelism) passed to a build.
struct BuildConfig {
  BuildConfig() : verbosity(NORMAL), dry_run(false), parallelism(1),
                  failures_allowed(1), max_load_average(-0.0f) {}

  enum Verbosity {
    NORMAL,
    QUIET,  // No output -- used when testing.
    VERBOSE
  };
  Verbosity verbosity;
  bool dry_run;
  int parallelism;
  int failures_allowed;
  /// The maximum load average we must not exceed. A negative value
  /// means that we do not have any limit.
  double max_load_average;
};

/// Builder wraps the build process: starting commands, updating status.
struct Builder {
  Builder(State* state, const BuildConfig& config,
          BuildLog* log, DiskInterface* disk_interface);
  ~Builder();

  /// Clean up after interrupted commands by deleting output files.
  void Cleanup();

  Node* AddTarget(const string& name, string* err);

  /// Add a target to the build, scanning dependencies.
  /// @return false on error.
  bool AddTarget(Node* target, string* err);

  /// Returns true if the build targets are already up to date.
  bool AlreadyUpToDate() const;

  /// Run the build.  Returns false on error.
  /// It is an error to call this function when AlreadyUpToDate() is true.
  bool Build(string* err);

  bool StartEdge(Edge* edge, string* err);
  void FinishEdge(Edge* edge, bool success, const string& output);

  /// Used for tests.
  void SetBuildLog(BuildLog* log) {
    scan_.set_build_log(log);
  }

  State* state_;
  const BuildConfig& config_;
  Plan plan_;
  auto_ptr<CommandRunner> command_runner_;
  BuildStatus* status_;

 private:
  DiskInterface* disk_interface_;
  DependencyScan scan_;

  // Unimplemented copy ctor and operator= ensure we don't copy the auto_ptr.
  Builder(const Builder &other);        // DO NOT IMPLEMENT
  void operator=(const Builder &other); // DO NOT IMPLEMENT
};

/// Tracks the status of a build: completion fraction, printing updates.
struct BuildStatus {
  explicit BuildStatus(const BuildConfig& config);
  void PlanHasTotalEdges(int total);
  void BuildEdgeStarted(Edge* edge);
  void BuildEdgeFinished(Edge* edge, bool success, const string& output,
                         int* start_time, int* end_time);
  void BuildFinished();

  /// Format the progress status string by replacing the placeholders.
  /// See the user manual for more information about the available
  /// placeholders.
  /// @param progress_status_format_ The format of the progress status.
  string FormatProgressStatus(const char* progress_status_format) const;

 private:
  void PrintStatus(Edge* edge);

  const BuildConfig& config_;

  /// Time the build started.
  int64_t start_time_millis_;

  int started_edges_, finished_edges_, total_edges_;

  bool have_blank_line_;

  /// Map of running edge to time the edge started running.
  typedef map<Edge*, int> RunningEdgeMap;
  RunningEdgeMap running_edges_;

  /// Whether we can do fancy terminal control codes.
  bool smart_terminal_;

  /// The custom progress status format to use.
  const char* progress_status_format_;

  struct RateInfo {
    RateInfo() : last_update_(0), rate_(-1) {}

    double rate() const { return rate_; }
    int last_update() const { return last_update_; }
    void Restart() { return stopwatch_.Restart(); }

    double UpdateRate(int edges, int update_hint) {
      if (update_hint != last_update_) {
        rate_ = edges / stopwatch_.Elapsed() + 0.5;
        last_update_ = update_hint;
      }
      return rate_;
    }

    template<class T>
    void snprinfRate(T buf, const char* format) {
      if (rate_ == -1)
        snprintf(buf, sizeof(buf), "?");
      else
        snprintf(buf, sizeof(buf), format, rate_);
    }

  private:
    Stopwatch stopwatch_;
    int last_update_;
    double rate_;
  };

  mutable RateInfo overall_rate_;
  mutable RateInfo current_rate_;
  const int current_rate_average_count_;

#ifdef _WIN32
  void* console_;
#endif
};

#endif  // NINJA_BUILD_H_