// file      : build2/context -*- C++ -*-
// copyright : Copyright (c) 2014-2016 Code Synthesis Ltd
// license   : MIT; see accompanying LICENSE file

#ifndef BUILD2_CONTEXT
#define BUILD2_CONTEXT

#include <build2/types>
#include <build2/utility>

#include <build2/scope>
#include <build2/variable>
#include <build2/operation>

namespace build2
{
  class file;

  extern string_pool extension_pool;
  extern string_pool project_name_pool;

  // Current action (meta/operation).
  //
  // The names unlike info are available during boot but may not yet be
  // lifted. The name is always for an outer operation (or meta operation
  // that hasn't been recognized as such yet).
  //
  extern const string* current_mname;
  extern const string* current_oname;

  extern const meta_operation_info* current_mif;
  extern const operation_info* current_inner_oif;
  extern const operation_info* current_outer_oif;
  extern execution_mode current_mode;

  inline void
  set_current_mif (const meta_operation_info& mif)
  {
    current_mif = &mif;
    current_mname = &mif.name;
  }

  inline void
  set_current_oif (const operation_info& inner_oif,
                   const operation_info* outer_oif = nullptr)
  {
    current_inner_oif = &inner_oif;
    current_outer_oif = outer_oif;
    current_oname = &(outer_oif == nullptr ? inner_oif : *outer_oif).name;
    current_mode = inner_oif.mode;
  }

  // Total number of dependency relationships in the current action.
  // Together with the target::dependents count it is incremented
  // during the rule search & match phase and is decremented during
  // execution with the expectation of it reaching 0. Used as a sanity
  // check.
  //
  extern uint64_t dependency_count;

  // Project-wide (as opposed to global) variable overrides. Returned by
  // reset().
  //
  struct variable_override
  {
    const variable& var; // Original variable.
    const variable& ovr; // Override variable.
    value val;
  };

  using variable_overrides = vector<variable_override>;

  // Variable override value cache.
  //
  extern variable_override_cache var_override_cache;

  // Reset the build state. In particular, this removes all the targets,
  // scopes, and variables.
  //
  variable_overrides
  reset (const strings& cmd_vars);

  // Return the project name or empty string if unnamed.
  //
  inline const string&
  project (scope& root)
  {
    auto l (root["project"]);
    return l ? cast<string> (l) : empty_string;
  }

  // Return the src/out directory corresponding to the given out/src. The
  // passed directory should be a sub-directory of out/src_root.
  //
  dir_path
  src_out (const dir_path& out, scope& root);

  dir_path
  src_out (const dir_path& out,
           const dir_path& out_root, const dir_path& src_root);

  dir_path
  out_src (const dir_path& src, scope& root);

  dir_path
  out_src (const dir_path& src,
           const dir_path& out_root, const dir_path& src_root);

  // Action phrases, e.g., "configure update exe{foo}", "updating exe{foo}",
  // and "updating exe{foo} is configured". Use like this:
  //
  // info << "while " << diag_doing (a, t);
  //
  class target;

  struct diag_phrase
  {
    const action& a;
    const target& t;
    void (*f) (ostream&, const action&, const target&);
  };

  inline ostream&
  operator<< (ostream& os, const diag_phrase& p)
  {
    p.f (os, p.a, p.t);
    return os;
  }

  void
  diag_do (ostream&, const action&, const target&);

  inline diag_phrase
  diag_do (const action& a, const target& t)
  {
    return diag_phrase {a, t, &diag_do};
  }

  void
  diag_doing (ostream&, const action&, const target&);

  inline diag_phrase
  diag_doing (const action& a, const target& t)
  {
    return diag_phrase {a, t, &diag_doing};
  }

  void
  diag_done (ostream&, const action&, const target&);

  inline diag_phrase
  diag_done (const action& a, const target& t)
  {
    return diag_phrase {a, t, &diag_done};
  }
}

#endif // BUILD2_CONTEXT