// file      : build/target-type -*- C++ -*-
// copyright : Copyright (c) 2014-2015 Code Synthesis Ltd
// license   : MIT; see accompanying LICENSE file

#ifndef BUILD_TARGET_TYPE
#define BUILD_TARGET_TYPE

#include <map>
#include <string>
#include <ostream>
#include <typeindex>

#include <butl/utility> // compare_c_string

#include <build/types>

namespace build
{
  class scope;
  class target;
  class target_key;
  class prerequisite_key;

  // Target type.
  //
  struct target_type
  {
    std::type_index id;
    const char* name;
    const target_type* base;
    target* (*factory) (const target_type&, dir_path, string, const string*);
    const string& (*extension) (const target_key&, scope&);
    target* (*search) (const prerequisite_key&);
    bool see_through; // A group with the default "see through" semantics.

    const target_type* origin; // Original target if this is an alias.

    bool
    is_a (const std::type_index&) const; // Defined in target.cxx

    template <typename T>
    bool
    is_a () const {return is_a (typeid (T));}
  };

  inline bool
  operator< (const target_type& x, const target_type& y)
  {
    return x.id < y.id;
  }

  inline std::ostream&
  operator<< (std::ostream& os, const target_type& tt)
  {
    return os << tt.name;
  }

  // Target type map.
  //
  struct target_type_ref
  {
    // Like reference_wrapper except it deletes the target type if it is
    // an alias (aliases are always dynamically allocated).
    //
    explicit
    target_type_ref (const target_type& r): p_ (&r)
    {
      assert (p_->origin == nullptr);
    }

    explicit
    target_type_ref (unique_ptr<target_type>&& p): p_ (p.release ())
    {
      assert (p_->origin != nullptr);
    }

    ~target_type_ref ()
    {
      if (p_ != nullptr && p_->origin != nullptr)
        delete p_;
    }

    explicit operator const target_type& () const {return *p_;}
    const target_type& get () const {return *p_;}

    target_type_ref (target_type_ref&& r): p_ (r.p_) {r.p_ = nullptr;}

  private:
    const target_type* p_;
  };

  using target_type_map_base = std::map<string, target_type_ref>;

  class target_type_map: public target_type_map_base
  {
  public:
    void
    insert (const target_type& tt) {emplace (tt.name, target_type_ref (tt));}

    template <typename T>
    void
    insert () {insert (T::static_type);}
  };
}

#endif // BUILD_TARGET_TYPE