// file      : libbuild2/build/script/script.hxx -*- C++ -*-
// license   : MIT; see accompanying LICENSE file

#ifndef LIBBUILD2_BUILD_SCRIPT_SCRIPT_HXX
#define LIBBUILD2_BUILD_SCRIPT_SCRIPT_HXX

#include <libbuild2/types.hxx>
#include <libbuild2/forward.hxx>
#include <libbuild2/utility.hxx>

#include <libbuild2/variable.hxx>

#include <libbuild2/script/script.hxx>

namespace build2
{
  namespace build
  {
    namespace script
    {
      using build2::script::line;
      using build2::script::line_type;
      using build2::script::command_expr;

      // Once parsed, the script can be executed in multiple threads with the
      // state (variable values, etc) maintained by the environment object.
      //
      class script
      {
      public:
        build2::script::lines lines;

        variable_pool var_pool;
        mutable shared_mutex var_pool_mutex;

        const variable& primary_target_var; // $>

        location start_loc;
        location end_loc;

        script ();

        script (script&&) = delete;
        script (const script&) = delete;
        script& operator= (script&&) = delete;
        script& operator= (const script&) = delete;
      };

      class environment: public build2::script::environment
      {
      public:
        environment (const script&, const target& primary_target);

        environment (environment&&) = delete;
        environment (const environment&) = delete;
        environment& operator= (environment&&) = delete;
        environment& operator= (const environment&) = delete;

      public:
        const build::script::script& script;

        // Note that if we pass the variable name as a string, then it will
        // be looked up in the wrong pool.
        //
        variable_map vars;

        const target& primary_target;

        virtual void
        set_variable (string&& name, names&&, const string& attrs) override;

        // Variables.
        //
      public:
        // Lookup the variable starting from this environment, then the
        // primary target, and then outer buildfile scopes.
        //
        using lookup_type = build2::lookup;

        lookup_type
        lookup (const variable&) const;

        lookup_type
        lookup (const string&) const;

        // As above but only look for buildfile variables.
        //
        lookup_type
        lookup_in_buildfile (const string&) const;

        // Return a value suitable for assignment. If the variable does not
        // exist in this environment's map, then a new one with the NULL value
        // is added and returned. Otherwise the existing value is returned.
        //
        value&
        assign (const variable& var) {return vars.assign (var);}

        // Return a value suitable for append/prepend. If the variable does
        // not exist in this environment's map, then outer scopes are searched
        // for the same variable. If found then a new variable with the found
        // value is added to the environment and returned. Otherwise this
        // function proceeds as assign() above.
        //
        value&
        append (const variable&);
      };
    }
  }
}

#endif // LIBBUILD2_BUILD_SCRIPT_SCRIPT_HXX