/* Copyright 2014 Samsung Electronics Co., Ltd.
 *
 * 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.
 */

#include "ecma-function-object.h"
#include "ecma-gc.h"
#include "ecma-globals.h"
#include "ecma-helpers.h"
#include "ecma-magic-strings.h"
#include "ecma-objects-properties.h"
#include "ecma-try-catch-macro.h"
#include "globals.h"

/** \addtogroup ecma ---TODO---
 * @{
 * 
 * \addtogroup ecmafunctionobject ECMA Function object related routines
 * @{
 */

/**
 * Pack 'is_strict' flag and opcode index to value
 * that can be stored in an [[Code]] internal property.
 *
 * @return packed value
 */
static uint32_t
ecma_pack_code_internal_property_value( bool is_strict, /**< is code strict? */
                                        opcode_counter_t opcode_idx) /**< index of first opcode */
{
  uint32_t value = opcode_idx;
  const uint32_t is_strict_bit_offset = sizeof(value) * JERRY_BITSINBYTE - 1;

  JERRY_ASSERT( ( ( value ) & ( 1u << is_strict_bit_offset ) ) == 0 );

  if ( is_strict )
    {
      value |= ( 1u << is_strict_bit_offset );
    }

  return value;
} /* ecma_pack_code_internal_property_value */

/**
 * Unpack 'is_strict' flag and opcode index from value
 * that can be stored in an [[Code]] internal property.
 *
 * @return opcode index
 */
static opcode_counter_t
ecma_unpack_code_internal_property_value( uint32_t value, /**< packed value */
                                          bool* out_is_strict_p) /**< out: is code strict? */
{
  JERRY_ASSERT( out_is_strict_p != NULL );

  const uint32_t is_strict_bit_offset = sizeof(value) * JERRY_BITSINBYTE - 1;

  bool is_strict = ( ( value & ( 1u << is_strict_bit_offset ) ) != 0 );
  *out_is_strict_p = is_strict;

  opcode_counter_t opcode_idx = (opcode_counter_t) ( value & ~( 1u << is_strict_bit_offset ) );

  return opcode_idx;
} /* ecma_unpack_code_internal_property_value */

/**
 * IsCallable operation.
 *
 * See also: ECMA-262 v5, 9.11
 *
 * @return true, if value is callable object;
 *         false - otherwise.
 */
bool
ecma_op_is_callable( ecma_value_t value) /**< ecma-value */
{
  if ( value.value_type != ECMA_TYPE_OBJECT )
    {
      return false;
    }

  ecma_object_t *obj_p = ecma_get_pointer( value.value);

  JERRY_ASSERT( obj_p != NULL );
  JERRY_ASSERT( !obj_p->is_lexical_environment );

  return ( obj_p->u.object.type == ECMA_OBJECT_TYPE_FUNCTION
           || obj_p->u.object.type == ECMA_OBJECT_TYPE_BOUND_FUNCTION );
} /* ecma_op_is_callable */

/**
 * Function object creation operation.
 *
 * See also: ECMA-262 v5, 13.2
 *
 * @return pointer to newly created Function object
 */
ecma_object_t*
ecma_op_create_function_object( const ecma_char_t* formal_parameter_list_p[], /**< formal parameters list */
                                size_t formal_parameters_number, /**< formal parameters list's length */
                                ecma_object_t *scope_p, /**< function's scope */
                                bool is_strict, /**< 'strict' flag */
                                opcode_counter_t first_opcode_idx) /**< index of first opcode of function's body */
{
  // 1., 4., 13.
  FIXME( Setup prototype of Function object to built-in Function prototype object (15.3.3.1) );

  ecma_object_t *f = ecma_create_object( NULL, true, ECMA_OBJECT_TYPE_FUNCTION);

  // 2., 6., 7., 8.
  /*
   * We don't setup [[Get]], [[Call]], [[Construct]], [[HasInstance]] for each function object.
   * Instead we set the object's type to ECMA_OBJECT_TYPE_FUNCTION
   * that defines which version of the routine should be used on demand.
   */

  // 3.
  ecma_property_t *class_prop_p = ecma_create_internal_property( f, ECMA_INTERNAL_PROPERTY_CLASS);
  class_prop_p->u.internal_property.value = ECMA_OBJECT_CLASS_FUNCTION;

  // 9.
  ecma_ref_object( scope_p);

  ecma_property_t *scope_prop_p = ecma_create_internal_property( f, ECMA_INTERNAL_PROPERTY_SCOPE);
  ecma_set_pointer( scope_prop_p->u.internal_property.value, scope_p);

  // 10., 11., 14., 15.
  if ( formal_parameters_number != 0 )
    {
      JERRY_UNIMPLEMENTED_REF_UNUSED_VARS( formal_parameter_list_p);
    }

  // 12.
  ecma_property_t *code_prop_p = ecma_create_internal_property( f, ECMA_INTERNAL_PROPERTY_CODE);
  code_prop_p->u.internal_property.value = ecma_pack_code_internal_property_value( is_strict,
                                                                                   first_opcode_idx);

  // 16.
  FIXME( Use 'new Object()' instead );
  ecma_object_t *proto_p = ecma_create_object( NULL, true, ECMA_OBJECT_TYPE_GENERAL);

  // 17.
  ecma_ref_object( f);

  ecma_property_descriptor_t prop_desc = (ecma_property_descriptor_t) {
      .is_value_defined = true,
      .value = ecma_make_object_value( f),

      .is_writable_defined = true,
      .writable = ECMA_PROPERTY_WRITABLE,

      .is_enumerable_defined = true,
      .enumerable = ECMA_PROPERTY_NOT_ENUMERABLE,

      .is_configurable_defined = true,
      .configurable = ECMA_PROPERTY_CONFIGURABLE,

      .is_get_defined = false,
      .get_p = NULL,

      .is_set_defined = false,
      .set_p = NULL
  };
  ecma_op_object_define_own_property( proto_p,
                                      ecma_get_magic_string( ECMA_MAGIC_STRING_CONSTRUCTOR),
                                      prop_desc,
                                      false);

  // 18.
  ecma_ref_object( proto_p);

  prop_desc.value = ecma_make_object_value( proto_p);
  prop_desc.configurable = ECMA_PROPERTY_NOT_CONFIGURABLE;
  ecma_op_object_define_own_property( f,
                                      ecma_get_magic_string( ECMA_MAGIC_STRING_PROTOTYPE),
                                      prop_desc,
                                      false);

  ecma_deref_object( proto_p);

  // 19.
  if ( is_strict )
    {
      ecma_object_t *thrower_p = ecma_op_get_throw_type_error();

      prop_desc = (ecma_property_descriptor_t) {
          .is_value_defined = false,
          .value = ecma_make_simple_value( ECMA_SIMPLE_VALUE_UNDEFINED),

          .is_writable_defined = false,
          .writable = ECMA_PROPERTY_NOT_WRITABLE,

          .is_enumerable_defined = true,
          .enumerable = ECMA_PROPERTY_NOT_ENUMERABLE,

          .is_configurable_defined = true,
          .configurable = ECMA_PROPERTY_NOT_CONFIGURABLE,

          .is_get_defined = true,
          .get_p = thrower_p,

          .is_set_defined = true,
          .set_p = thrower_p
      };

      ecma_op_object_define_own_property( f,
                                          ecma_get_magic_string( ECMA_MAGIC_STRING_CALLER),
                                          prop_desc,
                                          false);

      ecma_op_object_define_own_property( f,
                                          ecma_get_magic_string( ECMA_MAGIC_STRING_ARGUMENTS),
                                          prop_desc,
                                          false);

      ecma_deref_object( thrower_p);
    }

  return f;
} /* ecma_op_create_function_object */

/**
 * [[Call]] implementation for Function objects,
 * created through 13.2 (ECMA_OBJECT_TYPE_FUNCTION)
 * or 15.3.4.5 (ECMA_OBJECT_TYPE_BOUND_FUNCTION).
 *
 * @return completion value
 *         Returned value must be freed with ecma_free_completion_value
 */
ecma_completion_value_t
ecma_op_function_call( ecma_object_t *func_obj_p, /**< Function object */
                       ecma_value_t this_arg_value, /**< 'this' argument's value */
                       ecma_value_t* arguments_list_p, /**< arguments list */
                       size_t arguments_list_len) /**< length of arguments list */
{
  JERRY_ASSERT( func_obj_p != NULL && !func_obj_p->is_lexical_environment );
  JERRY_ASSERT( ecma_op_is_callable( ecma_make_object_value( func_obj_p)) );
  JERRY_ASSERT( arguments_list_len == 0 || arguments_list_p != NULL );

  if ( func_obj_p->u.object.type == ECMA_OBJECT_TYPE_FUNCTION )
    {
      ecma_completion_value_t ret_value;

      /* Entering Function Code (ECMA-262 v5, 10.4.3) */

      ecma_property_t *scope_prop_p = ecma_get_internal_property( func_obj_p, ECMA_INTERNAL_PROPERTY_SCOPE);
      ecma_property_t *code_prop_p = ecma_get_internal_property( func_obj_p, ECMA_INTERNAL_PROPERTY_CODE);

      ecma_object_t *scope_p = ecma_get_pointer( scope_prop_p->u.internal_property.value);
      uint32_t code_prop_value = code_prop_p->u.internal_property.value;

      bool is_strict;
      // 8.
      opcode_counter_t code_first_opcode_idx = ecma_unpack_code_internal_property_value( code_prop_value, &is_strict);

      ecma_value_t this_binding;
      // 1.
      if ( is_strict )
        {
          this_binding = ecma_copy_value( this_arg_value);
        }
      else if ( ecma_is_value_undefined( this_arg_value)
                || ecma_is_value_null( this_arg_value) )
        {
          // 2.
          FIXME( Assign Global object when it will be implemented );

          this_binding = ecma_make_simple_value( ECMA_SIMPLE_VALUE_UNDEFINED);
        }
      else
        {
          // 3., 4.
          ecma_completion_value_t completion = ecma_op_to_object( this_arg_value);
          JERRY_ASSERT( ecma_is_completion_value_normal( completion) );

          this_binding = completion.value;
        }

      // 5.
      ecma_object_t *local_env_p = ecma_create_lexical_environment( scope_p, ECMA_LEXICAL_ENVIRONMENT_DECLARATIVE);

      // 9.
      /* Declaration binding instantiation (ECMA-262 v5, 10.5), block 4 */
      TODO( Perform declaration binding instantion when [[FormalParameters]] list will be supported );
      if ( arguments_list_len != 0 )
        {
          JERRY_UNIMPLEMENTED_REF_UNUSED_VARS( arguments_list_p );
        }
    
      ecma_completion_value_t completion = run_int_from_pos( code_first_opcode_idx,
                                                             this_binding,
                                                             local_env_p,
                                                             is_strict);
      if ( ecma_is_completion_value_normal( completion) )
        {
          JERRY_ASSERT( ecma_is_empty_completion_value( completion) );

          ret_value = ecma_make_simple_completion_value( ECMA_SIMPLE_VALUE_UNDEFINED);
        }
      else
        {
          ret_value = completion;
        }

      ecma_deref_object( local_env_p);
      ecma_free_value( this_binding);

      return ret_value;
    }
  else
    {
      JERRY_ASSERT( func_obj_p->u.object.type == ECMA_OBJECT_TYPE_BOUND_FUNCTION );

      JERRY_UNIMPLEMENTED();
    }
} /* ecma_op_function_call */

/**
 * Get [[ThrowTypeError]] Function Object
 *
 * @return pointer to unique [[ThrowTypeError]] Function Object
 */
ecma_object_t*
ecma_op_get_throw_type_error( void)
{
  TODO( Create [[ThrowTypeError]] during engine initialization and return it from here );

  JERRY_UNIMPLEMENTED();
} /* ecma_op_get_throw_type_error */

/**
 * @}
 * @}
 */