/*
 * Copyright 2016 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.
 */

#include "cobalt/cssom/css_computed_style_declaration.h"

#include "cobalt/cssom/css_declared_style_data.h"
#include "cobalt/dom/dom_exception.h"

namespace cobalt {
namespace cssom {
// This returns the result of serializing a CSS declaration block.
// The current implementation does not handle shorthands.
//   https://www.w3.org/TR/cssom/#serialize-a-css-declaration-block
std::string CSSComputedStyleDeclaration::css_text(
    script::ExceptionState* /*exception_state*/) const {
  // TODO: This should enumerate all supported properties, not just
  // the declared ones.
  NOTIMPLEMENTED();
  return data_ ? data_->SerializeCSSDeclarationBlock() : std::string();
}

void CSSComputedStyleDeclaration::set_css_text(
    const std::string& /*css_text*/, script::ExceptionState* exception_state) {
  dom::DOMException::Raise(dom::DOMException::kInvalidAccessErr,
                           exception_state);
}

// The length attribute must return the number of CSS declarations in the
// declarations.
//   https://www.w3.org/TR/cssom/#dom-cssstyledeclaration-length
unsigned int CSSComputedStyleDeclaration::length() const {
  return data_ ? data_->length() : 0;
}

// The item(index) method must return the property name of the CSS declaration
// at position index.
//   https://www.w3.org/TR/cssom/#dom-cssstyledeclaration-item
base::optional<std::string> CSSComputedStyleDeclaration::Item(
    unsigned int index) const {
  const char* item = data_ ? data_->Item(index) : NULL;
  return item ? base::optional<std::string>(item) : base::nullopt;
}

std::string CSSComputedStyleDeclaration::GetDeclaredPropertyValueStringByKey(
    const PropertyKey key) const {
  if (!data_ || key == kNoneProperty) {
    return std::string();
  }
  const scoped_refptr<PropertyValue>& property_value =
      data_->GetPropertyValueReference(key);
  DCHECK(property_value);
  return property_value->ToString();
}

void CSSComputedStyleDeclaration::SetPropertyValue(
    const std::string& /*property_name*/, const std::string& /*property_value*/,
    script::ExceptionState* exception_state) {
  dom::DOMException::Raise(dom::DOMException::kInvalidAccessErr,
                           exception_state);
}

void CSSComputedStyleDeclaration::SetData(
    const scoped_refptr<const CSSComputedStyleData>& data) {
  data_ = data;
  // After setting |data_|, |data_with_inherited_properties_| needs to be
  // updated. It may have changed.
  UpdateInheritedData();
}

void CSSComputedStyleDeclaration::UpdateInheritedData() {
  if (!data_) {
    // If there's no data, then there can be no data with inherited properties.
    data_with_inherited_properties_ = NULL;
  } else if (data_->has_declared_inherited_properties()) {
    // Otherwise, if the data has inherited properties, then it's also the first
    // data with inherited properties.
    data_with_inherited_properties_ = data_;
  } else {
    // Otherwise, |data_with_inherited_properties_| should be set to the parent
    // computed style's |data_with_inherited_properties_|. This is because the
    // updates always cascade down the tree and the parent is guaranteed to
    // have already been updated when the child is updated.
    const scoped_refptr<CSSComputedStyleDeclaration>&
        parent_computed_style_declaration =
            data_->GetParentComputedStyleDeclaration();
    if (parent_computed_style_declaration) {
      data_with_inherited_properties_ =
          parent_computed_style_declaration->data_with_inherited_properties_;
    } else {
      data_with_inherited_properties_ = NULL;
    }
  }
}

const scoped_refptr<PropertyValue>&
CSSComputedStyleDeclaration::GetInheritedPropertyValueReference(
    PropertyKey key) const {
  DCHECK(data_with_inherited_properties_);
  return data_with_inherited_properties_->GetPropertyValueReference(key);
}

}  // namespace cssom
}  // namespace cobalt