/*
 * Copyright 2013 Google Inc.
 *
 * 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.
 */

// Author: pulkitg@google.com (Pulkit Goyal)

#include "pagespeed/opt/http/fallback_property_page.h"

#include "base/logging.h"
#include "pagespeed/kernel/http/google_url.h"

namespace net_instaweb {

namespace {

const char kFallbackPageCacheKeyQuerySuffix[] = "@fallback";
const char kFallbackPageCacheKeyBasePathSuffix[] = "#fallback";

}  // namespace

FallbackPropertyPage::FallbackPropertyPage(
    PropertyPage* actual_property_page,
    PropertyPage* property_page_with_fallback_values)
    :  actual_property_page_(actual_property_page),
       property_page_with_fallback_values_(property_page_with_fallback_values) {
  CHECK(actual_property_page != NULL);
}

FallbackPropertyPage::~FallbackPropertyPage() {
}

PropertyValue* FallbackPropertyPage::GetProperty(
      const PropertyCache::Cohort* cohort,
      const StringPiece& property_name) {
  PropertyValue* value = actual_property_page_->GetProperty(
      cohort, property_name);
  if (value->has_value() || property_page_with_fallback_values_ == NULL) {
    return value;
  }
  return property_page_with_fallback_values_->GetProperty(
      cohort, property_name);
}

PropertyValue* FallbackPropertyPage::GetFallbackProperty(
      const PropertyCache::Cohort* cohort,
      const StringPiece& property_name) {
  if (property_page_with_fallback_values_ == NULL) {
    return NULL;
  }
  return property_page_with_fallback_values_->GetProperty(
      cohort, property_name);
}

void FallbackPropertyPage::UpdateValue(
    const PropertyCache::Cohort* cohort, const StringPiece& property_name,
    const StringPiece& value) {
  actual_property_page_->UpdateValue(cohort, property_name, value);
  if (property_page_with_fallback_values_ != NULL) {
    property_page_with_fallback_values_->UpdateValue(
        cohort, property_name, value);
  }
}

void FallbackPropertyPage::WriteCohort(
    const PropertyCache::Cohort* cohort) {
  actual_property_page_->WriteCohort(cohort);
  if (property_page_with_fallback_values_ != NULL) {
    property_page_with_fallback_values_->WriteCohort(cohort);
  }
}

CacheInterface::KeyState FallbackPropertyPage::GetCacheState(
    const PropertyCache::Cohort* cohort) {
  return actual_property_page_->GetCacheState(cohort);
}

CacheInterface::KeyState FallbackPropertyPage::GetFallbackCacheState(
    const PropertyCache::Cohort* cohort) {
  if (property_page_with_fallback_values_ == NULL) {
    return CacheInterface::kNotFound;
  }
  return property_page_with_fallback_values_->GetCacheState(cohort);
}

void FallbackPropertyPage::DeleteProperty(const PropertyCache::Cohort* cohort,
                                          const StringPiece& property_name) {
  actual_property_page_->DeleteProperty(cohort, property_name);
  if (property_page_with_fallback_values_ != NULL) {
    property_page_with_fallback_values_->DeleteProperty(cohort, property_name);
  }
}

GoogleString FallbackPropertyPage::GetFallbackPageUrl(
    const GoogleUrl& request_url) {
  GoogleString key;
  GoogleString suffix;
  if (request_url.has_query()) {
    key = request_url.AllExceptQuery().as_string();
    suffix = kFallbackPageCacheKeyQuerySuffix;
  } else {
    GoogleString url(request_url.spec_c_str());
    int size = url.size();
    if (url[size - 1] == '/') {
      // It's common for site admins to canonicalize urls by redirecting "/a/b"
      // to "/a/b/".  In order to more effectively share fallback properties, we
      // strip the trailing '/' before dropping down a level.
      url.resize(size - 1);
    }
    GoogleUrl gurl(url);
    key = gurl.AllExceptLeaf().as_string();
    suffix = kFallbackPageCacheKeyBasePathSuffix;
  }
  return StrCat(key, suffix);
}

bool FallbackPropertyPage::IsFallbackUrl(const GoogleString& url) {
  return (url.find(kFallbackPageCacheKeyQuerySuffix) != GoogleString::npos ||
          url.find(kFallbackPageCacheKeyBasePathSuffix) != GoogleString::npos);
}

}  // namespace net_instaweb