// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "chrome/common/extensions/feature.h"

#include <map>

#include "base/command_line.h"
#include "base/lazy_instance.h"
#include "base/stringprintf.h"
#include "chrome/common/chrome_switches.h"

namespace {

struct Mappings {
  Mappings() {
    extension_types["extension"] = Extension::TYPE_EXTENSION;
    extension_types["theme"] = Extension::TYPE_THEME;
    extension_types["packaged_app"] = Extension::TYPE_PACKAGED_APP;
    extension_types["hosted_app"] = Extension::TYPE_HOSTED_APP;
    extension_types["platform_app"] = Extension::TYPE_PLATFORM_APP;

    contexts["blessed_extension"] =
        extensions::Feature::BLESSED_EXTENSION_CONTEXT;
    contexts["unblessed_extension"] =
        extensions::Feature::UNBLESSED_EXTENSION_CONTEXT;
    contexts["content_script"] = extensions::Feature::CONTENT_SCRIPT_CONTEXT;
    contexts["web_page"] = extensions::Feature::WEB_PAGE_CONTEXT;

    locations["component"] = extensions::Feature::COMPONENT_LOCATION;

    platforms["chromeos"] = extensions::Feature::CHROMEOS_PLATFORM;
  }

  std::map<std::string, Extension::Type> extension_types;
  std::map<std::string, extensions::Feature::Context> contexts;
  std::map<std::string, extensions::Feature::Location> locations;
  std::map<std::string, extensions::Feature::Platform> platforms;
};

static base::LazyInstance<Mappings> g_mappings =
    LAZY_INSTANCE_INITIALIZER;

// TODO(aa): Can we replace all this manual parsing with JSON schema stuff?

void ParseSet(const DictionaryValue* value,
              const std::string& property,
              std::set<std::string>* set) {
  ListValue* list_value = NULL;
  if (!value->GetList(property, &list_value))
    return;

  for (size_t i = 0; i < list_value->GetSize(); ++i) {
    std::string str_val;
    CHECK(list_value->GetString(i, &str_val)) << property << " " << i;
    set->insert(str_val);
  }
}

template<typename T>
void ParseEnum(const std::string& string_value,
               T* enum_value,
               const std::map<std::string, T>& mapping) {
  typename std::map<std::string, T>::const_iterator iter =
      mapping.find(string_value);
  CHECK(iter != mapping.end()) << string_value;
  *enum_value = iter->second;
}

template<typename T>
void ParseEnum(const DictionaryValue* value,
               const std::string& property,
               T* enum_value,
               const std::map<std::string, T>& mapping) {
  std::string string_value;
  if (!value->GetString(property, &string_value))
    return;
  ParseEnum(string_value, enum_value, mapping);
}

template<typename T>
void ParseEnumSet(const DictionaryValue* value,
                  const std::string& property,
                  std::set<T>* enum_set,
                  const std::map<std::string, T>& mapping) {
  std::string property_string;
  if (value->GetString(property, &property_string)) {
    if (property_string == "all") {
      for (typename std::map<std::string, T>::const_iterator j =
               mapping.begin(); j != mapping.end(); ++j) {
        enum_set->insert(j->second);
      }
    }
    return;
  }

  std::set<std::string> string_set;
  ParseSet(value, property, &string_set);
  for (std::set<std::string>::iterator iter = string_set.begin();
       iter != string_set.end(); ++iter) {
    T enum_value = static_cast<T>(0);
    ParseEnum(*iter, &enum_value, mapping);
    enum_set->insert(enum_value);
  }
}

}  // namespace

namespace extensions {

Feature::Feature()
  : location_(UNSPECIFIED_LOCATION),
    platform_(UNSPECIFIED_PLATFORM),
    min_manifest_version_(0),
    max_manifest_version_(0) {
}

Feature::~Feature() {
}

// static
scoped_ptr<Feature> Feature::Parse(const DictionaryValue* value) {
  scoped_ptr<Feature> feature(new Feature());

  ParseSet(value, "whitelist", feature->whitelist());
  ParseEnumSet<Extension::Type>(value, "extension_types",
                                feature->extension_types(),
                                g_mappings.Get().extension_types);
  ParseEnumSet<Context>(value, "contexts", feature->contexts(),
                        g_mappings.Get().contexts);
  ParseEnum<Location>(value, "location", &feature->location_,
                      g_mappings.Get().locations);
  ParseEnum<Platform>(value, "platform", &feature->platform_,
                      g_mappings.Get().platforms);

  value->GetInteger("min_manifest_version", &feature->min_manifest_version_);
  value->GetInteger("max_manifest_version", &feature->max_manifest_version_);

  return feature.Pass();
}

// static
Feature::Platform Feature::GetCurrentPlatform() {
#if defined(OS_CHROMEOS)
  return CHROMEOS_PLATFORM;
#else
  return UNSPECIFIED_PLATFORM;
#endif
}

// static
Feature::Location Feature::ConvertLocation(Extension::Location location) {
  if (location == Extension::COMPONENT)
    return COMPONENT_LOCATION;
  else
    return UNSPECIFIED_LOCATION;
}

std::string Feature::GetErrorMessage(Feature::Availability result) {
  switch (result) {
    case IS_AVAILABLE:
      return "";
    case NOT_FOUND_IN_WHITELIST:
      return "Not allowed for specified extension ID.";
    case INVALID_TYPE:
      return "Not allowed for specified package type (theme, app, etc.).";
    case INVALID_CONTEXT:
      return "Not allowed for specified context type content script, extension "
          "page, web page, etc.).";
    case INVALID_LOCATION:
      return "Not allowed for specified install location.";
    case INVALID_PLATFORM:
      return "Not allowed for specified platform.";
    case INVALID_MIN_MANIFEST_VERSION:
      return base::StringPrintf("Requires manifest version of at least %d.",
                                min_manifest_version_);
    case INVALID_MAX_MANIFEST_VERSION:
      return base::StringPrintf("Requires manifest version of %d or lower.",
                                max_manifest_version_);
    default:
      CHECK(false);
      return "";
  }
}

Feature::Availability Feature::IsAvailable(const std::string& extension_id,
                                           Extension::Type type,
                                           Location location,
                                           Context context,
                                           Platform platform,
                                           int manifest_version) {
  // Component extensions can access any feature.
  if (location == COMPONENT_LOCATION)
    return IS_AVAILABLE;

  if (!whitelist_.empty()) {
    if (whitelist_.find(extension_id) == whitelist_.end()) {
      // TODO(aa): This is gross. There should be a better way to test the
      // whitelist.
      CommandLine* command_line = CommandLine::ForCurrentProcess();
      if (!command_line->HasSwitch(switches::kWhitelistedExtensionID))
        return NOT_FOUND_IN_WHITELIST;

      std::string whitelist_switch_value =
          CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
              switches::kWhitelistedExtensionID);
      if (extension_id != whitelist_switch_value)
        return NOT_FOUND_IN_WHITELIST;
    }
  }

  if (!extension_types_.empty() &&
      extension_types_.find(type) == extension_types_.end()) {
    return INVALID_TYPE;
  }

  if (!contexts_.empty() &&
      contexts_.find(context) == contexts_.end()) {
    return INVALID_CONTEXT;
  }

  if (location_ != UNSPECIFIED_LOCATION && location_ != location)
    return INVALID_LOCATION;

  if (platform_ != UNSPECIFIED_PLATFORM && platform_ != platform)
    return INVALID_PLATFORM;

  if (min_manifest_version_ != 0 && manifest_version < min_manifest_version_)
    return INVALID_MIN_MANIFEST_VERSION;

  if (max_manifest_version_ != 0 && manifest_version > max_manifest_version_)
    return INVALID_MAX_MANIFEST_VERSION;

  return IS_AVAILABLE;
}

}  // namespace