// Copyright 2014 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 "extensions/common/permissions/permission_message_util.h"

#include "base/strings/string_number_conversions.h"
#include "base/strings/utf_string_conversions.h"
#include "extensions/common/permissions/permission_message.h"
#include "extensions/common/permissions/permission_set.h"
#include "extensions/common/url_pattern_set.h"
#include "grit/extensions_strings.h"
#include "net/base/registry_controlled_domains/registry_controlled_domain.h"
#include "ui/base/l10n/l10n_util.h"
#include "url/url_constants.h"

using extensions::PermissionMessage;
using extensions::PermissionSet;
using extensions::URLPatternSet;

namespace {

// Helper for GetDistinctHosts(): com > net > org > everything else.
bool RcdBetterThan(const std::string& a, const std::string& b) {
  if (a == b)
    return false;
  if (a == "com")
    return true;
  if (a == "net")
    return b != "com";
  if (a == "org")
    return b != "com" && b != "net";
  return false;
}

}  // namespace

namespace permission_message_util {

PermissionMessage CreateFromHostList(const std::set<std::string>& hosts) {
  std::vector<std::string> host_list(hosts.begin(), hosts.end());
  DCHECK(host_list.size());
  PermissionMessage::ID message_id;
  base::string16 message;
  base::string16 details;

  switch (host_list.size()) {
    case 1:
      message_id = PermissionMessage::kHosts1;
      message = l10n_util::GetStringFUTF16(IDS_EXTENSION_PROMPT_WARNING_1_HOST,
                                           base::UTF8ToUTF16(host_list[0]));
      break;
    case 2:
      message_id = PermissionMessage::kHosts2;
      message = l10n_util::GetStringFUTF16(IDS_EXTENSION_PROMPT_WARNING_2_HOSTS,
                                           base::UTF8ToUTF16(host_list[0]),
                                           base::UTF8ToUTF16(host_list[1]));
      break;
    case 3:
      message_id = PermissionMessage::kHosts3;
      message = l10n_util::GetStringFUTF16(IDS_EXTENSION_PROMPT_WARNING_3_HOSTS,
                                           base::UTF8ToUTF16(host_list[0]),
                                           base::UTF8ToUTF16(host_list[1]),
                                           base::UTF8ToUTF16(host_list[2]));
      break;
    default:
      message_id = PermissionMessage::kHosts4OrMore;

      const int kRetainedFilesMessageIDs[6] = {
          IDS_EXTENSION_PROMPT_WARNING_HOSTS_DEFAULT,
          IDS_EXTENSION_PROMPT_WARNING_HOST_SINGULAR,
          IDS_EXTENSION_PROMPT_WARNING_HOSTS_ZERO,
          IDS_EXTENSION_PROMPT_WARNING_HOSTS_TWO,
          IDS_EXTENSION_PROMPT_WARNING_HOSTS_FEW,
          IDS_EXTENSION_PROMPT_WARNING_HOSTS_MANY, };
      std::vector<int> message_ids;
      for (size_t i = 0; i < arraysize(kRetainedFilesMessageIDs); i++) {
        message_ids.push_back(kRetainedFilesMessageIDs[i]);
      }
      message = l10n_util::GetPluralStringFUTF16(message_ids, host_list.size());

      for (size_t i = 0; i < host_list.size(); ++i) {
        if (i > 0)
          details += base::ASCIIToUTF16("\n");
        details += l10n_util::GetStringFUTF16(
            IDS_EXTENSION_PROMPT_WARNING_HOST_LIST_ENTRY,
            base::UTF8ToUTF16(host_list[i]));
      }
  }

  return PermissionMessage(message_id, message, details);
}

std::set<std::string> GetDistinctHosts(const URLPatternSet& host_patterns,
                                       bool include_rcd,
                                       bool exclude_file_scheme) {
  // Use a vector to preserve order (also faster than a map on small sets).
  // Each item is a host split into two parts: host without RCDs and
  // current best RCD.
  typedef std::vector<std::pair<std::string, std::string> > HostVector;
  HostVector hosts_best_rcd;
  for (URLPatternSet::const_iterator i = host_patterns.begin();
       i != host_patterns.end();
       ++i) {
    if (exclude_file_scheme && i->scheme() == url::kFileScheme)
      continue;

    std::string host = i->host();

    // Add the subdomain wildcard back to the host, if necessary.
    if (i->match_subdomains())
      host = "*." + host;

    // If the host has an RCD, split it off so we can detect duplicates.
    std::string rcd;
    size_t reg_len = net::registry_controlled_domains::GetRegistryLength(
        host,
        net::registry_controlled_domains::EXCLUDE_UNKNOWN_REGISTRIES,
        net::registry_controlled_domains::EXCLUDE_PRIVATE_REGISTRIES);
    if (reg_len && reg_len != std::string::npos) {
      if (include_rcd)  // else leave rcd empty
        rcd = host.substr(host.size() - reg_len);
      host = host.substr(0, host.size() - reg_len);
    }

    // Check if we've already seen this host.
    HostVector::iterator it = hosts_best_rcd.begin();
    for (; it != hosts_best_rcd.end(); ++it) {
      if (it->first == host)
        break;
    }
    // If this host was found, replace the RCD if this one is better.
    if (it != hosts_best_rcd.end()) {
      if (include_rcd && RcdBetterThan(rcd, it->second))
        it->second = rcd;
    } else {  // Previously unseen host, append it.
      hosts_best_rcd.push_back(std::make_pair(host, rcd));
    }
  }

  // Build up the final vector by concatenating hosts and RCDs.
  std::set<std::string> distinct_hosts;
  for (HostVector::iterator it = hosts_best_rcd.begin();
       it != hosts_best_rcd.end();
       ++it)
    distinct_hosts.insert(it->first + it->second);
  return distinct_hosts;
}

}  // namespace permission_message_util