// Copyright (c) 2015 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.
//
// Utilities for the SafeBrowsing DB code.

#ifndef COMPONENTS_SAFE_BROWSING_DB_UTIL_H_
#define COMPONENTS_SAFE_BROWSING_DB_UTIL_H_

#include <cstring>
#include <string>
#include <vector>

#include "base/basictypes.h"
#include "base/strings/string_piece.h"
#include "base/time/time.h"

class GURL;

namespace safe_browsing {

// Different types of threats that SafeBrowsing protects against.
enum SBThreatType {
  // No threat at all.
  SB_THREAT_TYPE_SAFE,

  // The URL is being used for phishing.
  SB_THREAT_TYPE_URL_PHISHING,

  // The URL hosts malware.
  SB_THREAT_TYPE_URL_MALWARE,

  // The URL hosts unwanted programs.
  SB_THREAT_TYPE_URL_UNWANTED,

  // The download URL is malware.
  SB_THREAT_TYPE_BINARY_MALWARE_URL,

  // Url detected by the client-side phishing model.  Note that unlike the
  // above values, this does not correspond to a downloaded list.
  SB_THREAT_TYPE_CLIENT_SIDE_PHISHING_URL,

  // The Chrome extension or app (given by its ID) is malware.
  SB_THREAT_TYPE_EXTENSION,

  // Url detected by the client-side malware IP list. This IP list is part
  // of the client side detection model.
  SB_THREAT_TYPE_CLIENT_SIDE_MALWARE_URL,
};


// A truncated hash's type.
typedef uint32 SBPrefix;

// A full hash.
union SBFullHash {
  char full_hash[32];
  SBPrefix prefix;
};

// Used when we get a gethash response.
struct SBFullHashResult {
  SBFullHash hash;
  // TODO(shess): Refactor to allow ListType here.
  int list_id;
  std::string metadata;
};

// Caches individual response from GETHASH request.
struct SBCachedFullHashResult {
  SBCachedFullHashResult();
  explicit SBCachedFullHashResult(const base::Time& in_expire_after);
  ~SBCachedFullHashResult();

  base::Time expire_after;
  std::vector<SBFullHashResult> full_hashes;
};

// SafeBrowsing list names.
extern const char kMalwareList[];
extern const char kPhishingList[];
// Binary Download list name.
extern const char kBinUrlList[];
// SafeBrowsing client-side detection whitelist list name.
extern const char kCsdWhiteList[];
// SafeBrowsing download whitelist list name.
extern const char kDownloadWhiteList[];
// SafeBrowsing extension list name.
extern const char kExtensionBlacklist[];
// SafeBrowsing csd malware IP blacklist name.
extern const char kIPBlacklist[];
// SafeBrowsing unwanted URL list.
extern const char kUnwantedUrlList[];
// SafeBrowsing off-domain inclusion whitelist list name.
extern const char kInclusionWhitelist[];
// This array must contain all Safe Browsing lists.
extern const char* kAllLists[9];


enum ListType {
  INVALID = -1,
  MALWARE = 0,
  PHISH = 1,
  BINURL = 2,
  // Obsolete BINHASH = 3,
  CSDWHITELIST = 4,
  // SafeBrowsing lists are stored in pairs.  Keep ListType 5
  // available for a potential second list that we would store in the
  // csd-whitelist store file.
  DOWNLOADWHITELIST = 6,
  // See above comment. Leave 7 available.
  EXTENSIONBLACKLIST = 8,
  // See above comment. Leave 9 available.
  // Obsolete SIDEEFFECTFREEWHITELIST = 10,
  // See above comment. Leave 11 available.
  IPBLACKLIST = 12,
  // See above comment.  Leave 13 available.
  UNWANTEDURL = 14,
  // See above comment.  Leave 15 available.
  INCLUSIONWHITELIST = 16,
  // See above comment.  Leave 17 available.
};


inline bool SBFullHashEqual(const SBFullHash& a, const SBFullHash& b) {
  return !memcmp(a.full_hash, b.full_hash, sizeof(a.full_hash));
}

inline bool SBFullHashLess(const SBFullHash& a, const SBFullHash& b) {
  return memcmp(a.full_hash, b.full_hash, sizeof(a.full_hash)) < 0;
}

// Generate full hash for the given string.
SBFullHash SBFullHashForString(const base::StringPiece& str);
SBFullHash StringToSBFullHash(const std::string& hash_in);
std::string SBFullHashToString(const SBFullHash& hash_out);


// Maps a list name to ListType.
ListType GetListId(const base::StringPiece& name);

// Maps a ListId to list name. Return false if fails.
bool GetListName(ListType list_id, std::string* list);

// Canonicalizes url as per Google Safe Browsing Specification.
// See section 6.1 in
// http://code.google.com/p/google-safe-browsing/wiki/Protocolv2Spec.
void CanonicalizeUrl(const GURL& url, std::string* canonicalized_hostname,
                     std::string* canonicalized_path,
                     std::string* canonicalized_query);


// Generate the set of full hashes to check for |url|.  If
// |include_whitelist_hashes| is true we will generate additional path-prefixes
// to match against the csd whitelist.  E.g., if the path-prefix /foo is on the
// whitelist it should also match /foo/bar which is not the case for all the
// other lists.  We'll also always add a pattern for the empty path.
void UrlToFullHashes(const GURL& url, bool include_whitelist_hashes,
                     std::vector<SBFullHash>* full_hashes);

// Given a URL, returns all the hosts we need to check.  They are returned
// in order of size (i.e. b.c is first, then a.b.c).
void GenerateHostsToCheck(const GURL& url, std::vector<std::string>* hosts);

// Given a URL, returns all the paths we need to check.
void GeneratePathsToCheck(const GURL& url, std::vector<std::string>* paths);

// Given a URL, returns all the patterns we need to check.
void GeneratePatternsToCheck(const GURL& url, std::vector<std::string>* urls);

}  // namespace safe_browsing

#endif  // COMPONENTS_SAFE_BROWSING_DB_UTIL_H_