/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include <algorithm>
#include <iterator>
#include <string.h>
#include <stdio.h>
#include "readstrings.h"
#include "updatererrors.h"

#ifdef XP_WIN
#  define NS_tfopen _wfopen
#  define OPEN_MODE L"rb"
#  define NS_tstrlen wcslen
#  define NS_tstrcpy wcscpy
#else
#  define NS_tfopen fopen
#  define OPEN_MODE "r"
#  define NS_tstrlen strlen
#  define NS_tstrcpy strcpy
#endif

// stack based FILE wrapper to ensure that fclose is called.
class AutoFILE {
 public:
  explicit AutoFILE(FILE* fp) : fp_(fp) {}
  ~AutoFILE() {
    if (fp_) {
      fclose(fp_);
    }
  }
  operator FILE*() { return fp_; }

 private:
  FILE* fp_;
};

static const char kNL[] = "\r\n";
static const char kEquals[] = "=";
static const char kWhitespace[] = " \t";
static const char kRBracket[] = "]";

static const char* NS_strspnp(const char* delims, const char* str) {
  const char* d;
  do {
    for (d = delims; *d != '\0'; ++d) {
      if (*str == *d) {
        ++str;
        break;
      }
    }
  } while (*d);

  return str;
}

static char* NS_strtok(const char* delims, char** str) {
  if (!*str) {
    return nullptr;
  }

  char* ret = (char*)NS_strspnp(delims, *str);

  if (!*ret) {
    *str = ret;
    return nullptr;
  }

  char* i = ret;
  do {
    for (const char* d = delims; *d != '\0'; ++d) {
      if (*i == *d) {
        *i = '\0';
        *str = ++i;
        return ret;
      }
    }
    ++i;
  } while (*i);

  *str = nullptr;
  return ret;
}

/**
 * Find a key in a keyList containing zero-delimited keys ending with "\0\0".
 * Returns a zero-based index of the key in the list, or -1 if the key is not
 * found.
 */
static int find_key(const char* keyList, char* key) {
  if (!keyList) {
    return -1;
  }

  int index = 0;
  const char* p = keyList;
  while (*p) {
    if (strcmp(key, p) == 0) {
      return index;
    }

    p += strlen(p) + 1;
    index++;
  }

  // The key was not found if we came here
  return -1;
}

/**
 * A very basic parser for updater.ini taken mostly from nsINIParser.cpp
 * that can be used by standalone apps.
 *
 * @param path       Path to the .ini file to read
 * @param keyList    List of zero-delimited keys ending with two zero characters
 * @param numStrings Number of strings to read into results buffer - must be
 *                   equal to the number of keys
 * @param results    Array of strings. Array's length must be equal to
 *                   numStrings. Each string will be populated with the value
 *                   corresponding to the key with the same index in keyList.
 * @param section    Optional name of the section to read; defaults to "Strings"
 */
int ReadStrings(const NS_tchar* path, const char* keyList,
                unsigned int numStrings, mozilla::UniquePtr<char[]>* results,
                const char* section) {
  AutoFILE fp(NS_tfopen(path, OPEN_MODE));

  if (!fp) {
    return READ_ERROR;
  }

  /* get file size */
  if (fseek(fp, 0, SEEK_END) != 0) {
    return READ_ERROR;
  }

  long len = ftell(fp);
  if (len <= 0) {
    return READ_ERROR;
  }

  size_t flen = size_t(len);

  mozilla::UniquePtr<char[]> fileContents(new char[flen + 1]);
  if (!fileContents) {
    return READ_STRINGS_MEM_ERROR;
  }

  /* read the file in one swoop */
  if (fseek(fp, 0, SEEK_SET) != 0) {
    return READ_ERROR;
  }

  size_t rd = fread(fileContents.get(), sizeof(char), flen, fp);
  if (rd != flen) {
    return READ_ERROR;
  }

  fileContents[flen] = '\0';

  int result = ReadStringsFromBuffer(fileContents.get(), keyList, numStrings,
                                     results, section);
  return result;
}

// A wrapper function to read strings for the updater.
// Added for compatibility with the original code.
int ReadStrings(const NS_tchar* path, StringTable* results) {
  const unsigned int kNumStrings = 2;
  const char* kUpdaterKeys = "Title\0Info\0";
  mozilla::UniquePtr<char[]> updater_strings[kNumStrings];

  int result = ReadStrings(path, kUpdaterKeys, kNumStrings, updater_strings);

  if (result == OK) {
    results->title.swap(updater_strings[0]);
    results->info.swap(updater_strings[1]);
  }

  return result;
}

/**
 * A very basic parser for updater.ini taken mostly from nsINIParser.cpp
 * that can be used by standalone apps.
 *
 * @param stringBuffer The string buffer to parse
 * @param keyList      List of zero-delimited keys ending with two zero
 * characters
 * @param numStrings   Number of strings to read into results buffer - must be
 *                     equal to the number of keys
 * @param results      Array of strings. Array's length must be equal to
 *                     numStrings. Each string will be populated with the value
 *                     corresponding to the key with the same index in keyList.
 * @param section      Optional name of the section to read; defaults to
 * "Strings"
 */
int ReadStringsFromBuffer(char* stringBuffer, const char* keyList,
                          unsigned int numStrings,
                          mozilla::UniquePtr<char[]>* results,
                          const char* section) {
  bool inStringsSection = false;

  unsigned int read = 0;

  while (char* token = NS_strtok(kNL, &stringBuffer)) {
    if (token[0] == '#' || token[0] == ';') {  // it's a comment
      continue;
    }

    token = (char*)NS_strspnp(kWhitespace, token);
    if (!*token) {  // empty line
      continue;
    }

    if (token[0] == '[') {  // section header!
      ++token;
      char const* currSection = token;

      char* rb = NS_strtok(kRBracket, &token);
      if (!rb || NS_strtok(kWhitespace, &token)) {
        // there's either an unclosed [Section or a [Section]Moretext!
        // we could frankly decide that this INI file is malformed right
        // here and stop, but we won't... keep going, looking for
        // a well-formed [section] to continue working with
        inStringsSection = false;
      } else {
        if (section) {
          inStringsSection = strcmp(currSection, section) == 0;
        } else {
          inStringsSection = strcmp(currSection, "Strings") == 0;
        }
      }

      continue;
    }

    if (!inStringsSection) {
      // If we haven't found a section header (or we found a malformed
      // section header), or this isn't the [Strings] section don't bother
      // parsing this line.
      continue;
    }

    char* key = token;
    char* e = NS_strtok(kEquals, &token);
    if (!e) {
      continue;
    }

    int keyIndex = find_key(keyList, key);
    if (keyIndex >= 0 && (unsigned int)keyIndex < numStrings) {
      size_t valueSize = strlen(token) + 1;
      results[keyIndex] = mozilla::MakeUnique<char[]>(valueSize);

      strcpy(results[keyIndex].get(), token);
      read++;
    }
  }

  return (read == numStrings) ? OK : PARSE_ERROR;
}

IniReader::IniReader(const NS_tchar* iniPath,
                     const char* section /* = nullptr */) {
  if (iniPath) {
    mPath = mozilla::MakeUnique<NS_tchar[]>(NS_tstrlen(iniPath) + 1);
    NS_tstrcpy(mPath.get(), iniPath);
    mMaybeStatusCode = mozilla::Nothing();
  } else {
    mMaybeStatusCode = mozilla::Some(READ_STRINGS_MEM_ERROR);
  }
  if (section) {
    mSection = mozilla::MakeUnique<char[]>(strlen(section) + 1);
    strcpy(mSection.get(), section);
  } else {
    mSection.reset(nullptr);
  }
}

bool IniReader::MaybeAddKey(const char* key, size_t& insertionIndex) {
  if (!key || strlen(key) == 0 || mMaybeStatusCode.isSome()) {
    return false;
  }
  auto existingKey = std::find_if(mKeys.begin(), mKeys.end(),
                                  [=](mozilla::UniquePtr<char[]>& searchKey) {
                                    return strcmp(key, searchKey.get()) == 0;
                                  });
  if (existingKey != mKeys.end()) {
    // Key already in list
    insertionIndex = std::distance(mKeys.begin(), existingKey);
    return true;
  }

  // Key not already in list
  insertionIndex = mKeys.size();
  mKeys.emplace_back(mozilla::MakeUnique<char[]>(strlen(key) + 1));
  strcpy(mKeys.back().get(), key);
  return true;
}

void IniReader::AddKey(const char* key, mozilla::UniquePtr<char[]>* outputPtr) {
  size_t insertionIndex;
  if (!MaybeAddKey(key, insertionIndex)) {
    return;
  }

  if (!outputPtr) {
    return;
  }

  mNarrowOutputs.emplace_back();
  mNarrowOutputs.back().keyIndex = insertionIndex;
  mNarrowOutputs.back().outputPtr = outputPtr;
}

#ifdef XP_WIN
void IniReader::AddKey(const char* key,
                       mozilla::UniquePtr<wchar_t[]>* outputPtr) {
  size_t insertionIndex;
  if (!MaybeAddKey(key, insertionIndex)) {
    return;
  }

  if (!outputPtr) {
    return;
  }

  mWideOutputs.emplace_back();
  mWideOutputs.back().keyIndex = insertionIndex;
  mWideOutputs.back().outputPtr = outputPtr;
}

// Returns true on success, false on failure.
static bool ConvertToWide(const char* toConvert,
                          mozilla::UniquePtr<wchar_t[]>* result) {
  int bufferSize = MultiByteToWideChar(CP_UTF8, 0, toConvert, -1, nullptr, 0);
  *result = mozilla::MakeUnique<wchar_t[]>(bufferSize);
  int charsWritten =
      MultiByteToWideChar(CP_UTF8, 0, toConvert, -1, result->get(), bufferSize);
  return charsWritten > 0;
}
#endif

int IniReader::Read() {
  if (mMaybeStatusCode.isSome()) {
    return mMaybeStatusCode.value();
  }

  if (mKeys.empty()) {
    // If there's nothing to read, just report success and return.
    mMaybeStatusCode = mozilla::Some(OK);
    return OK;
  }

  // First assemble the key list, which will be a character array of
  // back-to-back null-terminated strings ending with a double null termination.
  size_t keyListSize = 1;  // For the final null
  for (const auto& key : mKeys) {
    keyListSize += strlen(key.get());
    keyListSize += 1;  // For the terminating null
  }
  mozilla::UniquePtr<char[]> keyList = mozilla::MakeUnique<char[]>(keyListSize);
  char* keyListPtr = keyList.get();
  for (const auto& key : mKeys) {
    strcpy(keyListPtr, key.get());
    // Point keyListPtr directly after the trailing null that strcpy wrote.
    keyListPtr += strlen(key.get()) + 1;
  }
  *keyListPtr = '\0';

  // Now make the array for the resulting data to be stored in
  mozilla::UniquePtr<mozilla::UniquePtr<char[]>[]> results =
      mozilla::MakeUnique<mozilla::UniquePtr<char[]>[]>(mKeys.size());

  // Invoke ReadStrings to read the file and store the data for us
  int statusCode = ReadStrings(mPath.get(), keyList.get(), mKeys.size(),
                               results.get(), mSection.get());
  mMaybeStatusCode = mozilla::Some(statusCode);

  if (statusCode != OK) {
    return statusCode;
  }

  // Now populate the requested locations with the requested data.
  for (const auto output : mNarrowOutputs) {
    char* valueBuffer = results[output.keyIndex].get();
    if (valueBuffer) {
      *(output.outputPtr) =
          mozilla::MakeUnique<char[]>(strlen(valueBuffer) + 1);
      strcpy(output.outputPtr->get(), valueBuffer);
    }
  }

#ifdef XP_WIN
  for (const auto output : mWideOutputs) {
    char* valueBuffer = results[output.keyIndex].get();
    if (valueBuffer) {
      if (!ConvertToWide(valueBuffer, output.outputPtr)) {
        statusCode = STRING_CONVERSION_ERROR;
      }
    }
  }
#endif

  return statusCode;
}