'use strict';

const {
  ArrayIsArray,
  DateNow,
  Number,
  NumberIsFinite,
  ObjectSetPrototypeOf,
  ReflectOwnKeys,
  Symbol,
} = primordials;

const { Buffer } = require('buffer');
const {
  codes: {
    ERR_FS_INVALID_SYMLINK_TYPE,
    ERR_INVALID_ARG_TYPE,
    ERR_INVALID_ARG_VALUE,
    ERR_INVALID_OPT_VALUE,
    ERR_INVALID_OPT_VALUE_ENCODING,
    ERR_OUT_OF_RANGE
  },
  hideStackFrames,
  uvException
} = require('internal/errors');
const {
  isArrayBufferView,
  isUint8Array,
  isDate,
  isBigUint64Array
} = require('internal/util/types');
const { once } = require('internal/util');
const { toPathIfFileURL } = require('internal/url');
const {
  validateInt32,
  validateUint32
} = require('internal/validators');
const pathModule = require('path');
const kType = Symbol('type');
const kStats = Symbol('stats');

const {
  O_APPEND,
  O_CREAT,
  O_EXCL,
  O_RDONLY,
  O_RDWR,
  O_SYNC,
  O_TRUNC,
  O_WRONLY,
  S_IFBLK,
  S_IFCHR,
  S_IFDIR,
  S_IFIFO,
  S_IFLNK,
  S_IFMT,
  S_IFREG,
  S_IFSOCK,
  UV_FS_SYMLINK_DIR,
  UV_FS_SYMLINK_JUNCTION,
  UV_DIRENT_UNKNOWN,
  UV_DIRENT_FILE,
  UV_DIRENT_DIR,
  UV_DIRENT_LINK,
  UV_DIRENT_FIFO,
  UV_DIRENT_SOCKET,
  UV_DIRENT_CHAR,
  UV_DIRENT_BLOCK
} = internalBinding('constants').fs;

const isWindows = process.platform === 'win32';

let fs;
function lazyLoadFs() {
  if (!fs) {
    fs = require('fs');
  }
  return fs;
}

function assertEncoding(encoding) {
  if (encoding && !Buffer.isEncoding(encoding)) {
    throw new ERR_INVALID_OPT_VALUE_ENCODING(encoding);
  }
}

class Dirent {
  constructor(name, type) {
    this.name = name;
    this[kType] = type;
  }

  isDirectory() {
    return this[kType] === UV_DIRENT_DIR;
  }

  isFile() {
    return this[kType] === UV_DIRENT_FILE;
  }

  isBlockDevice() {
    return this[kType] === UV_DIRENT_BLOCK;
  }

  isCharacterDevice() {
    return this[kType] === UV_DIRENT_CHAR;
  }

  isSymbolicLink() {
    return this[kType] === UV_DIRENT_LINK;
  }

  isFIFO() {
    return this[kType] === UV_DIRENT_FIFO;
  }

  isSocket() {
    return this[kType] === UV_DIRENT_SOCKET;
  }
}

class DirentFromStats extends Dirent {
  constructor(name, stats) {
    super(name, null);
    this[kStats] = stats;
  }
}

for (const name of ReflectOwnKeys(Dirent.prototype)) {
  if (name === 'constructor') {
    continue;
  }
  DirentFromStats.prototype[name] = function() {
    return this[kStats][name]();
  };
}

function copyObject(source) {
  const target = {};
  for (const key in source)
    target[key] = source[key];
  return target;
}

function getDirents(path, [names, types], callback) {
  let i;
  if (typeof callback === 'function') {
    const len = names.length;
    let toFinish = 0;
    callback = once(callback);
    for (i = 0; i < len; i++) {
      const type = types[i];
      if (type === UV_DIRENT_UNKNOWN) {
        const name = names[i];
        const idx = i;
        toFinish++;
        lazyLoadFs().lstat(pathModule.join(path, name), (err, stats) => {
          if (err) {
            callback(err);
            return;
          }
          names[idx] = new DirentFromStats(name, stats);
          if (--toFinish === 0) {
            callback(null, names);
          }
        });
      } else {
        names[i] = new Dirent(names[i], types[i]);
      }
    }
    if (toFinish === 0) {
      callback(null, names);
    }
  } else {
    const len = names.length;
    for (i = 0; i < len; i++) {
      names[i] = getDirent(path, names[i], types[i]);
    }
    return names;
  }
}

function getDirent(path, name, type, callback) {
  if (typeof callback === 'function') {
    if (type === UV_DIRENT_UNKNOWN) {
      lazyLoadFs().lstat(pathModule.join(path, name), (err, stats) => {
        if (err) {
          callback(err);
          return;
        }
        callback(null, new DirentFromStats(name, stats));
      });
    } else {
      callback(null, new Dirent(name, type));
    }
  } else if (type === UV_DIRENT_UNKNOWN) {
    const stats = lazyLoadFs().lstatSync(pathModule.join(path, name));
    return new DirentFromStats(name, stats);
  } else {
    return new Dirent(name, type);
  }
}

function getOptions(options, defaultOptions) {
  if (options === null || options === undefined ||
      typeof options === 'function') {
    return defaultOptions;
  }

  if (typeof options === 'string') {
    defaultOptions = { ...defaultOptions };
    defaultOptions.encoding = options;
    options = defaultOptions;
  } else if (typeof options !== 'object') {
    throw new ERR_INVALID_ARG_TYPE('options', ['string', 'Object'], options);
  }

  if (options.encoding !== 'buffer')
    assertEncoding(options.encoding);
  return options;
}

function handleErrorFromBinding(ctx) {
  if (ctx.errno !== undefined) {  // libuv error numbers
    const err = uvException(ctx);
    // eslint-disable-next-line no-restricted-syntax
    Error.captureStackTrace(err, handleErrorFromBinding);
    throw err;
  }
  if (ctx.error !== undefined) {  // Errors created in C++ land.
    // TODO(joyeecheung): currently, ctx.error are encoding errors
    // usually caused by memory problems. We need to figure out proper error
    // code(s) for this.
    // eslint-disable-next-line no-restricted-syntax
    Error.captureStackTrace(ctx.error, handleErrorFromBinding);
    throw ctx.error;
  }
}

// Check if the path contains null types if it is a string nor Uint8Array,
// otherwise return silently.
const nullCheck = hideStackFrames((path, propName, throwError = true) => {
  const pathIsString = typeof path === 'string';
  const pathIsUint8Array = isUint8Array(path);

  // We can only perform meaningful checks on strings and Uint8Arrays.
  if ((!pathIsString && !pathIsUint8Array) ||
      (pathIsString && !path.includes('\u0000')) ||
      (pathIsUint8Array && !path.includes(0))) {
    return;
  }

  const err = new ERR_INVALID_ARG_VALUE(
    propName,
    path,
    'must be a string or Uint8Array without null bytes'
  );
  if (throwError) {
    throw err;
  }
  return err;
});

function preprocessSymlinkDestination(path, type, linkPath) {
  if (!isWindows) {
    // No preprocessing is needed on Unix.
    return path;
  } else if (type === 'junction') {
    // Junctions paths need to be absolute and \\?\-prefixed.
    // A relative target is relative to the link's parent directory.
    path = pathModule.resolve(linkPath, '..', path);
    return pathModule.toNamespacedPath(path);
  } else {
    // Windows symlinks don't tolerate forward slashes.
    return ('' + path).replace(/\//g, '\\');
  }
}

// Constructor for file stats.
function StatsBase(dev, mode, nlink, uid, gid, rdev, blksize,
                   ino, size, blocks) {
  this.dev = dev;
  this.mode = mode;
  this.nlink = nlink;
  this.uid = uid;
  this.gid = gid;
  this.rdev = rdev;
  this.blksize = blksize;
  this.ino = ino;
  this.size = size;
  this.blocks = blocks;
}

StatsBase.prototype.isDirectory = function() {
  return this._checkModeProperty(S_IFDIR);
};

StatsBase.prototype.isFile = function() {
  return this._checkModeProperty(S_IFREG);
};

StatsBase.prototype.isBlockDevice = function() {
  return this._checkModeProperty(S_IFBLK);
};

StatsBase.prototype.isCharacterDevice = function() {
  return this._checkModeProperty(S_IFCHR);
};

StatsBase.prototype.isSymbolicLink = function() {
  return this._checkModeProperty(S_IFLNK);
};

StatsBase.prototype.isFIFO = function() {
  return this._checkModeProperty(S_IFIFO);
};

StatsBase.prototype.isSocket = function() {
  return this._checkModeProperty(S_IFSOCK);
};

const kNsPerMsBigInt = 10n ** 6n;
const kNsPerSecBigInt = 10n ** 9n;
const kMsPerSec = 10 ** 3;
const kNsPerMs = 10 ** 6;
function msFromTimeSpec(sec, nsec) {
  return sec * kMsPerSec + nsec / kNsPerMs;
}

function nsFromTimeSpecBigInt(sec, nsec) {
  return sec * kNsPerSecBigInt + nsec;
}

// The Date constructor performs Math.floor() to the timestamp.
// https://www.ecma-international.org/ecma-262/#sec-timeclip
// Since there may be a precision loss when the timestamp is
// converted to a floating point number, we manually round
// the timestamp here before passing it to Date().
// Refs: https://github.com/nodejs/node/pull/12607
function dateFromMs(ms) {
  return new Date(Number(ms) + 0.5);
}

function BigIntStats(dev, mode, nlink, uid, gid, rdev, blksize,
                     ino, size, blocks,
                     atimeNs, mtimeNs, ctimeNs, birthtimeNs) {
  StatsBase.call(this, dev, mode, nlink, uid, gid, rdev, blksize,
                 ino, size, blocks);

  this.atimeMs = atimeNs / kNsPerMsBigInt;
  this.mtimeMs = mtimeNs / kNsPerMsBigInt;
  this.ctimeMs = ctimeNs / kNsPerMsBigInt;
  this.birthtimeMs = birthtimeNs / kNsPerMsBigInt;
  this.atimeNs = atimeNs;
  this.mtimeNs = mtimeNs;
  this.ctimeNs = ctimeNs;
  this.birthtimeNs = birthtimeNs;
  this.atime = dateFromMs(this.atimeMs);
  this.mtime = dateFromMs(this.mtimeMs);
  this.ctime = dateFromMs(this.ctimeMs);
  this.birthtime = dateFromMs(this.birthtimeMs);
}

ObjectSetPrototypeOf(BigIntStats.prototype, StatsBase.prototype);
ObjectSetPrototypeOf(BigIntStats, StatsBase);

BigIntStats.prototype._checkModeProperty = function(property) {
  if (isWindows && (property === S_IFIFO || property === S_IFBLK ||
    property === S_IFSOCK)) {
    return false;  // Some types are not available on Windows
  }
  return (this.mode & BigInt(S_IFMT)) === BigInt(property);
};

function Stats(dev, mode, nlink, uid, gid, rdev, blksize,
               ino, size, blocks,
               atimeMs, mtimeMs, ctimeMs, birthtimeMs) {
  StatsBase.call(this, dev, mode, nlink, uid, gid, rdev, blksize,
                 ino, size, blocks);
  this.atimeMs = atimeMs;
  this.mtimeMs = mtimeMs;
  this.ctimeMs = ctimeMs;
  this.birthtimeMs = birthtimeMs;
  this.atime = dateFromMs(atimeMs);
  this.mtime = dateFromMs(mtimeMs);
  this.ctime = dateFromMs(ctimeMs);
  this.birthtime = dateFromMs(birthtimeMs);
}

ObjectSetPrototypeOf(Stats.prototype, StatsBase.prototype);
ObjectSetPrototypeOf(Stats, StatsBase);

// HACK: Workaround for https://github.com/standard-things/esm/issues/821.
// TODO(ronag): Remove this as soon as `esm` publishes a fixed version.
Stats.prototype.isFile = StatsBase.prototype.isFile;

Stats.prototype._checkModeProperty = function(property) {
  if (isWindows && (property === S_IFIFO || property === S_IFBLK ||
    property === S_IFSOCK)) {
    return false;  // Some types are not available on Windows
  }
  return (this.mode & S_IFMT) === property;
};

function getStatsFromBinding(stats, offset = 0) {
  if (isBigUint64Array(stats)) {
    return new BigIntStats(
      stats[0 + offset], stats[1 + offset], stats[2 + offset],
      stats[3 + offset], stats[4 + offset], stats[5 + offset],
      stats[6 + offset], stats[7 + offset], stats[8 + offset],
      stats[9 + offset],
      nsFromTimeSpecBigInt(stats[10 + offset], stats[11 + offset]),
      nsFromTimeSpecBigInt(stats[12 + offset], stats[13 + offset]),
      nsFromTimeSpecBigInt(stats[14 + offset], stats[15 + offset]),
      nsFromTimeSpecBigInt(stats[16 + offset], stats[17 + offset])
    );
  }
  return new Stats(
    stats[0 + offset], stats[1 + offset], stats[2 + offset],
    stats[3 + offset], stats[4 + offset], stats[5 + offset],
    stats[6 + offset], stats[7 + offset], stats[8 + offset],
    stats[9 + offset],
    msFromTimeSpec(stats[10 + offset], stats[11 + offset]),
    msFromTimeSpec(stats[12 + offset], stats[13 + offset]),
    msFromTimeSpec(stats[14 + offset], stats[15 + offset]),
    msFromTimeSpec(stats[16 + offset], stats[17 + offset])
  );
}

function stringToFlags(flags) {
  if (typeof flags === 'number') {
    return flags;
  }

  switch (flags) {
    case 'r' : return O_RDONLY;
    case 'rs' : // Fall through.
    case 'sr' : return O_RDONLY | O_SYNC;
    case 'r+' : return O_RDWR;
    case 'rs+' : // Fall through.
    case 'sr+' : return O_RDWR | O_SYNC;

    case 'w' : return O_TRUNC | O_CREAT | O_WRONLY;
    case 'wx' : // Fall through.
    case 'xw' : return O_TRUNC | O_CREAT | O_WRONLY | O_EXCL;

    case 'w+' : return O_TRUNC | O_CREAT | O_RDWR;
    case 'wx+': // Fall through.
    case 'xw+': return O_TRUNC | O_CREAT | O_RDWR | O_EXCL;

    case 'a' : return O_APPEND | O_CREAT | O_WRONLY;
    case 'ax' : // Fall through.
    case 'xa' : return O_APPEND | O_CREAT | O_WRONLY | O_EXCL;
    case 'as' : // Fall through.
    case 'sa' : return O_APPEND | O_CREAT | O_WRONLY | O_SYNC;

    case 'a+' : return O_APPEND | O_CREAT | O_RDWR;
    case 'ax+': // Fall through.
    case 'xa+': return O_APPEND | O_CREAT | O_RDWR | O_EXCL;
    case 'as+': // Fall through.
    case 'sa+': return O_APPEND | O_CREAT | O_RDWR | O_SYNC;
  }

  throw new ERR_INVALID_OPT_VALUE('flags', flags);
}

const stringToSymlinkType = hideStackFrames((type) => {
  let flags = 0;
  if (typeof type === 'string') {
    switch (type) {
      case 'dir':
        flags |= UV_FS_SYMLINK_DIR;
        break;
      case 'junction':
        flags |= UV_FS_SYMLINK_JUNCTION;
        break;
      case 'file':
        break;
      default:
        throw new ERR_FS_INVALID_SYMLINK_TYPE(type);
    }
  }
  return flags;
});

// converts Date or number to a fractional UNIX timestamp
function toUnixTimestamp(time, name = 'time') {
  // eslint-disable-next-line eqeqeq
  if (typeof time === 'string' && +time == time) {
    return +time;
  }
  if (NumberIsFinite(time)) {
    if (time < 0) {
      return DateNow() / 1000;
    }
    return time;
  }
  if (isDate(time)) {
    // Convert to 123.456 UNIX timestamp
    return time.getTime() / 1000;
  }
  throw new ERR_INVALID_ARG_TYPE(name, ['Date', 'Time in seconds'], time);
}

const validateOffsetLengthRead = hideStackFrames(
  (offset, length, bufferLength) => {
    if (offset < 0 || offset >= bufferLength) {
      throw new ERR_OUT_OF_RANGE('offset',
                                 `>= 0 && <= ${bufferLength}`, offset);
    }
    if (length < 0 || offset + length > bufferLength) {
      throw new ERR_OUT_OF_RANGE('length',
                                 `>= 0 && <= ${bufferLength - offset}`, length);
    }
  }
);

const validateOffsetLengthWrite = hideStackFrames(
  (offset, length, byteLength) => {
    if (offset > byteLength) {
      throw new ERR_OUT_OF_RANGE('offset', `<= ${byteLength}`, offset);
    }

    if (length > byteLength - offset) {
      throw new ERR_OUT_OF_RANGE('length', `<= ${byteLength - offset}`, length);
    }
  }
);

const validatePath = hideStackFrames((path, propName = 'path') => {
  if (typeof path !== 'string' && !isUint8Array(path)) {
    throw new ERR_INVALID_ARG_TYPE(propName, ['string', 'Buffer', 'URL'], path);
  }

  const err = nullCheck(path, propName, false);

  if (err !== undefined) {
    throw err;
  }
});

const getValidatedPath = hideStackFrames((fileURLOrPath, propName = 'path') => {
  const path = toPathIfFileURL(fileURLOrPath);
  validatePath(path, propName);
  return path;
});

const validateBufferArray = hideStackFrames((buffers, propName = 'buffers') => {
  if (!ArrayIsArray(buffers))
    throw new ERR_INVALID_ARG_TYPE(propName, 'ArrayBufferView[]', buffers);

  for (let i = 0; i < buffers.length; i++) {
    if (!isArrayBufferView(buffers[i]))
      throw new ERR_INVALID_ARG_TYPE(propName, 'ArrayBufferView[]', buffers);
  }

  return buffers;
});

let nonPortableTemplateWarn = true;

function warnOnNonPortableTemplate(template) {
  // Template strings passed to the mkdtemp() family of functions should not
  // end with 'X' because they are handled inconsistently across platforms.
  if (nonPortableTemplateWarn && template.endsWith('X')) {
    process.emitWarning('mkdtemp() templates ending with X are not portable. ' +
                        'For details see: https://nodejs.org/api/fs.html');
    nonPortableTemplateWarn = false;
  }
}

const defaultRmdirOptions = {
  retryDelay: 100,
  maxRetries: 0,
  recursive: false,
};

const validateRmdirOptions = hideStackFrames((options) => {
  if (options === undefined)
    return defaultRmdirOptions;
  if (options === null || typeof options !== 'object')
    throw new ERR_INVALID_ARG_TYPE('options', 'object', options);

  options = { ...defaultRmdirOptions, ...options };

  if (typeof options.recursive !== 'boolean')
    throw new ERR_INVALID_ARG_TYPE('recursive', 'boolean', options.recursive);

  validateInt32(options.retryDelay, 'retryDelay', 0);
  validateUint32(options.maxRetries, 'maxRetries');

  return options;
});


module.exports = {
  assertEncoding,
  BigIntStats,  // for testing
  copyObject,
  Dirent,
  getDirent,
  getDirents,
  getOptions,
  getValidatedPath,
  handleErrorFromBinding,
  nullCheck,
  preprocessSymlinkDestination,
  realpathCacheKey: Symbol('realpathCacheKey'),
  getStatsFromBinding,
  stringToFlags,
  stringToSymlinkType,
  Stats,
  toUnixTimestamp,
  validateBufferArray,
  validateOffsetLengthRead,
  validateOffsetLengthWrite,
  validatePath,
  validateRmdirOptions,
  warnOnNonPortableTemplate
};