'use strict';

const fs = require('graceful-fs');
const path = require('path');
const assert = require('assert');

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

function defaults(options) {
  const methods = ['unlink', 'chmod', 'stat', 'lstat', 'rmdir', 'readdir'];
  methods.forEach((m) => {
    options[m] = options[m] || fs[m];
    m = m + 'Sync';
    options[m] = options[m] || fs[m];
  });

  options.maxBusyTries = options.maxBusyTries || 3;
}

function rimraf(p, options, cb) {
  let busyTries = 0;

  if (typeof options === 'function') {
    cb = options;
    options = {};
  }

  assert(p, 'rimraf: missing path');
  assert.strictEqual(typeof p, 'string', 'rimraf: path should be a string');
  assert.strictEqual(
    typeof cb,
    'function',
    'rimraf: callback function required'
  );
  assert(options, 'rimraf: invalid options argument provided');
  assert.strictEqual(
    typeof options,
    'object',
    'rimraf: options should be object'
  );

  defaults(options);

  rimraf_(p, options, function CB(er) {
    if (er) {
      if (
        (er.code === 'EBUSY' ||
          er.code === 'ENOTEMPTY' ||
          er.code === 'EPERM') &&
        busyTries < options.maxBusyTries
      ) {
        busyTries++;
        const time = busyTries * 100;
        // try again, with the same exact callback as this one.
        return setTimeout(() => rimraf_(p, options, CB), time);
      }

      // already gone
      if (er.code === 'ENOENT') er = null;
    }

    cb(er);
  });
}

// Two possible strategies.
// 1. Assume it's a file.  unlink it, then do the dir stuff on EPERM or EISDIR
// 2. Assume it's a directory.  readdir, then do the file stuff on ENOTDIR
//
// Both result in an extra syscall when you guess wrong.  However, there
// are likely far more normal files in the world than directories.  This
// is based on the assumption that a the average number of files per
// directory is >= 1.
//
// If anyone ever complains about this, then I guess the strategy could
// be made configurable somehow.  But until then, YAGNI.
function rimraf_(p, options, cb) {
  assert(p);
  assert(options);
  assert(typeof cb === 'function');

  // sunos lets the root user unlink directories, which is... weird.
  // so we have to lstat here and make sure it's not a dir.
  options.lstat(p, (er, st) => {
    if (er && er.code === 'ENOENT') {
      return cb(null);
    }

    // Windows can EPERM on stat.  Life is suffering.
    if (er && er.code === 'EPERM' && isWindows) {
      return fixWinEPERM(p, options, er, cb);
    }

    if (st && st.isDirectory()) {
      return rmdir(p, options, er, cb);
    }

    options.unlink(p, (er) => {
      if (er) {
        if (er.code === 'ENOENT') {
          return cb(null);
        }
        if (er.code === 'EPERM') {
          return isWindows ?
              fixWinEPERM(p, options, er, cb)
            : rmdir(p, options, er, cb);
        }
        if (er.code === 'EISDIR') {
          return rmdir(p, options, er, cb);
        }
      }
      return cb(er);
    });
  });
}

function fixWinEPERM(p, options, er, cb) {
  assert(p);
  assert(options);
  assert(typeof cb === 'function');

  options.chmod(p, 0o666, (er2) => {
    if (er2) {
      cb(er2.code === 'ENOENT' ? null : er);
    } else {
      options.stat(p, (er3, stats) => {
        if (er3) {
          cb(er3.code === 'ENOENT' ? null : er);
        } else if (stats.isDirectory()) {
          rmdir(p, options, er, cb);
        } else {
          options.unlink(p, cb);
        }
      });
    }
  });
}

function fixWinEPERMSync(p, options, er) {
  let stats;

  assert(p);
  assert(options);

  try {
    options.chmodSync(p, 0o666);
  } catch (er2) {
    if (er2.code === 'ENOENT') {
      return;
    } else {
      throw er;
    }
  }

  try {
    stats = options.statSync(p);
  } catch (er3) {
    if (er3.code === 'ENOENT') {
      return;
    } else {
      throw er;
    }
  }

  if (stats.isDirectory()) {
    rmdirSync(p, options, er);
  } else {
    options.unlinkSync(p);
  }
}

function rmdir(p, options, originalEr, cb) {
  assert(p);
  assert(options);
  assert(typeof cb === 'function');

  // try to rmdir first, and only readdir on ENOTEMPTY or EEXIST (SunOS)
  // if we guessed wrong, and it's not a directory, then
  // raise the original error.
  options.rmdir(p, (er) => {
    if (
      er &&
      (er.code === 'ENOTEMPTY' || er.code === 'EEXIST' || er.code === 'EPERM')
    ) {
      rmkids(p, options, cb);
    } else if (er && er.code === 'ENOTDIR') {
      cb(originalEr);
    } else {
      cb(er);
    }
  });
}

function rmkids(p, options, cb) {
  assert(p);
  assert(options);
  assert(typeof cb === 'function');

  options.readdir(p, (er, files) => {
    if (er) return cb(er);

    let n = files.length;
    let errState;

    if (n === 0) return options.rmdir(p, cb);

    files.forEach((f) => {
      rimraf(path.join(p, f), options, (er) => {
        if (errState) {
          return;
        }
        if (er) return cb((errState = er));
        if (--n === 0) {
          options.rmdir(p, cb);
        }
      });
    });
  });
}

// this looks simpler, and is strictly *faster*, but will
// tie up the JavaScript thread and fail on excessively
// deep directory trees.
function rimrafSync(p, options) {
  let st;

  options = options || {};
  defaults(options);

  assert(p, 'rimraf: missing path');
  assert.strictEqual(typeof p, 'string', 'rimraf: path should be a string');
  assert(options, 'rimraf: missing options');
  assert.strictEqual(
    typeof options,
    'object',
    'rimraf: options should be object'
  );

  try {
    st = options.lstatSync(p);
  } catch (er) {
    if (er.code === 'ENOENT') {
      return;
    }

    // Windows can EPERM on stat.  Life is suffering.
    if (er.code === 'EPERM' && isWindows) {
      fixWinEPERMSync(p, options, er);
    }
  }

  try {
    // sunos lets the root user unlink directories, which is... weird.
    if (st && st.isDirectory()) {
      rmdirSync(p, options, null);
    } else {
      options.unlinkSync(p);
    }
  } catch (er) {
    if (er.code === 'ENOENT') {
      return;
    } else if (er.code === 'EPERM') {
      return isWindows ?
          fixWinEPERMSync(p, options, er)
        : rmdirSync(p, options, er);
    } else if (er.code !== 'EISDIR') {
      throw er;
    }
    rmdirSync(p, options, er);
  }
}

function rmdirSync(p, options, originalEr) {
  assert(p);
  assert(options);

  try {
    options.rmdirSync(p);
  } catch (er) {
    if (er.code === 'ENOTDIR') {
      throw originalEr;
    } else if (
      er.code === 'ENOTEMPTY' ||
      er.code === 'EEXIST' ||
      er.code === 'EPERM'
    ) {
      rmkidsSync(p, options);
    } else if (er.code !== 'ENOENT') {
      throw er;
    }
  }
}

function rmkidsSync(p, options) {
  assert(p);
  assert(options);
  options.readdirSync(p).forEach((f) => rimrafSync(path.join(p, f), options));

  if (isWindows) {
    // We only end up here once we got ENOTEMPTY at least once, and
    // at this point, we are guaranteed to have removed all the kids.
    // So, we know that it won't be ENOENT or ENOTDIR or anything else.
    // try really hard to delete stuff on windows, because it has a
    // PROFOUNDLY annoying habit of not closing handles promptly when
    // files are deleted, resulting in spurious ENOTEMPTY errors.
    const startTime = Date.now();
    do {
      try {
        const ret = options.rmdirSync(p, options);
        return ret;
      } catch {}
    } while (Date.now() - startTime < 500); // give up after 500ms
  } else {
    const ret = options.rmdirSync(p, options);
    return ret;
  }
}

module.exports = rimraf;
rimraf.sync = rimrafSync;