var fs = require('fs');
var path = require('path');
var common = require('./common');
var cp = require('./cp');
var rm = require('./rm');

common.register('mv', _mv, {
  cmdOptions: {
    'f': '!no_force',
    'n': 'no_force',
  },
});

// Checks if cureent file was created recently
function checkRecentCreated(sources, index) {
  var lookedSource = sources[index];
  return sources.slice(0, index).some(function (src) {
    return path.basename(src) === path.basename(lookedSource);
  });
}

//@
//@ ### mv([options ,] source [, source ...], dest')
//@ ### mv([options ,] source_array, dest')
//@
//@ Available options:
//@
//@ + `-f`: force (default behavior)
//@ + `-n`: no-clobber
//@
//@ Examples:
//@
//@ ```javascript
//@ mv('-n', 'file', 'dir/');
//@ mv('file1', 'file2', 'dir/');
//@ mv(['file1', 'file2'], 'dir/'); // same as above
//@ ```
//@
//@ Moves `source` file(s) to `dest`. Returns a [ShellString](#shellstringstr)
//@ indicating success or failure.
function _mv(options, sources, dest) {
  // Get sources, dest
  if (arguments.length < 3) {
    common.error('missing <source> and/or <dest>');
  } else if (arguments.length > 3) {
    sources = [].slice.call(arguments, 1, arguments.length - 1);
    dest = arguments[arguments.length - 1];
  } else if (typeof sources === 'string') {
    sources = [sources];
  } else {
    // TODO(nate): figure out if we actually need this line
    common.error('invalid arguments');
  }

  var exists = fs.existsSync(dest);
  var stats = exists && common.statFollowLinks(dest);

  // Dest is not existing dir, but multiple sources given
  if ((!exists || !stats.isDirectory()) && sources.length > 1) {
    common.error('dest is not a directory (too many sources)');
  }

  // Dest is an existing file, but no -f given
  if (exists && stats.isFile() && options.no_force) {
    common.error('dest file already exists: ' + dest);
  }

  sources.forEach(function (src, srcIndex) {
    if (!fs.existsSync(src)) {
      common.error('no such file or directory: ' + src, { continue: true });
      return; // skip file
    }

    // If here, src exists

    // When copying to '/path/dir':
    //    thisDest = '/path/dir/file1'
    var thisDest = dest;
    if (fs.existsSync(dest) && common.statFollowLinks(dest).isDirectory()) {
      thisDest = path.normalize(dest + '/' + path.basename(src));
    }

    var thisDestExists = fs.existsSync(thisDest);

    if (thisDestExists && checkRecentCreated(sources, srcIndex)) {
      // cannot overwrite file created recently in current execution, but we want to continue copying other files
      if (!options.no_force) {
        common.error("will not overwrite just-created '" + thisDest + "' with '" + src + "'", { continue: true });
      }
      return;
    }

    if (fs.existsSync(thisDest) && options.no_force) {
      common.error('dest file already exists: ' + thisDest, { continue: true });
      return; // skip file
    }

    if (path.resolve(src) === path.dirname(path.resolve(thisDest))) {
      common.error('cannot move to self: ' + src, { continue: true });
      return; // skip file
    }

    try {
      fs.renameSync(src, thisDest);
    } catch (e) {
      /* istanbul ignore next */
      if (e.code === 'EXDEV') {
        // If we're trying to `mv` to an external partition, we'll actually need
        // to perform a copy and then clean up the original file. If either the
        // copy or the rm fails with an exception, we should allow this
        // exception to pass up to the top level.
        cp({ recursive: true }, src, thisDest);
        rm({ recursive: true, force: true }, src);
      }
    }
  }); // forEach(src)
  return '';
} // mv
module.exports = _mv;
