/*!
 * serve-index
 * Copyright(c) 2011 Sencha Inc.
 * Copyright(c) 2011 TJ Holowaychuk
 * Copyright(c) 2014 Douglas Christopher Wilson
 * MIT Licensed
 */

// TODO: arrow key navigation
// TODO: make icons extensible

/**
 * Module dependencies.
 */

var accepts = require('accepts');
var createError = require('http-errors');
var debug = require('debug')('serve-index');
var fs = require('fs')
  , path = require('path')
  , normalize = path.normalize
  , sep = path.sep
  , extname = path.extname
  , join = path.join;
var Batch = require('batch');
var mime = require('mime-types');
var parseUrl = require('parseurl');
var resolve = require('path').resolve;

/*!
 * Icon cache.
 */

var cache = {};

/*!
 * Default template.
 */

var defaultTemplate = join(__dirname, 'public', 'directory.html');

/*!
 * Stylesheet.
 */

var defaultStylesheet = join(__dirname, 'public', 'style.css');

/**
 * Media types and the map for content negotiation.
 */

var mediaTypes = [
  'text/html',
  'text/plain',
  'application/json'
];

var mediaType = {
  'text/html': 'html',
  'text/plain': 'plain',
  'application/json': 'json'
};

/**
 * Serve directory listings with the given `root` path.
 *
 * See Readme.md for documentation of options.
 *
 * @param {String} path
 * @param {Object} options
 * @return {Function} middleware
 * @api public
 */

exports = module.exports = function serveIndex(root, options){
  options = options || {};

  // root required
  if (!root) throw new TypeError('serveIndex() root path required');

  // resolve root to absolute and normalize
  root = resolve(root);
  root = normalize(root + sep);

  var hidden = options.hidden
    , icons = options.icons
    , view = options.view || 'tiles'
    , filter = options.filter
    , template = options.template || defaultTemplate
    , stylesheet = options.stylesheet || defaultStylesheet;

  return function serveIndex(req, res, next) {
    if (req.method !== 'GET' && req.method !== 'HEAD') {
      res.statusCode = 'OPTIONS' === req.method
        ? 200
        : 405;
      res.setHeader('Allow', 'GET, HEAD, OPTIONS');
      res.end();
      return;
    }

    // parse URLs
    var url = parseUrl(req);
    var originalUrl = parseUrl.original(req);
    var dir = decodeURIComponent(url.pathname);
    var originalDir = decodeURIComponent(originalUrl.pathname);

    // join / normalize from root dir
    var path = normalize(join(root, dir));

    // null byte(s), bad request
    if (~path.indexOf('\0')) return next(createError(400));

    // malicious path
    if ((path + sep).substr(0, root.length) !== root) {
      debug('malicious path "%s"', path);
      return next(createError(403));
    }

    // determine ".." display
    var showUp = normalize(resolve(path) + sep) !== root;

    // check if we have a directory
    debug('stat "%s"', path);
    fs.stat(path, function(err, stat){
      if (err && err.code === 'ENOENT') {
        return next();
      }

      if (err) {
        err.status = err.code === 'ENAMETOOLONG'
          ? 414
          : 500;
        return next(err);
      }

      if (!stat.isDirectory()) return next();

      // fetch files
      debug('readdir "%s"', path);
      fs.readdir(path, function(err, files){
        if (err) return next(err);
        if (!hidden) files = removeHidden(files);
        if (filter) files = files.filter(function(filename, index, list) {
          return filter(filename, index, list, path);
        });
        files.sort();

        // content-negotiation
        var accept = accepts(req);
        var type = accept.type(mediaTypes);

        // not acceptable
        if (!type) return next(createError(406));
        exports[mediaType[type]](req, res, files, next, originalDir, showUp, icons, path, view, template, stylesheet);
      });
    });
  };
};

/**
 * Respond with text/html.
 */

exports.html = function(req, res, files, next, dir, showUp, icons, path, view, template, stylesheet){
  fs.readFile(template, 'utf8', function(err, str){
    if (err) return next(err);
    fs.readFile(stylesheet, 'utf8', function(err, style){
      if (err) return next(err);
      stat(path, files, function(err, stats){
        if (err) return next(err);
        files = files.map(function(file, i){ return { name: file, stat: stats[i] }; });
        files.sort(fileSort);
        if (showUp) files.unshift({ name: '..' });
        str = str
          .replace(/\{style\}/g, style.concat(iconStyle(files, icons)))
          .replace(/\{files\}/g, html(files, dir, icons, view))
          .replace(/\{directory\}/g, dir)
          .replace(/\{linked-path\}/g, htmlPath(dir));

        var buf = new Buffer(str, 'utf8');
        res.setHeader('Content-Type', 'text/html; charset=utf-8');
        res.setHeader('Content-Length', buf.length);
        res.end(buf);
      });
    });
  });
};

/**
 * Respond with application/json.
 */

exports.json = function(req, res, files){
  var body = JSON.stringify(files);
  var buf = new Buffer(body, 'utf8');

  res.setHeader('Content-Type', 'application/json; charset=utf-8');
  res.setHeader('Content-Length', buf.length);
  res.end(buf);
};

/**
 * Respond with text/plain.
 */

exports.plain = function(req, res, files){
  var body = files.join('\n') + '\n';
  var buf = new Buffer(body, 'utf8');

  res.setHeader('Content-Type', 'text/plain; charset=utf-8');
  res.setHeader('Content-Length', buf.length);
  res.end(buf);
};

/**
 * Sort function for with directories first.
 */

function fileSort(a, b) {
  return Number(b.stat && b.stat.isDirectory()) - Number(a.stat && a.stat.isDirectory()) ||
    String(a.name).toLocaleLowerCase().localeCompare(String(b.name).toLocaleLowerCase());
}

/**
 * Map html `dir`, returning a linked path.
 */

function htmlPath(dir) {
  var curr = [];
  return dir.split('/').map(function(part){
    curr.push(encodeURIComponent(part));
    return part ? '<a href="' + curr.join('/') + '">' + part + '</a>' : '';
  }).join(' / ');
}

/**
 * Get the icon data for the file name.
 */

function iconLookup(filename) {
  var ext = extname(filename);

  // try by extension
  if (icons[ext]) {
    return {
      className: 'icon-' + ext.substring(1),
      fileName: icons[ext]
    };
  }

  var mimetype = mime.lookup(ext);

  // default if no mime type
  if (mimetype === false) {
    return {
      className: 'icon-default',
      fileName: icons.default
    };
  }

  // try by mime type
  if (icons[mimetype]) {
    return {
      className: 'icon-' + mimetype.replace('/', '-'),
      fileName: icons[mimetype]
    };
  }

  var suffix = mimetype.split('+')[1];

  if (suffix && icons['+' + suffix]) {
    return {
      className: 'icon-' + suffix,
      fileName: icons['+' + suffix]
    };
  }

  var type = mimetype.split('/')[0];

  // try by type only
  if (icons[type]) {
    return {
      className: 'icon-' + type,
      fileName: icons[type]
    };
  }

  return {
    className: 'icon-default',
    fileName: icons.default
  };
}

/**
 * Load icon images, return css string.
 */

function iconStyle (files, useIcons) {
  if (!useIcons) return '';
  var className;
  var i;
  var iconName;
  var list = [];
  var rules = {};
  var selector;
  var selectors = {};
  var style = '';

  for (i = 0; i < files.length; i++) {
    var file = files[i];

    var isDir = '..' == file.name || (file.stat && file.stat.isDirectory());
    var icon = isDir
      ? { className: 'icon-directory', fileName: icons.folder }
      : iconLookup(file.name);
    var iconName = icon.fileName;

    selector = '#files .' + icon.className + ' .name';

    if (!rules[iconName]) {
      rules[iconName] = 'background-image: url(data:image/png;base64,' + load(iconName) + ');'
      selectors[iconName] = [];
      list.push(iconName);
    }

    if (selectors[iconName].indexOf(selector) === -1) {
      selectors[iconName].push(selector);
    }
  }

  for (i = 0; i < list.length; i++) {
    iconName = list[i];
    style += selectors[iconName].join(',\n') + ' {\n  ' + rules[iconName] + '\n}\n';
  }

  return style;
}

/**
 * Map html `files`, returning an html unordered list.
 */

function html(files, dir, useIcons, view) {
  return '<ul id="files" class="view-' + view + '">'
    + (view == 'details' ? (
      '<li class="header">'
      + '<span class="name">Name</span>'
      + '<span class="size">Size</span>'
      + '<span class="date">Modified</span>'
      + '</li>') : '')
    + files.map(function(file){
    var isDir = '..' == file.name || (file.stat && file.stat.isDirectory())
      , classes = []
      , path = dir.split('/').map(function (c) { return encodeURIComponent(c); });

    if (useIcons) {
      classes.push('icon');

      if (isDir) {
        classes.push('icon-directory');
      } else {
        var ext = extname(file.name);
        var icon = iconLookup(file.name);

        classes.push('icon');
        classes.push('icon-' + ext.substring(1));

        if (classes.indexOf(icon.className) === -1) {
          classes.push(icon.className);
        }
      }
    }

    path.push(encodeURIComponent(file.name));

    var date = file.stat && file.name !== '..'
      ? file.stat.mtime.toDateString() + ' ' + file.stat.mtime.toLocaleTimeString()
      : '';
    var size = file.stat && !isDir
      ? file.stat.size
      : '';

    return '<li><a href="'
      + normalizeSlashes(normalize(path.join('/')))
      + '" class="'
      + classes.join(' ') + '"'
      + ' title="' + file.name + '">'
      + '<span class="name">'+file.name+'</span>'
      + '<span class="size">'+size+'</span>'
      + '<span class="date">'+date+'</span>'
      + '</a></li>';

  }).join('\n') + '</ul>';
}

/**
 * Load and cache the given `icon`.
 *
 * @param {String} icon
 * @return {String}
 * @api private
 */

function load(icon) {
  if (cache[icon]) return cache[icon];
  return cache[icon] = fs.readFileSync(__dirname + '/public/icons/' + icon, 'base64');
}

/**
 * Normalizes the path separator from system separator
 * to URL separator, aka `/`.
 *
 * @param {String} path
 * @return {String}
 * @api private
 */

function normalizeSlashes(path) {
  return path.split(sep).join('/');
};

/**
 * Filter "hidden" `files`, aka files
 * beginning with a `.`.
 *
 * @param {Array} files
 * @return {Array}
 * @api private
 */

function removeHidden(files) {
  return files.filter(function(file){
    return '.' != file[0];
  });
}

/**
 * Stat all files and return array of stat
 * in same order.
 */

function stat(dir, files, cb) {
  var batch = new Batch();

  batch.concurrency(10);

  files.forEach(function(file){
    batch.push(function(done){
      fs.stat(join(dir, file), function(err, stat){
        if (err && err.code !== 'ENOENT') return done(err);

        // pass ENOENT as null stat, not error
        done(null, stat || null);
      });
    });
  });

  batch.end(cb);
}

/**
 * Icon map.
 */

var icons = {
  // base icons
  'default': 'page_white.png',
  'folder': 'folder.png',

  // generic mime type icons
  'image': 'image.png',
  'text': 'page_white_text.png',
  'video': 'film.png',

  // generic mime suffix icons
  '+json': 'page_white_code.png',
  '+xml': 'page_white_code.png',
  '+zip': 'box.png',

  // specific mime type icons
  'application/font-woff': 'font.png',
  'application/javascript': 'page_white_code_red.png',
  'application/json': 'page_white_code.png',
  'application/msword': 'page_white_word.png',
  'application/pdf': 'page_white_acrobat.png',
  'application/postscript': 'page_white_vector.png',
  'application/rtf': 'page_white_word.png',
  'application/vnd.ms-excel': 'page_white_excel.png',
  'application/vnd.ms-powerpoint': 'page_white_powerpoint.png',
  'application/vnd.oasis.opendocument.presentation': 'page_white_powerpoint.png',
  'application/vnd.oasis.opendocument.spreadsheet': 'page_white_excel.png',
  'application/vnd.oasis.opendocument.text': 'page_white_word.png',
  'application/x-7z-compressed': 'box.png',
  'application/x-sh': 'application_xp_terminal.png',
  'application/x-font-ttf': 'font.png',
  'application/x-msaccess': 'page_white_database.png',
  'application/x-shockwave-flash': 'page_white_flash.png',
  'application/x-sql': 'page_white_database.png',
  'application/x-tar': 'box.png',
  'application/x-xz': 'box.png',
  'application/xml': 'page_white_code.png',
  'application/zip': 'box.png',
  'image/svg+xml': 'page_white_vector.png',
  'text/css': 'page_white_code.png',
  'text/html': 'page_white_code.png',
  'text/less': 'page_white_code.png',

  // other, extension-specific icons
  '.accdb': 'page_white_database.png',
  '.apk': 'box.png',
  '.app': 'application_xp.png',
  '.as': 'page_white_actionscript.png',
  '.asp': 'page_white_code.png',
  '.aspx': 'page_white_code.png',
  '.bat': 'application_xp_terminal.png',
  '.bz2': 'box.png',
  '.c': 'page_white_c.png',
  '.cab': 'box.png',
  '.cfm': 'page_white_coldfusion.png',
  '.clj': 'page_white_code.png',
  '.cc': 'page_white_cplusplus.png',
  '.cgi': 'application_xp_terminal.png',
  '.cpp': 'page_white_cplusplus.png',
  '.cs': 'page_white_csharp.png',
  '.db': 'page_white_database.png',
  '.dbf': 'page_white_database.png',
  '.deb': 'box.png',
  '.dll': 'page_white_gear.png',
  '.dmg': 'drive.png',
  '.docx': 'page_white_word.png',
  '.erb': 'page_white_ruby.png',
  '.exe': 'application_xp.png',
  '.fnt': 'font.png',
  '.gam': 'controller.png',
  '.gz': 'box.png',
  '.h': 'page_white_h.png',
  '.ini': 'page_white_gear.png',
  '.iso': 'cd.png',
  '.jar': 'box.png',
  '.java': 'page_white_cup.png',
  '.jsp': 'page_white_cup.png',
  '.lua': 'page_white_code.png',
  '.lz': 'box.png',
  '.lzma': 'box.png',
  '.m': 'page_white_code.png',
  '.map': 'map.png',
  '.msi': 'box.png',
  '.mv4': 'film.png',
  '.otf': 'font.png',
  '.pdb': 'page_white_database.png',
  '.php': 'page_white_php.png',
  '.pl': 'page_white_code.png',
  '.pkg': 'box.png',
  '.pptx': 'page_white_powerpoint.png',
  '.psd': 'page_white_picture.png',
  '.py': 'page_white_code.png',
  '.rar': 'box.png',
  '.rb': 'page_white_ruby.png',
  '.rm': 'film.png',
  '.rom': 'controller.png',
  '.rpm': 'box.png',
  '.sass': 'page_white_code.png',
  '.sav': 'controller.png',
  '.scss': 'page_white_code.png',
  '.srt': 'page_white_text.png',
  '.tbz2': 'box.png',
  '.tgz': 'box.png',
  '.tlz': 'box.png',
  '.vb': 'page_white_code.png',
  '.vbs': 'page_white_code.png',
  '.xcf': 'page_white_picture.png',
  '.xlsx': 'page_white_excel.png',
  '.yaws': 'page_white_code.png'
};