/*!
 * telebit/serve-index
 * Copyright(c) 2018 AJ ONeal
 *
 * Derivative work of github.com/expressjs/serve-index
 * Copyright(c) 2011 Sencha Inc.
 * Copyright(c) 2011 TJ Holowaychuk
 * Copyright(c) 2014-2015 Douglas Christopher Wilson
 * MIT Licensed
 */

'use strict';

/**
 * Module dependencies.
 * @private
 */

var escapeHtml = require('escape-html');
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');

/**
 * Module exports.
 * @public
 */

var defaultPagepath = path.join(__dirname, 'public/directory.html');
var defaultStylepath = path.join(__dirname, 'public/style.css');
var defaultList = '<ul id="files" class="view-{view}">{head}{files}</ul>';
var defaultHead = '<li class="header">'
  + '<span class="name">Name</span>'
  + '<span class="size">Size</span>'
  + '<span class="date">Modified</span>'
  + '</li>'
  ;
var defaultFile = '<li><div>'
  + '<a href="{path}?download=true" class="download" title="Download {file.name}">'
    + '<span class="download">⬇️</span>'
  + '</a>'
  + '<a href="{path}" class="{classes}" title="{file.name}">'
    + '<span class="name">{file.name}</span>'
    + '<span class="size">{file.size}</span>'
    + '<span class="date">{file.date}</span>'
  + '</a>'
  + '</div></li>'
  ;
module.exports = function (opts) {
  if (!opts) { opts = {}; }
  return createHtmlRender({
    pagepath: opts.pagepath || defaultPagepath
  , stylepath: opts.stylepath || defaultStylepath
  , list: opts.list || defaultList
  , head: opts.head || defaultHead
  , file: opts.file || defaultFile
  , privatefiles: opts.privatefiles
  });
};

/*!
 * Icon cache.
 */

var cache = {};

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

function createHtmlFileList(opts, files, dir, useIcons, view) {
  var ftpls = files.map(function (file) {
    var classes = [];
    var isDir = file.stat && file.stat.isDirectory();
    var 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.toLocaleDateString() + ' ' + file.stat.mtime.toLocaleTimeString()
      : '';
    var size = file.stat && !isDir
      ? file.stat.size
      : '';
    var OCTAL = 8;
    var WORLD_READ = parseInt(4, OCTAL); // R(4)W(2)X(1)
    var hasWorldRead = file.stat.mode & WORLD_READ;

    if (!hasWorldRead && 'ignore' === opts.privatefiles) {
      return '';
    }
    return opts.file.replace(/{path}/g, escapeHtml(normalizeSlashes(normalize(path.join('/')))))
      .replace(/{classes}/g, escapeHtml(classes.join(' ')))
      .replace(/{file.name}/g, escapeHtml(file.name))
      .replace(/{file.size}/g, escapeHtml(size))
      .replace(/{file.date}/g, escapeHtml(date))
      ;
  }).filter(Boolean).join('\n');

  var html = opts.list
    .replace(/{view}/g, escapeHtml(view))
    .replace(/{head}/g, view === 'details' ? opts.head : '')
    .replace(/{files}/g, ftpls)
    ;

  return html;
}

/**
 * Create function to render html.
 */

function createHtmlRender(opts) {
  return function render(locals, callback) {
    // read template
    fs.readFile(opts.pagepath, 'utf8', function (err, pageStr) {
      fs.readFile(opts.stylepath, 'utf8', function (err, styleStr) {
        if (err) return callback(err);

        var body = pageStr
          .replace(/\{style\}/g, styleStr.concat(iconStyle(locals.fileList, locals.displayIcons)))
          .replace(/\{files\}/g, createHtmlFileList(opts, locals.fileList, locals.directory, locals.displayIcons, locals.viewName))
          .replace(/\{directory\}/g, escapeHtml(locals.directory))
          .replace(/\{linked-path\}/g, htmlPath(locals.directory))
          ;

        callback(null, body);
      });
    });
  };
}

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

function htmlPath(dir) {
  var parts = dir.split('/');
  var crumb = new Array(parts.length);

  for (var i = 0; i < parts.length; i++) {
    var part = parts[i];

    if (part) {
      parts[i] = encodeURIComponent(part);
      crumb[i] = '<a href="' + escapeHtml(parts.slice(0, i + 1).join('/')) + '">' + escapeHtml(part) + '</a>';
    }
  }

  return crumb.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 i;
  var list = [];
  var rules = {};
  var selector;
  var selectors = {};
  var style = '';

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

    var isDir = 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;
}

/**
 * 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('/');
}

/**
 * Send a response.
 * @private
 */

function send (res, type, body) {
  // security header for content sniffing
  res.setHeader('X-Content-Type-Options', 'nosniff');

  // standard headers
  res.setHeader('Content-Type', type + '; charset=utf-8');
  res.setHeader('Content-Length', Buffer.byteLength(body, 'utf8'));

  // body
  res.end(body, 'utf8');
}

/**
 * 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
  'font': 'font.png',
  '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/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-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',
  '.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'
};