/**
 * keys.js - emit key presses
 * Copyright (c) 2010-2015, Joyent, Inc. and other contributors (MIT License)
 * https://github.com/chjj/blessed
 */

// Originally taken from the node.js tree:
//
// Copyright Joyent, Inc. and other Node contributors. All rights reserved.
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:

// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.

var EventEmitter = require('events').EventEmitter;
var StringDecoder = require('string_decoder').StringDecoder;

/**
 * accepts a readable Stream instance and makes it emit "keypress" events
 */

function emitKeypressEvents(stream) {
  if (stream._keypressDecoder) return;
  var StringDecoder = require('string_decoder').StringDecoder; // lazy load
  stream._keypressDecoder = new StringDecoder('utf8');

  function onData(b) {
    if (EventEmitter.listenerCount(stream, 'keypress') > 0) {
      var r = stream._keypressDecoder.write(b);
      if (r) emitKey(stream, r);
    } else {
      // Nobody's watching anyway
      stream.removeListener('data', onData);
      stream.on('newListener', onNewListener);
    }
  }

  function onNewListener(event) {
    if (event == 'keypress') {
      stream.on('data', onData);
      stream.removeListener('newListener', onNewListener);
    }
  }

  if (EventEmitter.listenerCount(stream, 'keypress') > 0) {
    stream.on('data', onData);
  } else {
    stream.on('newListener', onNewListener);
  }
}
exports.emitKeypressEvents = emitKeypressEvents;

/*
  Some patterns seen in terminal key escape codes, derived from combos seen
  at http://www.midnight-commander.org/browser/lib/tty/key.c

  ESC letter
  ESC [ letter
  ESC [ modifier letter
  ESC [ 1 ; modifier letter
  ESC [ num char
  ESC [ num ; modifier char
  ESC O letter
  ESC O modifier letter
  ESC O 1 ; modifier letter
  ESC N letter
  ESC [ [ num ; modifier char
  ESC [ [ 1 ; modifier letter
  ESC ESC [ num char
  ESC ESC O letter

  - char is usually ~ but $ and ^ also happen with rxvt
  - modifier is 1 +
                (shift     * 1) +
                (left_alt  * 2) +
                (ctrl      * 4) +
                (right_alt * 8)
  - two leading ESCs apparently mean the same as one leading ESC
*/

// Regexes used for ansi escape code splitting
var metaKeyCodeReAnywhere = /(?:\x1b)([a-zA-Z0-9])/;
var metaKeyCodeRe = new RegExp('^' + metaKeyCodeReAnywhere.source + '$');
var functionKeyCodeReAnywhere =
    /(?:\x1b+)(O|N|\[|\[\[)(?:(\d+)(?:;(\d+))?([~^$])|(?:1;)?(\d+)?([a-zA-Z]))/;
var functionKeyCodeRe = new RegExp('^' + functionKeyCodeReAnywhere.source);

function emitKey(stream, s) {
  var ch,
      key = {
        name: undefined,
        ctrl: false,
        meta: false,
        shift: false
      },
      parts;

  if (Buffer.isBuffer(s)) {
    if (s[0] > 127 && s[1] === undefined) {
      s[0] -= 128;
      s = '\x1b' + s.toString(stream.encoding || 'utf-8');
    } else {
      s = s.toString(stream.encoding || 'utf-8');
    }
  }

  key.sequence = s;

  if (s === '\r') {
    // carriage return
    key.name = 'return';

  } else if (s === '\n') {
    // enter, should have been called linefeed
    key.name = 'enter';

  } else if (s === '\t') {
    // tab
    key.name = 'tab';

  } else if (s === '\b' || s === '\x7f' ||
             s === '\x1b\x7f' || s === '\x1b\b') {
    // backspace or ctrl+h
    key.name = 'backspace';
    key.meta = (s.charAt(0) === '\x1b');

  } else if (s === '\x1b' || s === '\x1b\x1b') {
    // escape key
    key.name = 'escape';
    key.meta = (s.length === 2);

  } else if (s === ' ' || s === '\x1b ') {
    key.name = 'space';
    key.meta = (s.length === 2);

  } else if (s.length === 1 && s <= '\x1a') {
    // ctrl+letter
    key.name = String.fromCharCode(s.charCodeAt(0) + 'a'.charCodeAt(0) - 1);
    key.ctrl = true;

  } else if (s.length === 1 && s >= 'a' && s <= 'z') {
    // lowercase letter
    key.name = s;

  } else if (s.length === 1 && s >= 'A' && s <= 'Z') {
    // shift+letter
    key.name = s.toLowerCase();
    key.shift = true;

  } else if (parts = metaKeyCodeRe.exec(s)) {
    // meta+character key
    key.name = parts[1].toLowerCase();
    key.meta = true;
    key.shift = /^[A-Z]$/.test(parts[1]);

  } else if (parts = functionKeyCodeRe.exec(s)) {
    // ansi escape sequence

    // reassemble the key code leaving out leading \x1b's,
    // the modifier key bitflag and any meaningless "1;" sequence
    var code = (parts[1] || '') + (parts[2] || '') +
               (parts[4] || '') + (parts[6] || ''),
        modifier = (parts[3] || parts[5] || 1) - 1;

    // Parse the key modifier
    key.ctrl = !!(modifier & 4);
    key.meta = !!(modifier & 10);
    key.shift = !!(modifier & 1);
    key.code = code;

    // Parse the key itself
    switch (code) {
      /* xterm/gnome ESC O letter */
      case 'OP': key.name = 'f1'; break;
      case 'OQ': key.name = 'f2'; break;
      case 'OR': key.name = 'f3'; break;
      case 'OS': key.name = 'f4'; break;

      /* xterm/rxvt ESC [ number ~ */
      case '[11~': key.name = 'f1'; break;
      case '[12~': key.name = 'f2'; break;
      case '[13~': key.name = 'f3'; break;
      case '[14~': key.name = 'f4'; break;

      /* from Cygwin and used in libuv */
      case '[[A': key.name = 'f1'; break;
      case '[[B': key.name = 'f2'; break;
      case '[[C': key.name = 'f3'; break;
      case '[[D': key.name = 'f4'; break;
      case '[[E': key.name = 'f5'; break;

      /* common */
      case '[15~': key.name = 'f5'; break;
      case '[17~': key.name = 'f6'; break;
      case '[18~': key.name = 'f7'; break;
      case '[19~': key.name = 'f8'; break;
      case '[20~': key.name = 'f9'; break;
      case '[21~': key.name = 'f10'; break;
      case '[23~': key.name = 'f11'; break;
      case '[24~': key.name = 'f12'; break;

      /* xterm ESC [ letter */
      case '[A': key.name = 'up'; break;
      case '[B': key.name = 'down'; break;
      case '[C': key.name = 'right'; break;
      case '[D': key.name = 'left'; break;
      case '[E': key.name = 'clear'; break;
      case '[F': key.name = 'end'; break;
      case '[H': key.name = 'home'; break;

      /* xterm/gnome ESC O letter */
      case 'OA': key.name = 'up'; break;
      case 'OB': key.name = 'down'; break;
      case 'OC': key.name = 'right'; break;
      case 'OD': key.name = 'left'; break;
      case 'OE': key.name = 'clear'; break;
      case 'OF': key.name = 'end'; break;
      case 'OH': key.name = 'home'; break;

      /* xterm/rxvt ESC [ number ~ */
      case '[1~': key.name = 'home'; break;
      case '[2~': key.name = 'insert'; break;
      case '[3~': key.name = 'delete'; break;
      case '[4~': key.name = 'end'; break;
      case '[5~': key.name = 'pageup'; break;
      case '[6~': key.name = 'pagedown'; break;

      /* putty */
      case '[[5~': key.name = 'pageup'; break;
      case '[[6~': key.name = 'pagedown'; break;

      /* rxvt */
      case '[7~': key.name = 'home'; break;
      case '[8~': key.name = 'end'; break;

      /* rxvt keys with modifiers */
      case '[a': key.name = 'up'; key.shift = true; break;
      case '[b': key.name = 'down'; key.shift = true; break;
      case '[c': key.name = 'right'; key.shift = true; break;
      case '[d': key.name = 'left'; key.shift = true; break;
      case '[e': key.name = 'clear'; key.shift = true; break;

      case '[2$': key.name = 'insert'; key.shift = true; break;
      case '[3$': key.name = 'delete'; key.shift = true; break;
      case '[5$': key.name = 'pageup'; key.shift = true; break;
      case '[6$': key.name = 'pagedown'; key.shift = true; break;
      case '[7$': key.name = 'home'; key.shift = true; break;
      case '[8$': key.name = 'end'; key.shift = true; break;

      case 'Oa': key.name = 'up'; key.ctrl = true; break;
      case 'Ob': key.name = 'down'; key.ctrl = true; break;
      case 'Oc': key.name = 'right'; key.ctrl = true; break;
      case 'Od': key.name = 'left'; key.ctrl = true; break;
      case 'Oe': key.name = 'clear'; key.ctrl = true; break;

      case '[2^': key.name = 'insert'; key.ctrl = true; break;
      case '[3^': key.name = 'delete'; key.ctrl = true; break;
      case '[5^': key.name = 'pageup'; key.ctrl = true; break;
      case '[6^': key.name = 'pagedown'; key.ctrl = true; break;
      case '[7^': key.name = 'home'; key.ctrl = true; break;
      case '[8^': key.name = 'end'; key.ctrl = true; break;

      /* misc. */
      case '[Z': key.name = 'tab'; key.shift = true; break;
      default: key.name = 'undefined'; break;

    }
  } else if (s.length > 1 && s[0] !== '\x1b') {
    // Got a longer-than-one string of characters.
    // Probably a paste, since it wasn't a control sequence.
    Array.prototype.forEach.call(s, function(c) {
      emitKey(stream, c);
    });
    return;
  }

  // Don't emit a key if no name was found
  if (key.name === undefined) {
    key = undefined;
  }

  if (s.length === 1) {
    ch = s;
  }

  if (key || ch) {
    stream.emit('keypress', ch, key);
  }
}