'use strict';

const readline = require('readline');
const actions = require('./actions');

/* eslint-disable no-control-regex */
const metaKeyCodeRe = /^(?:\x1b)([a-zA-Z0-9])$/;
const fnKeyRe = /^(?:\x1b+)(O|N|\[|\[\[)(?:(\d+)(?:;(\d+))?([~^$])|(?:1;)?(\d+)?([a-zA-Z]))/;

const keypress = (s = '', event = {}) => {
  let parts;
  let key = {
    name: event.name,
    ctrl: false,
    meta: false,
    shift: false,
    option: false,
    sequence: s,
    raw: s,
    ...event
  };

  if (Buffer.isBuffer(s)) {
    if (s[0] > 127 && s[1] === void 0) {
      s[0] -= 128;
      s = '\x1b' + String(s);
    } else {
      s = String(s);
    }
  } else if (s !== void 0 && typeof s !== 'string') {
    s = String(s);
  } else if (!s) {
    s = key.sequence || '';
  }

  key.sequence = key.sequence || s || key.name;

  if (s === '\r') {
    // carriage return
    key.raw = void 0;
    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 <= '\x1a') {
    // ctrl+letter
    key.name = String.fromCharCode(s.charCodeAt(0) + 'a'.charCodeAt(0) - 1);
    key.ctrl = true;
  } else if (s.length === 1 && s >= '0' && s <= '9') {
    // number
    key.name = 'number';
  } 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.meta = true;
    key.shift = /^[A-Z]$/.test(parts[1]);
  } else if ((parts = fnKeyRe.exec(s))) {
    let segs = [...s];

    if (segs[0] === '\u001b' && segs[1] === '\u001b') {
      key.option = true;
    }

    // ansi escape sequence
    // reassemble the key code leaving out leading \x1b's,
    // the modifier key bitflag and any meaningless "1;" sequence
    let code = [parts[1], parts[2], parts[4], parts[6]].filter(Boolean).join('');
    let 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;
      }
    }
  }
  return key;
};

keypress.listen = (stream, onKeypress) => {
  if (!stream || typeof stream.isRaw !== 'boolean') {
    throw new Error('Invalid stream passed');
  }

  let rl = readline.createInterface({ terminal: true, input: stream });
  readline.emitKeypressEvents(stream, rl);

  let on = (buf, key) => onKeypress(String(buf), keypress(buf, key), rl);
  let isRaw = stream.isRaw;

  stream.setRawMode(true);
  stream.on('keypress', on);
  rl.resume();

  let off = () => {
    stream.setRawMode(isRaw);
    stream.removeListener('keypress', on);
    rl.pause();
    rl.close();
  };

  return off;
};

keypress.action = (buf, key, customActions) => {
  let obj = { ...actions, ...customActions };
  if (key.ctrl) {
    key.action = obj.ctrl[key.name];
    return key;
  }

  if (key.option && obj.option) {
    key.action = obj.option[key.name];
    return key;
  }

  if (key.shift) {
    key.action = obj.shift[key.name];
    return key;
  }

  key.action = obj.keys[key.name];
  return key;
};

module.exports = keypress;