/**

* @license Apache-2.0

*

* Copyright (c) 2024 The Stdlib Authors.

*

* Licensed under the Apache License, Version 2.0 (the "License");

* you may not use this file except in compliance with the License.

* You may obtain a copy of the License at

*

* http://www.apache.org/licenses/LICENSE-2.0

*

* Unless required by applicable law or agreed to in writing, software

* distributed under the License is distributed on an "AS IS" BASIS,

* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

* See the License for the specific language governing permissions and

* limitations under the License.

*/

'use strict';

// MODULES //

var hasOwnProp = require( '@stdlib/assert/has-own-property' );

var pick = require( '@stdlib/utils/pick' );

var containsFactory = require( '@stdlib/array/base/assert/contains' ).factory;

var isUndefined = require( '@stdlib/assert/is-undefined' );

// VARIABLES //

// Control sequence prefix in ALT combinations:

var ALT_CSI = '\u001B';

// Properties in parsed keybinding:

var KEYBINDING_PROPS = [ 'name', 'ctrl', 'shift', 'meta' ];

/**

* Asserts if a sequence is an unrecognized symbol.

*

* ## Notes

*

* - `SHIFT+<symbol>` will result in a keybinding with the name of the resulting symbol and not the original symbol with shift enabled.

*

* @private

* @name isUnrecognizedSymbol

* @type {Function}

*/

var isUnrecognizedSymbol = containsFactory([

'`',

'~',

'!',

'@',

'#',

'$',

'%',

'^',

'&',

'*',

'(',

')',

'-',

'_',

'=',

'+',

'{',

'}',

'[',

']',

'|',

'\\',

':',

';',

'"',

'\'',

'<',

',',

'>',

'.',

'?',

'/'

]);

/**

* Table mapping unrecognized control sequences to their possible key objects.

*

* ## Notes

*

* - The following map is recorded as observed in gnome.

*

* @private

* @name CTRL_SEQUENCES_KEYMAP

* @type {Object}

*/

var CTRL_SEQUENCES_KEYMAP = {

'\u001F': [

{

'name': '/',

'ctrl': true,

'shift': false,

'meta': false

},

{

'name': '-',

'ctrl': true,

'shift': false,

'meta': true

},

{

'name': '7',

'ctrl': true,

'shift': false,

'meta': true

}

],

'\u001C': [

{

'name': '\\',

'ctrl': true,

'shift': false,

'meta': false

},

{

'name': '\\',

'ctrl': true,

'shift': true,

'meta': false

},

{

'name': '|',

'ctrl': true,

'shift': false,

'meta': false

},

{

'name': '4',

'ctrl': true,

'shift': false,

'meta': false

}

],

'\u001D': [

{

'name': ']',

'ctrl': true,

'shift': false,

'meta': false

},

{

'name': ']',

'ctrl': true,

'shift': true,

'meta': false

},

{

'name': '}',

'ctrl': true,

'shift': false,

'meta': false

},

{

'name': '5',

'ctrl': true,

'shift': false,

'meta': false

}

],

'\u001E': [

{

'name': '6',

'ctrl': true,

'shift': false,

'meta': false

},

{

'name': '6',

'ctrl': true,

'shift': true,

'meta': false

},

{

'name': '^',

'ctrl': true,

'shift': false,

'meta': false

}

]

};

// FUNCTIONS //

/**

* Parses unrecognized control sequences emitted by `ALT+<symbol>` combinations.

*

* @private

* @param {string} seq - control sequence

* @returns {(Object|null)} parsed key object or null if not a meta symbol sequence

*/

function parseMetaSymbolSequence( seq ) {

if (

!seq ||

seq.length !== 2 ||

seq[ 0 ] !== ALT_CSI ||

isUnrecognizedSymbol( seq[ 1 ] )

) {

return null;

}

return {

'name': seq[ 1 ],

'ctrl': false,

'shift': false,

'meta': true

};

}

// MAIN //

/**

* Parses a readline keypress object.

*

* @param {Object} key - readline keypress object

* @returns {Array<Object>} list of possible key objects

*/

function parseKey( key ) {

var out;

var seq;

// If key is already defined, no need to parse it...

if ( !isUndefined( key.name ) ) {

return [ pick( key, KEYBINDING_PROPS ) ];

}

seq = key.sequence;

// Check if it's an unrecognized symbol:

if ( isUnrecognizedSymbol( seq ) ) {

return [

{

'name': seq,

'ctrl': false,

'shift': false,

'meta': false

}

];

}

// Check if it's a `CTRL+<symbol>` combination:

if ( hasOwnProp( CTRL_SEQUENCES_KEYMAP, seq ) ) {

return CTRL_SEQUENCES_KEYMAP[ seq ];

}

// Check if it's a `META+<symbol>` combination:

out = parseMetaSymbolSequence( seq );

if ( out ) {

return [ out ];

}

return [ pick( key, KEYBINDING_PROPS ) ]; // couldn't parse, return original key

}

// EXPORTS //

module.exports = parseKey;