key_map.go

package prompt

import (
	"fmt"
	"sort"
	"strings"
)

// KeyMap can be used to customize or define the behavior of the Prompt for each
// special Key sequences that is entered by the User.
type KeyMap struct {
	AutoComplete AutoCompleteKeyMap
	Insert       InsertKeyMap

	errors []error
}

// KeyMapDefault uses KeyMapSingleLine as the default key-map.
var KeyMapDefault = KeyMapSingleLine

// KeyMapSingleLine defines sane key sequences for each supported action for a
// prompt that supports single-line inputs. Quite a few of these are the default
// short-cuts in BASH.
var KeyMapSingleLine = KeyMap{
	AutoComplete: AutoCompleteKeyMap{
		ChooseNext:     KeySequences{ArrowDown},
		ChoosePrevious: KeySequences{ArrowUp},
		Select:         KeySequences{Tab},
	},
	Insert: InsertKeyMap{
		Abort:                  KeySequences{CtrlC, CtrlD, Escape},
		AutoComplete:           KeySequences{CtrlSpace},
		DeleteCharCurrent:      KeySequences{Delete},
		DeleteCharPrevious:     KeySequences{Backspace, CtrlH},
		DeleteWordNext:         KeySequences{AltD},
		DeleteWordPrevious:     KeySequences{CtrlW},
		EraseEverything:        KeySequences{AltW},
		EraseToBeginningOfLine: KeySequences{CtrlU},
		EraseToEndOfLine:       KeySequences{CtrlK},
		HistoryNext:            KeySequences{ArrowDown},
		HistoryPrevious:        KeySequences{ArrowUp},
		MakeWordCapitalCase:    KeySequences{AltC},
		MakeWordLowerCase:      KeySequences{AltL},
		MakeWordUpperCase:      KeySequences{AltU},
		MoveDownOneLine:        KeySequences{},
		MoveLeftOneCharacter:   KeySequences{ArrowLeft},
		MoveRightOneCharacter:  KeySequences{ArrowRight},
		MoveToBeginning:        KeySequences{CtrlHome},
		MoveToBeginningOfLine:  KeySequences{Home},
		MoveToEnd:              KeySequences{CtrlEnd},
		MoveToEndOfLine:        KeySequences{End},
		MoveToWordNext:         KeySequences{CtrlArrowRight, AltF},
		MoveToWordPrevious:     KeySequences{CtrlArrowLeft, AltB},
		MoveUpOneLine:          KeySequences{},
		SwapCharacterNext:      KeySequences{CtrlN},
		SwapCharacterPrevious:  KeySequences{CtrlT},
		SwapWordNext:           KeySequences{AltN},
		SwapWordPrevious:       KeySequences{AltT},
		Terminate:              KeySequences{Enter},
	},
}

// KeyMapMultiLine defines sane key sequences for each supported action for a
// prompt that supports multi-line inputs.
var KeyMapMultiLine = KeyMap{
	AutoComplete: AutoCompleteKeyMap{
		ChooseNext:     KeySequences{ArrowDown},
		ChoosePrevious: KeySequences{ArrowUp},
		Select:         KeySequences{Tab},
	},
	Insert: InsertKeyMap{
		Abort:                  KeySequences{CtrlC, CtrlD, Escape},
		AutoComplete:           KeySequences{CtrlSpace},
		DeleteCharCurrent:      KeySequences{Delete},
		DeleteCharPrevious:     KeySequences{Backspace, CtrlH},
		DeleteWordNext:         KeySequences{AltD},
		DeleteWordPrevious:     KeySequences{CtrlW},
		EraseEverything:        KeySequences{AltW},
		EraseToBeginningOfLine: KeySequences{CtrlU},
		EraseToEndOfLine:       KeySequences{CtrlK},
		HistoryNext:            KeySequences{ShiftArrowDown},
		HistoryPrevious:        KeySequences{ShiftArrowUp},
		MakeWordCapitalCase:    KeySequences{AltC},
		MakeWordLowerCase:      KeySequences{AltL},
		MakeWordUpperCase:      KeySequences{AltU},
		MoveDownOneLine:        KeySequences{ArrowDown},
		MoveLeftOneCharacter:   KeySequences{ArrowLeft},
		MoveRightOneCharacter:  KeySequences{ArrowRight},
		MoveToBeginning:        KeySequences{CtrlHome},
		MoveToBeginningOfLine:  KeySequences{Home},
		MoveToEnd:              KeySequences{CtrlEnd},
		MoveToEndOfLine:        KeySequences{End},
		MoveToWordNext:         KeySequences{CtrlArrowRight, AltF},
		MoveToWordPrevious:     KeySequences{CtrlArrowLeft, AltB},
		MoveUpOneLine:          KeySequences{ArrowUp},
		SwapCharacterNext:      KeySequences{CtrlN},
		SwapCharacterPrevious:  KeySequences{CtrlT},
		SwapWordNext:           KeySequences{AltN},
		SwapWordPrevious:       KeySequences{AltT},
		Terminate:              KeySequences{Enter},
	},
}

// AutoCompleteKeyMap is the KeyMap used in AutoComplete mode.
type AutoCompleteKeyMap struct {
	ChooseNext     KeySequences
	ChoosePrevious KeySequences
	Select         KeySequences
}

// InsertKeyMap is the KeyMap used in Insert mode.
type InsertKeyMap struct {
	Abort                  KeySequences
	AutoComplete           KeySequences
	DeleteCharCurrent      KeySequences
	DeleteCharPrevious     KeySequences
	DeleteWordNext         KeySequences
	DeleteWordPrevious     KeySequences
	EraseEverything        KeySequences
	EraseToBeginningOfLine KeySequences
	EraseToEndOfLine       KeySequences
	HistoryNext            KeySequences
	HistoryPrevious        KeySequences
	MakeWordCapitalCase    KeySequences
	MakeWordLowerCase      KeySequences
	MakeWordUpperCase      KeySequences
	MoveDownOneLine        KeySequences
	MoveLeftOneCharacter   KeySequences
	MoveRightOneCharacter  KeySequences
	MoveToBeginning        KeySequences
	MoveToBeginningOfLine  KeySequences
	MoveToEnd              KeySequences
	MoveToEndOfLine        KeySequences
	MoveToWordNext         KeySequences
	MoveToWordPrevious     KeySequences
	MoveUpOneLine          KeySequences
	SwapCharacterNext      KeySequences
	SwapCharacterPrevious  KeySequences
	SwapWordNext           KeySequences
	SwapWordPrevious       KeySequences
	Terminate              KeySequences
}

// keyMapReversed is an internal representation of the KeyMap for easy
// programmatic access when acting on key sequences.
type keyMapReversed struct {
	AutoComplete map[KeySequence]Action
	Insert       map[KeySequence]Action
}

func (k *KeyMap) reverse() (*keyMapReversed, error) {
	rsp := &keyMapReversed{
		AutoComplete: make(map[KeySequence]Action),
		Insert:       make(map[KeySequence]Action),
	}

	k.errors = make([]error, 0)
	k.reverseAddKeySequences(rsp.AutoComplete, k.AutoComplete.ChooseNext, AutoCompleteChooseNext)
	k.reverseAddKeySequences(rsp.AutoComplete, k.AutoComplete.ChoosePrevious, AutoCompleteChoosePrevious)
	k.reverseAddKeySequences(rsp.AutoComplete, k.AutoComplete.Select, AutoCompleteSelect)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.Abort, Abort)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.AutoComplete, AutoComplete)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.DeleteCharCurrent, DeleteCharCurrent)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.DeleteCharPrevious, DeleteCharPrevious)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.DeleteWordNext, DeleteWordNext)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.DeleteWordPrevious, DeleteWordPrevious)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.EraseEverything, EraseEverything)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.EraseToBeginningOfLine, EraseToBeginningOfLine)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.EraseToEndOfLine, EraseToEndOfLine)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.HistoryNext, HistoryNext)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.HistoryPrevious, HistoryPrevious)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.MakeWordCapitalCase, MakeWordCapitalCase)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.MakeWordLowerCase, MakeWordLowerCase)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.MakeWordUpperCase, MakeWordUpperCase)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.MoveDownOneLine, MoveDownOneLine)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.MoveLeftOneCharacter, MoveLeftOneCharacter)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.MoveRightOneCharacter, MoveRightOneCharacter)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.MoveToBeginning, MoveToBeginning)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.MoveToBeginningOfLine, MoveToBeginningOfLine)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.MoveToEnd, MoveToEnd)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.MoveToEndOfLine, MoveToEndOfLine)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.MoveToWordNext, MoveToWordNext)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.MoveToWordPrevious, MoveToWordPrevious)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.MoveUpOneLine, MoveUpOneLine)
	k.reverseAddKeySequences(rsp.Insert, k.Insert.Terminate, Terminate)
	if len(k.errors) > 0 {
		errStrings := make([]string, len(k.errors))
		for idx, err := range k.errors {
			errStrings[idx] = fmt.Sprintf("- %v", err.Error())
		}
		sort.Strings(errStrings)

		return nil, fmt.Errorf("possible %w:\n%v", ErrDuplicateKeyAssignment, strings.Join(errStrings, "\n"))
	}

	return rsp, nil
}

func (k *KeyMap) reverseAddKeySequences(m map[KeySequence]Action, keySequences KeySequences, action Action) {
	for _, keySequence := range keySequences {
		if existingAction, ok := m[keySequence]; ok {
			k.errors = append(k.errors, fmt.Errorf(
				"more than one action defined for '%v': [%v, %v]",
				keySequence, existingAction, action,
			))
		}
		m[keySequence] = action
	}
}