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package survey
import (
"bytes"
"errors"
"io"
"os"
"strings"
"unicode/utf8"
"github.com/AlecAivazis/survey/v2/core"
"github.com/AlecAivazis/survey/v2/terminal"
)
// DefaultAskOptions is the default options on ask, using the OS stdio.
func defaultAskOptions() *AskOptions {
return &AskOptions{
Stdio: terminal.Stdio{
In: os.Stdin,
Out: os.Stdout,
Err: os.Stderr,
},
PromptConfig: PromptConfig{
PageSize: 7,
HelpInput: "?",
SuggestInput: "tab",
Icons: IconSet{
Error: Icon{
Text: "X",
Format: "red",
},
Help: Icon{
Text: "?",
Format: "cyan",
},
Question: Icon{
Text: "?",
Format: "green+hb",
},
MarkedOption: Icon{
Text: "[x]",
Format: "green",
},
UnmarkedOption: Icon{
Text: "[ ]",
Format: "default+hb",
},
SelectFocus: Icon{
Text: ">",
Format: "cyan+b",
},
},
Filter: func(filter string, value string, index int) (include bool) {
filter = strings.ToLower(filter)
// include this option if it matches
return strings.Contains(strings.ToLower(value), filter)
},
KeepFilter: false,
ShowCursor: false,
RemoveSelectAll: false,
RemoveSelectNone: false,
HideCharacter: '*',
},
}
}
func defaultPromptConfig() *PromptConfig {
return &defaultAskOptions().PromptConfig
}
func defaultIcons() *IconSet {
return &defaultPromptConfig().Icons
}
// OptionAnswer is an ergonomic alias for core.OptionAnswer
type OptionAnswer = core.OptionAnswer
// Icon holds the text and format to show for a particular icon
type Icon struct {
Text string
Format string
}
// IconSet holds the icons to use for various prompts
type IconSet struct {
HelpInput Icon
Error Icon
Help Icon
Question Icon
MarkedOption Icon
UnmarkedOption Icon
SelectFocus Icon
}
// Validator is a function passed to a Question after a user has provided a response.
// If the function returns an error, then the user will be prompted again for another
// response.
type Validator func(ans interface{}) error
// Transformer is a function passed to a Question after a user has provided a response.
// The function can be used to implement a custom logic that will result to return
// a different representation of the given answer.
//
// Look `TransformString`, `ToLower` `Title` and `ComposeTransformers` for more.
type Transformer func(ans interface{}) (newAns interface{})
// Question is the core data structure for a survey questionnaire.
type Question struct {
Name string
Prompt Prompt
Validate Validator
Transform Transformer
}
// PromptConfig holds the global configuration for a prompt
type PromptConfig struct {
PageSize int
Icons IconSet
HelpInput string
SuggestInput string
Filter func(filter string, option string, index int) bool
KeepFilter bool
ShowCursor bool
RemoveSelectAll bool
RemoveSelectNone bool
HideCharacter rune
}
// Prompt is the primary interface for the objects that can take user input
// and return a response.
type Prompt interface {
Prompt(config *PromptConfig) (interface{}, error)
Cleanup(*PromptConfig, interface{}) error
Error(*PromptConfig, error) error
}
// PromptAgainer Interface for Prompts that support prompting again after invalid input
type PromptAgainer interface {
PromptAgain(config *PromptConfig, invalid interface{}, err error) (interface{}, error)
}
// AskOpt allows setting optional ask options.
type AskOpt func(options *AskOptions) error
// AskOptions provides additional options on ask.
type AskOptions struct {
Stdio terminal.Stdio
Validators []Validator
PromptConfig PromptConfig
}
// WithStdio specifies the standard input, output and error files survey
// interacts with. By default, these are os.Stdin, os.Stdout, and os.Stderr.
func WithStdio(in terminal.FileReader, out terminal.FileWriter, err io.Writer) AskOpt {
return func(options *AskOptions) error {
options.Stdio.In = in
options.Stdio.Out = out
options.Stdio.Err = err
return nil
}
}
// WithFilter specifies the default filter to use when asking questions.
func WithFilter(filter func(filter string, value string, index int) (include bool)) AskOpt {
return func(options *AskOptions) error {
// save the filter internally
options.PromptConfig.Filter = filter
return nil
}
}
// WithKeepFilter sets the if the filter is kept after selections
func WithKeepFilter(KeepFilter bool) AskOpt {
return func(options *AskOptions) error {
// set the page size
options.PromptConfig.KeepFilter = KeepFilter
// nothing went wrong
return nil
}
}
// WithRemoveSelectAll remove the select all option in Multiselect
func WithRemoveSelectAll() AskOpt {
return func(options *AskOptions) error {
options.PromptConfig.RemoveSelectAll = true
return nil
}
}
// WithRemoveSelectNone remove the select none/unselect all in Multiselect
func WithRemoveSelectNone() AskOpt {
return func(options *AskOptions) error {
options.PromptConfig.RemoveSelectNone = true
return nil
}
}
// WithValidator specifies a validator to use while prompting the user
func WithValidator(v Validator) AskOpt {
return func(options *AskOptions) error {
// add the provided validator to the list
options.Validators = append(options.Validators, v)
// nothing went wrong
return nil
}
}
type wantsStdio interface {
WithStdio(terminal.Stdio)
}
// WithPageSize sets the default page size used by prompts
func WithPageSize(pageSize int) AskOpt {
return func(options *AskOptions) error {
// set the page size
options.PromptConfig.PageSize = pageSize
// nothing went wrong
return nil
}
}
// WithHelpInput changes the character that prompts look for to give the user helpful information.
func WithHelpInput(r rune) AskOpt {
return func(options *AskOptions) error {
// set the input character
options.PromptConfig.HelpInput = string(r)
// nothing went wrong
return nil
}
}
// WithIcons sets the icons that will be used when prompting the user
func WithIcons(setIcons func(*IconSet)) AskOpt {
return func(options *AskOptions) error {
// update the default icons with whatever the user says
setIcons(&options.PromptConfig.Icons)
// nothing went wrong
return nil
}
}
// WithShowCursor sets the show cursor behavior when prompting the user
func WithShowCursor(ShowCursor bool) AskOpt {
return func(options *AskOptions) error {
// set the page size
options.PromptConfig.ShowCursor = ShowCursor
// nothing went wrong
return nil
}
}
// WithHideCharacter sets the default character shown instead of the password for password inputs
func WithHideCharacter(char rune) AskOpt {
return func(options *AskOptions) error {
// set the hide character
options.PromptConfig.HideCharacter = char
// nothing went wrong
return nil
}
}
/*
AskOne performs the prompt for a single prompt and asks for validation if required.
Response types should be something that can be casted from the response type designated
in the documentation. For example:
name := ""
prompt := &survey.Input{
Message: "name",
}
survey.AskOne(prompt, &name)
*/
func AskOne(p Prompt, response interface{}, opts ...AskOpt) error {
err := Ask([]*Question{{Prompt: p}}, response, opts...)
if err != nil {
return err
}
return nil
}
/*
Ask performs the prompt loop, asking for validation when appropriate. The response
type can be one of two options. If a struct is passed, the answer will be written to
the field whose name matches the Name field on the corresponding question. Field types
should be something that can be casted from the response type designated in the
documentation. Note, a survey tag can also be used to identify a Otherwise, a
map[string]interface{} can be passed, responses will be written to the key with the
matching name. For example:
qs := []*survey.Question{
{
Name: "name",
Prompt: &survey.Input{Message: "What is your name?"},
Validate: survey.Required,
Transform: survey.Title,
},
}
answers := struct{ Name string }{}
err := survey.Ask(qs, &answers)
*/
func Ask(qs []*Question, response interface{}, opts ...AskOpt) error {
// build up the configuration options
options := defaultAskOptions()
for _, opt := range opts {
if opt == nil {
continue
}
if err := opt(options); err != nil {
return err
}
}
// if we weren't passed a place to record the answers
if response == nil {
// we can't go any further
return errors.New("cannot call Ask() with a nil reference to record the answers")
}
validate := func(q *Question, val interface{}) error {
if q.Validate != nil {
if err := q.Validate(val); err != nil {
return err
}
}
for _, v := range options.Validators {
if err := v(val); err != nil {
return err
}
}
return nil
}
// go over every question
for _, q := range qs {
// If Prompt implements controllable stdio, pass in specified stdio.
if p, ok := q.Prompt.(wantsStdio); ok {
p.WithStdio(options.Stdio)
}
var ans interface{}
var validationErr error
// prompt and validation loop
for {
if validationErr != nil {
if err := q.Prompt.Error(&options.PromptConfig, validationErr); err != nil {
return err
}
}
var err error
if promptAgainer, ok := q.Prompt.(PromptAgainer); ok && validationErr != nil {
ans, err = promptAgainer.PromptAgain(&options.PromptConfig, ans, validationErr)
} else {
ans, err = q.Prompt.Prompt(&options.PromptConfig)
}
if err != nil {
return err
}
validationErr = validate(q, ans)
if validationErr == nil {
break
}
}
if q.Transform != nil {
// check if we have a transformer available, if so
// then try to acquire the new representation of the
// answer, if the resulting answer is not nil.
if newAns := q.Transform(ans); newAns != nil {
ans = newAns
}
}
// tell the prompt to cleanup with the validated value
if err := q.Prompt.Cleanup(&options.PromptConfig, ans); err != nil {
return err
}
// add it to the map
if err := core.WriteAnswer(response, q.Name, ans); err != nil {
return err
}
}
// return the response
return nil
}
// paginate returns a single page of choices given the page size, the total list of
// possible choices, and the current selected index in the total list.
func paginate(pageSize int, choices []core.OptionAnswer, sel int) ([]core.OptionAnswer, int) {
var start, end, cursor int
if len(choices) < pageSize {
// if we dont have enough options to fill a page
start = 0
end = len(choices)
cursor = sel
} else if sel < pageSize/2 {
// if we are in the first half page
start = 0
end = pageSize
cursor = sel
} else if len(choices)-sel-1 < pageSize/2 {
// if we are in the last half page
start = len(choices) - pageSize
end = len(choices)
cursor = sel - start
} else {
// somewhere in the middle
above := pageSize / 2
below := pageSize - above
cursor = pageSize / 2
start = sel - above
end = sel + below
}
// return the subset we care about and the index
return choices[start:end], cursor
}
type IterableOpts interface {
IterateOption(int, core.OptionAnswer) interface{}
}
func computeCursorOffset(tmpl string, data IterableOpts, opts []core.OptionAnswer, idx, tWidth int) int {
tmpls, err := core.GetTemplatePair(tmpl)
if err != nil {
return 0
}
t := tmpls[0]
renderOpt := func(ix int, opt core.OptionAnswer) string {
var buf bytes.Buffer
_ = t.ExecuteTemplate(&buf, "option", data.IterateOption(ix, opt))
return buf.String()
}
offset := len(opts) - idx
for i, o := range opts {
if i < idx {
continue
}
renderedOpt := renderOpt(i, o)
valWidth := utf8.RuneCount([]byte(renderedOpt))
if valWidth > tWidth {
splitCount := valWidth / tWidth
if valWidth%tWidth == 0 {
splitCount -= 1
}
offset += splitCount
}
}
return offset
}
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