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gcz/survey/select.go

330 lines
8.9 KiB

package survey
import (
"errors"
"fmt"
"git.yaojiankang.top/hupeh/gcz/survey/core"
"git.yaojiankang.top/hupeh/gcz/survey/terminal"
)
/*
Select is a prompt that presents a list of various options to the user
for them to select using the arrow keys and enter. Response type is a string.
color := ""
prompt := &survey.Select{
Message: "Choose a color:",
Options: []string{"red", "blue", "green"},
}
survey.AskOne(prompt, &color)
*/
type Select struct {
Renderer
Message string
Options []string
Default interface{}
Help string
PageSize int
VimMode bool
FilterMessage string
Filter func(filter string, value string, index int) bool
Description func(value string, index int) string
filter string
selectedIndex int
showingHelp bool
}
// SelectTemplateData is the data available to the templates when processing
type SelectTemplateData struct {
Select
PageEntries []core.OptionAnswer
SelectedIndex int
Answer string
ShowAnswer bool
ShowHelp bool
Description func(value string, index int) string
Config *PromptConfig
// These fields are used when rendering an individual option
CurrentOpt core.OptionAnswer
CurrentIndex int
}
// IterateOption sets CurrentOpt and CurrentIndex appropriately so a select option can be rendered individually
func (s SelectTemplateData) IterateOption(ix int, opt core.OptionAnswer) interface{} {
copy := s
copy.CurrentIndex = ix
copy.CurrentOpt = opt
return copy
}
func (s SelectTemplateData) GetDescription(opt core.OptionAnswer) string {
if s.Description == nil {
return ""
}
return s.Description(opt.Value, opt.Index)
}
var SelectQuestionTemplate = `
{{- define "option"}}
{{- if eq .SelectedIndex .CurrentIndex }}{{color .Config.Icons.SelectFocus.Format }}{{ .Config.Icons.SelectFocus.Text }} {{else}}{{color "default"}} {{end}}
{{- .CurrentOpt.Value}}{{ if ne ($.GetDescription .CurrentOpt) "" }} - {{color "cyan"}}{{ $.GetDescription .CurrentOpt }}{{end}}
{{- color "reset"}}
{{end}}
{{- if .ShowHelp }}{{- color .Config.Icons.Help.Format }}{{ .Config.Icons.Help.Text }} {{ .Help }}{{color "reset"}}{{"\n"}}{{end}}
{{- color .Config.Icons.Question.Format }}{{ .Config.Icons.Question.Text }} {{color "reset"}}
{{- color "default+hb"}}{{ .Message }}{{ .FilterMessage }}{{color "reset"}}
{{- if .ShowAnswer}}{{color "cyan"}} {{.Answer}}{{color "reset"}}{{"\n"}}
{{- else}}
{{- " "}}{{- color "cyan"}}[Use arrows to move, type to filter{{- if and .Help (not .ShowHelp)}}, {{ .Config.HelpInput }} for more help{{end}}]{{color "reset"}}
{{- "\n"}}
{{- range $ix, $option := .PageEntries}}
{{- template "option" $.IterateOption $ix $option}}
{{- end}}
{{- end}}`
// OnChange is called on every keypress.
func (s *Select) OnChange(key rune, config *PromptConfig) bool {
options := s.filterOptions(config)
oldFilter := s.filter
// if the user pressed the enter key and the index is a valid option
if key == terminal.KeyEnter || key == '\n' {
// if the selected index is a valid option
if len(options) > 0 && s.selectedIndex < len(options) {
// we're done (stop prompting the user)
return true
}
// we're not done (keep prompting)
return false
// if the user pressed the up arrow or 'k' to emulate vim
} else if (key == terminal.KeyArrowUp || (s.VimMode && key == 'k')) && len(options) > 0 {
// if we are at the top of the list
if s.selectedIndex == 0 {
// start from the button
s.selectedIndex = len(options) - 1
} else {
// otherwise we are not at the top of the list so decrement the selected index
s.selectedIndex--
}
// if the user pressed down or 'j' to emulate vim
} else if (key == terminal.KeyTab || key == terminal.KeyArrowDown || (s.VimMode && key == 'j')) && len(options) > 0 {
// if we are at the bottom of the list
if s.selectedIndex == len(options)-1 {
// start from the top
s.selectedIndex = 0
} else {
// increment the selected index
s.selectedIndex++
}
// only show the help message if we have one
} else if string(key) == config.HelpInput && s.Help != "" {
s.showingHelp = true
// if the user wants to toggle vim mode on/off
} else if key == terminal.KeyEscape {
s.VimMode = !s.VimMode
// if the user hits any of the keys that clear the filter
} else if key == terminal.KeyDeleteWord || key == terminal.KeyDeleteLine {
s.filter = ""
// if the user is deleting a character in the filter
} else if key == terminal.KeyDelete || key == terminal.KeyBackspace {
// if there is content in the filter to delete
if s.filter != "" {
runeFilter := []rune(s.filter)
// subtract a line from the current filter
s.filter = string(runeFilter[0 : len(runeFilter)-1])
// we removed the last value in the filter
}
} else if key >= terminal.KeySpace {
s.filter += string(key)
// make sure vim mode is disabled
s.VimMode = false
}
s.FilterMessage = ""
if s.filter != "" {
s.FilterMessage = " " + s.filter
}
if oldFilter != s.filter {
// filter changed
options = s.filterOptions(config)
if len(options) > 0 && len(options) <= s.selectedIndex {
s.selectedIndex = len(options) - 1
}
}
// figure out the options and index to render
// figure out the page size
pageSize := s.PageSize
// if we dont have a specific one
if pageSize == 0 {
// grab the global value
pageSize = config.PageSize
}
// TODO if we have started filtering and were looking at the end of a list
// and we have modified the filter then we should move the page back!
opts, idx := paginate(pageSize, options, s.selectedIndex)
tmplData := SelectTemplateData{
Select: *s,
SelectedIndex: idx,
ShowHelp: s.showingHelp,
Description: s.Description,
PageEntries: opts,
Config: config,
}
// render the options
_ = s.RenderWithCursorOffset(SelectQuestionTemplate, tmplData, opts, idx)
// keep prompting
return false
}
func (s *Select) filterOptions(config *PromptConfig) []core.OptionAnswer {
// the filtered list
answers := []core.OptionAnswer{}
// if there is no filter applied
if s.filter == "" {
return core.OptionAnswerList(s.Options)
}
// the filter to apply
filter := s.Filter
if filter == nil {
filter = config.Filter
}
for i, opt := range s.Options {
// i the filter says to include the option
if filter(s.filter, opt, i) {
answers = append(answers, core.OptionAnswer{
Index: i,
Value: opt,
})
}
}
// return the list of answers
return answers
}
func (s *Select) Prompt(config *PromptConfig) (interface{}, error) {
// if there are no options to render
if len(s.Options) == 0 {
// we failed
return "", errors.New("please provide options to select from")
}
s.selectedIndex = 0
if s.Default != nil {
switch defaultValue := s.Default.(type) {
case string:
var found bool
for i, opt := range s.Options {
if opt == defaultValue {
s.selectedIndex = i
found = true
}
}
if !found {
return "", fmt.Errorf("default value %q not found in options", defaultValue)
}
case int:
if defaultValue >= len(s.Options) {
return "", fmt.Errorf("default index %d exceeds the number of options", defaultValue)
}
s.selectedIndex = defaultValue
default:
return "", errors.New("default value of select must be an int or string")
}
}
// figure out the page size
pageSize := s.PageSize
// if we dont have a specific one
if pageSize == 0 {
// grab the global value
pageSize = config.PageSize
}
// figure out the options and index to render
opts, idx := paginate(pageSize, core.OptionAnswerList(s.Options), s.selectedIndex)
cursor := s.NewCursor()
cursor.Save() // for proper cursor placement during selection
cursor.Hide() // hide the cursor
defer cursor.Show() // show the cursor when we're done
defer cursor.Restore() // clear any accessibility offsetting on exit
tmplData := SelectTemplateData{
Select: *s,
SelectedIndex: idx,
Description: s.Description,
ShowHelp: s.showingHelp,
PageEntries: opts,
Config: config,
}
// ask the question
err := s.RenderWithCursorOffset(SelectQuestionTemplate, tmplData, opts, idx)
if err != nil {
return "", err
}
rr := s.NewRuneReader()
_ = rr.SetTermMode()
defer func() {
_ = rr.RestoreTermMode()
}()
// start waiting for input
for {
r, _, err := rr.ReadRune()
if err != nil {
return "", err
}
if r == terminal.KeyInterrupt {
return "", terminal.InterruptErr
}
if r == terminal.KeyEndTransmission {
break
}
if s.OnChange(r, config) {
break
}
}
options := s.filterOptions(config)
s.filter = ""
s.FilterMessage = ""
if s.selectedIndex < len(options) {
return options[s.selectedIndex], err
}
return options[0], err
}
func (s *Select) Cleanup(config *PromptConfig, val interface{}) error {
cursor := s.NewCursor()
cursor.Restore()
return s.Render(
SelectQuestionTemplate,
SelectTemplateData{
Select: *s,
Answer: val.(core.OptionAnswer).Value,
ShowAnswer: true,
Description: s.Description,
Config: config,
},
)
}