go-prompt/completion.go

196 lines
4.5 KiB
Go

package prompt
import (
"log"
"strings"
"github.com/mattn/go-runewidth"
)
const (
shortenSuffix = "..."
leftPrefix = " "
leftSuffix = " "
rightPrefix = " "
rightSuffix = " "
)
var (
leftMargin = runewidth.StringWidth(leftPrefix + leftSuffix)
rightMargin = runewidth.StringWidth(rightPrefix + rightSuffix)
completionMargin = leftMargin + rightMargin
)
// Suggest is printed when completing.
type Suggest struct {
Text string
Description string
}
// CompletionManager manages which suggestion is now selected.
type CompletionManager struct {
selected int // -1 means nothing one is selected.
tmp []Suggest
max uint16
completer Completer
verticalScroll int
wordSeparator string
showAtStart bool
}
// GetSelectedSuggestion returns the selected item.
func (c *CompletionManager) GetSelectedSuggestion() (s Suggest, ok bool) {
if c.selected == -1 {
return Suggest{}, false
} else if c.selected < -1 {
log.Printf("[ERROR] shoud be reached here, selected=%d", c.selected)
c.selected = -1
return Suggest{}, false
}
return c.tmp[c.selected], true
}
// GetSuggestions returns the list of suggestion.
func (c *CompletionManager) GetSuggestions() []Suggest {
return c.tmp
}
// Reset to select nothing.
func (c *CompletionManager) Reset() {
c.selected = -1
c.verticalScroll = 0
c.Update(*NewDocument())
return
}
// Update to update the suggestions.
func (c *CompletionManager) Update(in Document) {
c.tmp = c.completer(in)
return
}
// Previous to select the previous suggestion item.
func (c *CompletionManager) Previous() {
if c.verticalScroll == c.selected && c.selected > 0 {
c.verticalScroll--
}
c.selected--
c.update()
return
}
// Next to select the next suggestion item.
func (c *CompletionManager) Next() {
if c.verticalScroll+int(c.max)-1 == c.selected {
c.verticalScroll++
}
c.selected++
c.update()
return
}
// Completing returns whether the CompletionManager selects something one.
func (c *CompletionManager) Completing() bool {
return c.selected != -1
}
func (c *CompletionManager) update() {
max := int(c.max)
if len(c.tmp) < max {
max = len(c.tmp)
}
if c.selected >= len(c.tmp) {
c.Reset()
} else if c.selected < -1 {
c.selected = len(c.tmp) - 1
c.verticalScroll = len(c.tmp) - max
}
}
func deleteBreakLineCharacters(s string) string {
s = strings.Replace(s, "\n", "", -1)
s = strings.Replace(s, "\r", "", -1)
return s
}
func formatTexts(o []string, max int, prefix, suffix string) (new []string, width int) {
l := len(o)
n := make([]string, l)
lenPrefix := runewidth.StringWidth(prefix)
lenSuffix := runewidth.StringWidth(suffix)
lenShorten := runewidth.StringWidth(shortenSuffix)
min := lenPrefix + lenSuffix + lenShorten
for i := 0; i < l; i++ {
o[i] = deleteBreakLineCharacters(o[i])
w := runewidth.StringWidth(o[i])
if width < w {
width = w
}
}
if width == 0 {
return n, 0
}
if min >= max {
log.Println("[WARN] formatTexts: max is lower than length of prefix and suffix.")
return n, 0
}
if lenPrefix+width+lenSuffix > max {
width = max - lenPrefix - lenSuffix
}
for i := 0; i < l; i++ {
x := runewidth.StringWidth(o[i])
if x <= width {
spaces := strings.Repeat(" ", width-x)
n[i] = prefix + o[i] + spaces + suffix
} else if x > width {
x := runewidth.Truncate(o[i], width, shortenSuffix)
// When calling runewidth.Truncate("您好xxx您好xxx", 11, "...") returns "您好xxx..."
// But the length of this result is 10. So we need fill right using runewidth.FillRight.
n[i] = prefix + runewidth.FillRight(x, width) + suffix
}
}
return n, lenPrefix + width + lenSuffix
}
func formatSuggestions(suggests []Suggest, max int) (new []Suggest, width int) {
num := len(suggests)
new = make([]Suggest, num)
left := make([]string, num)
for i := 0; i < num; i++ {
left[i] = suggests[i].Text
}
right := make([]string, num)
for i := 0; i < num; i++ {
right[i] = suggests[i].Description
}
left, leftWidth := formatTexts(left, max, leftPrefix, leftSuffix)
if leftWidth == 0 {
return []Suggest{}, 0
}
right, rightWidth := formatTexts(right, max-leftWidth, rightPrefix, rightSuffix)
for i := 0; i < num; i++ {
new[i] = Suggest{Text: left[i], Description: right[i]}
}
return new, leftWidth + rightWidth
}
// NewCompletionManager returns initialized CompletionManager object.
func NewCompletionManager(completer Completer, max uint16) *CompletionManager {
return &CompletionManager{
selected: -1,
max: max,
completer: completer,
verticalScroll: 0,
}
}