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gcz/survey/renderer.go

195 lines
4.9 KiB

package survey
import (
"bytes"
"fmt"
"git.yaojiankang.top/hupeh/gcz/survey/core"
"git.yaojiankang.top/hupeh/gcz/survey/terminal"
"golang.org/x/term"
)
type Renderer struct {
stdio terminal.Stdio
renderedErrors bytes.Buffer
renderedText bytes.Buffer
}
type ErrorTemplateData struct {
Error error
Icon Icon
}
var ErrorTemplate = `{{color .Icon.Format }}{{ .Icon.Text }} Sorry, your reply was invalid: {{ .Error.Error }}{{color "reset"}}
`
func (r *Renderer) WithStdio(stdio terminal.Stdio) {
r.stdio = stdio
}
func (r *Renderer) Stdio() terminal.Stdio {
return r.stdio
}
func (r *Renderer) NewRuneReader() *terminal.RuneReader {
return terminal.NewRuneReader(r.stdio)
}
func (r *Renderer) NewCursor() *terminal.Cursor {
return &terminal.Cursor{
In: r.stdio.In,
Out: r.stdio.Out,
}
}
func (r *Renderer) Error(config *PromptConfig, invalid error) error {
// cleanup the currently rendered errors
r.resetPrompt(r.countLines(r.renderedErrors))
r.renderedErrors.Reset()
// cleanup the rest of the prompt
r.resetPrompt(r.countLines(r.renderedText))
r.renderedText.Reset()
userOut, layoutOut, err := core.RunTemplate(ErrorTemplate, &ErrorTemplateData{
Error: invalid,
Icon: config.Icons.Error,
})
if err != nil {
return err
}
// send the message to the user
if _, err := fmt.Fprint(terminal.NewAnsiStdout(r.stdio.Out), userOut); err != nil {
return err
}
// add the printed text to the rendered error buffer so we can cleanup later
r.appendRenderedError(layoutOut)
return nil
}
func (r *Renderer) OffsetCursor(offset int) {
cursor := r.NewCursor()
for offset > 0 {
cursor.PreviousLine(1)
offset--
}
}
func (r *Renderer) Render(tmpl string, data interface{}) error {
// cleanup the currently rendered text
lineCount := r.countLines(r.renderedText)
r.resetPrompt(lineCount)
r.renderedText.Reset()
// render the template summarizing the current state
userOut, layoutOut, err := core.RunTemplate(tmpl, data)
if err != nil {
return err
}
// print the summary
if _, err := fmt.Fprint(terminal.NewAnsiStdout(r.stdio.Out), userOut); err != nil {
return err
}
// add the printed text to the rendered text buffer so we can cleanup later
r.AppendRenderedText(layoutOut)
// nothing went wrong
return nil
}
func (r *Renderer) RenderWithCursorOffset(tmpl string, data IterableOpts, opts []core.OptionAnswer, idx int) error {
cursor := r.NewCursor()
cursor.Restore() // clear any accessibility offsetting
if err := r.Render(tmpl, data); err != nil {
return err
}
cursor.Save()
offset := computeCursorOffset(MultiSelectQuestionTemplate, data, opts, idx, r.termWidthSafe())
r.OffsetCursor(offset)
return nil
}
// appendRenderedError appends text to the renderer's error buffer
// which is used to track what has been printed. It is not exported
// as errors should only be displayed via Error(config, error).
func (r *Renderer) appendRenderedError(text string) {
r.renderedErrors.WriteString(text)
}
// AppendRenderedText appends text to the renderer's text buffer
// which is used to track of what has been printed. The buffer is used
// to calculate how many lines to erase before updating the prompt.
func (r *Renderer) AppendRenderedText(text string) {
r.renderedText.WriteString(text)
}
func (r *Renderer) resetPrompt(lines int) {
// clean out current line in case tmpl didnt end in newline
cursor := r.NewCursor()
cursor.HorizontalAbsolute(0)
terminal.EraseLine(r.stdio.Out, terminal.ERASE_LINE_ALL)
// clean up what we left behind last time
for i := 0; i < lines; i++ {
cursor.PreviousLine(1)
terminal.EraseLine(r.stdio.Out, terminal.ERASE_LINE_ALL)
}
}
func (r *Renderer) termWidth() (int, error) {
fd := int(r.stdio.Out.Fd())
termWidth, _, err := term.GetSize(fd)
return termWidth, err
}
func (r *Renderer) termWidthSafe() int {
w, err := r.termWidth()
if err != nil || w == 0 {
// if we got an error due to terminal.GetSize not being supported
// on current platform then just assume a very wide terminal
w = 10000
}
return w
}
// countLines will return the count of `\n` with the addition of any
// lines that have wrapped due to narrow terminal width
func (r *Renderer) countLines(buf bytes.Buffer) int {
w := r.termWidthSafe()
bufBytes := buf.Bytes()
count := 0
curr := 0
for curr < len(bufBytes) {
var delim int
// read until the next newline or the end of the string
relDelim := bytes.IndexRune(bufBytes[curr:], '\n')
if relDelim != -1 {
count += 1 // new line found, add it to the count
delim = curr + relDelim
} else {
delim = len(bufBytes) // no new line found, read rest of text
}
str := string(bufBytes[curr:delim])
if lineWidth := terminal.StringWidth(str); lineWidth > w {
// account for word wrapping
count += lineWidth / w
if (lineWidth % w) == 0 {
// content whose width is exactly a multiplier of available width should not
// count as having wrapped on the last line
count -= 1
}
}
curr = delim + 1
}
return count
}