/
layout.go
475 lines (409 loc) · 11.7 KB
/
layout.go
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package peco
import (
"fmt"
"sync"
"time"
"unicode/utf8"
"github.com/mattn/go-runewidth"
"github.com/nsf/termbox-go"
)
// LayoutType describes the types of layout that peco can take
type LayoutType string
const (
// LayoutTypeTopDown is the default. All the items read from top to bottom
LayoutTypeTopDown = "top-down"
// LayoutTypeBottomUp changes the layout to read from bottom to up
LayoutTypeBottomUp = "bottom-up"
)
// IsValidLayoutType checks if a string is a supported layout type
func IsValidLayoutType(v LayoutType) bool {
return v == LayoutTypeTopDown || v == LayoutTypeBottomUp
}
// VerticalAnchor describes the direction to which elements in the
// layout are anchored to
type VerticalAnchor int
const (
// AnchorTop anchors elements towards the top of the screen
AnchorTop VerticalAnchor = iota + 1
// AnchorBottom anchors elements towards the bottom of the screen
AnchorBottom
)
// IsValidVerticalAnchor checks if the specified anchor is supported
func IsValidVerticalAnchor(anchor VerticalAnchor) bool {
return anchor == AnchorTop || anchor == AnchorBottom
}
// Layout represents the component that controls where elements are placed on screen
type Layout interface {
PrintStatus(string, time.Duration)
DrawPrompt()
DrawScreen([]Match)
MovePage(PagingRequest)
}
// Utility function
func mergeAttribute(a, b termbox.Attribute) termbox.Attribute {
if a&0x0F == 0 || b&0x0F == 0 {
return a | b
}
return ((a - 1) | (b - 1)) + 1
}
// Utility function
func printScreen(x, y int, fg, bg termbox.Attribute, msg string, fill bool) {
for len(msg) > 0 {
c, w := utf8.DecodeRuneInString(msg)
if c == utf8.RuneError {
c = '?'
w = 1
}
msg = msg[w:]
screen.SetCell(x, y, c, fg, bg)
x += runewidth.RuneWidth(c)
}
if !fill {
return
}
width, _ := screen.Size()
for ; x < width; x++ {
screen.SetCell(x, y, ' ', fg, bg)
}
}
// AnchorSettings groups items that are required to control
// where an anchored item is actually placed
type AnchorSettings struct {
anchor VerticalAnchor // AnchorTop or AnchorBottom
anchorOffset int // offset this many lines from the anchor
}
// NewAnchorSettings creates a new AnchorSetting struct. Panics if
// an unknown VerticalAnchor is sent
func NewAnchorSettings(anchor VerticalAnchor, offset int) *AnchorSettings {
if !IsValidVerticalAnchor(anchor) {
panic("Invalid vertical anchor specified")
}
return &AnchorSettings{anchor, offset}
}
// AnchorPosition returns the starting y-offset, based on the
// anchor type and offset
func (as AnchorSettings) AnchorPosition() int {
var pos int
switch as.anchor {
case AnchorTop:
pos = as.anchorOffset
case AnchorBottom:
_, h := screen.Size()
pos = h - as.anchorOffset - 1 // -1 is required because y is 0 base, but h is 1 base
default:
panic("Unknown anchor type!")
}
return pos
}
// UserPrompt draws the prompt line
type UserPrompt struct {
*Ctx
*AnchorSettings
prefix string
prefixLen int
}
// NewUserPrompt creates a new UserPrompt struct
func NewUserPrompt(ctx *Ctx, anchor VerticalAnchor, anchorOffset int) *UserPrompt {
prefix := ctx.config.Prompt
if len(prefix) <= 0 { // default
prefix = "QUERY>"
}
prefixLen := runewidth.StringWidth(prefix)
return &UserPrompt{
Ctx: ctx,
AnchorSettings: &AnchorSettings{anchor, anchorOffset},
prefix: prefix,
prefixLen: prefixLen,
}
}
// Draw draws the query prompt
func (u UserPrompt) Draw() {
location := u.AnchorPosition()
// print "QUERY>"
printScreen(0, location, u.config.Style.BasicFG(), u.config.Style.BasicBG(), u.prefix, false)
if u.CaretPos() <= 0 { // XXX Do we really need this?
u.SetCaretPos(0) // sanity
}
if u.CaretPos().Int() > u.QueryLen() { // XXX Do we really need this?
u.SetCaretPos(u.QueryLen())
}
if u.CaretPos().Int() == u.QueryLen() {
// the entire string + the caret after the string
fg := u.config.Style.QueryFG()
bg := u.config.Style.QueryBG()
qs := u.QueryString()
ql := runewidth.StringWidth(qs)
printScreen(u.prefixLen+1, location, fg, bg, qs, false)
printScreen(u.prefixLen+1+ql, location, fg|termbox.AttrReverse, bg|termbox.AttrReverse, " ", false)
printScreen(u.prefixLen+1+ql+1, location, fg, bg, "", true)
} else {
// the caret is in the middle of the string
prev := 0
for i, r := range []rune(u.Query()) {
fg := u.config.Style.QueryFG()
bg := u.config.Style.QueryBG()
if i == u.CaretPos().Int() {
fg |= termbox.AttrReverse
bg |= termbox.AttrReverse
}
screen.SetCell(u.prefixLen+1+prev, location, r, fg, bg)
prev += runewidth.RuneWidth(r)
}
}
width, _ := screen.Size()
pmsg := fmt.Sprintf("%s [%d/%d]", u.Matcher().String(), u.currentPage.index, u.maxPage)
printScreen(width-runewidth.StringWidth(pmsg), location, u.config.Style.BasicFG(), u.config.Style.BasicBG(), pmsg, false)
}
// StatusBar draws the status message bar
type StatusBar struct {
*Ctx
*AnchorSettings
clearTimer *time.Timer
timerMutex *sync.Mutex
}
// NewStatusBar creates a new StatusBar struct
func NewStatusBar(ctx *Ctx, anchor VerticalAnchor, anchorOffset int) *StatusBar {
return &StatusBar{
ctx,
NewAnchorSettings(anchor, anchorOffset),
nil,
&sync.Mutex{},
}
}
func (s *StatusBar) stopTimer() {
s.timerMutex.Lock()
defer s.timerMutex.Unlock()
if t := s.clearTimer; t != nil {
t.Stop()
s.clearTimer = nil
}
}
// PrintStatus prints a new status message. This also resets the
// timer created by ClearStatus()
func (s *StatusBar) PrintStatus(msg string, clearDelay time.Duration) {
s.stopTimer()
s.timerMutex.Lock()
location := s.AnchorPosition()
w, _ := screen.Size()
width := runewidth.StringWidth(msg)
for width > w {
_, rw := utf8.DecodeRuneInString(msg)
width = width - rw
msg = msg[rw:]
}
var pad []byte
if w > width {
pad = make([]byte, w-width)
for i := 0; i < w-width; i++ {
pad[i] = ' '
}
}
fgAttr := s.config.Style.BasicFG()
bgAttr := s.config.Style.BasicBG()
if w > width {
printScreen(0, location, fgAttr, bgAttr, string(pad), false)
}
if width > 0 {
printScreen(w-width, location, fgAttr|termbox.AttrReverse|termbox.AttrBold, bgAttr|termbox.AttrReverse, msg, false)
}
screen.Flush()
s.timerMutex.Unlock()
// if everything is successful AND the clearDelay timer is specified,
// then set a timer to clear the status
if clearDelay != 0 {
s.clearTimer = time.AfterFunc(clearDelay, func() {
s.PrintStatus("", 0)
})
}
}
// ListArea represents the area where the actual line buffer is
// displayed in the screen
type ListArea struct {
*Ctx
*AnchorSettings
sortTopDown bool
}
// NewListArea creates a new ListArea struct
func NewListArea(ctx *Ctx, anchor VerticalAnchor, anchorOffset int, sortTopDown bool) *ListArea {
return &ListArea{
ctx,
NewAnchorSettings(anchor, anchorOffset),
sortTopDown,
}
}
// Draw displays the ListArea on the screen
func (l *ListArea) Draw(targets []Match, perPage int) {
currentPage := l.currentPage
start := l.AnchorPosition()
var y int
var fgAttr, bgAttr termbox.Attribute
for n := 0; n < perPage; n++ {
switch {
case n+currentPage.offset == l.currentLine-1:
fgAttr = l.config.Style.SelectedFG()
bgAttr = l.config.Style.SelectedBG()
case l.selection.Has(n+currentPage.offset+1) || l.SelectedRange().Has(n+currentPage.offset+1):
fgAttr = l.config.Style.SavedSelectionFG()
bgAttr = l.config.Style.SavedSelectionBG()
default:
fgAttr = l.config.Style.BasicFG()
bgAttr = l.config.Style.BasicBG()
}
targetIdx := currentPage.offset + n
if targetIdx >= len(targets) {
break
}
if l.sortTopDown {
y = n + start
} else {
y = start - n
}
target := targets[targetIdx]
line := target.Line()
matches := target.Indices()
if matches == nil {
printScreen(0, y, fgAttr, bgAttr, line, true)
} else {
prev := 0
index := 0
for _, m := range matches {
if m[0] > index {
c := line[index:m[0]]
printScreen(prev, y, fgAttr, bgAttr, c, false)
prev += runewidth.StringWidth(c)
index += len(c)
}
c := line[m[0]:m[1]]
printScreen(prev, y, l.config.Style.MatchedFG(), mergeAttribute(bgAttr, l.config.Style.MatchedBG()), c, true)
prev += runewidth.StringWidth(c)
index += len(c)
}
m := matches[len(matches)-1]
if m[0] > index {
printScreen(prev, y, l.config.Style.QueryFG(), mergeAttribute(bgAttr, l.config.Style.QueryBG()), line[m[0]:m[1]], true)
} else if len(line) > m[1] {
printScreen(prev, y, fgAttr, bgAttr, line[m[1]:len(line)], true)
}
}
}
}
// BasicLayout is... the basic layout :) At this point this is the
// only struct for layouts, which means that while the position
// of components may be configurable, the actual types of components
// that are used are set and static
type BasicLayout struct {
*Ctx
*StatusBar
prompt *UserPrompt
list *ListArea
}
// NewDefaultLayout creates a new Layout in the default format (top-down)
func NewDefaultLayout(ctx *Ctx) *BasicLayout {
return &BasicLayout{
Ctx: ctx,
StatusBar: NewStatusBar(ctx, AnchorBottom, 0),
// The prompt is at the top
prompt: NewUserPrompt(ctx, AnchorTop, 0),
// The list area is at the top, after the prompt
// It's also displayed top-to-bottom order
list: NewListArea(ctx, AnchorTop, 1, true),
}
}
// NewBottomUpLayout creates a new Layout in bottom-up format
func NewBottomUpLayout(ctx *Ctx) *BasicLayout {
return &BasicLayout{
Ctx: ctx,
StatusBar: NewStatusBar(ctx, AnchorBottom, 0),
// The prompt is at the bottom, above the status bar
prompt: NewUserPrompt(ctx, AnchorBottom, 1),
// The list area is at the bottom, above the prompt
// IT's displayed in bottom-to-top order
list: NewListArea(ctx, AnchorBottom, 2, false),
}
}
// CalculatePage calculates which page we're displaying
func (l *BasicLayout) CalculatePage(targets []Match, perPage int) error {
CALCULATE_PAGE:
currentPage := l.currentPage
currentPage.index = ((l.currentLine - 1) / perPage) + 1
if currentPage.index <= 0 {
currentPage.index = 1
}
currentPage.offset = (currentPage.index - 1) * perPage
currentPage.perPage = perPage
if len(targets) == 0 {
l.maxPage = 1
} else {
l.maxPage = ((len(targets) + perPage - 1) / perPage)
}
if l.maxPage < currentPage.index {
if len(targets) == 0 && l.QueryLen() == 0 {
// wait for targets
return fmt.Errorf("no targets or query. nothing to do")
}
l.currentLine = currentPage.offset
goto CALCULATE_PAGE
}
return nil
}
func (l *BasicLayout) DrawPrompt() {
l.prompt.Draw()
}
// DrawScreen draws the entire screen
func (l *BasicLayout) DrawScreen(targets []Match) {
if err := screen.Clear(l.config.Style.BasicFG(), l.config.Style.BasicBG()); err != nil {
return
}
if l.currentLine > len(targets) && len(targets) > 0 {
l.currentLine = len(targets)
}
perPage := linesPerPage()
if err := l.CalculatePage(targets, perPage); err != nil {
return
}
l.DrawPrompt()
l.list.Draw(targets, perPage)
if err := screen.Flush(); err != nil {
return
}
}
func linesPerPage() int {
_, height := screen.Size()
return height - 2 // list area is always the display area - 2 lines for prompt and status
}
// MovePage moves the cursor
func (l *BasicLayout) MovePage(p PagingRequest) {
if l.list.sortTopDown {
switch p {
case ToLineAbove:
l.currentLine--
case ToLineBelow:
l.currentLine++
case ToScrollPageDown:
l.currentLine += linesPerPage()
case ToScrollPageUp:
l.currentLine -= linesPerPage()
}
} else {
switch p {
case ToLineAbove:
l.currentLine++
case ToLineBelow:
l.currentLine--
case ToScrollPageDown:
l.currentLine -= linesPerPage()
case ToScrollPageUp:
l.currentLine += linesPerPage()
}
}
if l.currentLine < 1 {
if l.current != nil {
// Go to last page, if possible
l.currentLine = len(l.current)
} else {
l.currentLine = 1
}
} else if l.current != nil && l.currentLine > len(l.current) {
l.currentLine = 1
}
}