package ui
import (
"os"
"os/signal"
"sync/atomic"
"syscall"
"github.com/gdamore/tcell/v2"
)
// Use unbuffered channels (always blocking unless somebody can read
// immediately) We are merely using this as a proxy to tcell screen internal
// event channel.
var Events = make(chan tcell.Event)
var Quit = make(chan struct{})
var Callbacks = make(chan func(), 50)
// QueueFunc queues a function to be called in the main goroutine. This can be
// used to prevent race conditions from delayed functions
func QueueFunc(fn func()) {
Callbacks <- fn
}
// Use a buffered channel of size 1 to avoid blocking callers of Invalidate()
var Redraw = make(chan bool, 1)
// Invalidate marks the entire UI as invalid and request a redraw as soon as
// possible. Invalidate can be called from any goroutine and will never block.
func Invalidate() {
if atomic.SwapUint32(&state.dirty, 1) != 1 {
Redraw <- true
}
}
var state struct {
content DrawableInteractive
ctx *Context
screen tcell.Screen
popover *Popover
dirty uint32 // == 1 if render has been queued in Redraw channel
// == 1 if suspend is pending
suspending uint32
}
func Initialize(content DrawableInteractive) error {
screen, err := tcell.NewScreen()
if err != nil {
return err
}
if err = screen.Init(); err != nil {
return err
}
screen.Clear()
screen.HideCursor()
screen.EnablePaste()
width, height := screen.Size()
state.content = content
state.screen = screen
state.ctx = NewContext(width, height, state.screen, onPopover)
Invalidate()
if beeper, ok := content.(DrawableInteractiveBeeper); ok {
beeper.OnBeep(screen.Beep)
}
content.Focus(true)
go state.screen.ChannelEvents(Events, Quit)
return nil
}
func onPopover(p *Popover) {
state.popover = p
}
func Exit() {
close(Quit)
}
var SuspendQueue = make(chan bool, 1)
func QueueSuspend() {
if atomic.SwapUint32(&state.suspending, 1) != 1 {
SuspendQueue <- true
}
}
func Suspend() error {
var err error
if atomic.SwapUint32(&state.suspending, 0) != 0 {
err = state.screen.Suspend()
if err == nil {
sigcont := make(chan os.Signal, 1)
signal.Notify(sigcont, syscall.SIGCONT)
err = syscall.Kill(0, syscall.SIGTSTP)
if err == nil {
<-sigcont
}
signal.Reset(syscall.SIGCONT)
err = state.screen.Resume()
state.content.Draw(state.ctx)
state.screen.Show()
}
}
return err
}
func Close() {
state.screen.Fini()
}
func Render() {
if atomic.SwapUint32(&state.dirty, 0) != 0 {
// reset popover for the next Draw
state.popover = nil
state.content.Draw(state.ctx)
if state.popover != nil {
// if the Draw resulted in a popover, draw it
state.popover.Draw(state.ctx)
}
state.screen.Show()
}
}
func EnableMouse() {
state.screen.EnableMouse()
}
func HandleEvent(event tcell.Event) {
if event, ok := event.(*tcell.EventResize); ok {
state.screen.Clear()
width, height := event.Size()
state.ctx = NewContext(width, height, state.screen, onPopover)
Invalidate()
}
// if we have a popover, and it can handle the event, it does so
if state.popover == nil || !state.popover.Event(event) {
// otherwise, we send the event to the main content
state.content.Event(event)
}
}
