use tcell via porting over code from awesome-gocui

vendor/github.com/jesseduffield/gocui/tcell_driver.go

@@ -0,0 +1,205 @@
+// Copyright 2020 The gocui Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gocui
+
+import (
+	"github.com/gdamore/tcell/v2"
+)
+
+var screen tcell.Screen
+
+// tcellInit initializes tcell screen for use.
+func tcellInit() error {
+	if s, e := tcell.NewScreen(); e != nil {
+		return e
+	} else if e = s.Init(); e != nil {
+		return e
+	} else {
+		screen = s
+		return nil
+	}
+}
+
+// tcellSetCell sets the character cell at a given location to the given
+// content (rune) and attributes using provided OutputMode
+func tcellSetCell(x, y int, ch rune, fg, bg Attribute, omode OutputMode) {
+	st := getTcellStyle(fg, bg, omode)
+	screen.SetContent(x, y, ch, nil, st)
+}
+
+// getTcellStyle creates tcell.Style from Attributes
+func getTcellStyle(fg, bg Attribute, omode OutputMode) tcell.Style {
+	st := tcell.StyleDefault
+
+	// extract colors and attributes
+	if fg != ColorDefault {
+		st = st.Foreground(getTcellColor(fg, omode))
+		st = setTcellFontEffectStyle(st, fg)
+	}
+	if bg != ColorDefault {
+		st = st.Background(getTcellColor(bg, omode))
+		st = setTcellFontEffectStyle(st, bg)
+	}
+
+	return st
+}
+
+// setTcellFontEffectStyle add additional attributes to tcell.Style
+func setTcellFontEffectStyle(st tcell.Style, attr Attribute) tcell.Style {
+	if attr&AttrBold != 0 {
+		st = st.Bold(true)
+	}
+	if attr&AttrUnderline != 0 {
+		st = st.Underline(true)
+	}
+	if attr&AttrReverse != 0 {
+		st = st.Reverse(true)
+	}
+	if attr&AttrBlink != 0 {
+		st = st.Blink(true)
+	}
+	if attr&AttrDim != 0 {
+		st = st.Dim(true)
+	}
+	if attr&AttrItalic != 0 {
+		st = st.Italic(true)
+	}
+	if attr&AttrStrikeThrough != 0 {
+		st = st.StrikeThrough(true)
+	}
+	return st
+}
+
+// gocuiEventType represents the type of event.
+type gocuiEventType uint8
+
+// GocuiEvent represents events like a keys, mouse actions, or window resize.
+//  The 'Mod', 'Key' and 'Ch' fields are valid if 'Type' is 'eventKey'.
+//  The 'MouseX' and 'MouseY' fields are valid if 'Type' is 'eventMouse'.
+//  The 'Width' and 'Height' fields are valid if 'Type' is 'eventResize'.
+//  The 'Err' field is valid if 'Type' is 'eventError'.
+type GocuiEvent struct {
+	Type   gocuiEventType
+	Mod    Modifier
+	Key    Key
+	Ch     rune
+	Width  int
+	Height int
+	Err    error
+	MouseX int
+	MouseY int
+	N      int
+}
+
+// Event types.
+const (
+	eventNone gocuiEventType = iota
+	eventKey
+	eventResize
+	eventMouse
+	eventInterrupt
+	eventError
+	eventRaw
+)
+
+var (
+	lastMouseKey tcell.ButtonMask = tcell.ButtonNone
+	lastMouseMod tcell.ModMask    = tcell.ModNone
+)
+
+// pollEvent get tcell.Event and transform it into gocuiEvent
+func pollEvent() GocuiEvent {
+	tev := screen.PollEvent()
+	switch tev := tev.(type) {
+	case *tcell.EventInterrupt:
+		return GocuiEvent{Type: eventInterrupt}
+	case *tcell.EventResize:
+		w, h := tev.Size()
+		return GocuiEvent{Type: eventResize, Width: w, Height: h}
+	case *tcell.EventKey:
+		k := tev.Key()
+		ch := rune(0)
+		if k == tcell.KeyRune {
+			k = 0 // if rune remove key (so it can match rune instead of key)
+			ch = tev.Rune()
+			if ch == ' ' {
+				// special handling for spacebar
+				k = 32 // tcell keys ends at 31 or starts at 256
+				ch = rune(0)
+			}
+		}
+		mod := tev.Modifiers()
+		// remove control modifier and setup special handling of ctrl+spacebar, etc.
+		if mod == tcell.ModCtrl && k == 32 {
+			mod = 0
+			ch = rune(0)
+			k = tcell.KeyCtrlSpace
+		} else if mod == tcell.ModCtrl || mod == tcell.ModShift {
+			// remove Ctrl or Shift if specified
+			// - shift - will be translated to the final code of rune
+			// - ctrl  - is translated in the key
+			mod = 0
+		}
+		return GocuiEvent{
+			Type: eventKey,
+			Key:  Key(k),
+			Ch:   ch,
+			Mod:  Modifier(mod),
+		}
+	case *tcell.EventMouse:
+		x, y := tev.Position()
+		button := tev.Buttons()
+		mouseKey := MouseRelease
+		mouseMod := ModNone
+		// process mouse wheel
+		if button&tcell.WheelUp != 0 {
+			mouseKey = MouseWheelUp
+		}
+		if button&tcell.WheelDown != 0 {
+			mouseKey = MouseWheelDown
+		}
+		if button&tcell.WheelLeft != 0 {
+			mouseKey = MouseWheelLeft
+		}
+		if button&tcell.WheelRight != 0 {
+			mouseKey = MouseWheelRight
+		}
+
+		// process button events (not wheel events)
+		button &= tcell.ButtonMask(0xff)
+		if button != tcell.ButtonNone && lastMouseKey == tcell.ButtonNone {
+			lastMouseKey = button
+			lastMouseMod = tev.Modifiers()
+		}
+
+		switch tev.Buttons() {
+		case tcell.ButtonNone:
+			if lastMouseKey != tcell.ButtonNone {
+				switch lastMouseKey {
+				case tcell.ButtonPrimary:
+					mouseKey = MouseLeft
+				case tcell.ButtonSecondary:
+					mouseKey = MouseRight
+				case tcell.ButtonMiddle:
+					mouseKey = MouseMiddle
+				}
+				mouseMod = Modifier(lastMouseMod)
+				lastMouseMod = tcell.ModNone
+				lastMouseKey = tcell.ButtonNone
+			}
+		}
+
+		return GocuiEvent{
+			Type:   eventMouse,
+			MouseX: x,
+			MouseY: y,
+			Key:    mouseKey,
+			Ch:     0,
+			Mod:    mouseMod,
+		}
+	default:
+		return GocuiEvent{Type: eventNone}
+	}
+}