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package femto
import (
"github.com/atotto/clipboard"
)
// The Cursor struct stores the location of the cursor in the view
// The complicated part about the cursor is storing its location.
// The cursor must be displayed at an x, y location, but since the buffer
// uses a rope to store text, to insert text we must have an index. It
// is also simpler to use character indicies for other tasks such as
// selection.
type Cursor struct {
buf *Buffer
Loc
// Last cursor x position
LastVisualX int
// The current selection as a range of character numbers (inclusive)
CurSelection [2]Loc
// The original selection as a range of character numbers
// This is used for line and word selection where it is necessary
// to know what the original selection was
OrigSelection [2]Loc
// Which cursor index is this (for multiple cursors)
Num int
}
// Goto puts the cursor at the given cursor's location and gives
// the current cursor its selection too
func (c *Cursor) Goto(b Cursor) {
c.X, c.Y, c.LastVisualX = b.X, b.Y, b.LastVisualX
c.OrigSelection, c.CurSelection = b.OrigSelection, b.CurSelection
}
// GotoLoc puts the cursor at the given cursor's location and gives
// the current cursor its selection too
func (c *Cursor) GotoLoc(l Loc) {
c.X, c.Y = l.X, l.Y
c.LastVisualX = c.GetVisualX()
}
// CopySelection copies the user's selection to either "primary"
// or "clipboard"
func (c *Cursor) CopySelection(target string) {
if c.HasSelection() {
clipboard.WriteAll(c.GetSelection())
}
}
// ResetSelection resets the user's selection
func (c *Cursor) ResetSelection() {
c.CurSelection[0] = c.buf.Start()
c.CurSelection[1] = c.buf.Start()
}
// SetSelectionStart sets the start of the selection
func (c *Cursor) SetSelectionStart(pos Loc) {
c.CurSelection[0] = pos
}
// SetSelectionEnd sets the end of the selection
func (c *Cursor) SetSelectionEnd(pos Loc) {
c.CurSelection[1] = pos
}
// HasSelection returns whether or not the user has selected anything
func (c *Cursor) HasSelection() bool {
return c.CurSelection[0] != c.CurSelection[1]
}
// DeleteSelection deletes the currently selected text
func (c *Cursor) DeleteSelection() {
if c.CurSelection[0].GreaterThan(c.CurSelection[1]) {
c.buf.Remove(c.CurSelection[1], c.CurSelection[0])
c.Loc = c.CurSelection[1]
} else if !c.HasSelection() {
return
} else {
c.buf.Remove(c.CurSelection[0], c.CurSelection[1])
c.Loc = c.CurSelection[0]
}
}
// GetSelection returns the cursor's selection
func (c *Cursor) GetSelection() string {
if InBounds(c.CurSelection[0], c.buf) && InBounds(c.CurSelection[1], c.buf) {
if c.CurSelection[0].GreaterThan(c.CurSelection[1]) {
return c.buf.Substr(c.CurSelection[1], c.CurSelection[0])
}
return c.buf.Substr(c.CurSelection[0], c.CurSelection[1])
}
return ""
}
// SelectLine selects the current line
func (c *Cursor) SelectLine() {
c.Start()
c.SetSelectionStart(c.Loc)
c.End()
if c.buf.NumLines-1 > c.Y {
c.SetSelectionEnd(c.Loc.Move(1, c.buf))
} else {
c.SetSelectionEnd(c.Loc)
}
c.OrigSelection = c.CurSelection
}
// AddLineToSelection adds the current line to the selection
func (c *Cursor) AddLineToSelection() {
if c.Loc.LessThan(c.OrigSelection[0]) {
c.Start()
c.SetSelectionStart(c.Loc)
c.SetSelectionEnd(c.OrigSelection[1])
}
if c.Loc.GreaterThan(c.OrigSelection[1]) {
c.End()
c.SetSelectionEnd(c.Loc.Move(1, c.buf))
c.SetSelectionStart(c.OrigSelection[0])
}
if c.Loc.LessThan(c.OrigSelection[1]) && c.Loc.GreaterThan(c.OrigSelection[0]) {
c.CurSelection = c.OrigSelection
}
}
// SelectWord selects the word the cursor is currently on
func (c *Cursor) SelectWord() {
if len(c.buf.Line(c.Y)) == 0 {
return
}
if !IsWordChar(string(c.RuneUnder(c.X))) {
c.SetSelectionStart(c.Loc)
c.SetSelectionEnd(c.Loc.Move(1, c.buf))
c.OrigSelection = c.CurSelection
return
}
forward, backward := c.X, c.X
for backward > 0 && IsWordChar(string(c.RuneUnder(backward-1))) {
backward--
}
c.SetSelectionStart(Loc{backward, c.Y})
c.OrigSelection[0] = c.CurSelection[0]
for forward < Count(c.buf.Line(c.Y))-1 && IsWordChar(string(c.RuneUnder(forward+1))) {
forward++
}
c.SetSelectionEnd(Loc{forward, c.Y}.Move(1, c.buf))
c.OrigSelection[1] = c.CurSelection[1]
c.Loc = c.CurSelection[1]
}
// AddWordToSelection adds the word the cursor is currently on
// to the selection
func (c *Cursor) AddWordToSelection() {
if c.Loc.GreaterThan(c.OrigSelection[0]) && c.Loc.LessThan(c.OrigSelection[1]) {
c.CurSelection = c.OrigSelection
return
}
if c.Loc.LessThan(c.OrigSelection[0]) {
backward := c.X
for backward > 0 && IsWordChar(string(c.RuneUnder(backward-1))) {
backward--
}
c.SetSelectionStart(Loc{backward, c.Y})
c.SetSelectionEnd(c.OrigSelection[1])
}
if c.Loc.GreaterThan(c.OrigSelection[1]) {
forward := c.X
for forward < Count(c.buf.Line(c.Y))-1 && IsWordChar(string(c.RuneUnder(forward+1))) {
forward++
}
c.SetSelectionEnd(Loc{forward, c.Y}.Move(1, c.buf))
c.SetSelectionStart(c.OrigSelection[0])
}
c.Loc = c.CurSelection[1]
}
// SelectTo selects from the current cursor location to the given
// location
func (c *Cursor) SelectTo(loc Loc) {
if loc.GreaterThan(c.OrigSelection[0]) {
c.SetSelectionStart(c.OrigSelection[0])
c.SetSelectionEnd(loc)
} else {
c.SetSelectionStart(loc)
c.SetSelectionEnd(c.OrigSelection[0])
}
}
// WordRight moves the cursor one word to the right
func (c *Cursor) WordRight() {
for IsWhitespace(c.RuneUnder(c.X)) {
if c.X == Count(c.buf.Line(c.Y)) {
c.Right()
return
}
c.Right()
}
c.Right()
for IsWordChar(string(c.RuneUnder(c.X))) {
if c.X == Count(c.buf.Line(c.Y)) {
return
}
c.Right()
}
}
// WordLeft moves the cursor one word to the left
func (c *Cursor) WordLeft() {
c.Left()
for IsWhitespace(c.RuneUnder(c.X)) {
if c.X == 0 {
return
}
c.Left()
}
c.Left()
for IsWordChar(string(c.RuneUnder(c.X))) {
if c.X == 0 {
return
}
c.Left()
}
c.Right()
}
// RuneUnder returns the rune under the given x position
func (c *Cursor) RuneUnder(x int) rune {
line := []rune(c.buf.Line(c.Y))
if len(line) == 0 {
return '\n'
}
if x >= len(line) {
return '\n'
} else if x < 0 {
x = 0
}
return line[x]
}
// UpN moves the cursor up N lines (if possible)
func (c *Cursor) UpN(amount int) {
proposedY := c.Y - amount
if proposedY < 0 {
proposedY = 0
c.LastVisualX = 0
} else if proposedY >= c.buf.NumLines {
proposedY = c.buf.NumLines - 1
}
runes := []rune(c.buf.Line(proposedY))
c.X = c.GetCharPosInLine(proposedY, c.LastVisualX)
if c.X > len(runes) || (amount < 0 && proposedY == c.Y) {
c.X = len(runes)
}
c.Y = proposedY
}
// DownN moves the cursor down N lines (if possible)
func (c *Cursor) DownN(amount int) {
c.UpN(-amount)
}
// Up moves the cursor up one line (if possible)
func (c *Cursor) Up() {
c.UpN(1)
}
// Down moves the cursor down one line (if possible)
func (c *Cursor) Down() {
c.DownN(1)
}
// Left moves the cursor left one cell (if possible) or to
// the previous line if it is at the beginning
func (c *Cursor) Left() {
if c.Loc == c.buf.Start() {
return
}
if c.X > 0 {
c.X--
} else {
c.Up()
c.End()
}
c.LastVisualX = c.GetVisualX()
}
// Right moves the cursor right one cell (if possible) or
// to the next line if it is at the end
func (c *Cursor) Right() {
if c.Loc == c.buf.End() {
return
}
if c.X < Count(c.buf.Line(c.Y)) {
c.X++
} else {
c.Down()
c.Start()
}
c.LastVisualX = c.GetVisualX()
}
// End moves the cursor to the end of the line it is on
func (c *Cursor) End() {
c.X = Count(c.buf.Line(c.Y))
c.LastVisualX = c.GetVisualX()
}
// Start moves the cursor to the start of the line it is on
func (c *Cursor) Start() {
c.X = 0
c.LastVisualX = c.GetVisualX()
}
// StartOfText moves the cursor to the first non-whitespace rune of
// the line it is on
func (c *Cursor) StartOfText() {
c.Start()
for IsWhitespace(c.RuneUnder(c.X)) {
if c.X == Count(c.buf.Line(c.Y)) {
break
}
c.Right()
}
}
// GetCharPosInLine gets the char position of a visual x y
// coordinate (this is necessary because tabs are 1 char but
// 4 visual spaces)
func (c *Cursor) GetCharPosInLine(lineNum, visualPos int) int {
// Get the tab size
tabSize := int(c.buf.Settings["tabsize"].(float64))
visualLineLen := StringWidth(c.buf.Line(lineNum), tabSize)
if visualPos > visualLineLen {
visualPos = visualLineLen
}
width := WidthOfLargeRunes(c.buf.Line(lineNum), tabSize)
if visualPos >= width {
return visualPos - width
}
return visualPos / tabSize
}
// GetVisualX returns the x value of the cursor in visual spaces
func (c *Cursor) GetVisualX() int {
runes := []rune(c.buf.Line(c.Y))
tabSize := int(c.buf.Settings["tabsize"].(float64))
if c.X > len(runes) {
c.X = len(runes) - 1
}
if c.X < 0 {
c.X = 0
}
return StringWidth(string(runes[:c.X]), tabSize)
}
// StoreVisualX stores the current visual x value in the cursor
func (c *Cursor) StoreVisualX() {
c.LastVisualX = c.GetVisualX()
}
// Relocate makes sure that the cursor is inside the bounds
// of the buffer If it isn't, it moves it to be within the
// buffer's lines
func (c *Cursor) Relocate() {
if c.Y < 0 {
c.Y = 0
} else if c.Y >= c.buf.NumLines {
c.Y = c.buf.NumLines - 1
}
if c.X < 0 {
c.X = 0
} else if c.X > Count(c.buf.Line(c.Y)) {
c.X = Count(c.buf.Line(c.Y))
}
}