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package main
import (
"fmt"
"strconv"
"github.com/charmbracelet/bubbletea"
)
// UTF-8 box drawing characters.
const (
boxHorizontal = '─'
boxVertical = '│'
boxTopLeft = '┌'
boxTopRight = '┐'
boxBottomLeft = '└'
boxBottomRight = '┘'
)
// sigDigs is the number of significant digits when printing a number.
const sigDigs = 64
type UI struct {
calc Calculator
windowWidth int // Width of the window measured in characters.
}
func (ui UI) Init() tea.Cmd {
return nil
}
func (ui UI) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
switch msg := msg.(type) {
case tea.WindowSizeMsg:
ui.windowWidth = msg.Width
case tea.KeyMsg:
switch msg.String() {
case "ctrl+c", "Q":
return ui, tea.Quit
case "J", "K":
ui.calc.swap()
case "D":
ui.calc.buf = ""
case "C":
ui.calc.buf = ""
ui.calc.stack = ui.calc.stack[:0]
case "N":
ui.calc.negate()
case "+", "-", "*", "/", "%", "^":
if err := ui.calc.performOp(msg.String()[0]); err != nil {
panic(err)
}
case "backspace":
if len(ui.calc.buf) > 0 {
ui.calc.buf = ui.calc.buf[:len(ui.calc.buf)-1]
}
case "enter":
if fn := parseFunction(ui.calc.buf); fn != nil {
fn(ui.calc.stack)
} else if con := parseConstant(ui.calc.buf); con != nil {
ui.calc.stack = append(ui.calc.stack, *con)
} else if f, err := strconv.ParseFloat(ui.calc.buf, 64); err == nil {
ui.calc.stack = append(ui.calc.stack, f)
}
ui.calc.buf = ""
default:
ui.calc.buf += msg.String()
}
}
return ui, nil
}
func (ui UI) View() string {
var s string
for _, f := range ui.calc.stack {
s += printNum(f) + "\n"
}
s += boxTop(ui.windowWidth) + "\n"
s += fmt.Sprintf("%[1]c%-*s%[1]c\n", boxVertical, ui.windowWidth-2, ui.calc.buf)
s += boxBottom(ui.windowWidth)
return s
}
func printNum(v float64) string {
return fmt.Sprintf(" %.*g", sigDigs, v)
}
// boxTop returns the top of a UTF-8 box, 'width' characters wide (including
// corners).
func boxTop(width int) string {
if width < 1 {
return ""
}
row := make([]rune, width)
row[0] = boxTopLeft
row[width-1] = boxTopRight
if width > 1 {
fill(row[1:width-1], boxHorizontal)
}
return string(row)
}
// boxBottom returns the botom of a UTF-8 box, 'width' characters wide
// (including corners).
func boxBottom(width int) string {
if width < 1 {
return ""
}
row := make([]rune, width)
row[0] = boxBottomLeft
row[width-1] = boxBottomRight
if width > 1 {
fill(row[1:width-1], boxHorizontal)
}
return string(row)
}
// fill fills s with c.
func fill(s []rune, c rune) {
for i := range s {
s[i] = c
}
}
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