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package main
import (
"fmt"
"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 = 17
// maxWidth is the maximum width that the window will grow to.
const maxWidth = 32
type UI struct {
calc Calculator
width int // Width of the window measured in characters.
height int
}
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.width = msg.Width
ui.height = msg.Height
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 "A":
ui.calc.angleMode = !ui.calc.angleMode
case "N":
ui.calc.negate()
case "+", "-", "*", "/", "%", "^":
operator := msg.String()[0]
if err := ui.calc.performOperation(operator); 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)
} else if v, err := ui.calc.parseBuffer(); err == nil {
ui.calc.stack.push(v)
}
ui.calc.buf = ""
default:
ui.calc.buf += msg.String()
}
}
return ui, nil
}
func (ui UI) View() string {
s := padding(ui)
width := min(ui.width, maxWidth)
// Angle mode.
s += fmt.Sprintf("%*s\n", width-1, ui.calc.angleMode)
// Stack.
top := boxTop(width)
bottom := boxBottom(width)
s += top + "\n"
for _, f := range ui.calc.stack {
s += fmt.Sprintf("%[1]c%[2]*.[2]*s%[1]c\n", boxVertical, width-2, printNum(f))
}
s += bottom + "\n"
// Buffer.
s += top + "\n"
s += fmt.Sprintf("%[1]c>%[2]*.[2]*s%[1]c\n", boxVertical, width-3, ui.calc.buf)
s += bottom
return s
}
func padding(ui UI) string {
var ( // Number of lines occupied by each ui element.
angleMode = 1
stack = len(ui.calc.stack) + 2
buf = 3
)
padlines := ui.height - angleMode - stack - buf
if padlines < 1 {
return ""
}
s := make([]byte, padlines)
for i := 0; i < padlines; i++ {
s[i] = '\n'
}
return string(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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