elves/elvish

package main

import (
    "log"
    "os"
    "strings"
    "unicode"

    "golang.org/x/sys/windows"

    "src.elv.sh/pkg/sys/ewindows"
)

func main() {
    restore := setup(os.Stdin, os.Stdout)
    defer restore()

    log.Println("ready")
    console, err := windows.GetStdHandle(windows.STD_INPUT_HANDLE)
    if err != nil {
        log.Fatalf("GetStdHandle(STD_INPUT_HANDLE): %v", err)
    }
    for {
        var buf [1]ewindows.InputRecord
        nr, err := ewindows.ReadConsoleInput(console, buf[:])
        if nr == 0 {
            log.Fatal("no event read")
        }
        if err != nil {
            log.Fatal(err)
        }
        event := buf[0].GetEvent()
        switch event := event.(type) {
        case *ewindows.KeyEvent:
            typ := "up"
            if event.BKeyDown != 0 {
                typ = "down"
            }
            r := rune(event.UChar[0]) + rune(event.UChar[1])<<8
            rs := "(" + string(r) + ")"
            if unicode.IsControl(r) {
                rs = "   "
            }
            var mods []string
            testMod := func(mask uint32, name string) {
                if event.DwControlKeyState&mask != 0 {
                    mods = append(mods, name)
                }
            }
            testMod(0x1, "right alt")
            testMod(0x2, "left alt")
            testMod(0x4, "right ctrl")
            testMod(0x8, "left ctrl")
            testMod(0x10, "shift")
            // testMod(0x20, "numslock")
            testMod(0x40, "scrolllock")
            testMod(0x80, "capslock")
            testMod(0x100, "enhanced")

            log.Printf("%4s, key code = %02x, char = %04x %s, mods = %s\n",
                typ, event.WVirtualKeyCode, r, rs, strings.Join(mods, ", "))
        }
    }
}

const (
    wantedInMode = windows.ENABLE_WINDOW_INPUT |
        windows.ENABLE_MOUSE_INPUT | windows.ENABLE_PROCESSED_INPUT
    wantedOutMode = windows.ENABLE_PROCESSED_OUTPUT |
        windows.ENABLE_VIRTUAL_TERMINAL_PROCESSING
)

func setup(in, out *os.File) func() {
    hIn := windows.Handle(in.Fd())
    hOut := windows.Handle(out.Fd())

    var oldInMode, oldOutMode uint32
    err := windows.GetConsoleMode(hIn, &oldInMode)
    if err != nil {
        log.Fatal(err)
    }
    err = windows.GetConsoleMode(hOut, &oldOutMode)
    if err != nil {
        log.Fatal(err)
    }

    err = windows.SetConsoleMode(hIn, wantedInMode)
    if err != nil {
        log.Fatal(err)
    }
    err = windows.SetConsoleMode(hOut, wantedOutMode)
    if err != nil {
        log.Fatal(err)
    }

    return func() {
        err := windows.SetConsoleMode(hIn, oldInMode)
        if err != nil {
            log.Fatal(err)
        }
        err = windows.SetConsoleMode(hOut, oldOutMode)
        if err != nil {
            log.Fatal(err)
        }
    }
}