/*
The MIT License (MIT)

Copyright © 2020-2025 pacman64

Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the “Software”), to deal
in the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
of the Software, and to permit persons to whom the Software is furnished to do
so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/

/*
Single-file source-code for gobble.

To compile a smaller-sized command-line app, you can use the `go` command as
follows:

go build -ldflags "-s -w" -trimpath gobble.go
*/

package main

import (
	"bytes"
	"io"
	"os"
	"os/exec"
)

const info = `
gobble [command...] [args...]

Read all bytes from standard input, and only then emit them out, or run
the command given, sending those bytes to its standard input.
`

func main() {
	if len(os.Args) > 1 {
		switch os.Args[1] {
		case `-h`, `--h`, `-help`, `--help`:
			os.Stderr.WriteString(info[1:])
			return
		}
	}

	// wait until the last byte is read
	input, err := io.ReadAll(os.Stdin)
	if err != nil {
		showError(err)
		os.Exit(1)
	}

	// emit data just read and quit, if no command was given
	if len(os.Args) == 1 {
		os.Stdout.Write(input)
		return
	}

	// run a command, using the data just read for its stdin
	name := os.Args[1]
	args := os.Args[2:]
	cmd := exec.Command(name, args...)
	cmd.Stdin = bytes.NewReader(input)
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr

	if err := cmd.Start(); err != nil {
		showError(err)
	}

	if err := cmd.Wait(); err != nil {
		showError(err)
	}

	os.Exit(cmd.ProcessState.ExitCode())
}

// showError gives a consistent style/look to any of the app's own errors
func showError(err error) {
	os.Stderr.WriteString("\x1b[31m")
	os.Stderr.WriteString(err.Error())
	os.Stderr.WriteString("\x1b[0m\n")
}