cb

#!/bin/bash

# from: https://gist.github.com/RichardBronosky/56d8f614fab2bacdd8b048fb58d0c0c7

LINUX_copy(){
    cat | xclip -selection clipboard
}

LINUX_paste(){
    xclip -selection clipboard -o
}

WSL_copy(){
    cat | /mnt/c/Windows/System32/clip.exe
}

WSL_paste(){
    /mnt/c/Windows/System32/WindowsPowerShell/v1.0/powershell.exe Get-Clipboard | sed 's/\r//'
}

CYGWIN_copy(){
    cat > /dev/clipboard
}

CYGWIN_paste(){
    cat /dev/clipboard
}


MAC_copy(){
    cat | pbcopy
}

MAC_paste(){
    pbpaste
}

stdin_is_a_pipe(){
    [[ -p /dev/stdin ]]
}

stdin_is_a_tty(){
    [[ -t 0 ]]
}

stdin_is_pipe_like(){
    stdin_is_a_pipe || ! stdin_is_a_tty
}

stdout_is_pipe_like(){
    ! stdout_is_a_tty # meaning # it must be a pipe or redirection
}

stdout_is_a_tty(){
    [[ -t 1 ]]
}

requested_open_ended(){
    [[ "${args[0]:-}" == "-" ]]
}

requested_test_suite(){
    [[ "${args[0]:-}" == "--test" ]]
}

enable_tee_like_chaining(){
    # see `man tee`
    if stdout_is_pipe_like; then
        ${os}_paste
    elif requested_open_ended; then
        ${os}_paste
        echo
    fi
}

prevent_prompt_from_being_on_the_same_line(){
    if stdout_is_a_tty; then # we don't have to be strict about not altering the output
        echo
    fi
}

detect_os(){
    if [[ -f /proc/version ]] && grep -iq Microsoft /proc/version; then
        printf WSL
    else
        case "$(uname -s)" in
            Linux*)     printf LINUX;;
            Darwin*)    printf MAC;;
            CYGWIN*)    printf CYGWIN;;
        esac
    fi
}

test_suite(){
    # setup
    printf '1234' | ${BASH_SOURCE[0]}

    printf "\n1. output to TTY\n"
    ${BASH_SOURCE[0]}
    printf "1234 should be above.\n"

    printf "\n2. output to pipe\n"
    ${BASH_SOURCE[0]} | cat; echo
    printf "1234 should be above.\n"

    printf "\n3. input from pipe and output to pipe\n"
    printf '1234' | ${BASH_SOURCE[0]} | cat; echo
    printf "1234 should be above.\n"
}

function debug(){
    stdin_is_a_pipe      && echo "stdin_is_a_pipe: 1"     >> /tmp/ono ||  echo "stdin_is_a_pipe: 0"     >> /tmp/ono
    stdin_is_a_tty       && echo "stdin_is_a_tty: 1"      >> /tmp/ono ||  echo "stdin_is_a_tty: 0"      >> /tmp/ono
    stdin_is_pipe_like   && echo "stdin_is_pipe_like: 1"  >> /tmp/ono ||  echo "stdin_is_pipe_like: 0"  >> /tmp/ono
    stdout_is_pipe_like  && echo "stdout_is_pipe_like: 1" >> /tmp/ono ||  echo "stdout_is_pipe_like: 0" >> /tmp/ono
    stdout_is_a_tty      && echo "stdout_is_a_tty: 1"     >> /tmp/ono ||  echo "stdout_is_a_tty: 0"     >> /tmp/ono
    echo >> /tmp/ono
}

main(){
    os="$(detect_os)"
    if stdin_is_pipe_like; then
        ${os}_copy
        enable_tee_like_chaining
    else # stdin is not pipe-like
        ${os}_paste
        prevent_prompt_from_being_on_the_same_line
    fi
}

args=("$@")
if requested_test_suite; then
    export DEBUG=1
    test_suite
else
    [[ ${DEBUG:-} == 1 ]] && debug
    main
fi