# Environment variables:
#
# PS1_SHOWHOSTNAME
#       'auto' (default):       Only show hostname over SSH
#       'yes':                  Always show hostname
#       anything else:          Never show hostname


__show-hostname ()
{
    case "${PS1_SHOWHOSTNAME}" in
        (''|auto)
            [ "${SSH_CONNECTION}" ]
            return $?;;
        (yes)
            return 0;;
        (*)
            return 1;;
    esac
}

__set-title ()
{
    local title
    local git_root=$(git root 2> /dev/null)

    if [ ${git_root} ]
    then
        title=$(basename ${git_root})
    else
        local path=${PWD/~/\~}

        if __show-hostname
        then
            title="${USER}@${HOSTNAME}:${path}"
        else
            title="${USER}:${path}"
        fi
    fi

    # Cf. console_codes(4):
    #
    #   ESC ] 2 ; txt ST        Set window title to txt.
    #
    # ST is a "string terminator", either "ESC \" or "BEL".

    echo -ne "\E]2;${title}\a"
}

# In order to know how much space PS1 takes, Bash needs us to delimit
# non-printing characters with \[ and \].
__start-nonprinting ()
{
    if [ ${BUILDING_PS1} ]
    then
        echo -en '\['
    fi
}

__end-nonprinting ()
{
    if [ ${BUILDING_PS1} ]
    then
        echo -en '\]'
    fi
}

__fontify ()
{
    local -A codes
    codes[red]='31'
    codes[green]='32'
    codes[blue]='34'
    codes[white]='37'
    codes[bold]='1'
    codes[dim]='2'
    codes[clear]='0'

    local text=$1
    shift

    output=$(__start-nonprinting)
    output+='\E['

    for ((i=1; i<=$#; i++))
    do
        output+=${codes[${!i}]}

        if ((i<$#))
        then
            output+=';'
        else
            output+='m'
        fi
    done

    output+=$(__end-nonprinting)

    output+="${text}"
    output+=$(__start-nonprinting)
    output+='\E[0m'
    output+=$(__end-nonprinting)

    echo -en "${output}"
}

__set-prompt ()
{
    local last_status=$1
    BUILDING_PS1=t
    PS1=''

    if [ ${last_status} -ne 0 ]
    then
        PS1+=$(__fontify "${last_status} " bold red) 
    fi

    PS1+=$(__fontify '\u' green)

    if __show-hostname
    then
        PS1+=$(__fontify '@' dim)
        PS1+=$(__fontify '\H' bold green)
    fi

    PS1+=$(__fontify : dim)
    PS1+=$(__fontify '\w' bold blue)
    PS1+=$(__fontify "$(__git_ps1 '(%s)')" red)
    PS1+=$(__fontify '\$' dim)
    PS1+=' '

    unset BUILDING_PS1
}

__current-column ()
{
    # Cf. console_codes(4) § ECMA-48 Status Report Commands

    local position
    read -sdR -p$'\E[6n' position

    local pattern='\[[0-9]+;([0-9]+)'

    if [[ ${position} =~ ${pattern} ]]
    then
        echo ${BASH_REMATCH[1]}
    else
        echo 0
    fi
}

__draw-rule ()
{
    local rule=''
    local column=$(__current-column)

    for ((i=column; i<=COLUMNS; i++))
    do
        rule+=—
    done
    __fontify ${rule} dim
}

__refresh-terminal ()
{
    local last_status=$?

    __set-title
    __set-prompt ${last_status}
    __draw-rule
}


. /usr/lib/git-core/git-sh-prompt
GIT_PS1_SHOWDIRTYSTATE=t
GIT_PS1_SHOWUPSTREAM=auto

export PROMPT_COMMAND=__refresh-terminal