##
##  OSSP due - Dynamic User Environment
##  Copyright (c) 1994-2004 Ralf S. Engelschall <rse@engelschall.com>
##  Copyright (c) 1994-2004 The OSSP Project <http://www.ossp.org/>
##
##  This file is part of OSSP due, a dynamic user environment
##  which can found at http://www.ossp.org/pkg/tool/due/
##
##  Permission to use, copy, modify, and distribute this software for
##  any purpose with or without fee is hereby granted, provided that
##  the above copyright notice and this permission notice appear in all
##  copies.
##
##  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
##  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
##  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
##  IN NO EVENT SHALL THE AUTHORS AND COPYRIGHT HOLDERS AND THEIR
##  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
##  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
##  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
##  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
##  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
##  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
##  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
##  SUCH DAMAGE.
##
##  ~/.duerc: OSSP due run-command script
##

#   global DUE variables holding names of available
#   and actually loaded modules
DUE_AVAILABLE=""
DUE_LOADED=""

#   the DUE frontend command
function due () {
    #   parse command line
    local opt_h=no
    local opt_v=${DUE_VERBOSE:-no}
    local opt_p=""
    local opt
    OPTIND=1
    while getopts hvp: opt; do
        case ${opt} in
            h ) opt_h=yes     ;;
            v ) opt_v=yes     ;;
            p ) opt_p=$OPTARG ;;
        esac
    done
    shift $((${OPTIND} - 1))
    if [ ".${opt_h}" = .h ]; then
        echo "Usage: due [-h] [-v] [-p <module-path>] load [+|-]<module> ..."
        return 0
    fi

    #   determine path to DUE modules
    local mod_path_system=""
    local mod_path="${DUE_PATH:-"$HOME/.due:@"}"
    if [ ".${opt_p}" != . ]; then
        mod_path="${opt_p}"
    fi
    mod_path=`echo "${mod_path}" |\
              sed -e "s;@;${mod_path_system};" |\
              sed -e 's/::/:/g' -e 's/^://' -e 's/:$//'`

    #   determine available modules
    if [ -z ${DUE_AVAILABLE} ]; then
        local mod_dir
        for mod_dir in ${mod_path//:/ }; do
            [ ".${mod_dir}" = . ] && continue
            [ -d ${mod_dir} ] || continue
            local mod_name
            for mod_name in . `cd ${mod_dir} && echo due.*.sh`; do
                [ ".${mod_name}" = ".." -o ".${mod_name}" = ".*" ] && continue
                mod_name=${mod_name/#due./}
                mod_name=${mod_name/%.sh/}
                eval "DUE_AVAILABLE=\"${DUE_AVAILABLE}${DUE_AVAILABLE:+,}${mod_name}\""
            done
        done
    fi

    #   dispatch into commands    
    cmd="$1"
    shift
    case "${cmd}" in
        load )
            #   by default all modules are disabled
            local mod_name
            for mod_name in ${DUE_AVAILABLE//,/ }; do
                eval "local mod_enable_${mod_name}=no"
            done

            #   determine whether to enable or disable requested module(s)
            for mod_name in "$@"; do
                local val=yes
                case "${mod_name}" in
                    +* ) val=yes; mod_name=${mod_name:1} ;;
                    -* ) val=no;  mod_name=${mod_name:1} ;;
                esac
                if [ ".${mod_name}" = .all ]; then
                    for mod_name in ${DUE_AVAILABLE//,/ }; do
                        eval "mod_enable_${mod_name}=${val}"
                    done
                else
                    local exists
                    eval "exists=\${mod_enable_${mod_name}}"
                    if [ ".${exists}" = . ]; then
                        echo "due:ERROR: invalid module \"${mod_name}\"" 1>&2
                        return 1
                    fi
                    eval "mod_enable_${mod_name}=${val}"
                fi
            done

            #   load enabled (and still not loaded) modules
            for mod_name in ${DUE_AVAILABLE//,/ }; do
                eval "val=\${mod_enable_${mod_name}}"
                if [ ".${val}" = .yes ]; then
                    local loadit=yes
                    for loaded in ${DUE_LOADED//,/ }; do
                        if [ ".${loaded}" = ".${mod_name}" ]; then
                            #   module already loaded
                            loadit=no
                            break
                        fi
                    done
                    if [ ".${loadit}" = .yes ]; then
                        local mod_file=""
                        local mod_dir
                        for mod_dir in ${mod_path//:/ }; do
                            [ ".${mod_dir}" = . ] && continue
                            if [ -f "${mod_dir}/due.${mod_name}.sh" ]; then
                                mod_file="${mod_dir}/due.${mod_name}.sh"
                                break
                            fi
                        done
                        if [ ".${mod_file}" = . ]; then
                            #   should not happen here again
                            echo "due:ERROR: invalid module \"${mod_name}\"" 1>&2
                            return 1
                        fi
                        local verbose=${DUE_VERBOSE}
                        DUE_VERBOSE=${opt_v}
                        source ${mod_file}
                        DUE_VERBOSE=${verbose}
                        DUE_LOADED="${DUE_LOADED}${DUE_LOADED:+,}${mod_name}"
                        if [ ".${opt_v}" = .yes ]; then
                            echo "due: loaded shell module \"${mod_name}\"" 1>&2
                        fi
                    fi
                fi
            done
            ;;
        * )
            echo "due:ERROR: invalid command \"${cmd}\"" 1>&2
            return 1
            ;;
    esac
    return 0
}