#!/bin/bash
#################################################################################################
# title         :git-myshellconfig-checkout                                                     #
# description   :checkout git detached HEAD                                                     #
# author        :Jakobus Schürz                                                                 #
# changes by    :Jakobus Schürz                                                                 #
# created       :17.01.2019                                                                     #
# updated       :28.10.2020                                                                     #
# version       :2.0                                                                            #
# usage         :git myshellconfig-checkout [-h]                                                #
# notes         :                                                                               #
#################################################################################################

[ -z "${SGIT+x}" ] && SGIT=git
    [ -z "${MSC_LOGDIR+x}" ]                  && export MSC_LOGDIR="${HOME}/logs"
    [ -z "${MSC_LOGFILE+x}" ]                 && export MSC_LOGFILE="${MSC_LOGDIR}/myshellconfig.log"
#MSC_LOGDIR="./logs"
#MSC_LOGFILE="${MSC_LOGDIR}/git.log"
[ -d "${MSC_LOGDIR}" ] || mkdir -p "${MSC_LOGDIR}"
[ -z "${MSC_GIT_REMOTE_NAME+x}" ] && export MSC_GIT_REMOTE_NAME=origin
[ -z "${MSC_GIT_BRANCH+x}" ] && export MSC_GIT_BRANCH=master



gitupdateend() {
    cat << EOF >> "${MSC_LOGFILE}"

+-----ENDE git update repo $(date) ---------------------------------+
 
EOF
}

ENTRY
cat << EOF >> "${MSC_LOGFILE}"
+-----BEGINN git update repo $(date) -------------------------------+
EOF

set -- $(getopt -u -o hrs  --long headless,force-repo-update,force-submodules-update -- "$@" )

while [ $# -gt 0 ]; do
    case $1 in
        -h|--headless)
            # Headless repo local
            echo "git remote name: ${MSC_GIT_REMOTE_NAME}"
            PRE="${MSC_GIT_REMOTE_NAME}"
            echo "git PRE: ${PRE}"
            shift
            ;;
        -r|--force-repo-update)
            dorepomodupdate="true"
            shift
            ;;
        -s|--force-submodules-update)
            dosubmodupdate="true"
            shift
            ;;
        *)
            PRE=""
            shift
            ;;
    esac
done
# If MSC_GIT_TAG is set, checkout is always headless. 
logwarn "git PRE: ${PRE}"
[ -z "${MSC_GIT_TAG:+x}" ] || { export MSC_GIT_BRANCH=${MSC_GIT_TAG}; export PRE=""; echo "DEBUG"; }
logwarn "git PRE: ${PRE}"

# Output
#echo -n " remote: ${MSC_GIT_REMOTE_NAME}, branch: ${MSC_GIT_BRANCH}: "

# Check for updates in submodules only if last check was INTERVALL hours in the past
#if [ $(cat ${MSC_BASE%/}${MSC_BASE:+/}.last_update_submodules 2>/dev/null || echo 0 ) \
[ -z "${MSC_GIT_UPD_REPO_STATFILE+x}" ] && export MSC_GIT_UPD_REPO_STATFILE="${MSC_BASE%/}${MSC_BASE:+/}.last_update_repo" 
[ -z "${MSC_GIT_UPD_SUBMOD_STATFILE+x}" ] && export MSC_GIT_UPD_SUBMOD_STATFILE="${MSC_BASE%/}${MSC_BASE:+/}.last_update_submodules" 

if [ $(stat --printf %Y ${MSC_GIT_UPD_REPO_STATFILE}  2>/dev/null || echo 0 ) \
    -lt $(date --date="${MSC_GIT_REPO_UPDATE_INTERVALL-${MSC_GIT_REPO_UPDATE_INTERVALL_DEFAULT}} hours ago" "+%s") \
    -a ${MSC_GIT_REPO_UPDATE-${MSC_GIT_REPO_UPDATE_DEFAULT-true}} ]; then
    [ -z "${dorepoupdate+x}" ] && dorepoupdate="true"
fi
    
if [ $(stat --printf %Y ${MSC_GIT_UPD_SUBMOD_STATFILE}  2>/dev/null || echo 0 ) \
    -lt $(date --date="${MSC_GIT_SUBMODULES_UPDATE_INTERVALL-${MSC_GIT_SUBMODULES_UPDATE_INTERVALL_DEFAULT}} hours ago" "+%s") \
    -a ${MSC_GIT_SUBMODULES_UPDATE-${MSC_GIT_SUBMODULES_UPDATE_DEFAULT-true}} ]; then
    [ -z "${dosubmodupdate+x}" ] && dosubmodupdate="true"
fi

#echo $SGIT fetch ${MSC_GIT_REMOTE_NAME} -p 1>&2 
if $dorepoupdate; then
    loginfo "fetch repo${dosubmodupdate:+ and submodules}"
    $SGIT fetch ${dosubmodupdate:+--recurse-submodules} ${MSC_GIT_REMOTE_NAME} -p  2>>"${MSC_LOGFILE}"|| { logwarn fetch failed; gitupdateend; exit 1; }
    if ${dosubmodupdate:-false}; then 
        lastupdatesubmodules
    fi

    echo "Check for local changes:" >> "${MSC_LOGFILE}"
    if $SGIT diff-index --ignore-submodules --exit-code HEAD -- >> "${MSC_LOGFILE}" ; then
        cat << EOF >> "${MSC_LOGFILE}"
        no changes in local repo
        $SGIT checkout repo ${PRE}${PRE:+/}${MSC_GIT_BRANCH}
EOF
        $SGIT checkout ${PRE}${PRE:+/}${MSC_GIT_BRANCH} 1>>"${MSC_LOGFILE}" 2>>"${MSC_LOGFILE}"|| { gitupdateend; exit 2; }
        $SGIT merge FETCH_HEAD 1>>"${MSC_LOGFILE}" 2>>"${MSC_LOGFILE}"|| { gitupdateend; exit 3; }
        touch $MSC_GIT_UPD_REPO_STATFILE
    else
        logwarn -n "    Lokale Änderungen festgestellt:"
        echo "    Siehe Logfile ${MSC_LOGFILE}" >&2
        cat << EOF >> "${MSC_LOGFILE}"
        um die Änderung zurückzusetzen bitte

          $SGIT checkout \$FILENAME

        oder um alle lokalen Änderungen auf einmal zurückzusetzen:

          $SGIT checkout .

        ausführen

        Die Änderungen sind:
        $($SGIT diff-index HEAD --|awk '{print $5, $6}')
        $($SGIT diff-index -p HEAD --)
EOF

        gitupdateend
        exit 4

    fi

    loginfo "repo${dosubmodupdate:+ and submodules} synced"

    if ${dosubmodupdate:-false}; then 
        loginfo "update and commit submodules"
        logdebug "$($SGIT submodule update --remote)"
        logdebug "$($SGIT commit -a -m 'update submodules')"
        touch $MSC_GIT_UPD_SUBMOD_STATFILE
        logwarn "submodules synced"
    fi
fi

EXIT
exit $rc