#!/bin/bash
#################################################################################################
# title         :git-myshellconfig-checkout                                                        #
# description   :checkout git detached HEAD                                                     #
# author        :Jakobus Schürz                                                                 #
# changes by    :Jakobus Schürz                                                                 #
# created       :17.01.2019                                                                     #
# updated       :                                                                               #
# version       :1.0                                                                            #
# usage         :./git-checkout 	                                                        #
# notes         :                                                                               #
#################################################################################################

[ -z "${SGIT+x}" ] && SGIT=git
    [ -z "${MYSHELLCONFIG_LOGDIR+x}" ]                  && export MYSHELLCONFIG_LOGDIR="${HOME}/logs"
    [ -z "${MYSHELLCONFIG_LOGFILE+x}" ]                 && export MYSHELLCONFIG_LOGFILE="${MYSHELLCONFIG_LOGDIR}/myshellconfig.log"
#MYSHELLCONFIG_LOGDIR="./logs"
#MYSHELLCONFIG_LOGFILE="${MYSHELLCONFIG_LOGDIR}/git.log"
[ -d "${MYSHELLCONFIG_LOGDIR}" ] || mkdir -p "${MYSHELLCONFIG_LOGDIR}"
[ -z "${MYSHELLCONFIG_GIT_REMOTE_NAME+x}" ] && export MYSHELLCONFIG_GIT_REMOTE_NAME=origin
[ -z "${MYSHELLCONFIG_GIT_BRANCH+x}" ] && export MYSHELLCONFIG_GIT_BRANCH=master

ENTRY
cat << EOF >> "${MYSHELLCONFIG_LOGFILE}"
+-----BEGINN $(date) -------------------------------+
EOF

case $1 in
    -h)
        # Headless repo local
        PRE="${MYSHELLCONFIG_GIT_REMOTE_NAME}"
        ;;
    *)
        PRE=""
        ;;
esac
# If TAG is set, checkout is always headless. 
[ -z "${MYSHELLCONFIG_GIT_TAG:+x}" ] || { export MYSHELLCONFIG_GIT_BRANCH=${MYSHELLCONFIG_GIT_TAG}; export PRE=""; }

# Output
#echo -n " remote: ${MYSHELLCONFIG_GIT_REMOTE_NAME}, branch: ${MYSHELLCONFIG_GIT_BRANCH}: "

#echo $SGIT fetch ${MYSHELLCONFIG_GIT_REMOTE_NAME} -p 1>&2 
$SGIT fetch ${MYSHELLCONFIG_GIT_REMOTE_NAME} -p  2>>"${MYSHELLCONFIG_LOGFILE}"|| { logwarn fetch failed; exit 1; }

if $SGIT diff-index --ignore-submodules --exit-code HEAD -- >> "${MYSHELLCONFIG_LOGFILE}" ; then
    cat << EOF >> "${MYSHELLCONFIG_LOGFILE}"
Check for local changes:
    no changes in local repo
    $SGIT checkout repo ${PRE}${PRE:+/}${MYSHELLCONFIG_GIT_BRANCH}
EOF
    #echo "checkout origin/master as detached HEAD"
    $SGIT checkout ${PRE}${PRE:+/}${MYSHELLCONFIG_GIT_BRANCH} 1>>"${MYSHELLCONFIG_LOGFILE}" 2>>"${MYSHELLCONFIG_LOGFILE}"|| exit 2
    $SGIT merge FETCH_HEAD 1>>"${MYSHELLCONFIG_LOGFILE}" 2>>"${MYSHELLCONFIG_LOGFILE}"|| exit 3
else
    cat << EOF >> "${MYSHELLCONFIG_LOGFILE}"
Check for local changes:
    Ich habe lokale Änderungen festgestellt
    um die Änderung zurückzusetzen bitte

      $SGIT checkout \$FILENAME

    oder um alle lokalen Änderungen auf einmal zurückzusetzen:

      $SGIT checkout .

    ausführen

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

    logwarn "Lokale Änderungen festgestellt: Siehe Logfile ${MYSHELLCONFIG_LOGFILE}" >&2
cat << EOF >> "${MYSHELLCONFIG_LOGFILE}"

+-----ENDE $(date) ---------------------------------+
 
EOF
    exit 4

fi

if ${MYSHELLCONFIG_GIT_UPDATE_SUBMODULES-${MYSHELLCONFIG_GIT_UPDATE_SUBMODULES_DEFAULT-true}}; then
logdebug "update submodules"
    rc=0

    logdebug "update submodules" >&2
    # Submodules always have origin and master as repo and branch to track
    $SGIT submodule init 1>>"${MYSHELLCONFIG_LOGFILE}" 2>&1|| { logwarn "update submodules failed on ini"; rc=5; }
    $SGIT submodule sync 1>>"${MYSHELLCONFIG_LOGFILE}" 2>&1|| { logwarn "sync submodules failed on sync"; rc=6;  }
    $SGIT submodule foreach "git checkout master"  1>>"${MYSHELLCONFIG_LOGFILE}" 2>&1               || { logwarn "checkout master submodules failed on set upstream"; rc=7;  }
    $SGIT submodule foreach "git branch -u origin/master master"  1>>"${MYSHELLCONFIG_LOGFILE}" 2>&1|| { logwarn "set-upstream submodules failed on set upstream"; rc=8;  }
    $SGIT submodule update --recursive --remote --merge 1>>"${MYSHELLCONFIG_LOGFILE}" 2>&1          || { logwarn " update submodules failed on update"; rc=9;  }
    logdebug "submodules updated" >&2

logdebug "update submodules ENDE"
else
    logdebug "Do not update submodules. It's denied by environment MYSHELLCONFIG_GIT_UPDATE_SUBMODULES: ${MYSHELLCONFIG_GIT_UPDATE_SUBMODULES-${MYSHELLCONFIG_GIT_UPDATE_SUBMODULES_DEFAULT-true}}"
fi

EXIT
exit $rc