#!/bin/bash
ORIGIN=$(git remote | grep -i origin)
if [[ ! $ORIGIN ]];then
    echo "Remote named 'origin' is required."
    exit
fi

# if there's a remote called "upstream" presume we're on a fork
ONFORK=$(git remote | grep -i upstream)

# get branch name
BRANCH=$(git rev-parse --abbrev-ref HEAD)


spacer() {
    echo "------------------------------------------------------------------------------------------"
}
echoAndRun() {
    echo "$1"
    $1
    spacer
}
gitmaintenance() {
    # gc calls prune as well https://git-scm.com/docs/git-gc
    echoAndRun "git gc"
}
checkoutMaster() {
    echoAndRun "git checkout master"
}
checkoutLastBranch() {
    echoAndRun "git checkout -"
}
pullUpstreamMaster() {
    echoAndRun "git pull upstream master"
}
pullMaster() {
    echoAndRun "git pull origin master"
}
pushOriginMaster() {
    echoAndRun "git push origin master"
}
offerToMergeFromMaster() {
    read -r -p "Merge from master? [y/N] " response
    if [[ $response =~ ^([yY][eE][sS]|[yY])$ ]]
    then
        echoAndRun "git merge master"
    fi    
}

spacer

if [ "$ONFORK" ]
then
    echo "On a fork"
    echo "Upstream remote detected. Will update fork and push to origin master."
    spacer
    if [ "$BRANCH" == "master" ]; then
        pullUpstreamMaster
        gitmaintenance
        pushOriginMaster
    else
        checkoutMaster
        pullUpstreamMaster
        gitmaintenance
        pushOriginMaster
        checkoutLastBranch
        offerToMergeFromMaster
    fi;
else
    if [ "$BRANCH" == 'master' ]; then
        echo "On master"
        echoAndRun "git pull"
        gitmaintenance
    else
        echo "On a branch"
        checkoutMaster
        pullMaster
        gitmaintenance
        checkoutLastBranch
        offerToMergeFromMaster
    fi;
fi