#!/bin/bash

# Log output:
#
# * 51c333e    (12 days)    <Gary Bernhardt>   add vim-eunuch
#
# The time massaging regexes start with ^[^<]* because that ensures that they
# only operate before the first "<". That "<" will be the beginning of the
# author name, ensuring that we don't destroy anything in the commit message
# that looks like time.
#
# The log format uses } characters between each field, and `column` is later
# used to split on them. A } in the commit subject or any other field will
# break this.

HASH="%C(yellow)%h%Creset"
RELATIVE_TIME="%Cgreen(%ar)%Creset"
AUTHOR="%C(bold blue)<%an>%Creset"
REFS="%C(red)%d%Creset"
SUBJECT="%s"
DEFAULT_REMOTE="upstream"
ROOT_BRANCH="master"

FORMAT="$HASH}$RELATIVE_TIME}$AUTHOR}$REFS $SUBJECT"

show_git_head() {
    pretty_git_log -1
    git show -p --pretty="tformat:"
}

pretty_git_log() {
    git log --graph --pretty="tformat:${FORMAT}" $* |
        # Replace (2 years ago) with (2 years)
        #sed -Ee 's/(^[^<]*) ago)/\1)/' |
        sed -e 's/ ago//' |
        # Replace (2 years, 5 months) with (2 years)
        #sed -Ee 's/(^[^<]*), [[:digit:]]+ .*months?)/\1)/' |
        sed -e 's/(^[^<]*), [[:digit:]]+ .*months?)/)/' |
        # Line columns up based on } delimiter
        column -s '}' -t |
        # Page only if we need to
        less -FXRS
}

sync_to_remote() {
    REMOTE=$1
    : ${REMOTE:=$DEFAULT_REMOTE}
    BRANCH=`git rev-parse --abbrev-ref HEAD`
    echo "Synching with ${REMOTE}"
    git fetch ${REMOTE} && git rebase ${REMOTE}/${BRANCH};
}

update_branch() {
    BRANCH=$1
    : ${BRANCH:=$ROOT_BRANCH}
    REMOTE=$2
    : ${REMOTE:=$DEFAULT_REMOTE}
    echo Updating ${BRANCH} from ${REMOTE}
    # check stash stack before and after
    old_stash=$(git rev-parse -q --verify refs/stash)
    git stash
    new_stash=$(git rev-parse -q --verify refs/stash)
    # checkout branch and sync to remote, then come back
    git checkout ${BRANCH} && git sync ${REMOTE} && git checkout -
    # if the stash added to the stack, pop it back off
    [ "$old_stash" != "$new_stash" ] && git stash pop
}

get_pr() {
    REMOTE=$2
    : ${REMOTE:="upstream"}
    git fetch ${REMOTE} pull/${1}/head:pr/${1}
    git checkout pr/${1}
}

del_pr() {
    BRANCH=`git rev-parse --abbrev-ref HEAD`
    if [[ ! ${BRANCH} =~ ^pr\/ ]]; then
        echo "Not a PR branch, aborting!"
        exit 1
    fi
    git checkout - && git branch -D ${BRANCH}
}

clean_branches() {
    BRANCHES=`git branch | grep -v 'master\|develop\|\*'`
    for i in ${BRANCHES}; do
        git branch -d $i
    done
}

backport_pr() {
    PR=$1
    BRANCH=$2
    [ -z "$BRANCH" ] && BRANCH=`git rev-parse --abbrev-ref HEAD`
    REMOTE=$3
    : ${REMOTE:=$DEFAULT_REMOTE}
    THISBRANCH=`git rev-parse --abbrev-ref HEAD`

    if [ -z "$PR" ]; then
        echo "Please specify a PR to backport"
        exit 1
    fi

    echo Backporting ${PR} to ${BRANCH} from ${REMOTE}
    git fetch ${REMOTE} pull/${1}/head:pr/${1}
    git checkout ${BRANCH} && curl -s "https://github.com/elastic/kibana/pull/${PR}.patch" | git am
    [ "$THISBRANCH" != "$BRANCH" ] && git checkout -
}