#!/bin/bash
#
# We fail CI if the word "F I X M E" is detedcted, as a whole word,
# in any case.  The word is not matched if there are word-characters
# abutted to it.

set -e
set -o pipefail

ORIGIN=origin
BASE_BRANCHES='main stable'

tlref () {
    echo "refs/remotes/$ORIGIN/$tbranch"
}

x () {
    echo "+ $*"
    "$@"
}

git_checkout_maybe_clean () {
    x=$1; shift
    if
	$x git checkout -q "$1"
    then :
    else 
	echo "Checkout failed, trying with git clean"
	x git clean -xdff
	x git checkout -q "$1"
    fi
}

old_branch=$(git symbolic-ref -q HEAD || test $? = 1)

restore_old_branch () {
    case "$old_branch" in
	refs/heads/*)
	    git_checkout_maybe_clean '' "${old_branch#refs/heads/}" ||
		echo '*** Failed to return to original branch ***'
	    ;;
	*)
	    echo "*** Was not originally on a branch, HEAD changed! ***"
	    ;;
    esac
}

trap 'restore_old_branch' 0

refspecs=()
for tbranch in $BASE_BRANCHES; do
    refspecs+=(+"refs/heads/$tbranch:$(tlref)")
done

# TODO really we want something like the converse of
#  git fetch --shallow-exclude
# but it doesn't seem to exist.
git fetch --unshallow "$ORIGIN" "${refspecs[@]}"

for tbranch in $BASE_BRANCHES; do
    trevlist="$(tlref)..HEAD"
    tcount=$(git rev-list --count "$trevlist")
    printf "HEAD is %3d commits ahead of %s\n" "$tcount" "$tbranch"
    if [ "$count" ] && [ $count -le $tcount ]; then continue; fi
    count=$tcount
    branch=$tbranch
    revlist=$trevlist
done

echo "Testing every commit not already on $branch"

commits=$(git rev-list --reverse "$revlist")

i=0
for commit in $commits; do
    banner='##############################'
    printf "|\n%s %d/%d %s\n|\n" "$banner" "$i" "$count" "$banner"
    git log -n1 "$commit" | sed 's/^/| /'
    echo '|'

    git_checkout_maybe_clean x "$commit"

    if x "$@"; then :; else
	rc="$?"
	printf "
|
========================= Failed after $i/$count =========================
|
Earliest broken commit is
  "
	git --no-pager log -n1 --pretty=oneline "$commit"
	exit "$rc"
    fi
    i=$(( $i + 1 ))
done

echo "|
$banner ok $banner
|"

rc=0