#!/usr/bin/env bash

# Ensures that the working tree is clean, and Documentation/ is up to
# date, and then commits Documentation/*.1 to the man branch, and
# Documentation/*.html to the html branch.

set -uexo pipefail

test "$#" -eq 2

# Must be full ref name, i.e. refs/heads/man, etc.
man_ref="$1"
html_ref="$2"

git diff-index --quiet HEAD --  # no uncommitted changes
git rev-parse --verify "$man_ref"
git rev-parse --verify "$html_ref"
echo "$man_ref" | grep -qE '^refs/heads'
echo "$html_ref" | grep -qE '^refs/heads'

"${MAKE:-make}"

mkdir -p t/tmp
tmpdir="$(mktemp -d "t/tmp/update-doc-branches-XXXXXX")"
trap "$(printf 'rm -rf %q' "$tmpdir")" EXIT
tmpidx="$tmpdir/git-index.tmp"

for fmt in man html; do
    rm -f "$tmpidx"
    for f in $(git ls-files 'Documentation/*.md'); do
        base="$(basename "$f" .md)"
        if test "$fmt" = man; then
            ref="$man_ref"
            GIT_INDEX_FILE="$tmpidx" git add -f "Documentation/$base.1"
        else
            ref="$html_ref"
            GIT_INDEX_FILE="$tmpidx" git add -f "Documentation/$base.html"
        fi
    done
    msg="Update $fmt pages for $(git describe --always)"
    tree=$(GIT_INDEX_FILE="$tmpidx" git write-tree --prefix=Documentation)
    commit=$(echo "$msg" | git commit-tree "$tree" -p refs/heads/"$fmt")
    git update-ref "$ref" "$commit"
done