#!/bin/sh
# Release markers refer to source commits, not Maven's workspace version edits.
set -eu

mode=${1:-}
version=${2:-}
tag="portal-release-$version"
if [ -z "$version" ] || ! git check-ref-format "refs/tags/$tag"; then
    echo 'Usage: sh scripts/release-notes.sh generate|publish VERSION' >&2
    exit 1
fi
commit=$(git rev-parse HEAD)

case "$mode" in
    generate)
        # Fetch failures must not masquerade as a first release.
        if [ "$(git rev-parse --is-shallow-repository)" = true ]; then
            git fetch --unshallow origin
        fi
        git fetch origin 'refs/tags/portal-release-*:refs/tags/portal-release-*'
        previous=$(git describe --tags --abbrev=0 --match 'portal-release-*' --exclude "$tag" HEAD 2>/dev/null || true)
        range=HEAD
        if [ -n "$previous" ]; then
            range="$previous..HEAD"
        fi
        changes=$(git log --reverse --format='- %s (`%h`)' "$range" --)
        printf '# Changes in %s\n\nSource commit: `%s`\n\n' "$version" "$commit"
        if [ -n "$previous" ]; then
            printf 'Since release tag `%s` (nearest release in this branch history).\n\n' "$previous"
        else
            printf 'First recorded release: includes all available source history.\n\n'
        fi
        if [ -n "$changes" ]; then
            printf '%s\n' "$changes"
        else
            printf 'No source changes since the previous release.\n'
        fi
        ;;
    publish)
        if git show-ref --verify --quiet "refs/tags/$tag"; then
            if [ "$(git rev-parse "refs/tags/$tag^{commit}")" != "$commit" ]; then
                echo "Release tag $tag already identifies another commit" >&2
                exit 1
            fi
        else
            git -c user.name='Jenkins' -c user.email='jenkins@locusworks.net' \
                tag -a "$tag" "$commit" -m "Release $version"
        fi
        # Never overwrite a remote release marker.
        git push origin "refs/tags/$tag:refs/tags/$tag"
        ;;
    *)
        echo 'Usage: sh scripts/release-notes.sh generate|publish VERSION' >&2
        exit 1
        ;;
esac