#!/usr/bin/env sh

set -eu

if [ $# -ne 1 ]; then
    echo "usage: ${0##*/} v2.N.P" >&2
    exit 64
fi
new_proxy_version="$1"

bindir=$( cd "${0%/*}" && pwd )
rootdir=$( cd "$bindir"/.. && pwd )

old_proxy_version="$(tr -d '\n' <"$rootdir/.proxy-version")"
if [ -z "$old_proxy_version" ]; then
    echo 'Missing .proxy-version' >&2
    exit 1
fi

old_proxy_rev="release/$old_proxy_version"

# Ensure the proxy version actually exists...
if ! bin/fetch-proxy "$new_proxy_version" >/dev/null; then
    echo "Failed to fetch proxy version $new_proxy_version"
    exit 1
fi
new_proxy_rev="release/$new_proxy_version"

# Checkout the linkerd2-proxy repo to resolve the new proxy version to a SHA
# and obtain the commit log since the prior version.
tmp=$(mktemp -d -t l2-proxy.XXX)
git clone --depth=100 https://github.com/linkerd/linkerd2-proxy "$tmp"
cd "$tmp"

if ! git rev-parse --verify --quiet "${old_proxy_rev}" ; then
    echo "The old proxy-version ${old_proxy_version} does not exist in the last 100 proxy commits." >&2
    exit 2
fi

# Commit message
(
    echo "proxy: ${new_proxy_version}"
    echo ""
    # Include the log message, stripping the version header and GPG trailer.
    git tag -l --format='%(contents)' "$new_proxy_rev" | \
        sed -e 1,2d -e '/^---*BEGIN /,$d'
    echo ""
    # Include the history, with references to pull requests.
    echo "---"
    echo ""
    refs="${old_proxy_rev}..${new_proxy_rev}"
    git log --pretty=oneline --abbrev-commit --reverse "$refs" | \
        sed -Ee 's,^[a-f0-9]{7} ,* ,' \
            -e  's, \((#[0-9]+)\), (linkerd/linkerd2-proxy\1),'
) >"$tmp/commit.txt"

cd "$rootdir"
echo "$new_proxy_version" >"$rootdir/.proxy-version"

git commit --file="$tmp/commit.txt" --edit -- "$rootdir/.proxy-version"

rm -rf "$tmp"

git --no-pager show HEAD