#!/bin/bash

set -Eeuo pipefail

if [[ $# -ne 2 ]]; then
    echo "usage: $0 <site-dir> <branch>" >&2
    exit 2
fi

SITE_DIR="$1"
BRANCH="$2"

if [[ ! -d "$SITE_DIR" ]]; then
    echo "site directory not found: $SITE_DIR" >&2
    exit 1
fi

if ! git rev-parse --git-dir >/dev/null 2>&1; then
    echo "must be run inside a git repository" >&2
    exit 1
fi

TMP_DIR="$(mktemp -d)"
cleanup() {
    git worktree remove --force "$TMP_DIR" >/dev/null 2>&1 || true
}
trap cleanup EXIT

git fetch origin "$BRANCH" || true

if git show-ref --verify --quiet "refs/remotes/origin/$BRANCH"; then
    git worktree add --detach "$TMP_DIR" "origin/$BRANCH"
else
    git worktree add --detach "$TMP_DIR"
    git -C "$TMP_DIR" checkout --orphan "$BRANCH"
fi

find "$TMP_DIR" -mindepth 1 -maxdepth 1 ! -name '.git' -exec rm -rf {} +
cp -R "$SITE_DIR"/. "$TMP_DIR"/
touch "$TMP_DIR/.nojekyll"

git -C "$TMP_DIR" config user.name "${GIT_AUTHOR_NAME:-Forgejo Actions}"
git -C "$TMP_DIR" config user.email "${GIT_AUTHOR_EMAIL:-forgejo-actions@localhost}"
git -C "$TMP_DIR" add -A

if git -C "$TMP_DIR" diff --cached --quiet; then
    echo "no docs changes to publish"
    exit 0
fi

git -C "$TMP_DIR" commit -m "Publish docs for ${GITHUB_SHA:-local build}"
git -C "$TMP_DIR" push --force origin "HEAD:${BRANCH}"