#!/usr/bin/env bash
#
# Build a link post from a JSON payload on stdin and preview it on the mudge
# blog server (http://mudge:8000, served by blog-server.service straight out
# of www/) without touching git at all: no pull, no commit, no push. The post
# file is deleted from posts/ again right after the preview build, so this
# never leaves a trace in the repo or in git history.
#
#   ssh mudge '$HOME/samhuri.net/bin/preview-link' <<'JSON'
#   {"title": "Magical Wristband", "link": "https://example.net/x",
#    "body": "Optional commentary.", "tags": "gear, tech"}
#   JSON
#
# Prints the preview URL on stdout, progress on stderr. Used by the
# dashboard's "Publish Beta" button.

set -euo pipefail

# Non-interactive SSH sessions get a bare PATH; make sure rbenv is reachable.
export PATH="$HOME/.rbenv/bin:$HOME/.rbenv/shims:$PATH"
if command -v rbenv >/dev/null 2>&1; then
  eval "$(rbenv init - bash)"
fi

# Run from the repo root regardless of where the script lives.
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
REPO="${SAMHURI_REPO:-$(cd "$SCRIPT_DIR/.." && pwd)}"
cd "$REPO"

payload="$(cat)"
if [ -z "${payload//[[:space:]]/}" ]; then
  echo "Error: empty payload on stdin" >&2
  exit 1
fi

echo "==> Building preview" >&2
# `bake mudge` logs its own build progress to stdout (not stderr), so only the
# final line -- the preview URL `preview_link` puts last -- is what we want.
printf '%s' "$payload" | bundle exec bake preview_link | tee /dev/stderr | tail -n 1