#!/bin/bash
# xmrblocks health check — managed by Ansible (roles/xmrblocks)
#
# The exit code is the answer and systemd keeps it:
#     systemctl is-failed xmrblocks-healthcheck.service
# Reporting anywhere else is optional and generic.
#
# This fetches a real page rather than just opening the port. The binary
# resolves its HTML as "./templates" relative to the working directory, so a
# deploy that got WorkingDirectory wrong listens happily on 8081 and fails
# every request. A TCP check would call that healthy.

URL="${XMRBLOCKS_URL:-http://127.0.0.1:8081}"
PUSH_URL="${HEALTHCHECK_PUSH_URL:-}"
PUSH_TOKEN="${HEALTHCHECK_PUSH_TOKEN:-}"

report() {
    local status=$1
    local msg=$2

    # No push URL is normal, not an error: the exit code below is still a
    # complete answer for anything reading unit state.
    [ -n "$PUSH_URL" ] || return 0

    local encoded_msg="${msg// /%20}"
    local _ok=false
    [ "${status}" = "up" ] && _ok=true
    curl -s --max-time 15 --retry 2 -o /dev/null -X POST \
        -H "Authorization: Bearer ${PUSH_TOKEN}" \
        "${PUSH_URL}?success=${_ok}&error=${encoded_msg}" || true
}

# 90s, not the obvious 10 or 25. The index page renders ~46 KB from the LMDB,
# and this pool is a spinning-disk mirror shared with a syncing monerod: a COLD
# request measured 68 SECONDS, while the two immediately after it took 0.87s and
# 0.012s. A short timeout here does not detect a slow explorer, it manufactures
# a false DOWN every time the page cache has gone cold between runs.
body=$(curl -s --max-time 90 -w '\n%{http_code}' "${URL}/" 2>/dev/null)
code=$(printf '%s' "$body" | tail -1)

if [ -z "$code" ] || [ "$code" = "000" ]; then
    report "down" "xmrblocks not responding"
    exit 1
fi

if [ "$code" != "200" ]; then
    report "down" "xmrblocks HTTP ${code}"
    exit 1
fi

# A 200 that is not the explorer is still a failure. The index page always
# carries the project name in its title.
if ! printf '%s' "$body" | grep -qi "monero"; then
    report "down" "xmrblocks served 200 but not an explorer page (templates missing?)"
    exit 1
fi

report "up" "OK"
exit 0