#!/usr/bin/env bash
# lib-ssh.sh — shared SSH deploy-key helpers for the pangolin deploy pipelines
# (site / server). `source` this from deploy-*.sh.
#
# Provides:
#   setup_ssh     -> registers the EXIT cleanup trap first, then writes
#                    $DEPLOY_SSH_KEY to a temp private key (mode 600),
#                    registers the deploy host in a dedicated known_hosts
#                    file, and exports SSH / RSYNC_SSH (ssh command strings)
#                    + SSH_KEY_FILE.
#   teardown_ssh  -> removes the temp private key + known_hosts file.
#
# Requires env: DEPLOY_SSH_KEY (PEM content of the deploy private key,
# authorized for root on the target host).
#
# Target host is hardcoded to the pangolin1 VPS IP (103.119.13.48): the CI
# runner has no access to the user's local ~/.ssh/config, so the `pangolin1`
# alias cannot be resolved there — the bare IP is used instead. Override with
# DEPLOY_HOST / DEPLOY_PORT if a caller needs to retarget.
#
# No command substitution ($()) is used anywhere, per repo bash conventions.

DEPLOY_HOST="${DEPLOY_HOST:-103.119.13.48}"
DEPLOY_PORT="${DEPLOY_PORT:-22}"
SSH_KEY_FILE="${SSH_KEY_FILE:-/tmp/pangolin_deploy_key.$$}"
SSH_KNOWN_HOSTS_FILE="${SSH_KNOWN_HOSTS_FILE:-/tmp/pangolin_deploy_known_hosts.$$}"

# setup_ssh — write the deploy key, register known_hosts, export SSH/RSYNC_SSH.
setup_ssh() {
  # Register cleanup FIRST: if anything below fails mid-setup (e.g. a
  # transient ssh-keyscan error under `set -e`), the private key file must
  # still be removed on exit rather than leaking.
  trap teardown_ssh EXIT

  if [ -z "${DEPLOY_SSH_KEY:-}" ]; then
    echo "==> setup_ssh: DEPLOY_SSH_KEY is empty" >&2
    return 1
  fi

  mkdir -p ~/.ssh
  chmod 700 ~/.ssh

  # Pre-create the key file with restrictive perms *before* writing any key
  # material into it, so there is no window at the default umask between
  # file creation and chmod.
  install -m 600 /dev/null "${SSH_KEY_FILE}"

  # `printf '%s\n'` 末尾补一个换行：Forgejo/Gitea 存 secret 会去掉结尾换行,
  # 而缺结尾换行的 OpenSSH 格式私钥会被判为 "invalid format" 拒绝加载,
  # 退化成无密钥 → Permission denied。多补的换行对已含结尾换行的 PEM 无害。
  printf '%s\n' "${DEPLOY_SSH_KEY}" > "${SSH_KEY_FILE}"

  # Populate a dedicated known_hosts file via TOFU keyscan. This is
  # belt-and-suspenders: `accept-new` below will pin the host key on first
  # real connection regardless, so a transient keyscan failure must not
  # abort the deploy.
  ssh-keyscan -p "${DEPLOY_PORT}" -H "${DEPLOY_HOST}" >> "${SSH_KNOWN_HOSTS_FILE}" 2>/dev/null || true

  # IdentitiesOnly=yes:只用上面 -i 指定的 key,不把 agent/默认 key 也递上去
  #   (否则会触发服务器 MaxAuthTries「Too many authentication failures」)。
  # BatchMode=yes:纯非交互,认证失败即退出,不回落到密码提示卡住。
  _ssh_opts="-i ${SSH_KEY_FILE} -p ${DEPLOY_PORT} -o IdentitiesOnly=yes -o BatchMode=yes -o StrictHostKeyChecking=accept-new -o UserKnownHostsFile=${SSH_KNOWN_HOSTS_FILE}"
  SSH="ssh ${_ssh_opts}"
  RSYNC_SSH="ssh ${_ssh_opts}"
  export SSH RSYNC_SSH SSH_KEY_FILE SSH_KNOWN_HOSTS_FILE DEPLOY_HOST DEPLOY_PORT
  echo "==> setup_ssh: key written to ${SSH_KEY_FILE}, known_hosts pinned (accept-new) for ${DEPLOY_HOST}:${DEPLOY_PORT}"
}

# teardown_ssh — remove the temp private key + known_hosts file.
teardown_ssh() {
  rm -f "${SSH_KEY_FILE}" "${SSH_KNOWN_HOSTS_FILE}"
  echo "==> teardown_ssh: removed ${SSH_KEY_FILE}"
}