#!/usr/bin/env bash
# Sunshine TLS cert management, backed by a root CA stored in 1Password.
#
# Lifecycle:
#   1. cert-bootstrap.sh (one time, anywhere) generates the CA and uploads it
#      to 1Password.
#   2. install.sh on each host calls fetch_and_install_certs, which:
#       - reads the CA cert + key from 1Password (op CLI must be signed in)
#       - mints a host cert with SANs for <hostname>.lan and the LAN IP
#       - drops cert/key into ~/.config/sunshine/credentials/{cacert,cakey}.pem
#       - installs the CA into /etc/ca-certificates so the host trusts itself
#
# Replacing Sunshine's cert invalidates the fingerprint that previously-paired
# Moonlight clients pinned. After first cert install, re-pair each client once.

: "${OP_VAULT:=Private}"
: "${OP_CA_ITEM:=Omarchy-Stream Root CA}"
: "${CERT_DAYS:=365}"
: "${CERT_RENEW_THRESHOLD_DAYS:=30}"

SUNSHINE_CRED_DIR="$HOME/.config/sunshine/credentials"
SUNSHINE_CERT="$SUNSHINE_CRED_DIR/cacert.pem"
SUNSHINE_KEY="$SUNSHINE_CRED_DIR/cakey.pem"
SYSTEM_TRUST_ANCHOR="/etc/ca-certificates/trust-source/anchors/omarchy-stream-ca.pem"

# --- 1Password helpers ----------------------------------------------------

op_require_signin() {
  if ! command -v op >/dev/null 2>&1; then
    err "1Password CLI ('op') not found on PATH."
    err "Install it: yay -S 1password-cli"
    return 1
  fi
  if ! op whoami >/dev/null 2>&1; then
    err "Not signed in to 1Password CLI."
    err "Sign in first (in this shell): ${BOLD}eval \$(op signin)${RESET}"
    err "Or set OP_SERVICE_ACCOUNT_TOKEN in the environment for non-interactive use."
    return 1
  fi
  return 0
}

# Read a single field from the CA item. Returns 0 if the field exists.
op_read_ca_field() {
  local field="$1"
  op read --no-newline "op://${OP_VAULT}/${OP_CA_ITEM}/${field}" 2>/dev/null
}

# --- Cert state inspection ------------------------------------------------

# True if the on-disk cert is valid and not expiring within the renew threshold.
cert_is_current() {
  [[ -f "$SUNSHINE_CERT" ]] || return 1
  local expires_in_seconds
  expires_in_seconds=$(( CERT_RENEW_THRESHOLD_DAYS * 86400 ))
  openssl x509 -in "$SUNSHINE_CERT" -checkend "$expires_in_seconds" -noout >/dev/null 2>&1
}

# True if the on-disk cert is signed by the CA at $1 (pem path).
cert_signed_by_ca() {
  local ca_pem="$1"
  [[ -f "$SUNSHINE_CERT" && -f "$ca_pem" ]] || return 1
  openssl verify -CAfile "$ca_pem" "$SUNSHINE_CERT" >/dev/null 2>&1
}

cert_has_san_for() {
  local needle="$1"
  [[ -f "$SUNSHINE_CERT" ]] || return 1
  openssl x509 -in "$SUNSHINE_CERT" -noout -ext subjectAltName 2>/dev/null \
    | grep -qE "(DNS:${needle}\b|IP Address:${needle}\b)"
}

# --- Cert minting ---------------------------------------------------------

# Pick a non-link-local IPv4 on a globally-scoped interface.
detect_lan_ip() {
  ip -4 -o addr show scope global 2>/dev/null \
    | awk '{print $4}' | cut -d/ -f1 | head -n1
}

# Mint a host cert under a temp dir using the CA files passed in.
# Args: tmpdir ca_cert ca_key hostname_lc lan_ip
# Writes: $tmpdir/host-cert.pem, $tmpdir/host-key.pem
mint_host_cert() {
  local tmpdir="$1" ca_cert="$2" ca_key="$3" host_lc="$4" lan_ip="$5"

  cat >"$tmpdir/host.cnf" <<EOF
[req]
distinguished_name = dn
req_extensions = v3_req
prompt = no

[dn]
CN = ${host_lc}.lan
O = omarchy-stream

[v3_req]
basicConstraints = CA:FALSE
keyUsage = critical, digitalSignature, keyEncipherment
extendedKeyUsage = serverAuth, clientAuth
subjectAltName = @alt_names

[alt_names]
DNS.1 = ${host_lc}.lan
IP.1 = ${lan_ip}
EOF

  openssl genrsa -out "$tmpdir/host-key.pem" 2048 2>/dev/null
  openssl req -new \
    -key "$tmpdir/host-key.pem" \
    -out "$tmpdir/host.csr" \
    -config "$tmpdir/host.cnf" 2>/dev/null
  openssl x509 -req \
    -in "$tmpdir/host.csr" \
    -CA "$ca_cert" -CAkey "$ca_key" -CAcreateserial \
    -out "$tmpdir/host-cert.pem" \
    -days "$CERT_DAYS" -sha256 \
    -extensions v3_req -extfile "$tmpdir/host.cnf" 2>/dev/null
}

# --- System trust store ---------------------------------------------------

install_ca_to_system_trust() {
  local ca_pem="$1"
  # Idempotent: compare sha256 first to avoid pointless update-ca-trust runs.
  if [[ -f "$SYSTEM_TRUST_ANCHOR" ]] \
     && cmp -s "$ca_pem" "$SYSTEM_TRUST_ANCHOR"; then
    ok "CA already in system trust store"
    return 0
  fi
  info "Installing CA into $SYSTEM_TRUST_ANCHOR"
  as_root install -m 0644 "$ca_pem" "$SYSTEM_TRUST_ANCHOR"
  as_root update-ca-trust extract >/dev/null
  ok "System trust store refreshed (update-ca-trust)"
}

# --- Top-level orchestration ---------------------------------------------

# Called from install.sh. Honors FORCE_CERTS=1 to bypass freshness check.
fetch_and_install_certs() {
  op_require_signin || return 1

  local host_lc lan_ip
  host_lc="${HOSTNAME_SHORT,,}"
  lan_ip="$(detect_lan_ip)"
  if [[ -z "$lan_ip" ]]; then
    err "Could not detect a LAN IP — no globally-scoped IPv4 found."
    return 1
  fi
  info "Cert subject: CN=${host_lc}.lan, SAN: DNS:${host_lc}.lan, IP:${lan_ip}"

  # Stage CA in tmpfs (XDG_RUNTIME_DIR is tmpfs on Arch/systemd).
  local tmpdir
  tmpdir="$(mktemp -d "${XDG_RUNTIME_DIR:-/tmp}/omarchy-certs.XXXXXX")"
  chmod 700 "$tmpdir"
  # shellcheck disable=SC2064
  trap "rm -rf '$tmpdir'" EXIT

  info "Fetching CA from 1Password (vault: ${OP_VAULT}, item: ${OP_CA_ITEM})"
  if ! op_read_ca_field cert >"$tmpdir/ca-cert.pem" || [[ ! -s "$tmpdir/ca-cert.pem" ]]; then
    err "Failed to read 'cert' field from 1Password item ${OP_CA_ITEM}."
    err "Run scripts/cert-bootstrap.sh first to create the CA item."
    return 1
  fi
  if ! op_read_ca_field key >"$tmpdir/ca-key.pem" || [[ ! -s "$tmpdir/ca-key.pem" ]]; then
    err "Failed to read 'key' field from 1Password item ${OP_CA_ITEM}."
    return 1
  fi
  chmod 600 "$tmpdir/ca-key.pem"

  # Always install CA into system trust regardless of host-cert freshness.
  install_ca_to_system_trust "$tmpdir/ca-cert.pem"

  # Decide whether to mint a new host cert.
  if [[ "${FORCE_CERTS:-0}" -eq 0 ]] \
     && cert_is_current \
     && cert_signed_by_ca "$tmpdir/ca-cert.pem" \
     && cert_has_san_for "${host_lc}.lan" \
     && cert_has_san_for "${lan_ip}"; then
    ok "Sunshine cert is current, signed by CA, and matches expected SANs — skipping mint"
    return 0
  fi

  info "Minting host cert (${CERT_DAYS} days)"
  mint_host_cert "$tmpdir" "$tmpdir/ca-cert.pem" "$tmpdir/ca-key.pem" "$host_lc" "$lan_ip"

  mkdir -p "$SUNSHINE_CRED_DIR"
  install -m 0644 "$tmpdir/host-cert.pem" "$SUNSHINE_CERT"
  install -m 0600 "$tmpdir/host-key.pem"  "$SUNSHINE_KEY"
  ok "Installed Sunshine cert at $SUNSHINE_CERT"
  ok "Installed Sunshine key at $SUNSHINE_KEY"

  warn "Cert replaced. Previously-paired Moonlight clients must re-pair via https://localhost:47990."
}