#!/usr/bin/env sh
set -eu

log() { echo "[vault-oidc] $*"; }

status_json="$(vault status -format=json || true)"
if [ -z "${status_json}" ]; then
  log "vault status failed; check VAULT_ADDR and VAULT_TOKEN"
  exit 1
fi

if ! printf '%s' "${status_json}" | grep -q '"initialized":[[:space:]]*true'; then
  log "vault not initialized; skipping"
  exit 0
fi

if printf '%s' "${status_json}" | grep -q '"sealed":[[:space:]]*true'; then
  log "vault sealed; skipping"
  exit 0
fi

: "${VAULT_OIDC_DISCOVERY_URL:?set VAULT_OIDC_DISCOVERY_URL}"
: "${VAULT_OIDC_CLIENT_ID:?set VAULT_OIDC_CLIENT_ID}"
: "${VAULT_OIDC_CLIENT_SECRET:?set VAULT_OIDC_CLIENT_SECRET}"

default_role="${VAULT_OIDC_DEFAULT_ROLE:-admin}"
scopes="${VAULT_OIDC_SCOPES:-openid profile email groups}"
user_claim="${VAULT_OIDC_USER_CLAIM:-preferred_username}"
groups_claim="${VAULT_OIDC_GROUPS_CLAIM:-groups}"
redirect_uris="${VAULT_OIDC_REDIRECT_URIS:-https://secret.bstein.dev/ui/vault/auth/oidc/oidc/callback}"
bound_audiences="${VAULT_OIDC_BOUND_AUDIENCES:-${VAULT_OIDC_CLIENT_ID}}"
bound_claims_type="${VAULT_OIDC_BOUND_CLAIMS_TYPE:-string}"

admin_group="${VAULT_OIDC_ADMIN_GROUP:-admin}"
admin_policies="${VAULT_OIDC_ADMIN_POLICIES:-default,vault-admin}"
dev_group="${VAULT_OIDC_DEV_GROUP:-dev}"
dev_policies="${VAULT_OIDC_DEV_POLICIES:-default,dev-kv}"
user_group="${VAULT_OIDC_USER_GROUP:-${dev_group}}"
user_policies="${VAULT_OIDC_USER_POLICIES:-${VAULT_OIDC_TOKEN_POLICIES:-${dev_policies}}}"

if ! vault auth list -format=json | grep -q '"oidc/"'; then
  log "enabling oidc auth method"
  vault auth enable oidc
fi

log "configuring oidc auth"
vault write auth/oidc/config \
  oidc_discovery_url="${VAULT_OIDC_DISCOVERY_URL}" \
  oidc_client_id="${VAULT_OIDC_CLIENT_ID}" \
  oidc_client_secret="${VAULT_OIDC_CLIENT_SECRET}" \
  default_role="${default_role}"

vault auth tune -listing-visibility=unauth oidc >/dev/null

build_bound_claims() {
  claim="$1"
  groups="$2"
  json="{\"${claim}\":["
  first=1
  old_ifs=$IFS
  IFS=,
  for item in $groups; do
    item="$(printf '%s' "$item" | sed 's/^[[:space:]]*//;s/[[:space:]]*$//')"
    if [ -z "${item}" ]; then
      continue
    fi
    if [ "${first}" -eq 0 ]; then
      json="${json},"
    fi
    json="${json}\"${item}\""
    first=0
  done
  IFS=$old_ifs
  json="${json}]}"
  printf '%s' "${json}"
}

configure_role() {
  role_name="$1"
  role_groups="$2"
  role_policies="$3"
  if [ -z "${role_name}" ] || [ -z "${role_groups}" ] || [ -z "${role_policies}" ]; then
    log "skipping role ${role_name} (missing groups or policies)"
    return
  fi
  claims="$(build_bound_claims "${groups_claim}" "${role_groups}")"
  claims_file="$(mktemp)"
  printf '%s' "${claims}" > "${claims_file}"
  scopes_csv="$(printf '%s' "${scopes}" | tr ' ' ',' | tr -s ',' | sed 's/^,//;s/,$//')"
  role_args="user_claim=${user_claim} oidc_scopes=${scopes_csv} token_policies=${role_policies} bound_audiences=${bound_audiences} bound_claims=@${claims_file} bound_claims_type=${bound_claims_type}"
  if [ -n "${groups_claim}" ]; then
    role_args="${role_args} groups_claim=${groups_claim}"
  fi
  old_ifs=$IFS
  IFS=,
  for uri in $redirect_uris; do
    trimmed="$(printf '%s' "$uri" | sed 's/^[[:space:]]*//;s/[[:space:]]*$//')"
    if [ -n "${trimmed}" ]; then
      role_args="${role_args} allowed_redirect_uris=${trimmed}"
    fi
  done
  IFS=$old_ifs
  log "configuring oidc role ${role_name}"
  vault write "auth/oidc/role/${role_name}" ${role_args}
  rm -f "${claims_file}"
}

configure_role "admin" "${admin_group}" "${admin_policies}"
configure_role "dev" "${dev_group}" "${dev_policies}"
configure_role "user" "${user_group}" "${user_policies}"