#!/usr/bin/env bash
#
# One-time project bootstrap, run from a workstation BEFORE the first
# `pulumi up`.
#
# Everything here exists because Pulumi cannot create it:
#
#   * the GCS bucket that holds Pulumi's own state
#   * the passphrase that encrypts that state
#   * the service account that RUNS Pulumi in Cloud Build
#   * Gitea's signing secrets -- INTERNAL_TOKEN must be a valid Gitea-issued
#     JWT, so `gitea generate secret` has to produce it, and the values must
#     exist before the VM first boots and tries to render app.ini
#
# Idempotent: safe to re-run.
#
# Usage: scripts/bootstrap.sh <project-id> [region]   (default region: us-east1)

set -euo pipefail

PROJECT="${1:-}"
REGION="${2:-us-east1}"

if [[ -z "${PROJECT}" ]]; then
    echo "usage: $0 <project-id> [region]" >&2
    exit 1
fi

STATE_BUCKET="${PROJECT}-pulumi-state"
INFRA_SA="cb-infra"
INFRA_SA_EMAIL="${INFRA_SA}@${PROJECT}.iam.gserviceaccount.com"
GITEA_IMAGE="docker.io/gitea/gitea:latest"

log() { echo "==> $*"; }

command -v gcloud >/dev/null || { echo "gcloud is required" >&2; exit 1; }

# ---------------------------------------------------------------------------
log "enabling APIs"
# ---------------------------------------------------------------------------
gcloud services enable --project="${PROJECT}" \
    compute.googleapis.com \
    dns.googleapis.com \
    artifactregistry.googleapis.com \
    cloudbuild.googleapis.com \
    secretmanager.googleapis.com \
    iap.googleapis.com \
    storage.googleapis.com \
    logging.googleapis.com \
    monitoring.googleapis.com \
    cloudscheduler.googleapis.com \
    iamcredentials.googleapis.com \
    oslogin.googleapis.com

# ---------------------------------------------------------------------------
log "creating Pulumi state bucket gs://${STATE_BUCKET}"
# ---------------------------------------------------------------------------
if ! gcloud storage buckets describe "gs://${STATE_BUCKET}" --project="${PROJECT}" >/dev/null 2>&1; then
    gcloud storage buckets create "gs://${STATE_BUCKET}" \
        --project="${PROJECT}" \
        --location="${REGION}" \
        --uniform-bucket-level-access \
        --public-access-prevention
fi
# Versioning is the undo button for a corrupted or truncated state file.
gcloud storage buckets update "gs://${STATE_BUCKET}" --versioning --project="${PROJECT}"

# ---------------------------------------------------------------------------
log "creating secrets"
# ---------------------------------------------------------------------------
ensure_secret() {
    local name="$1"
    if ! gcloud secrets describe "${name}" --project="${PROJECT}" >/dev/null 2>&1; then
        gcloud secrets create "${name}" --project="${PROJECT}" \
            --replication-policy=automatic --labels=app=gitea
    fi
}

has_version() {
    gcloud secrets versions list "$1" --project="${PROJECT}" \
        --filter='state:ENABLED' --limit=1 --format='value(name)' 2>/dev/null | grep -q .
}

# Pulumi's state encryption passphrase. Generated here so it never lives in a
# shell history or a config file.
ensure_secret pulumi-config-passphrase
if ! has_version pulumi-config-passphrase; then
    log "generating Pulumi state passphrase"
    openssl rand -base64 48 | tr -d '\n' \
        | gcloud secrets versions add pulumi-config-passphrase --project="${PROJECT}" --data-file=-
fi

# The GitHub PAT for the Cloud Build connection. Created empty on purpose --
# a PAT is an interactive artifact and cannot be generated here.
ensure_secret github-pat
if ! has_version github-pat; then
    echo "    NOTE: secret 'github-pat' has no value yet."
    echo "          Create a GitHub PAT with repo + read:user scope and run:"
    echo "            printf %s '<token>' | gcloud secrets versions add github-pat --project=${PROJECT} --data-file=-"
fi

# The ACME contact address Caddy registers with Let's Encrypt. A secret only to
# keep it out of this public repository and out of instance metadata. Created
# empty: the address is yours to choose, not something to generate.
ensure_secret gitea-acme-email
if ! has_version gitea-acme-email; then
    echo "    NOTE: secret 'gitea-acme-email' has no value yet. Caddy still issues"
    echo "          certificates without it, but with no contact address. Set it with:"
    echo "            printf %s 'you@example.com' | gcloud secrets versions add gitea-acme-email --project=${PROJECT} --data-file=-"
fi

# Gitea's signing secrets. These MUST come from `gitea generate secret`:
# INTERNAL_TOKEN is a JWT, and a random string there produces an instance that
# starts and then fails every internal API call in a confusing way.
declare -A GITEA_SECRETS=(
    [gitea-secret-key]=SECRET_KEY
    [gitea-internal-token]=INTERNAL_TOKEN
    [gitea-oauth2-jwt-secret]=JWT_SECRET
    [gitea-lfs-jwt-secret]=LFS_JWT_SECRET
)

runner=""
for candidate in podman docker; do
    command -v "${candidate}" >/dev/null 2>&1 && { runner="${candidate}"; break; }
done

for name in "${!GITEA_SECRETS[@]}"; do
    ensure_secret "${name}"
    if has_version "${name}"; then
        log "secret ${name} already populated -- leaving it alone"
        continue
    fi
    if [[ -z "${runner}" ]]; then
        echo "    WARNING: no podman/docker available; cannot generate ${name}." >&2
        echo "             Install one and re-run, or the VM will skip rendering app.ini." >&2
        continue
    fi
    log "generating ${name}"
    # The upstream image is used only as a throwaway generator here; the
    # deployed image is our own Debian 13 build.
    "${runner}" run --rm "${GITEA_IMAGE}" gitea generate secret "${GITEA_SECRETS[$name]}" \
        | tr -d '\n' \
        | gcloud secrets versions add "${name}" --project="${PROJECT}" --data-file=-
done

# ---------------------------------------------------------------------------
log "creating the Pulumi runner service account ${INFRA_SA_EMAIL}"
# ---------------------------------------------------------------------------
# This is the chicken-and-egg account: it is the identity that runs `pulumi up`,
# so it cannot be created by `pulumi up`.
if ! gcloud iam service-accounts describe "${INFRA_SA_EMAIL}" --project="${PROJECT}" >/dev/null 2>&1; then
    gcloud iam service-accounts create "${INFRA_SA}" \
        --project="${PROJECT}" \
        --display-name="Cloud Build: infrastructure (runs Pulumi)"

    # Service account creation is eventually consistent. Binding a role to an
    # account the IAM API cannot see yet fails with
    #   INVALID_ARGUMENT: Service account ... does not exist
    # even though creation just succeeded. Wait for it to appear.
    log "waiting for ${INFRA_SA_EMAIL} to propagate"
    for _ in $(seq 1 30); do
        gcloud iam service-accounts describe "${INFRA_SA_EMAIL}" \
            --project="${PROJECT}" >/dev/null 2>&1 && break
        sleep 2
    done
fi

# `describe` returning the account is necessary but not sufficient -- the IAM
# policy backend can still reject it for a while longer. And each
# add-iam-policy-binding is a read-modify-write of the whole project policy, so
# a run of them in sequence can also collide with itself. Retry on both.
add_project_binding() {
    local member="$1" role="$2" out=""
    for attempt in $(seq 1 10); do
        if out=$(gcloud projects add-iam-policy-binding "${PROJECT}" \
                    --member="${member}" \
                    --role="${role}" \
                    --condition=None \
                    --quiet 2>&1); then
            return 0
        fi
        case "${out}" in
            *"does not exist"*|*oncurrent*)
                sleep $(( attempt * 3 ))
                ;;
            *)
                echo "${out}" >&2
                return 1
                ;;
        esac
    done
    echo "giving up on ${role}:" >&2
    echo "${out}" >&2
    return 1
}

# Broad by necessity -- Pulumi manages IAM, compute, DNS, and secrets bindings.
# Deliberately a different identity from cb-image@, which only pushes images.
INFRA_ROLES=(
    roles/compute.admin
    roles/dns.admin
    roles/artifactregistry.admin
    roles/secretmanager.admin
    roles/iam.serviceAccountAdmin
    roles/iam.serviceAccountUser
    roles/resourcemanager.projectIamAdmin
    roles/serviceusage.serviceUsageAdmin
    roles/cloudscheduler.admin
    roles/cloudbuild.builds.editor
    roles/iap.tunnelResourceAccessor
    roles/compute.osAdminLogin
    roles/logging.logWriter
)
for role in "${INFRA_ROLES[@]}"; do
    log "  granting ${role}"
    add_project_binding "serviceAccount:${INFRA_SA_EMAIL}" "${role}"
done

# Pulumi's state lives in the bucket, so the runner needs write access to it --
# scoped to that bucket rather than project-wide storage admin. Same
# propagation caveat applies.
bucket_bound=false
for attempt in $(seq 1 10); do
    if out=$(gcloud storage buckets add-iam-policy-binding "gs://${STATE_BUCKET}" \
                --project="${PROJECT}" \
                --member="serviceAccount:${INFRA_SA_EMAIL}" \
                --role=roles/storage.admin 2>&1); then
        bucket_bound=true
        break
    fi
    case "${out}" in
        *"does not exist"*|*oncurrent*) sleep $(( attempt * 3 )) ;;
        *) echo "${out}" >&2; exit 1 ;;
    esac
done
# Without this the loop would fall through after exhausting its retries and the
# script would print its success summary having granted nothing.
if [[ "${bucket_bound}" != true ]]; then
    echo "failed to grant storage.admin on gs://${STATE_BUCKET} after 10 attempts:" >&2
    echo "${out}" >&2
    exit 1
fi

cat <<SUMMARY

Bootstrap complete.

  Pulumi backend : gs://${STATE_BUCKET}
  Pulumi runner  : ${INFRA_SA_EMAIL}

Next:
  1. Install the Cloud Build GitHub App on your repository and note the
     installation id, then populate the github-pat secret (see note above).
  2. Confirm DNS delegation:  dig NS <your-domain>
  3. cd infra
     pulumi login gs://${STATE_BUCKET}
     pulumi stack init prod
     pulumi config set gcp:project ${PROJECT}
     pulumi config set gitea:infraBuildServiceAccount ${INFRA_SA_EMAIL}
     # ...plus domain, dnsZone, githubOwner, githubAppInstallationId
     pulumi up
  4. make build     # or, spelled out:
     gcloud builds submit --config cloudbuild/image.yaml --project ${PROJECT} \\
       --region ${REGION} \\
       --service-account projects/${PROJECT}/serviceAccounts/cb-image@${PROJECT}.iam.gserviceaccount.com

SUMMARY