#!/usr/bin/env bash
# Registry plumbing: REGISTRY_MODE none | local | mirror | remote. A script, not ctlptl,
# because ctlptl cannot express `mirror`.
# Usage: registry.sh up | down | status
# Notes: docs/notes/registry.md
set -euo pipefail
cd "$(dirname "$0")"

source ./lib/config.sh
load_config

REG_NAME="${CLUSTER}-registry"
REG_PORT="${REGISTRY_PORT:-5005}"
K="kubectl --context ${KUBECONTEXT}"

# ── CA trust ───────────────────────────────────────────────────────────────
# Copy REGISTRY_CA_FILE into every kind node's trust store (nodes don't inherit host trust).
install_ca_into_nodes() {
    [ -n "${REGISTRY_CA_FILE:-}" ] || return 0

    if [ ! -r "$REGISTRY_CA_FILE" ]; then
        echo "REGISTRY_CA_FILE is set but not readable: $REGISTRY_CA_FILE" >&2
        exit 1
    fi

    echo "  distributing CA to kind nodes"
    local node
    for node in $(kind get nodes --name "$CLUSTER"); do
        docker cp "$REGISTRY_CA_FILE" "$node:/usr/local/share/ca-certificates/corp-registry.crt"
        docker exec "$node" update-ca-certificates >/dev/null 2>&1
        docker exec "$node" systemctl restart containerd
    done
}

# Point containerd at a registry host. The cluster config already set
# config_path=/etc/containerd/certs.d, so this is a per-node drop-in and needs no
# cluster recreate — which is what lets registry mode change on a live cluster.
write_hosts_toml() {
    local host="$1" upstream="$2" skip_verify="${3:-false}"
    local node
    for node in $(kind get nodes --name "$CLUSTER"); do
        docker exec "$node" mkdir -p "/etc/containerd/certs.d/${host}"
        docker exec -i "$node" cp /dev/stdin "/etc/containerd/certs.d/${host}/hosts.toml" <<TOML
server = "${upstream}"

[host."${upstream}"]
  capabilities = ["pull", "resolve"]
  skip_verify = ${skip_verify}
TOML
    done
}

# ── the local container (local + mirror) ───────────────────────────────────

start_registry_container() {
    if [ "$(docker inspect -f '{{.State.Running}}' "$REG_NAME" 2>/dev/null || true)" = "true" ]; then
        echo "  registry container '$REG_NAME' already running"
        return
    fi
    docker rm -f "$REG_NAME" >/dev/null 2>&1 || true

    local args=(-d --restart=always --name "$REG_NAME"
                -p "127.0.0.1:${REG_PORT}:5000")

    if [ "$REGISTRY_MODE" = "mirror" ]; then
        if [ -z "${REGISTRY_REMOTE_URL:-}" ]; then
            echo "REGISTRY_MODE=mirror needs REGISTRY_REMOTE_URL in ctrl/.env" >&2
            exit 1
        fi
        echo "  starting pull-through cache of ${REGISTRY_REMOTE_URL}"
        args+=(-e "REGISTRY_PROXY_REMOTEURL=${REGISTRY_REMOTE_URL}")
        [ -n "${REGISTRY_USER:-}" ]     && args+=(-e "REGISTRY_PROXY_USERNAME=${REGISTRY_USER}")
        [ -n "${REGISTRY_PASSWORD:-}" ] && args+=(-e "REGISTRY_PROXY_PASSWORD=${REGISTRY_PASSWORD}")
        if [ -n "${REGISTRY_CA_FILE:-}" ]; then
            args+=(-v "$(readlink -f "$REGISTRY_CA_FILE"):/etc/ssl/certs/corp-ca.crt:ro")
        fi
    else
        echo "  starting local registry"
    fi

    docker run "${args[@]}" "$REGISTRY_IMAGE" >/dev/null
}

# The registry must share a network with the nodes so they can resolve it by
# container name; localhost inside a node is the node, not the host.
join_kind_network() {
    if docker inspect -f '{{json .NetworkSettings.Networks}}' "$REG_NAME" | grep -q '"kind"'; then
        return
    fi
    docker network connect kind "$REG_NAME" >/dev/null 2>&1 || true
}

# The documented contract that tells tooling (Tilt, skaffold) where the local
# registry is, so they don't have to be configured separately.
apply_hosting_configmap() {
    $K apply -f - <<YAML >/dev/null
apiVersion: v1
kind: ConfigMap
metadata:
  name: local-registry-hosting
  namespace: kube-public
data:
  localRegistryHosting.v1: |
    host: "localhost:${REG_PORT}"
    help: "https://kind.sigs.k8s.io/docs/user/local-registry/"
YAML
}

# ── modes ──────────────────────────────────────────────────────────────────

up() {
    echo "registry: ${REGISTRY_MODE}"
    case "$REGISTRY_MODE" in
        none)
            echo "  no registry — images are built straight into the node"
            ;;

        local|mirror)
            start_registry_container
            join_kind_network
            install_ca_into_nodes
            # Nodes reach the registry by container name on the shared network;
            # the host reaches it on localhost:PORT. Both names must resolve.
            write_hosts_toml "localhost:${REG_PORT}" "http://${REG_NAME}:5000"
            if [ "$REGISTRY_MODE" = "mirror" ]; then
                # Anything asking for docker.io transparently goes to the cache.
                write_hosts_toml "docker.io" "http://${REG_NAME}:5000"
            fi
            apply_hosting_configmap
            echo "  ready at localhost:${REG_PORT}"
            ;;

        remote)
            if [ -z "${REGISTRY_REMOTE_URL:-}" ]; then
                echo "REGISTRY_MODE=remote needs REGISTRY_REMOTE_URL in ctrl/.env" >&2
                exit 1
            fi
            install_ca_into_nodes
            local host="${REGISTRY_REMOTE_URL#*://}"; host="${host%%/*}"
            if [ -n "${REGISTRY_USER:-}" ]; then
                echo "  creating imagePullSecret for ${host}"
                $K create secret docker-registry regcred \
                    --docker-server="$host" \
                    --docker-username="$REGISTRY_USER" \
                    --docker-password="$REGISTRY_PASSWORD" \
                    --dry-run=client -o yaml | $K apply -f - >/dev/null
                # Attach to the default ServiceAccount so plain pods inherit it.
                $K patch serviceaccount default \
                    -p '{"imagePullSecrets":[{"name":"regcred"}]}' >/dev/null
            fi
            echo "  pulling directly from ${host}"
            ;;

        *)
            echo "unknown REGISTRY_MODE '$REGISTRY_MODE' (expected none|local|mirror|remote)" >&2
            exit 1
            ;;
    esac
}

down() {
    if docker inspect "$REG_NAME" >/dev/null 2>&1; then
        echo "removing registry container '$REG_NAME'"
        docker rm -f "$REG_NAME" >/dev/null
    fi
}

status() {
    echo "mode      ${REGISTRY_MODE}"
    if docker inspect "$REG_NAME" >/dev/null 2>&1; then
        echo "container ${REG_NAME}  $(docker inspect -f '{{.State.Status}}' "$REG_NAME")"
        echo "endpoint  localhost:${REG_PORT}"
    else
        echo "container none"
    fi
    [ -n "${REGISTRY_REMOTE_URL:-}" ] && echo "upstream  ${REGISTRY_REMOTE_URL}"
    [ -n "${REGISTRY_CA_FILE:-}" ]    && echo "ca        ${REGISTRY_CA_FILE}"
    return 0
}

case "${1:-status}" in
    up)     up ;;
    down)   down ;;
    status) status ;;
    *)      echo "usage: $0 [up|down|status]" >&2; exit 1 ;;
esac