#!/usr/bin/env bash
#
# Installs the update agent's systemd timer. Root, once per machine, idempotent.
#
# Separate from install.sh because the installed base never runs install.sh
# again — existing servers upgrade through deploy/update.sh, which runs as the
# service account and cannot write to /etc/systemd. Without this as its own
# entry point, every server that already exists would show the update button
# permanently disabled.
#
#   sudo bash deploy/install-agent.sh
#
set -euo pipefail

ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
APP_USER="${APP_USER:-clupilot}"

[[ $EUID -eq 0 ]] || { echo "Please run as root: sudo bash deploy/install-agent.sh" >&2; exit 1; }
id -u "$APP_USER" >/dev/null 2>&1 || { echo "No such account: $APP_USER" >&2; exit 1; }

install -o "$APP_USER" -g "$APP_USER" -d "$ROOT/storage/app/deploy"
chmod +x "$ROOT/deploy/update-agent.sh"

cat > /etc/systemd/system/clupilot-update-agent.service <<EOF
[Unit]
Description=CluPilot update agent
After=docker.service
Requires=docker.service

[Service]
Type=oneshot
User=$APP_USER
WorkingDirectory=$ROOT
ExecStart=$ROOT/deploy/update-agent.sh
EOF

cat > /etc/systemd/system/clupilot-update-agent.timer <<'EOF'
[Unit]
Description=Check for CluPilot updates and run requested ones

[Timer]
# Every minute: a `git fetch` against one remote is not a nuisance at this
# rate, and the panel now shows a live countdown to the next tick — a wait
# that reads as "obviously nothing is happening" at five minutes reads as
# "obviously working" at one.
OnBootSec=3min
OnUnitActiveSec=1min
# Tightened along with the interval above: at five minutes a 30s fuzz was a
# rounding error; at one minute it is half the interval, and the panel's
# countdown would sit at 0:00 for as long as systemd felt like waiting.
AccuracySec=5s

[Install]
WantedBy=timers.target
EOF

# ── The proxy's console allowlist ────────────────────────────────────────────
# The proxy has its own allowlist and it runs BEFORE the application, so
# everything the owner adds in the console has no effect until the proxy is
# told. The agent regenerates this fragment from the console's own list.
#
# Entirely optional: an installation may sit behind nginx, Zoraxy, or nothing at
# all, and none of that is a reason for the update agent itself to fail to
# install.
CADDYFILE="${CADDYFILE:-/etc/caddy/Caddyfile}"
ALLOWFILE="/etc/caddy/clupilot-console-allow.conf"

if command -v caddy >/dev/null 2>&1 && [[ -f "$CADDYFILE" ]]; then
    echo "  Wiring the console allowlist into Caddy"

    # Seed it before anything imports it: an import of a missing file makes the
    # whole proxy config invalid, and that takes the public site down too.
    ALLOWLIST_READY=0

    if [[ -s "$ALLOWFILE" ]] && grep -q '@allowed remote_ip .' "$ALLOWFILE"; then
        ALLOWLIST_READY=1
    else
        # Compose discovers its own file from the working directory — naming it
        # here guessed wrong once.
        if ( cd "$ROOT" && runuser -u "$APP_USER" -- docker compose exec -T app \
                php artisan clupilot:console-access caddy ) > "$ALLOWFILE.new" 2>/dev/null \
            && grep -q '@allowed remote_ip .' "$ALLOWFILE.new"; then
            mv -f "$ALLOWFILE.new" "$ALLOWFILE"
            ALLOWLIST_READY=1
        else
            # NO fallback matcher here. A loopback-only list looks like a valid
            # allowlist, passes validation, and locks out every remote operator
            # the moment Caddy reloads — because the application happened to be
            # unavailable for the ten seconds this ran.
            rm -f "$ALLOWFILE.new"
            echo "  ! Could not read the console allowlist from the application."
            echo "    Leaving the proxy configuration untouched."
        fi
    fi

    [[ -f "$ALLOWFILE" ]] && { chown "$APP_USER":root "$ALLOWFILE"; chmod 0644 "$ALLOWFILE"; }

    # Replace a hard-coded matcher with the import, once. Backed up and
    # validated first — a broken Caddyfile is an outage of everything, not just
    # of the console.
    if [[ "$ALLOWLIST_READY" == "1" ]] && ! grep -q "import $ALLOWFILE" "$CADDYFILE"; then
        # Exactly one, or none of them. An unqualified substitution would
        # rewrite a matcher belonging to some other site — and the result would
        # still validate, so the first sign of it would be that site's access
        # control quietly changing.
        matches="$(grep -cE '^[[:space:]]*@allowed remote_ip ' "$CADDYFILE" || true)"

        if [[ "$matches" == "1" ]]; then
            cp -a "$CADDYFILE" "$CADDYFILE.clupilot.bak"
            sed -i "s|^\([[:space:]]*\)@allowed remote_ip .*|\1import $ALLOWFILE|" "$CADDYFILE"

            if caddy validate --config "$CADDYFILE" --adapter caddyfile >/dev/null 2>&1; then
                if systemctl reload caddy >/dev/null 2>&1; then
                    echo "  Console allowlist is now managed from the console."
                else
                    # Handed to the agent. Without this marker the file already
                    # matches what the agent would generate, so nothing would
                    # ever trigger another reload and the proxy would keep the
                    # old hard-coded list indefinitely.
                    : > "$ROOT/storage/app/deploy/.caddy-reload-pending"
                    chown "$APP_USER":"$APP_USER" "$ROOT/storage/app/deploy/.caddy-reload-pending"
                    echo "  ! Caddy did not reload — the agent retries within a minute."
                fi
            else
                echo "  ! Caddy rejected the change — restoring the previous config."
                mv -f "$CADDYFILE.clupilot.bak" "$CADDYFILE"
            fi
        else
            # Said out loud rather than assumed. Nothing to replace, or more
            # than one candidate and no way to tell which belongs to the
            # console — either way, carrying on silently would leave the
            # console's allowlist a decoration while the proxy kept its own.
            echo "  ! Found $matches single-line '@allowed remote_ip' entries in $CADDYFILE (expected exactly 1)."
            echo "    Put this inside the console's site block yourself, then reload Caddy:"
            echo "        import $ALLOWFILE"
        fi
    fi

    # Narrow on purpose: one command, no arguments, nothing else.
    cat > /etc/sudoers.d/clupilot-caddy-reload <<EOF
$APP_USER ALL=(root) NOPASSWD: /usr/bin/systemctl reload caddy
EOF
    chmod 0440 /etc/sudoers.d/clupilot-caddy-reload
    visudo -cf /etc/sudoers.d/clupilot-caddy-reload >/dev/null || rm -f /etc/sudoers.d/clupilot-caddy-reload
fi

# ── The console inside the tunnel ────────────────────────────────────────────
# The gateway serves the console on the WireGuard hub address using the
# certificate the public Caddy already obtains for that same hostname — a
# certificate is bound to the NAME, not to the address serving it. Finding it
# has to happen here, as root: the storage is Caddy's and the paths contain the
# ACME directory, which is not something to ask an operator to type.
VPN_HOST="$(sed -n 's/^VPN_INTERNAL_HOST=//p' "$ROOT/.env" 2>/dev/null | tail -1)"

if [[ -z "$VPN_HOST" ]]; then
    # Cleared. Reconciled here too, because the updater exits early when the
    # checkout has not moved — so without this there may be no path at all that
    # stops the services, and clients would keep being handed a resolver that
    # is no longer meant to exist.
    runuser -u "$APP_USER" -- sh -c "
        cd '$ROOT'
        if grep -qE '^COMPOSE_PROFILES=.*vpn' .env 2>/dev/null || grep -qE '^VPN_READY=' .env 2>/dev/null; then
            docker compose --profile vpn stop vpn-dns vpn-gateway >/dev/null 2>&1 || true
            docker compose --profile vpn rm -f vpn-dns vpn-gateway >/dev/null 2>&1 || true
            sed -i '/^VPN_CERT_PATH=/d;/^VPN_KEY_PATH=/d;/^VPN_READY=/d' .env
            profiles=\"\$(sed -n 's/^COMPOSE_PROFILES=//p' .env | tail -1)\"
            profiles=\"\$(printf '%s' \"\$profiles\" | tr ',' '\n' | grep -vx 'vpn' | grep -v '^\$' | paste -sd, - || true)\"
            sed -i '/^COMPOSE_PROFILES=/d' .env
            [ -n \"\$profiles\" ] && printf 'COMPOSE_PROFILES=%s\n' \"\$profiles\" >> .env
            docker compose exec -T app php artisan config:clear >/dev/null 2>&1 || true
            echo '  Tunnel gateway disabled — VPN_INTERNAL_HOST is empty.'
        fi
    " || true
fi

if [[ -n "$VPN_HOST" ]]; then
    # From the project's .env, because that is the file Compose reads for the
    # mount. Looking only at the default would report "no certificate" on an
    # installation whose storage is somewhere else.
    CADDY_DATA="$(sed -n 's/^CADDY_DATA_DIR=//p' "$ROOT/.env" 2>/dev/null | tail -1)"
    CADDY_DATA="${CADDY_DATA:-${CADDY_DATA_DIR:-/var/lib/caddy/.local/share/caddy}}"
    # -print -quit, not | head -1: under `set -o pipefail` a find that is still
    # producing output when head exits returns SIGPIPE, and the whole agent
    # installation aborts — on the perfectly ordinary case of one certificate
    # existing under two issuer directories.
    cert="$(find "$CADDY_DATA/certificates" -name "${VPN_HOST}.crt" -print -quit 2>/dev/null)"
    key="${cert%.crt}.key"

    if [[ -n "$cert" && -f "$key" ]]; then
        # Paths as the gateway container sees them: the storage is mounted at /certs.
        rel="${cert#$CADDY_DATA/}"
        runuser -u "$APP_USER" -- sh -c "
            cd '$ROOT'
            sed -i '/^VPN_CERT_PATH=/d;/^VPN_KEY_PATH=/d' .env
            printf 'VPN_CERT_PATH=/certs/%s\n' '$rel' >> .env
            printf 'VPN_KEY_PATH=/certs/%s\n' '${rel%.crt}.key' >> .env
        "
        # No chmod. The gateway container runs as root and reads these through
        # the read-only mount already; making the private key world-readable
        # would let every local account copy the console's TLS identity.
        # Enabled AND started here. The updater exits early when the checkout
        # has not moved, so leaving this to "the next deploy" leaves the
        # gateway stopped and the success message a lie.
        runuser -u "$APP_USER" -- sh -c "
            cd '$ROOT'
            grep -qE '^COMPOSE_PROFILES=.*vpn' .env \
                || { grep -qE '^COMPOSE_PROFILES=' .env \
                     && sed -i 's/^COMPOSE_PROFILES=\\(.*\\)\$/COMPOSE_PROFILES=\\1,vpn/' .env \
                     || printf 'COMPOSE_PROFILES=vpn\n' >> .env; }
            docker compose --profile vpn up -d vpn-dns vpn-gateway
        " >/dev/null 2>&1 || true

        # `up -d` succeeds once the containers are CREATED. One that starts and
        # exits — Caddy unable to read the certificate, or to bind the hub
        # address — still counts as success there, so the state is checked.
        sleep 3
        vpn_started=0
        if runuser -u "$APP_USER" -- sh -c "cd '$ROOT' && docker compose --profile vpn ps --status running --services" 2>/dev/null \
             | grep -q '^vpn-gateway$' \
           && runuser -u "$APP_USER" -- sh -c "cd '$ROOT' && docker compose --profile vpn ps --status running --services" 2>/dev/null \
             | grep -q '^vpn-dns$'; then
            vpn_started=1
        fi

        # The marker, and only on success. Certificate paths alone would report
        # the tunnel ready after a failed start, and the application would hand
        # out configs naming a resolver that never came up.
        runuser -u "$APP_USER" -- sh -c "
            cd '$ROOT'
            sed -i '/^VPN_READY=/d' .env
            printf 'VPN_READY=%s\n' '$([[ $vpn_started -eq 1 ]] && echo true || echo false)' >> .env
        "

        if [[ $vpn_started -ne 1 ]]; then
            echo "  ! Could not start the tunnel gateway — check: docker compose --profile vpn up -d"
        fi

        # The application caches its configuration. Without rebuilding it here,
        # vpn_ready stays false and client configs keep omitting the tunnel
        # resolver — the gateway running but nothing pointed at it.
        runuser -u "$APP_USER" -- sh -c "
            cd '$ROOT'
            docker compose exec -T app php artisan config:clear >/dev/null 2>&1
            docker compose exec -T app php artisan config:cache >/dev/null 2>&1
        " || true

        # Only when it is true. Announcing success while the gateway failed to
        # start is worse than silence: it sends the operator looking somewhere
        # else entirely.
        if [[ $vpn_started -eq 1 ]]; then
            echo "  Console reachable inside the tunnel at https://$VPN_HOST"
        fi
    else
        # Nothing usable for the CURRENT hostname. Leaving the old paths, the
        # profile and the readiness marker in place would have the application
        # advertise the renamed endpoint as ready while the gateway still
        # served the previous name.
        runuser -u "$APP_USER" -- sh -c "
            cd '$ROOT'
            sed -i '/^VPN_CERT_PATH=/d;/^VPN_KEY_PATH=/d;/^VPN_READY=/d' .env
            docker compose --profile vpn stop vpn-dns vpn-gateway >/dev/null 2>&1 || true
            # And the profile with it, or the next ordinary `up -d` starts a
            # Caddy with empty tls paths that can only crash.
            profiles=\"\$(sed -n 's/^COMPOSE_PROFILES=//p' .env | tail -1)\"
            profiles=\"\$(printf '%s' \"\$profiles\" | tr ',' '\n' | grep -vx 'vpn' | grep -v '^\$' | paste -sd, - || true)\"
            sed -i '/^COMPOSE_PROFILES=/d' .env
            [ -n \"\$profiles\" ] && printf 'COMPOSE_PROFILES=%s\n' \"\$profiles\" >> .env
            docker compose exec -T app php artisan config:clear >/dev/null 2>&1 || true
        " || true

        echo "  ! No certificate for $VPN_HOST in $CADDY_DATA yet."
        echo "    Reach https://$VPN_HOST publicly once so Caddy obtains it, then run this again."
    fi
fi

systemctl daemon-reload
systemctl enable --now clupilot-update-agent.timer >/dev/null

# Run it once now, so the panel has a status to show instead of "never reported
# in" for the first minute.
systemctl start clupilot-update-agent.service || true

echo "Update agent installed and running (clupilot-update-agent.timer)."