#!/bin/bash

# Stalwart install hooks.
#
# Installing a mail server is not like installing any other app: the container
# starting successfully means almost nothing. Mail only works once DNS, reverse
# DNS and outbound port 25 are right, and every one of those lives OUTSIDE the
# box — at the registrar and the VPS provider. So the job of these hooks is to
# say plainly what still has to be done, with the actual values to enter, rather
# than reporting "installed" and leaving the admin to discover weeks later that
# their mail is landing in spam.

# Echo the admin credentials for the standard final-message block (word-split
# by the caller into positional args: user pass).
stalwart_install_message_data()
{
    printf '%s %s' "${CFG_STALWART_ADMIN_USER:-admin}" "${CFG_STALWART_ADMIN_PASSWORD:-}"
}

stalwart_install_post_start()
{
    local app_name="$1"

    ((menu_number++))
    echo ""
    echo "---- $menu_number. Mail server checks + the DNS records you still need"
    echo ""

    # Resolved admin port comes from the compose tag (format `external:internal`),
    # the same source adguard's hook reads — the legacy $usedport1 isn't populated
    # by the current install pipeline.
    local compose_file="$containers_dir$app_name/docker-compose.yml"
    local admin_pair admin_port
    admin_pair=$(tagsManagerGetTagContent "$compose_file" "PORTS_TAG_1" 2>/dev/null)
    admin_port="${admin_pair%%:*}"

    # ---- 1. Can this host even send mail? --------------------------------
    # Most cheap VPS providers block outbound 25 by default (and several only
    # unblock on request). A blocked port 25 means no mail EVER leaves the box,
    # and nothing in the WebUI would otherwise reveal it.
    isNotice "Checking outbound port 25 (required to deliver mail to other servers)…"
    if command -v timeout >/dev/null 2>&1 \
       && timeout 8 bash -c 'exec 3<>/dev/tcp/gmail-smtp-in.l.google.com/25' 2>/dev/null; then
        isSuccessful "Outbound port 25 is open."
    else
        isError "Outbound port 25 appears BLOCKED or filtered on this host."
        isNotice "  Most VPS providers block it by default. Ask your provider to unblock"
        isNotice "  outbound 25, or mail will queue and never deliver."
    fi

    # ---- 2. Reverse DNS --------------------------------------------------
    # Receiving servers check that the sending IP resolves back to a name. A
    # generic provider PTR (e.g. static.1.2.3.4.provider.net) is a common reason
    # for mail being junked, and it can only be fixed in the provider's panel.
    if [[ -n "$public_ip_v4" ]] && command -v dig >/dev/null 2>&1; then
        local ptr; ptr=$(dig +short -x "$public_ip_v4" 2>/dev/null | head -1)
        if [[ -n "$ptr" ]]; then
            isNotice "Reverse DNS (PTR) for $public_ip_v4 is: ${ptr%.}"
            isNotice "  It should match your mail hostname. Set it in your VPS provider's panel."
        else
            isError "No reverse DNS (PTR) record for $public_ip_v4 — set one at your VPS provider."
        fi
    fi

    # ---- 3. Is the admin console actually there? -------------------------
    # Stalwart v0.16 does not ship the WebUI inside the Docker image: the admin
    # console is a single-page app the server fetches from GitHub on first
    # start. If this host had no outbound HTTPS at that moment the download
    # silently fails, the server still comes up healthy, and /admin and
    # /account answer 404 forever with nothing to explain why. Checking it here
    # turns "the panel is broken" into a one-line, fixable cause.
    isNotice "Checking the admin console (WebUI) responds…"
    local admin_code
    admin_code=$(runFileOp docker exec stalwart-service curl -fsS -o /dev/null -w '%{http_code}' \
        --max-time 5 http://localhost:8080/admin 2>/dev/null | tr -d '\r')
    if [[ "$admin_code" == "404" ]]; then
        isError "The admin console is missing (/admin returns 404)."
        isNotice "  Stalwart does not bundle the WebUI — it downloads it from"
        isNotice "  https://github.com/stalwartlabs/webui/releases/latest on first start."
        isNotice "  That download failed, so /admin and /account will 404 until it succeeds."
        isNotice "  Allow outbound HTTPS to github.com from this host, then restart the"
        isNotice "  container: docker restart stalwart-service"
        isNotice "  The mail server itself is unaffected — only the web interface is."
    elif [[ -z "$admin_code" ]]; then
        isError "Could not probe the admin console (no response from the container)."
    else
        isSuccessful "Admin console is being served (HTTP $admin_code)."
    fi

    # ---- 4. The records the admin must add themselves --------------------
    # Printed with real values so they can be pasted at the registrar. DKIM is
    # deliberately NOT guessed here: Stalwart generates the keypair on first
    # run, and the public key must be copied from its admin UI.
    local mail_host="${host_setup:-your-mail-hostname}"
    local mail_domain="${mail_host#*.}"
    echo ""
    isNotice "DNS records to add at your domain registrar:"
    echo "    MX     @              10 ${mail_host}"
    echo "    A      ${mail_host}   ${public_ip_v4:-<the IP of this server>}"
    echo "    TXT    @              \"v=spf1 mx -all\""
    echo "    TXT    _dmarc         \"v=DMARC1; p=quarantine; rua=mailto:postmaster@${mail_domain}\""
    echo "    TXT    <selector>._domainkey   (DKIM — copy from Stalwart's admin UI once it has"
    echo "                                    generated the key; it is not known until then)"
    echo ""

    # ---- 5. Where to go next ---------------------------------------------
    if [[ -n "$admin_port" ]]; then
        isNotice "Finish setup in the admin interface:"
        [[ -n "$public_ip_v4" ]] && echo "    http://$public_ip_v4:$admin_port/"
        echo ""
        isNotice "Sign in as '${CFG_STALWART_ADMIN_USER:-admin}' with the password shown below,"
        isNotice "then add your domain and create mailboxes."
    fi

    isNotice "Until MX, PTR, SPF, DKIM and DMARC are all in place, expect delivery"
    isNotice "problems — that is normal for a new mail server, not a fault in the app."
}