#!/bin/bash
# cloudflareMigrationDns.sh
# Setzt DNS Records für Amazon SES Migration + Cloudflare
# Unterstützt: DKIM, SPF (Merge), DMARC, MX, Autodiscover
# NEU: Setzt mail/imap/smtp/pop Subdomains für domain-spezifischen Mailserver-Zugang

set -e

# --- KONFIGURATION ---
AWS_REGION=${AWS_REGION:-"us-east-2"}
DRY_RUN=${DRY_RUN:-"false"}

# IP des Mailservers - PFLICHT wenn keine CNAME-Kette gewünscht
# export MAIL_SERVER_IP="1.2.3.4"
MAIL_SERVER_IP=${MAIL_SERVER_IP:-""}

# Ziel-Server für Mailclients. Standard: mail.<kundendomain>
# Wenn MAIL_SERVER_IP gesetzt ist, bekommt mail.<domain> einen A-Record
# und imap/smtp/pop/webmail zeigen per CNAME auf mail.<domain>
TARGET_MAIL_SERVER=${TARGET_MAIL_SERVER:-"mail.${DOMAIN_NAME}"}

# --- CHECKS ---
if [ -z "$DOMAIN_NAME" ]; then echo "❌ Fehler: DOMAIN_NAME fehlt."; exit 1; fi
if [ -z "$CF_API_TOKEN" ]; then echo "❌ Fehler: CF_API_TOKEN fehlt."; exit 1; fi
if ! command -v jq &> /dev/null; then echo "❌ Fehler: 'jq' fehlt."; exit 1; fi
if ! command -v aws &> /dev/null; then echo "❌ Fehler: 'aws' CLI fehlt."; exit 1; fi

if [ -z "$MAIL_SERVER_IP" ] && [ "$TARGET_MAIL_SERVER" == "mail.$DOMAIN_NAME" ]; then
    echo "⚠️  WARNUNG: MAIL_SERVER_IP ist nicht gesetzt!"
    echo "   mail.$DOMAIN_NAME braucht einen A-Record."
    echo "   Bitte setzen: export MAIL_SERVER_IP=<IP deines Servers>"
    exit 1
fi

echo "============================================================"
echo " 🛡️  DNS Migration Setup für: $DOMAIN_NAME"
echo " 🌍  Region: $AWS_REGION"
echo " 📬  Mail-Server Target: $TARGET_MAIL_SERVER"
[ -n "$MAIL_SERVER_IP" ] && echo " 🖥️  Server IP: $MAIL_SERVER_IP"
[ "$DRY_RUN" = "true" ] && echo " ⚠️  DRY RUN MODE - Keine Änderungen!"
echo "============================================================"

# 1. ZONE ID HOLEN
echo "🔍 Suche Cloudflare Zone ID..."
ZONE_ID=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones?name=$DOMAIN_NAME" \
    -H "Authorization: Bearer $CF_API_TOKEN" -H "Content-Type: application/json" | jq -r '.result[0].id')

if [ "$ZONE_ID" == "null" ] || [ -z "$ZONE_ID" ]; then
    echo "❌ Zone nicht gefunden."
    exit 1
fi
echo "   ✅ Zone ID: $ZONE_ID"

# ------------------------------------------------------------------
# FUNKTION: ensure_record
# ------------------------------------------------------------------
ensure_record() {
    local type=$1
    local name=$2
    local content=$3
    local proxied=${4:-false}
    local priority=$5

    echo "   ⚙️  Prüfe $type $name..."

    local search_res=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/dns_records?type=$type&name=$name" \
        -H "Authorization: Bearer $CF_API_TOKEN" -H "Content-Type: application/json")
    
    local rec_id=$(echo "$search_res" | jq -r '.result[0].id')
    local rec_content=$(echo "$search_res" | jq -r '.result[0].content')

    if [ "$type" == "MX" ]; then
        json_data=$(jq -n --arg t "$type" --arg n "$name" --arg c "$content" --argjson p "$proxied" --argjson prio "$priority" \
            '{type: $t, name: $n, content: $c, ttl: 3600, proxied: $p, priority: $prio}')
    else
        json_data=$(jq -n --arg t "$type" --arg n "$name" --arg c "$content" --argjson p "$proxied" \
            '{type: $t, name: $n, content: $c, ttl: 3600, proxied: $p}')
    fi

    if [ "$rec_id" == "null" ]; then
        if [ "$DRY_RUN" = "true" ]; then
            echo "      [DRY] Würde ERSTELLEN: $content"
        else
            res=$(curl -s -X POST "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/dns_records" \
                -H "Authorization: Bearer $CF_API_TOKEN" -H "Content-Type: application/json" --data "$json_data")
            if [ "$(echo $res | jq -r .success)" == "true" ]; then
                echo "      ✅ Erstellt."
            else
                echo "      ❌ Fehler: $(echo $res | jq -r .errors[0].message)"
            fi
        fi
    else
        if [ "$rec_content" == "$content" ]; then
            echo "      🆗 Identisch. Überspringe."
        else
            if [ "$type" == "MX" ] && [ "$name" == "$DOMAIN_NAME" ]; then
                echo "      ⛔ MX existiert aber anders! Gefunden: $rec_content / Erwartet: $content"
                echo "         Bitte Record ID $rec_id manuell löschen."
                return
            fi
            if [ "$DRY_RUN" = "true" ]; then
                echo "      [DRY] Würde UPDATEN: '$rec_content' → '$content'"
            else
                res=$(curl -s -X PUT "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/dns_records/$rec_id" \
                    -H "Authorization: Bearer $CF_API_TOKEN" -H "Content-Type: application/json" --data "$json_data")
                if [ "$(echo $res | jq -r .success)" == "true" ]; then
                    echo "      🔄 Aktualisiert."
                else
                    echo "      ❌ Fehler: $(echo $res | jq -r .errors[0].message)"
                fi
            fi
        fi
    fi
}

# ------------------------------------------------------------------
# SCHRITT 1: MAIL FROM ermitteln
# ------------------------------------------------------------------
echo ""
echo "--- 1. MAIL FROM Domain ---"
if [ -z "$MAIL_FROM_DOMAIN" ]; then
    SES_JSON=$(aws sesv2 get-email-identity --email-identity $DOMAIN_NAME --region $AWS_REGION 2>/dev/null)
    MAIL_FROM_DOMAIN=$(echo "$SES_JSON" | jq -r '.MailFromAttributes.MailFromDomain')
    if [ "$MAIL_FROM_DOMAIN" == "null" ] || [ -z "$MAIL_FROM_DOMAIN" ]; then
        MAIL_FROM_DOMAIN="mail.$DOMAIN_NAME"
        echo "   ⚠️ Kein MAIL FROM in SES. Fallback: $MAIL_FROM_DOMAIN"
    fi
else
    echo "   Nutze: $MAIL_FROM_DOMAIN"
fi

# ------------------------------------------------------------------
# SCHRITT 2: DKIM Records
# ------------------------------------------------------------------
echo ""
echo "--- 2. DKIM Records ---"
TOKENS=$(aws ses get-identity-dkim-attributes --identities $DOMAIN_NAME --region $AWS_REGION \
    --query "DkimAttributes.\"$DOMAIN_NAME\".DkimTokens" --output text)
for token in $TOKENS; do
    ensure_record "CNAME" "${token}._domainkey.$DOMAIN_NAME" "${token}.dkim.amazonses.com" false
done

# ------------------------------------------------------------------
# SCHRITT 3: SES Verification
# ------------------------------------------------------------------
echo ""
echo "--- 3. SES Verification TXT ---"
VERIF_TOKEN=$(aws ses get-identity-verification-attributes --identities $DOMAIN_NAME \
    --region $AWS_REGION --query "VerificationAttributes.\"$DOMAIN_NAME\".VerificationToken" --output text)
if [ "$VERIF_TOKEN" != "None" ] && [ -n "$VERIF_TOKEN" ]; then
    ensure_record "TXT" "_amazonses.$DOMAIN_NAME" "$VERIF_TOKEN" false
fi

# ------------------------------------------------------------------
# SCHRITT 4: MAIL FROM Subdomain (MX + SPF)
# ------------------------------------------------------------------
echo ""
echo "--- 4. MAIL FROM Subdomain ($MAIL_FROM_DOMAIN) ---"
ensure_record "MX" "$MAIL_FROM_DOMAIN" "feedback-smtp.$AWS_REGION.amazonses.com" false 10
ensure_record "TXT" "$MAIL_FROM_DOMAIN" "v=spf1 include:amazonses.com ~all" false

# ------------------------------------------------------------------
# SCHRITT 5: Root Domain SPF
# ------------------------------------------------------------------
echo ""
echo "--- 5. Root Domain SPF ---"
if [ -n "$OLD_PROVIDER_SPF" ]; then
    FINAL_SPF="v=spf1 include:amazonses.com $OLD_PROVIDER_SPF ~all"
else
    FINAL_SPF="v=spf1 include:amazonses.com ~all"
fi
ensure_record "TXT" "$DOMAIN_NAME" "$FINAL_SPF" false

# ------------------------------------------------------------------
# SCHRITT 6: Root Domain MX
# ------------------------------------------------------------------
# WICHTIG: Der MX Record zeigt auf Amazon SES (inbound-smtp.*.amazonaws.com),
# da eingehende Mails über SES → S3 → SQS → Worker → DMS laufen.
# Der DMS ist NICHT direkt aus dem Internet erreichbar.
# Dieser Record wird daher NICHT angefasst.
echo ""
echo "--- 6. Root Domain MX (nur Info, wird nicht geändert) ---"
EXISTING_MX=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/dns_records?type=MX&name=$DOMAIN_NAME" \
    -H "Authorization: Bearer $CF_API_TOKEN" -H "Content-Type: application/json" | jq -r '.result[0].content')
if [ "$EXISTING_MX" == "null" ] || [ -z "$EXISTING_MX" ]; then
    echo "   ⚠️  Kein MX Record gefunden! Bitte manuell in SES/Cloudflare setzen:"
    echo "      inbound-smtp.$AWS_REGION.amazonaws.com (Prio 10)"
else
    echo "   ℹ️  MX vorhanden: $EXISTING_MX (wird nicht geändert)"
fi

# ------------------------------------------------------------------
# SCHRITT 7: DMARC
# ------------------------------------------------------------------
echo ""
echo "--- 7. DMARC ---"
ensure_record "TXT" "_dmarc.$DOMAIN_NAME" "v=DMARC1; p=none; rua=mailto:postmaster@$DOMAIN_NAME" false

# ------------------------------------------------------------------
# SCHRITT 8 (NEU): Mailclient Subdomains
# ------------------------------------------------------------------
echo ""
echo "--- 8. Mailclient Subdomains (A + CNAME) ---"

if [ -n "$MAIL_SERVER_IP" ]; then
    # A-Record für mail.<domain> direkt auf Server-IP
    ensure_record "A" "mail.$DOMAIN_NAME" "$MAIL_SERVER_IP" false
else
    # CNAME auf externen Ziel-Host (nur wenn verschieden)
    if [ "$TARGET_MAIL_SERVER" != "mail.$DOMAIN_NAME" ]; then
        ensure_record "CNAME" "mail.$DOMAIN_NAME" "$TARGET_MAIL_SERVER" false
    fi
fi

# imap, smtp, pop, webmail → CNAME auf mail.<domain>
ensure_record "CNAME" "imap.$DOMAIN_NAME"    "mail.$DOMAIN_NAME" false
ensure_record "CNAME" "smtp.$DOMAIN_NAME"    "mail.$DOMAIN_NAME" false
ensure_record "CNAME" "pop.$DOMAIN_NAME"     "mail.$DOMAIN_NAME" false
ensure_record "CNAME" "webmail.$DOMAIN_NAME" "mail.$DOMAIN_NAME" false

# ------------------------------------------------------------------
# SCHRITT 9: Autodiscover / Autoconfig
# ------------------------------------------------------------------
echo ""
echo "--- 9. Autodiscover / Autoconfig ---"
ensure_record "CNAME" "autodiscover.$DOMAIN_NAME" "mail.$DOMAIN_NAME" false
ensure_record "CNAME" "autoconfig.$DOMAIN_NAME"   "mail.$DOMAIN_NAME" false

echo ""
echo "============================================================"
echo "✅ Fertig für Domain: $DOMAIN_NAME"
echo ""
echo "   Mailclient-Konfiguration für Kunden:"
echo "   IMAP:    imap.$DOMAIN_NAME    Port 993 (SSL)"
echo "   SMTP:    smtp.$DOMAIN_NAME    Port 587 (STARTTLS) oder 465 (SSL)"
echo "   POP3:    pop.$DOMAIN_NAME     Port 995 (SSL)"
echo "   Webmail: webmail.$DOMAIN_NAME"
echo "============================================================"