-- CreateEnum
CREATE TYPE "PricePhase" AS ENUM ('PREVIEW', 'EARLY_BIRD', 'REGULAR');

-- CreateEnum
CREATE TYPE "BookingStatus" AS ENUM ('PENDING', 'CONFIRMED', 'CANCELED', 'EXPIRED', 'NEEDS_REVIEW');

-- CreateEnum
CREATE TYPE "PaymentStatus" AS ENUM ('UNPAID', 'PROCESSING', 'PARTIALLY_PAID', 'PAID', 'FAILED', 'PARTIALLY_REFUNDED', 'REFUNDED');

-- CreateEnum
CREATE TYPE "PlanType" AS ENUM ('FULL', 'TWO_INSTALLMENTS', 'THREE_INSTALLMENTS');

-- CreateEnum
CREATE TYPE "InstallmentStatus" AS ENUM ('PENDING', 'PROCESSING', 'PAID', 'FAILED', 'REQUIRES_ACTION', 'CANCELED');

-- CreateEnum
CREATE TYPE "ReservationStatus" AS ENUM ('ACTIVE', 'HELD', 'CONVERTED', 'RELEASED');

-- CreateEnum
CREATE TYPE "RedemptionStatus" AS ENUM ('RESERVED', 'COMPLETED', 'RELEASED');

-- CreateEnum
CREATE TYPE "StripeEventStatus" AS ENUM ('PROCESSING', 'PROCESSED', 'IGNORED', 'FAILED');

-- CreateEnum
CREATE TYPE "EmailStatus" AS ENUM ('PENDING', 'SENT', 'FAILED');

-- CreateEnum
CREATE TYPE "ActorType" AS ENUM ('ADMIN', 'CUSTOMER', 'STRIPE', 'WORKER', 'SYSTEM');

-- CreateTable
CREATE TABLE "Camp" (
    "id" TEXT NOT NULL,
    "salesEnabled" BOOLEAN NOT NULL DEFAULT false,
    "capacity" INTEGER NOT NULL DEFAULT 10,
    "capacityConfirmed" BOOLEAN NOT NULL DEFAULT false,
    "stammmodelQuota" INTEGER NOT NULL DEFAULT 4,
    "stammmodelQuotaConfirmed" BOOLEAN NOT NULL DEFAULT false,
    "campStartDate" DATE,
    "campEndDate" DATE,
    "dateConfirmed" BOOLEAN NOT NULL DEFAULT false,
    "locationName" TEXT,
    "locationRegion" TEXT,
    "locationConfirmed" BOOLEAN NOT NULL DEFAULT false,
    "accommodationText" TEXT,
    "accommodationConfirmed" BOOLEAN NOT NULL DEFAULT false,
    "servicesConfirmed" BOOLEAN NOT NULL DEFAULT false,
    "organizerName" TEXT,
    "organizerAddress" TEXT,
    "organizerEmail" TEXT,
    "organizerPhone" TEXT,
    "organizerConfirmed" BOOLEAN NOT NULL DEFAULT false,
    "taxNote" TEXT,
    "taxConfirmed" BOOLEAN NOT NULL DEFAULT false,
    "termsVersion" TEXT,
    "termsUrl" TEXT,
    "termsApproved" BOOLEAN NOT NULL DEFAULT false,
    "travelLawChecked" BOOLEAN NOT NULL DEFAULT false,
    "installmentsApproved" BOOLEAN NOT NULL DEFAULT false,
    "installmentRuleApproved" BOOLEAN NOT NULL DEFAULT false,
    "reservationMinutes" INTEGER NOT NULL DEFAULT 30,
    "finalInstallmentLeadDays" INTEGER NOT NULL DEFAULT 30,
    "minInstallmentGapDays" INTEGER NOT NULL DEFAULT 14,
    "testPhaseOverride" "PricePhase",
    "updatedAt" TIMESTAMP(3) NOT NULL,
    "updatedBy" TEXT,

    CONSTRAINT "Camp_pkey" PRIMARY KEY ("id")
);

-- CreateTable
CREATE TABLE "Booking" (
    "id" TEXT NOT NULL,
    "reference" TEXT NOT NULL,
    "campId" TEXT NOT NULL,
    "status" "BookingStatus" NOT NULL DEFAULT 'PENDING',
    "paymentStatus" "PaymentStatus" NOT NULL DEFAULT 'UNPAID',
    "livemode" BOOLEAN NOT NULL,
    "idempotencyKey" TEXT NOT NULL,
    "statusTokenHash" TEXT NOT NULL,
    "firstName" TEXT NOT NULL,
    "lastName" TEXT NOT NULL,
    "email" TEXT NOT NULL,
    "phone" TEXT NOT NULL,
    "country" TEXT NOT NULL,
    "notes" TEXT,
    "adultConfirmedAt" TIMESTAMP(3) NOT NULL,
    "termsAcceptedAt" TIMESTAMP(3) NOT NULL,
    "termsVersion" TEXT NOT NULL,
    "accommodationAcknowledgedAt" TIMESTAMP(3) NOT NULL,
    "privacyAcknowledgedAt" TIMESTAMP(3) NOT NULL,
    "installmentMandateAt" TIMESTAMP(3),
    "pricePhase" "PricePhase" NOT NULL,
    "basePriceCents" INTEGER NOT NULL,
    "phaseDiscountCents" INTEGER NOT NULL,
    "voucherDiscountCents" INTEGER NOT NULL,
    "totalCents" INTEGER NOT NULL,
    "planType" "PlanType" NOT NULL,
    "priceSnapshot" JSONB NOT NULL,
    "priceLockedUntil" TIMESTAMP(3) NOT NULL,
    "voucherId" TEXT,
    "stripeCustomerId" TEXT,
    "stripeCheckoutSessionId" TEXT,
    "stripeCheckoutUrl" TEXT,
    "stripePaymentMethodId" TEXT,
    "paymentMethodDetachedAt" TIMESTAMP(3),
    "paidCents" INTEGER NOT NULL DEFAULT 0,
    "refundedCents" INTEGER NOT NULL DEFAULT 0,
    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    "updatedAt" TIMESTAMP(3) NOT NULL,
    "confirmedAt" TIMESTAMP(3),
    "canceledAt" TIMESTAMP(3),
    "cancelReason" TEXT,
    "reviewReason" TEXT,

    CONSTRAINT "Booking_pkey" PRIMARY KEY ("id")
);

-- CreateTable
CREATE TABLE "Installment" (
    "id" TEXT NOT NULL,
    "bookingId" TEXT NOT NULL,
    "seq" INTEGER NOT NULL,
    "amountCents" INTEGER NOT NULL,
    "dueAt" TIMESTAMP(3),
    "status" "InstallmentStatus" NOT NULL DEFAULT 'PENDING',
    "attemptCount" INTEGER NOT NULL DEFAULT 0,
    "lastAttemptAt" TIMESTAMP(3),
    "nextAttemptAt" TIMESTAMP(3),
    "failureCode" TEXT,
    "paidAt" TIMESTAMP(3),
    "refundedCents" INTEGER NOT NULL DEFAULT 0,
    "stripePaymentIntentId" TEXT,
    "stripeChargeId" TEXT,
    "checkoutSessionId" TEXT,
    "checkoutExpiresAt" TIMESTAMP(3),
    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    "updatedAt" TIMESTAMP(3) NOT NULL,

    CONSTRAINT "Installment_pkey" PRIMARY KEY ("id")
);

-- CreateTable
CREATE TABLE "Refund" (
    "id" TEXT NOT NULL,
    "bookingId" TEXT NOT NULL,
    "installmentId" TEXT,
    "stripeRefundId" TEXT NOT NULL,
    "amountCents" INTEGER NOT NULL,
    "status" TEXT NOT NULL,
    "reason" TEXT,
    "createdBy" TEXT,
    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    "updatedAt" TIMESTAMP(3) NOT NULL,

    CONSTRAINT "Refund_pkey" PRIMARY KEY ("id")
);

-- CreateTable
CREATE TABLE "SeatReservation" (
    "id" TEXT NOT NULL,
    "bookingId" TEXT NOT NULL,
    "campId" TEXT NOT NULL,
    "livemode" BOOLEAN NOT NULL,
    "status" "ReservationStatus" NOT NULL DEFAULT 'ACTIVE',
    "expiresAt" TIMESTAMP(3) NOT NULL,
    "releasedAt" TIMESTAMP(3),
    "releaseReason" TEXT,
    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    "updatedAt" TIMESTAMP(3) NOT NULL,

    CONSTRAINT "SeatReservation_pkey" PRIMARY KEY ("id")
);

-- CreateTable
CREATE TABLE "Voucher" (
    "id" TEXT NOT NULL,
    "code" TEXT NOT NULL,
    "active" BOOLEAN NOT NULL DEFAULT true,
    "validFrom" TIMESTAMP(3),
    "validUntil" TIMESTAMP(3),
    "maxRedemptions" INTEGER NOT NULL DEFAULT 1,
    "boundEmail" TEXT,
    "internalNote" TEXT,
    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    "updatedAt" TIMESTAMP(3) NOT NULL,

    CONSTRAINT "Voucher_pkey" PRIMARY KEY ("id")
);

-- CreateTable
CREATE TABLE "VoucherRedemption" (
    "id" TEXT NOT NULL,
    "voucherId" TEXT NOT NULL,
    "bookingId" TEXT NOT NULL,
    "livemode" BOOLEAN NOT NULL,
    "status" "RedemptionStatus" NOT NULL DEFAULT 'RESERVED',
    "releasedAt" TIMESTAMP(3),
    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    "updatedAt" TIMESTAMP(3) NOT NULL,

    CONSTRAINT "VoucherRedemption_pkey" PRIMARY KEY ("id")
);

-- CreateTable
CREATE TABLE "StripeEvent" (
    "id" TEXT NOT NULL,
    "type" TEXT NOT NULL,
    "livemode" BOOLEAN NOT NULL,
    "status" "StripeEventStatus" NOT NULL DEFAULT 'PROCESSING',
    "error" TEXT,
    "attempts" INTEGER NOT NULL DEFAULT 1,
    "receivedAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    "processedAt" TIMESTAMP(3),

    CONSTRAINT "StripeEvent_pkey" PRIMARY KEY ("id")
);

-- CreateTable
CREATE TABLE "EmailMessage" (
    "id" TEXT NOT NULL,
    "dedupeKey" TEXT NOT NULL,
    "bookingId" TEXT,
    "toAddress" TEXT NOT NULL,
    "subject" TEXT NOT NULL,
    "textBody" TEXT NOT NULL,
    "htmlBody" TEXT NOT NULL,
    "status" "EmailStatus" NOT NULL DEFAULT 'PENDING',
    "attempts" INTEGER NOT NULL DEFAULT 0,
    "lastError" TEXT,
    "sentAt" TIMESTAMP(3),
    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    "updatedAt" TIMESTAMP(3) NOT NULL,

    CONSTRAINT "EmailMessage_pkey" PRIMARY KEY ("id")
);

-- CreateTable
CREATE TABLE "AuditLog" (
    "id" TEXT NOT NULL,
    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    "actorType" "ActorType" NOT NULL,
    "actorId" TEXT,
    "action" TEXT NOT NULL,
    "entityType" TEXT NOT NULL,
    "entityId" TEXT NOT NULL,
    "details" JSONB,

    CONSTRAINT "AuditLog_pkey" PRIMARY KEY ("id")
);

-- CreateTable
CREATE TABLE "RateLimitBucket" (
    "key" TEXT NOT NULL,
    "windowStart" TIMESTAMP(3) NOT NULL,
    "count" INTEGER NOT NULL,

    CONSTRAINT "RateLimitBucket_pkey" PRIMARY KEY ("key")
);

-- CreateTable
CREATE TABLE "user" (
    "id" TEXT NOT NULL,
    "name" TEXT NOT NULL,
    "email" TEXT NOT NULL,
    "emailVerified" BOOLEAN NOT NULL DEFAULT false,
    "image" TEXT,
    "twoFactorEnabled" BOOLEAN DEFAULT false,
    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    "updatedAt" TIMESTAMP(3) NOT NULL,

    CONSTRAINT "user_pkey" PRIMARY KEY ("id")
);

-- CreateTable
CREATE TABLE "session" (
    "id" TEXT NOT NULL,
    "expiresAt" TIMESTAMP(3) NOT NULL,
    "token" TEXT NOT NULL,
    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    "updatedAt" TIMESTAMP(3) NOT NULL,
    "ipAddress" TEXT,
    "userAgent" TEXT,
    "userId" TEXT NOT NULL,

    CONSTRAINT "session_pkey" PRIMARY KEY ("id")
);

-- CreateTable
CREATE TABLE "account" (
    "id" TEXT NOT NULL,
    "accountId" TEXT NOT NULL,
    "providerId" TEXT NOT NULL,
    "userId" TEXT NOT NULL,
    "accessToken" TEXT,
    "refreshToken" TEXT,
    "idToken" TEXT,
    "accessTokenExpiresAt" TIMESTAMP(3),
    "refreshTokenExpiresAt" TIMESTAMP(3),
    "scope" TEXT,
    "password" TEXT,
    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    "updatedAt" TIMESTAMP(3) NOT NULL,

    CONSTRAINT "account_pkey" PRIMARY KEY ("id")
);

-- CreateTable
CREATE TABLE "verification" (
    "id" TEXT NOT NULL,
    "identifier" TEXT NOT NULL,
    "value" TEXT NOT NULL,
    "expiresAt" TIMESTAMP(3) NOT NULL,
    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    "updatedAt" TIMESTAMP(3) NOT NULL,

    CONSTRAINT "verification_pkey" PRIMARY KEY ("id")
);

-- CreateTable
CREATE TABLE "twoFactor" (
    "id" TEXT NOT NULL,
    "secret" TEXT NOT NULL,
    "backupCodes" TEXT NOT NULL,
    "userId" TEXT NOT NULL,

    CONSTRAINT "twoFactor_pkey" PRIMARY KEY ("id")
);

-- CreateTable
CREATE TABLE "rateLimit" (
    "id" TEXT NOT NULL,
    "key" TEXT NOT NULL,
    "count" INTEGER NOT NULL,
    "lastRequest" BIGINT NOT NULL,

    CONSTRAINT "rateLimit_pkey" PRIMARY KEY ("id")
);

-- CreateIndex
CREATE UNIQUE INDEX "Booking_reference_key" ON "Booking"("reference");

-- CreateIndex
CREATE UNIQUE INDEX "Booking_idempotencyKey_key" ON "Booking"("idempotencyKey");

-- CreateIndex
CREATE UNIQUE INDEX "Booking_statusTokenHash_key" ON "Booking"("statusTokenHash");

-- CreateIndex
CREATE UNIQUE INDEX "Booking_stripeCheckoutSessionId_key" ON "Booking"("stripeCheckoutSessionId");

-- CreateIndex
CREATE INDEX "Booking_livemode_status_idx" ON "Booking"("livemode", "status");

-- CreateIndex
CREATE INDEX "Booking_email_idx" ON "Booking"("email");

-- CreateIndex
CREATE INDEX "Booking_createdAt_idx" ON "Booking"("createdAt");

-- CreateIndex
CREATE UNIQUE INDEX "Installment_stripePaymentIntentId_key" ON "Installment"("stripePaymentIntentId");

-- CreateIndex
CREATE UNIQUE INDEX "Installment_stripeChargeId_key" ON "Installment"("stripeChargeId");

-- CreateIndex
CREATE UNIQUE INDEX "Installment_checkoutSessionId_key" ON "Installment"("checkoutSessionId");

-- CreateIndex
CREATE INDEX "Installment_status_dueAt_idx" ON "Installment"("status", "dueAt");

-- CreateIndex
CREATE UNIQUE INDEX "Installment_bookingId_seq_key" ON "Installment"("bookingId", "seq");

-- CreateIndex
CREATE UNIQUE INDEX "Refund_stripeRefundId_key" ON "Refund"("stripeRefundId");

-- CreateIndex
CREATE UNIQUE INDEX "SeatReservation_bookingId_key" ON "SeatReservation"("bookingId");

-- CreateIndex
CREATE INDEX "SeatReservation_campId_livemode_status_expiresAt_idx" ON "SeatReservation"("campId", "livemode", "status", "expiresAt");

-- CreateIndex
CREATE UNIQUE INDEX "Voucher_code_key" ON "Voucher"("code");

-- CreateIndex
CREATE UNIQUE INDEX "VoucherRedemption_bookingId_key" ON "VoucherRedemption"("bookingId");

-- CreateIndex
CREATE INDEX "VoucherRedemption_voucherId_livemode_status_idx" ON "VoucherRedemption"("voucherId", "livemode", "status");

-- CreateIndex
CREATE UNIQUE INDEX "EmailMessage_dedupeKey_key" ON "EmailMessage"("dedupeKey");

-- CreateIndex
CREATE INDEX "EmailMessage_status_createdAt_idx" ON "EmailMessage"("status", "createdAt");

-- CreateIndex
CREATE INDEX "AuditLog_entityType_entityId_idx" ON "AuditLog"("entityType", "entityId");

-- CreateIndex
CREATE INDEX "AuditLog_createdAt_idx" ON "AuditLog"("createdAt");

-- CreateIndex
CREATE UNIQUE INDEX "user_email_key" ON "user"("email");

-- CreateIndex
CREATE UNIQUE INDEX "session_token_key" ON "session"("token");

-- CreateIndex
CREATE INDEX "session_userId_idx" ON "session"("userId");

-- CreateIndex
CREATE INDEX "account_userId_idx" ON "account"("userId");

-- CreateIndex
CREATE INDEX "verification_identifier_idx" ON "verification"("identifier");

-- CreateIndex
CREATE INDEX "twoFactor_secret_idx" ON "twoFactor"("secret");

-- CreateIndex
CREATE INDEX "twoFactor_userId_idx" ON "twoFactor"("userId");

-- CreateIndex
CREATE UNIQUE INDEX "rateLimit_key_key" ON "rateLimit"("key");

-- AddForeignKey
ALTER TABLE "Booking" ADD CONSTRAINT "Booking_campId_fkey" FOREIGN KEY ("campId") REFERENCES "Camp"("id") ON DELETE RESTRICT ON UPDATE CASCADE;

-- AddForeignKey
ALTER TABLE "Booking" ADD CONSTRAINT "Booking_voucherId_fkey" FOREIGN KEY ("voucherId") REFERENCES "Voucher"("id") ON DELETE SET NULL ON UPDATE CASCADE;

-- AddForeignKey
ALTER TABLE "Installment" ADD CONSTRAINT "Installment_bookingId_fkey" FOREIGN KEY ("bookingId") REFERENCES "Booking"("id") ON DELETE RESTRICT ON UPDATE CASCADE;

-- AddForeignKey
ALTER TABLE "Refund" ADD CONSTRAINT "Refund_bookingId_fkey" FOREIGN KEY ("bookingId") REFERENCES "Booking"("id") ON DELETE RESTRICT ON UPDATE CASCADE;

-- AddForeignKey
ALTER TABLE "Refund" ADD CONSTRAINT "Refund_installmentId_fkey" FOREIGN KEY ("installmentId") REFERENCES "Installment"("id") ON DELETE SET NULL ON UPDATE CASCADE;

-- AddForeignKey
ALTER TABLE "SeatReservation" ADD CONSTRAINT "SeatReservation_bookingId_fkey" FOREIGN KEY ("bookingId") REFERENCES "Booking"("id") ON DELETE RESTRICT ON UPDATE CASCADE;

-- AddForeignKey
ALTER TABLE "SeatReservation" ADD CONSTRAINT "SeatReservation_campId_fkey" FOREIGN KEY ("campId") REFERENCES "Camp"("id") ON DELETE RESTRICT ON UPDATE CASCADE;

-- AddForeignKey
ALTER TABLE "VoucherRedemption" ADD CONSTRAINT "VoucherRedemption_voucherId_fkey" FOREIGN KEY ("voucherId") REFERENCES "Voucher"("id") ON DELETE RESTRICT ON UPDATE CASCADE;

-- AddForeignKey
ALTER TABLE "VoucherRedemption" ADD CONSTRAINT "VoucherRedemption_bookingId_fkey" FOREIGN KEY ("bookingId") REFERENCES "Booking"("id") ON DELETE RESTRICT ON UPDATE CASCADE;

-- AddForeignKey
ALTER TABLE "EmailMessage" ADD CONSTRAINT "EmailMessage_bookingId_fkey" FOREIGN KEY ("bookingId") REFERENCES "Booking"("id") ON DELETE SET NULL ON UPDATE CASCADE;

-- AddForeignKey
ALTER TABLE "session" ADD CONSTRAINT "session_userId_fkey" FOREIGN KEY ("userId") REFERENCES "user"("id") ON DELETE CASCADE ON UPDATE CASCADE;

-- AddForeignKey
ALTER TABLE "account" ADD CONSTRAINT "account_userId_fkey" FOREIGN KEY ("userId") REFERENCES "user"("id") ON DELETE CASCADE ON UPDATE CASCADE;

-- AddForeignKey
ALTER TABLE "twoFactor" ADD CONSTRAINT "twoFactor_userId_fkey" FOREIGN KEY ("userId") REFERENCES "user"("id") ON DELETE CASCADE ON UPDATE CASCADE;

-- ---------------------------------------------------------------------------
-- Unveraenderlicher Preis-Snapshot und Zahlungsplan (Briefing Abschnitt 9).
-- Der bei Buchung vereinbarte Preis darf auch durch einen Programmfehler oder
-- einen direkten Datenbankzugriff nicht nachtraeglich veraendert werden.
-- Eine Vertragsaenderung heisst: stornieren und neu buchen.
-- ---------------------------------------------------------------------------
CREATE OR REPLACE FUNCTION booking_snapshot_immutable() RETURNS trigger AS $$
BEGIN
  IF NEW."reference" IS DISTINCT FROM OLD."reference"
     OR NEW."livemode" IS DISTINCT FROM OLD."livemode"
     OR NEW."idempotencyKey" IS DISTINCT FROM OLD."idempotencyKey"
     OR NEW."pricePhase" IS DISTINCT FROM OLD."pricePhase"
     OR NEW."basePriceCents" IS DISTINCT FROM OLD."basePriceCents"
     OR NEW."phaseDiscountCents" IS DISTINCT FROM OLD."phaseDiscountCents"
     OR NEW."voucherDiscountCents" IS DISTINCT FROM OLD."voucherDiscountCents"
     OR NEW."totalCents" IS DISTINCT FROM OLD."totalCents"
     OR NEW."planType" IS DISTINCT FROM OLD."planType"
     OR NEW."priceSnapshot" IS DISTINCT FROM OLD."priceSnapshot"
     OR NEW."priceLockedUntil" IS DISTINCT FROM OLD."priceLockedUntil"
     OR NEW."voucherId" IS DISTINCT FROM OLD."voucherId"
  THEN
    RAISE EXCEPTION 'Preis-Snapshot der Buchung % ist unveraenderlich', OLD."id";
  END IF;
  RETURN NEW;
END
$$ LANGUAGE plpgsql;

CREATE TRIGGER booking_snapshot_immutable
  BEFORE UPDATE ON "Booking"
  FOR EACH ROW EXECUTE FUNCTION booking_snapshot_immutable();

CREATE OR REPLACE FUNCTION installment_plan_immutable() RETURNS trigger AS $$
BEGIN
  IF NEW."bookingId" IS DISTINCT FROM OLD."bookingId"
     OR NEW."seq" IS DISTINCT FROM OLD."seq"
     OR NEW."amountCents" IS DISTINCT FROM OLD."amountCents"
     OR NEW."dueAt" IS DISTINCT FROM OLD."dueAt"
  THEN
    RAISE EXCEPTION 'Rate % ist Teil des vereinbarten Zahlungsplans und unveraenderlich', OLD."id";
  END IF;
  RETURN NEW;
END
$$ LANGUAGE plpgsql;

CREATE TRIGGER installment_plan_immutable
  BEFORE UPDATE ON "Installment"
  FOR EACH ROW EXECUTE FUNCTION installment_plan_immutable();

-- Plausibilitaet auf Datenbankebene.
ALTER TABLE "Booking" ADD CONSTRAINT "Booking_amounts_check"
  CHECK ("totalCents" > 0 AND "basePriceCents" > 0 AND "phaseDiscountCents" >= 0
         AND "voucherDiscountCents" >= 0 AND "paidCents" >= 0 AND "refundedCents" >= 0
         AND "totalCents" = "basePriceCents" - "phaseDiscountCents" - "voucherDiscountCents");
ALTER TABLE "Installment" ADD CONSTRAINT "Installment_amount_check"
  CHECK ("amountCents" > 0 AND "seq" BETWEEN 1 AND 3 AND "refundedCents" >= 0);
ALTER TABLE "Camp" ADD CONSTRAINT "Camp_limits_check"
  CHECK ("capacity" >= 0 AND "stammmodelQuota" >= 0 AND "reservationMinutes" BETWEEN 30 AND 1440
         AND "finalInstallmentLeadDays" >= 0 AND "minInstallmentGapDays" >= 1);
ALTER TABLE "Voucher" ADD CONSTRAINT "Voucher_limits_check"
  CHECK ("maxRedemptions" >= 1 AND "code" = upper("code"));