-- ============================================
-- TEMPLATE-SAAS: Subscriptions
-- Schema: billing
-- Version: 1.0.0
-- ============================================

CREATE TABLE billing.subscriptions (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    tenant_id UUID NOT NULL REFERENCES tenants.tenants(id) ON DELETE CASCADE,
    plan_id UUID NOT NULL REFERENCES plans.plans(id),

    -- Stripe
    stripe_subscription_id VARCHAR(255) UNIQUE,
    stripe_customer_id VARCHAR(255),

    -- Status
    status tenants.subscription_status DEFAULT 'trialing' NOT NULL,

    -- Billing interval
    interval billing.billing_interval DEFAULT 'month',

    -- Current period
    current_period_start TIMESTAMPTZ,
    current_period_end TIMESTAMPTZ,

    -- Trial
    trial_start TIMESTAMPTZ,
    trial_end TIMESTAMPTZ,

    -- Cancellation
    cancel_at TIMESTAMPTZ,
    canceled_at TIMESTAMPTZ,
    cancel_reason VARCHAR(500),

    -- Pricing at subscription time
    price_amount DECIMAL(10, 2),
    currency VARCHAR(3) DEFAULT 'USD',

    -- Metadata
    metadata JSONB DEFAULT '{}'::jsonb,

    -- Audit
    created_at TIMESTAMPTZ DEFAULT NOW() NOT NULL,
    updated_at TIMESTAMPTZ DEFAULT NOW() NOT NULL,

    -- Constraints
    CONSTRAINT unique_active_subscription UNIQUE (tenant_id)  -- One active sub per tenant
);

-- Subscription items (for metered/usage-based)
CREATE TABLE billing.subscription_items (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    subscription_id UUID NOT NULL REFERENCES billing.subscriptions(id) ON DELETE CASCADE,

    -- Stripe
    stripe_subscription_item_id VARCHAR(255),
    stripe_price_id VARCHAR(255),

    -- Item details
    product_name VARCHAR(200),
    quantity INT DEFAULT 1,

    -- Pricing
    unit_amount DECIMAL(10, 2),

    -- For metered billing
    is_metered BOOLEAN DEFAULT FALSE,

    created_at TIMESTAMPTZ DEFAULT NOW() NOT NULL
);

-- Indexes
CREATE INDEX idx_subscriptions_tenant ON billing.subscriptions(tenant_id);
CREATE INDEX idx_subscriptions_stripe ON billing.subscriptions(stripe_subscription_id);
CREATE INDEX idx_subscriptions_status ON billing.subscriptions(status);
CREATE INDEX idx_subscription_items_sub ON billing.subscription_items(subscription_id);

-- RLS
ALTER TABLE billing.subscriptions ENABLE ROW LEVEL SECURITY;
ALTER TABLE billing.subscription_items ENABLE ROW LEVEL SECURITY;

CREATE POLICY subscriptions_tenant_isolation ON billing.subscriptions
    USING (tenant_id = current_setting('app.current_tenant_id', true)::UUID);

CREATE POLICY subscription_items_tenant_isolation ON billing.subscription_items
    USING (subscription_id IN (
        SELECT id FROM billing.subscriptions
        WHERE tenant_id = current_setting('app.current_tenant_id', true)::UUID
    ));

-- Trigger
CREATE OR REPLACE FUNCTION billing.update_updated_at()
RETURNS TRIGGER AS $$
BEGIN
    NEW.updated_at = NOW();
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;

CREATE TRIGGER trg_subscriptions_updated_at
    BEFORE UPDATE ON billing.subscriptions
    FOR EACH ROW
    EXECUTE FUNCTION billing.update_updated_at();

-- Comments
COMMENT ON TABLE billing.subscriptions IS 'Active subscriptions per tenant';
COMMENT ON TABLE billing.subscription_items IS 'Line items within a subscription';