CREATE EXTENSION IF NOT EXISTS "uuid-ossp";
CREATE EXTENSION IF NOT EXISTS pgcrypto;

CREATE TABLE users (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  email TEXT NOT NULL UNIQUE,
  display_name TEXT NOT NULL,
  password_hash TEXT NOT NULL,
  role TEXT NOT NULL DEFAULT 'user' CHECK (role IN ('user','admin')),
  created_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE TABLE products (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  name TEXT NOT NULL,
  price_cents INT NOT NULL CHECK (price_cents >= 0),
  active BOOLEAN NOT NULL DEFAULT TRUE,
  created_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE TABLE ledger (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  user_id UUID NOT NULL REFERENCES users(id),
  amount_cents INT NOT NULL,
  kind TEXT NOT NULL CHECK (kind IN ('topup','purchase','adjustment')),
  ref_id UUID,
  created_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE TABLE orders (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  user_id UUID NOT NULL REFERENCES users(id),
  total_cents INT NOT NULL CHECK (total_cents >= 0),
  created_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE TABLE order_items (
  order_id UUID NOT NULL REFERENCES orders(id) ON DELETE CASCADE,
  product_id UUID NOT NULL REFERENCES products(id),
  qty INT NOT NULL CHECK (qty > 0),
  price_cents INT NOT NULL CHECK (price_cents >= 0),
  PRIMARY KEY (order_id, product_id)
);

CREATE TABLE inventory_movements (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  product_id UUID NOT NULL REFERENCES products(id),
  qty INT NOT NULL,
  reason TEXT NOT NULL CHECK (reason IN ('purchase','consumption','correction')),
  note TEXT,
  created_by UUID REFERENCES users(id),
  created_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE VIEW user_balances AS
SELECT user_id, COALESCE(SUM(amount_cents),0) AS balance_cents
FROM ledger GROUP BY user_id;

CREATE VIEW product_stock AS
SELECT p.id AS product_id, COALESCE(SUM(m.qty),0) AS stock
FROM products p
LEFT JOIN inventory_movements m ON m.product_id = p.id
GROUP BY p.id;