-- nl2sql-bench/server/db/schema.sql
-- E-commerce database schema for NL2SQL-Bench
-- Designed for in-memory SQLite: realistic, universally understood domain.

CREATE TABLE IF NOT EXISTS categories (
    id          INTEGER PRIMARY KEY,
    name        TEXT    NOT NULL UNIQUE
);

CREATE TABLE IF NOT EXISTS products (
    id              INTEGER PRIMARY KEY,
    name            TEXT    NOT NULL,
    category_id     INTEGER NOT NULL REFERENCES categories(id),
    price           REAL    NOT NULL CHECK(price >= 0),
    stock_quantity  INTEGER NOT NULL DEFAULT 0
);

CREATE TABLE IF NOT EXISTS customers (
    id          INTEGER PRIMARY KEY,
    name        TEXT    NOT NULL,
    email       TEXT    NOT NULL UNIQUE,
    country     TEXT    NOT NULL,
    tier        TEXT    NOT NULL DEFAULT 'bronze'   -- bronze | silver | gold
                CHECK(tier IN ('bronze', 'silver', 'gold')),
    created_at  TEXT    NOT NULL   -- ISO-8601 date string
);

CREATE TABLE IF NOT EXISTS orders (
    id              INTEGER PRIMARY KEY,
    customer_id     INTEGER NOT NULL REFERENCES customers(id),
    status          TEXT    NOT NULL DEFAULT 'pending'
                    CHECK(status IN ('pending','processing','shipped','delivered','cancelled')),
    created_at      TEXT    NOT NULL,
    total_amount    REAL    NOT NULL CHECK(total_amount >= 0)
);

CREATE TABLE IF NOT EXISTS order_items (
    id          INTEGER PRIMARY KEY,
    order_id    INTEGER NOT NULL REFERENCES orders(id),
    product_id  INTEGER NOT NULL REFERENCES products(id),
    quantity    INTEGER NOT NULL CHECK(quantity > 0),
    unit_price  REAL    NOT NULL CHECK(unit_price >= 0)
);

CREATE TABLE IF NOT EXISTS reviews (
    id          INTEGER PRIMARY KEY,
    product_id  INTEGER NOT NULL REFERENCES products(id),
    customer_id INTEGER NOT NULL REFERENCES customers(id),
    rating      INTEGER NOT NULL CHECK(rating BETWEEN 1 AND 5),
    created_at  TEXT    NOT NULL
);

-- Indexes for common join/filter patterns
CREATE INDEX IF NOT EXISTS idx_products_category   ON products(category_id);
CREATE INDEX IF NOT EXISTS idx_orders_customer     ON orders(customer_id);
CREATE INDEX IF NOT EXISTS idx_orders_status       ON orders(status);
CREATE INDEX IF NOT EXISTS idx_orders_created      ON orders(created_at);
CREATE INDEX IF NOT EXISTS idx_order_items_order   ON order_items(order_id);
CREATE INDEX IF NOT EXISTS idx_order_items_product ON order_items(product_id);
CREATE INDEX IF NOT EXISTS idx_reviews_product     ON reviews(product_id);
CREATE INDEX IF NOT EXISTS idx_customers_country   ON customers(country);
CREATE INDEX IF NOT EXISTS idx_customers_tier      ON customers(tier);