CREATE TYPE product_status AS ENUM ('draft', 'published', 'unpublished');

-- rate_to_base: units of this currency per 1 unit of the base currency
-- (USD base: CNY 7.2 means 1 USD = 7.2 CNY).
CREATE TABLE currencies (
    code CHAR(3) PRIMARY KEY,
    name JSONB NOT NULL,
    symbol TEXT NOT NULL,
    exponent SMALLINT NOT NULL,
    is_base BOOLEAN NOT NULL DEFAULT FALSE,
    rate_to_base NUMERIC(20, 8) NOT NULL CHECK (rate_to_base > 0),
    enabled BOOLEAN NOT NULL DEFAULT TRUE
);

INSERT INTO currencies (code, name, symbol, exponent, is_base, rate_to_base)
VALUES
    ('USD', '{"en": "US Dollar", "zh": "美元"}', '$', 2, TRUE, 1),
    ('CNY', '{"en": "Chinese Yuan", "zh": "人民币"}', '¥', 2, FALSE, 7.2),
    ('EUR', '{"en": "Euro", "zh": "欧元"}', '€', 2, FALSE, 0.92),
    ('JPY', '{"en": "Japanese Yen", "zh": "日元"}', '¥', 0, FALSE, 150);

CREATE TABLE categories (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    parent_id UUID REFERENCES categories (id),
    name JSONB NOT NULL,
    slug TEXT NOT NULL UNIQUE,
    position INT NOT NULL DEFAULT 0
);

INSERT INTO categories (name, slug, position)
VALUES
    ('{"en": "Electronics", "zh": "电子产品"}', 'electronics', 1),
    ('{"en": "Fashion", "zh": "时尚服饰"}', 'fashion', 2),
    ('{"en": "Home & Living", "zh": "家居生活"}', 'home-living', 3);

CREATE TABLE products (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    shop_id UUID NOT NULL REFERENCES shops (id),
    category_id UUID REFERENCES categories (id),
    slug TEXT NOT NULL,
    name JSONB NOT NULL,
    description JSONB NOT NULL DEFAULT '{}',
    images JSONB NOT NULL DEFAULT '[]',
    status product_status NOT NULL DEFAULT 'draft',
    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    UNIQUE (shop_id, slug)
);

CREATE INDEX idx_products_status ON products (status);
CREATE INDEX idx_products_category ON products (category_id);

CREATE TABLE skus (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    product_id UUID NOT NULL REFERENCES products (id) ON DELETE CASCADE,
    sku_code TEXT NOT NULL,
    attributes JSONB NOT NULL DEFAULT '{}',
    price_minor BIGINT NOT NULL CHECK (price_minor >= 0),
    currency CHAR(3) NOT NULL REFERENCES currencies (code),
    stock INT NOT NULL DEFAULT 0 CHECK (stock >= 0),
    active BOOLEAN NOT NULL DEFAULT TRUE,
    UNIQUE (product_id, sku_code)
);

CREATE INDEX idx_skus_product ON skus (product_id);