CREATE TYPE order_status AS ENUM (
    'pending_payment',
    'paid',
    'fulfilling',
    'shipped',
    'completed',
    'cancelled'
);

CREATE TYPE shipment_status AS ENUM ('pending', 'shipped', 'delivered');

CREATE TYPE invoice_status AS ENUM ('requested', 'issued', 'cancelled');

CREATE TYPE invoice_kind AS ENUM ('personal', 'company');

CREATE SEQUENCE order_no_seq;
CREATE SEQUENCE shipment_no_seq;
CREATE SEQUENCE invoice_no_seq;

CREATE TABLE orders (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    order_no TEXT NOT NULL UNIQUE,
    shop_id UUID NOT NULL REFERENCES shops (id),
    user_id UUID NOT NULL REFERENCES users (id),
    status order_status NOT NULL DEFAULT 'pending_payment',
    currency CHAR(3) NOT NULL REFERENCES currencies (code),
    total_minor BIGINT NOT NULL CHECK (total_minor >= 0),
    shipping_address JSONB NOT NULL,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE INDEX idx_orders_user ON orders (user_id);
CREATE INDEX idx_orders_shop ON orders (shop_id);

CREATE TABLE order_items (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    order_id UUID NOT NULL REFERENCES orders (id) ON DELETE CASCADE,
    sku_id UUID NOT NULL REFERENCES skus (id),
    product_name JSONB NOT NULL,
    sku_code TEXT NOT NULL,
    image TEXT,
    unit_price_minor BIGINT NOT NULL CHECK (unit_price_minor >= 0),
    qty INT NOT NULL CHECK (qty > 0)
);

CREATE INDEX idx_order_items_order ON order_items (order_id);

CREATE TABLE shipments (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    shipment_no TEXT NOT NULL UNIQUE,
    order_id UUID NOT NULL REFERENCES orders (id),
    carrier TEXT NOT NULL,
    tracking_no TEXT NOT NULL,
    status shipment_status NOT NULL DEFAULT 'pending',
    shipped_at TIMESTAMPTZ,
    delivered_at TIMESTAMPTZ,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE INDEX idx_shipments_order ON shipments (order_id);

CREATE TABLE shipment_items (
    shipment_id UUID NOT NULL REFERENCES shipments (id) ON DELETE CASCADE,
    order_item_id UUID NOT NULL REFERENCES order_items (id),
    qty INT NOT NULL CHECK (qty > 0),
    PRIMARY KEY (shipment_id, order_item_id)
);

CREATE TABLE invoices (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    invoice_no TEXT UNIQUE,
    order_id UUID NOT NULL REFERENCES orders (id),
    user_id UUID NOT NULL REFERENCES users (id),
    title TEXT NOT NULL,
    tax_no TEXT,
    kind invoice_kind NOT NULL,
    amount_minor BIGINT NOT NULL CHECK (amount_minor >= 0),
    currency CHAR(3) NOT NULL,
    status invoice_status NOT NULL DEFAULT 'requested',
    issued_at TIMESTAMPTZ,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

-- at most one open (requested/issued) invoice per order
CREATE UNIQUE INDEX one_open_invoice_per_order ON invoices (order_id)
WHERE status IN ('requested', 'issued');

CREATE INDEX idx_invoices_user ON invoices (user_id);