-- invoice_event_types stores the different types of invoice events. 
CREATE TABLE IF NOT EXISTS invoice_event_types(
    id INTEGER PRIMARY KEY,

    description TEXT NOT NULL
);


-- invoice_event_types defines the different types of invoice events.
-- Insert events explicitly, checking their existence first.
INSERT INTO invoice_event_types (id, description)
SELECT id, description FROM (
    -- invoice_created is the event type used when an invoice is created.
    SELECT 0 AS id, 'invoice_created' AS description UNION ALL
    -- invoice_canceled is the event type used when an invoice is canceled.
    SELECT 1, 'invoice_canceled' UNION ALL
    -- invoice_settled is the event type used when an invoice is settled.
    SELECT 2, 'invoice_settled' UNION ALL
    -- setid_created is the event type used when an AMP sub invoice
    -- corresponding to the set_id is created.
    SELECT 3, 'setid_created' UNION ALL
    -- setid_canceled is the event type used when an AMP sub invoice
    -- corresponding to the set_id is canceled.
    SELECT 4, 'setid_canceled' UNION ALL
    -- setid_settled is the event type used when an AMP sub invoice
    -- corresponding to the set_id is settled.
    SELECT 5, 'setid_settled'
) AS new_values
WHERE NOT EXISTS (
    SELECT 1 FROM invoice_event_types
        WHERE invoice_event_types.id = new_values.id
);
-- invoice_events stores all major events related to the node's invoices and
-- AMP sub invoices. This table can be used to create a historical view of what
-- happened to the node's invoices.
CREATE TABLE IF NOT EXISTS invoice_events (
    id INTEGER PRIMARY KEY,

    -- added_at is the timestamp when this event was added.
    added_at TIMESTAMP NOT NULL,

    -- event_type is the type of this event.
    event_type INTEGER NOT NULL REFERENCES invoice_event_types(id) ON DELETE CASCADE,

    -- invoice_id is the reference to the invoice this event was added for.
    invoice_id BIGINT NOT NULL REFERENCES invoices(id) ON DELETE CASCADE,

    -- set_id is the reference to the AMP sub invoice this event was added for.
    -- May be NULL if the event is not related to an AMP sub invoice.
    set_id BLOB REFERENCES amp_sub_invoices(set_id) ON DELETE CASCADE
);

CREATE INDEX IF NOT EXISTS invoice_events_added_at_idx ON invoice_events(added_at);
CREATE INDEX IF NOT EXISTS invoice_events_event_type_idx ON invoice_events(event_type);
CREATE INDEX IF NOT EXISTS invoice_events_invoice_id_idx ON invoice_events(invoice_id);
CREATE INDEX IF NOT EXISTS invoice_events_set_id_idx ON invoice_events(set_id);