-- Membership: platform-managed levels, an append-only growth ledger, and the
-- customer's current level on `users`. Messaging: per-customer system messages
-- emitted by order/shipment/refund events with unread state and soft deletion.

CREATE TABLE member_levels (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    name JSONB NOT NULL,
    icon TEXT NOT NULL,
    growth_threshold BIGINT NOT NULL CHECK (growth_threshold >= 0),
    benefits JSONB NOT NULL,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    CONSTRAINT member_levels_icon CHECK (btrim(icon) <> '')
);

-- Thresholds are unique; level order follows the threshold.
CREATE UNIQUE INDEX member_levels_threshold_idx ON member_levels (growth_threshold);

ALTER TABLE users ADD COLUMN level UUID REFERENCES member_levels (id);
CREATE INDEX users_level_idx ON users (level);

CREATE TABLE growth_logs (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id UUID NOT NULL REFERENCES users (id) ON DELETE CASCADE,
    -- Growth value in whole base-currency units; 0 only for sub-unit orders.
    delta BIGINT NOT NULL CHECK (delta >= 0),
    growth_total BIGINT NOT NULL CHECK (growth_total >= 0),
    reason TEXT NOT NULL,
    reference_type TEXT,
    reference_id UUID,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

-- One accrual per user and referenced order, so a retried completion is a no-op.
CREATE UNIQUE INDEX growth_logs_reference_idx
    ON growth_logs (user_id, reference_type, reference_id)
    WHERE reference_id IS NOT NULL;
CREATE INDEX growth_logs_user_idx
    ON growth_logs (user_id, created_at DESC, id DESC);

CREATE TYPE message_kind AS ENUM ('order_paid', 'order_shipped', 'refund_completed');
CREATE TYPE message_status AS ENUM ('unread', 'read');

CREATE TABLE messages (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id UUID NOT NULL REFERENCES users (id) ON DELETE CASCADE,
    kind message_kind NOT NULL,
    title JSONB NOT NULL,
    body JSONB NOT NULL,
    reference_type TEXT,
    reference_id UUID,
    status message_status NOT NULL DEFAULT 'unread',
    read_at TIMESTAMPTZ,
    deleted_at TIMESTAMPTZ,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    CONSTRAINT messages_read_consistent CHECK (
        (status = 'unread' AND read_at IS NULL)
        OR (status = 'read' AND read_at IS NOT NULL)
    )
);

-- One message per customer, kind, and reference: re-running an event handler
-- conflicts instead of duplicating. Soft-deleted rows still occupy the slot so
-- a re-run cannot resurrect a deleted message as a new one.
CREATE UNIQUE INDEX messages_event_idx
    ON messages (user_id, kind, reference_type, reference_id)
    WHERE reference_id IS NOT NULL;
CREATE INDEX messages_user_idx
    ON messages (user_id, created_at DESC, id DESC)
    WHERE deleted_at IS NULL;
CREATE INDEX messages_unread_idx
    ON messages (user_id)
    WHERE deleted_at IS NULL AND status = 'unread';