-- Cumulative usage quotas + self-service user registration for the public API.
--
-- The free anonymous tier is capped at a lifetime number of calls (enforced in
-- Redis, keyed by client IP). To keep calling beyond the free quota a caller
-- registers an account and self-issues an API key with a higher quota.
-- quota_total = 0 means unlimited.
--
-- Registration is the one place the public server writes to PostgreSQL (it
-- inserts an app_user and its api_key); every other public route stays
-- read-only. Request counting still lives entirely in Redis.

ALTER TABLE api_key ADD COLUMN IF NOT EXISTS quota_total BIGINT NOT NULL DEFAULT 0;

ALTER TABLE api_key DROP CONSTRAINT IF EXISTS api_key_tier_chk;
ALTER TABLE api_key ADD CONSTRAINT api_key_tier_chk
    CHECK (tier IN ('free', 'registered', 'partner', 'internal'));

CREATE TABLE IF NOT EXISTS app_user (
    id            UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    email         TEXT NOT NULL,
    password_hash TEXT NOT NULL,
    api_key_id    UUID REFERENCES api_key (id) ON DELETE SET NULL,
    created_at    TIMESTAMPTZ NOT NULL DEFAULT now()
);

-- Case-insensitive uniqueness so each email registers at most once.
CREATE UNIQUE INDEX IF NOT EXISTS idx_app_user_email ON app_user (lower(email));