-- Add the confirm deeplink token and the confirmation purpose to email_confirmations.
-- purpose tags what verifying the code/token does (email login, identity link, email
-- change, or account deletion); link_token_hash holds the SHA-256 hex of the one-click
-- deeplink token (only the hash is stored, mirroring the session-token model).
-- Expand-contract: both columns are additive. purpose gets a NOT NULL DEFAULT so
-- existing rows fill in; link_token_hash is nullable with a partial-unique index. A
-- backend image rollback stays DB-safe — older code simply ignores the new columns. The
-- table shape changes, so the generated go-jet model for this table is regenerated.

-- +goose Up
ALTER TABLE backend.email_confirmations
    ADD COLUMN purpose text NOT NULL DEFAULT 'link',
    ADD COLUMN link_token_hash text;
ALTER TABLE backend.email_confirmations
    ADD CONSTRAINT email_confirmations_purpose_chk
        CHECK ((purpose = ANY (ARRAY['login'::text, 'link'::text, 'change'::text, 'delete'::text])));
CREATE UNIQUE INDEX email_confirmations_link_token_hash_key
    ON backend.email_confirmations (link_token_hash)
    WHERE link_token_hash IS NOT NULL;

-- +goose Down
DROP INDEX IF EXISTS backend.email_confirmations_link_token_hash_key;
ALTER TABLE backend.email_confirmations
    DROP CONSTRAINT IF EXISTS email_confirmations_purpose_chk;
ALTER TABLE backend.email_confirmations
    DROP COLUMN IF EXISTS link_token_hash,
    DROP COLUMN IF EXISTS purpose;