-- Adds the "extended" zone kind, which answers authoritatively only for the
-- records it holds and falls through to recursion for everything else.
--
-- SQLite has no ALTER TABLE ... DROP/ADD CONSTRAINT, so the CHECK constraint
-- on zones.kind is widened by rebuilding the table. The rebuilt table keeps
-- the same name, column order and row ids, so records.zone_id references
-- remain valid without touching the records table at all.

CREATE TABLE zones_new (
    id          INTEGER PRIMARY KEY AUTOINCREMENT,
    name        TEXT    NOT NULL UNIQUE,
    kind        TEXT    NOT NULL DEFAULT 'forward'
                CHECK (kind IN ('forward', 'reverse4', 'reverse6', 'extended')),
    description TEXT    NOT NULL DEFAULT '',
    enabled     INTEGER NOT NULL DEFAULT 1,
    default_ttl INTEGER NOT NULL DEFAULT 3600,
    primary_ns  TEXT    NOT NULL,
    admin_email TEXT    NOT NULL,
    serial      INTEGER NOT NULL DEFAULT 1,
    refresh     INTEGER NOT NULL DEFAULT 7200,
    retry       INTEGER NOT NULL DEFAULT 3600,
    expire      INTEGER NOT NULL DEFAULT 1209600,
    minimum     INTEGER NOT NULL DEFAULT 3600,
    auto_serial INTEGER NOT NULL DEFAULT 1,
    created_at  INTEGER NOT NULL DEFAULT (unixepoch()),
    updated_at  INTEGER NOT NULL DEFAULT (unixepoch())
);

INSERT INTO zones_new (id, name, kind, description, enabled, default_ttl, primary_ns,
    admin_email, serial, refresh, retry, expire, minimum, auto_serial, created_at, updated_at)
SELECT id, name, kind, description, enabled, default_ttl, primary_ns,
    admin_email, serial, refresh, retry, expire, minimum, auto_serial, created_at, updated_at
FROM zones;

DROP TABLE zones;
ALTER TABLE zones_new RENAME TO zones;

CREATE INDEX idx_zones_enabled ON zones (enabled);
CREATE INDEX idx_zones_kind ON zones (kind);