CREATE TABLE alert_silences (
    id uuid PRIMARY KEY,
    name text NOT NULL CHECK (char_length(name) BETWEEN 1 AND 160),
    reason text NOT NULL CHECK (char_length(reason) BETWEEN 1 AND 500),
    owner text NOT NULL CHECK (char_length(owner) BETWEEN 1 AND 255),
    matchers jsonb NOT NULL CHECK (jsonb_typeof(matchers) = 'object'),
    starts_at timestamptz NOT NULL,
    expires_at timestamptz NOT NULL CHECK (expires_at > starts_at),
    status text NOT NULL DEFAULT 'active' CHECK (status IN ('active', 'expired', 'revoked')),
    created_by text NOT NULL CHECK (char_length(created_by) BETWEEN 1 AND 255),
    created_at timestamptz NOT NULL DEFAULT now(),
    revoked_by text,
    revoked_at timestamptz,
    expired_at timestamptz,
    revision bigint NOT NULL DEFAULT 1 CHECK (revision > 0),
    CHECK ((status = 'revoked' AND revoked_at IS NOT NULL) OR (status <> 'revoked' AND revoked_at IS NULL)),
    CHECK ((status = 'expired' AND expired_at IS NOT NULL) OR (status <> 'expired' AND expired_at IS NULL))
);

CREATE INDEX alert_silences_active_expiry_idx ON alert_silences (expires_at, id) WHERE status = 'active';
CREATE INDEX alert_silences_listing_idx ON alert_silences (starts_at DESC, id DESC);

CREATE TABLE maintenance_windows (
    id uuid PRIMARY KEY,
    name text NOT NULL CHECK (char_length(name) BETWEEN 1 AND 160),
    reason text NOT NULL CHECK (char_length(reason) BETWEEN 1 AND 500),
    selector jsonb NOT NULL CHECK (jsonb_typeof(selector) = 'object'),
    starts_at timestamptz NOT NULL,
    ends_at timestamptz NOT NULL CHECK (ends_at > starts_at),
    status text NOT NULL DEFAULT 'active' CHECK (status IN ('active', 'expired', 'revoked')),
    created_by text NOT NULL CHECK (char_length(created_by) BETWEEN 1 AND 255),
    created_at timestamptz NOT NULL DEFAULT now(),
    revoked_by text,
    revoked_at timestamptz,
    expired_at timestamptz,
    revision bigint NOT NULL DEFAULT 1 CHECK (revision > 0),
    CHECK ((status = 'revoked' AND revoked_at IS NOT NULL) OR (status <> 'revoked' AND revoked_at IS NULL)),
    CHECK ((status = 'expired' AND expired_at IS NOT NULL) OR (status <> 'expired' AND expired_at IS NULL))
);

CREATE INDEX maintenance_windows_active_expiry_idx ON maintenance_windows (ends_at, id) WHERE status = 'active';
CREATE INDEX maintenance_windows_listing_idx ON maintenance_windows (starts_at DESC, id DESC);