-- Phase 27 / FEAT-05: DTC history synced to remote server.
-- Pi pushes current DTC snapshot; server diffs against stored state.

CREATE TABLE IF NOT EXISTS dtc_events (
    id SERIAL PRIMARY KEY,
    device_id INTEGER NOT NULL REFERENCES devices(id) ON DELETE CASCADE,
    code VARCHAR(10) NOT NULL,
    description TEXT NOT NULL DEFAULT '',
    mil_on BOOLEAN NOT NULL DEFAULT FALSE,
    is_active BOOLEAN NOT NULL DEFAULT TRUE,
    first_seen_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    last_seen_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    cleared_at TIMESTAMPTZ,
    UNIQUE (device_id, code)
);

CREATE INDEX IF NOT EXISTS idx_dtc_events_device_active
    ON dtc_events (device_id, is_active);