CREATE TABLE unit (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    code TEXT NOT NULL,
    name TEXT NOT NULL,
    description TEXT,
    enabled BOOLEAN NOT NULL DEFAULT TRUE,
    run_time_sec INTEGER NOT NULL DEFAULT 0 CHECK (run_time_sec >= 0),
    stop_time_sec INTEGER NOT NULL DEFAULT 0 CHECK (stop_time_sec >= 0),
    acc_time_sec INTEGER NOT NULL DEFAULT 0 CHECK (acc_time_sec >= 0),
    bl_time_sec INTEGER NOT NULL DEFAULT 0 CHECK (bl_time_sec >= 0),
    require_manual_ack_after_fault BOOLEAN NOT NULL DEFAULT TRUE,
    created_at TIMESTAMPTZ DEFAULT NOW(),
    updated_at TIMESTAMPTZ DEFAULT NOW(),
    UNIQUE (code)
);

ALTER TABLE equipment
    ADD COLUMN unit_id UUID REFERENCES unit(id) ON DELETE SET NULL;

CREATE INDEX idx_equipment_unit_id ON equipment(unit_id);

CREATE TABLE event (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    event_type TEXT NOT NULL,
    level TEXT NOT NULL DEFAULT 'info',
    unit_id UUID REFERENCES unit(id) ON DELETE SET NULL,
    equipment_id UUID REFERENCES equipment(id) ON DELETE SET NULL,
    source_id UUID REFERENCES source(id) ON DELETE SET NULL,
    message TEXT NOT NULL,
    payload JSONB,
    created_at TIMESTAMPTZ DEFAULT NOW()
);

CREATE INDEX idx_event_created_at ON event(created_at DESC);
CREATE INDEX idx_event_type ON event(event_type);
CREATE INDEX idx_event_unit_id ON event(unit_id);
CREATE INDEX idx_event_equipment_id ON event(equipment_id);
CREATE INDEX idx_event_source_id ON event(source_id);