CREATE TABLE IF NOT EXISTS lesson_collaborative_canvases (
    lesson_id UUID PRIMARY KEY REFERENCES lessons(id) ON DELETE CASCADE,
    organization_id UUID NOT NULL REFERENCES organizations(id) ON DELETE CASCADE,
    canvas_state JSONB NOT NULL DEFAULT '{}'::jsonb,
    updated_by UUID REFERENCES users(id) ON DELETE SET NULL,
    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
);

CREATE INDEX IF NOT EXISTS idx_lesson_collaborative_canvases_org_id
    ON lesson_collaborative_canvases (organization_id);