-- Standalone exam-prep content hierarchy (DET, IELTS, TOEFL, etc.) — isolated from LMS Learn English tables.
CREATE SCHEMA IF NOT EXISTS exam_prep;

-- Top-level catalog "course" (e.g. Duolingo English Test, IELTS); admin-configurable labels.
CREATE TABLE exam_prep.catalog_courses (
    id BIGSERIAL PRIMARY KEY,
    name VARCHAR(255) NOT NULL,
    description TEXT,
    thumbnail TEXT,
    sort_order INTEGER NOT NULL DEFAULT 0,
    created_at TIMESTAMPTZ NOT NULL DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMPTZ
);

CREATE INDEX idx_exam_prep_catalog_courses_sort ON exam_prep.catalog_courses (sort_order, id);