-- Tear down the legacy course / learning-tree schema so a new hierarchy can be introduced.
BEGIN;

-- Entry-assessment automation on sub_courses (from 000024)
DROP TRIGGER IF EXISTS trg_sub_courses_create_entry_assessment ON sub_courses;
DROP FUNCTION IF EXISTS create_sub_course_entry_assessment();
DROP FUNCTION IF EXISTS clone_default_initial_assessment_items(BIGINT);
DROP INDEX IF EXISTS idx_question_sets_unique_subcourse_initial_assessment;

ALTER TABLE question_sets DROP COLUMN IF EXISTS sub_course_video_id;

-- Dependent objects first
DROP TABLE IF EXISTS user_sub_course_video_progress CASCADE;
DROP TABLE IF EXISTS user_practice_progress CASCADE;
DROP TABLE IF EXISTS sub_course_prerequisites CASCADE;
DROP TABLE IF EXISTS user_sub_course_progress CASCADE;

DROP TABLE IF EXISTS sub_module_practices CASCADE;
DROP TABLE IF EXISTS sub_module_capstones CASCADE;
DROP TABLE IF EXISTS sub_module_lessons CASCADE;
DROP TABLE IF EXISTS sub_module_videos CASCADE;
DROP TABLE IF EXISTS sub_modules CASCADE;
DROP TABLE IF EXISTS module_capstones CASCADE;
DROP TABLE IF EXISTS modules CASCADE;
DROP TABLE IF EXISTS levels CASCADE;

DROP TABLE IF EXISTS sub_course_videos CASCADE;
DROP TABLE IF EXISTS sub_courses CASCADE;
DROP TABLE IF EXISTS course_sub_categories CASCADE;
DROP TABLE IF EXISTS courses CASCADE;
DROP TABLE IF EXISTS course_categories CASCADE;

-- Keep learner practice completion for the questions system (no sub_course column)
CREATE TABLE user_practice_progress (
    id BIGSERIAL PRIMARY KEY,
    user_id BIGINT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    question_set_id BIGINT NOT NULL REFERENCES question_sets(id) ON DELETE CASCADE,
    completed_at TIMESTAMPTZ,
    updated_at TIMESTAMPTZ,
    created_at TIMESTAMPTZ NOT NULL DEFAULT CURRENT_TIMESTAMP,
    UNIQUE (user_id, question_set_id)
);

CREATE INDEX idx_user_practice_progress_user_id ON user_practice_progress(user_id);

COMMIT;