-- Add AUDIO question type and image_url support

-- 1. Extend question_type CHECK constraint to include AUDIO
ALTER TABLE questions
  DROP CONSTRAINT IF EXISTS questions_question_type_check;

ALTER TABLE questions
  ADD CONSTRAINT questions_question_type_check
  CHECK (question_type IN ('MCQ', 'TRUE_FALSE', 'SHORT_ANSWER', 'AUDIO'));

-- 2. Add image_url column to questions
ALTER TABLE questions
  ADD COLUMN IF NOT EXISTS image_url TEXT;

-- 3. Create question_audio_answers table for storing correct answer text
CREATE TABLE IF NOT EXISTS question_audio_answers (
    id BIGSERIAL PRIMARY KEY,
    question_id BIGINT NOT NULL REFERENCES questions(id) ON DELETE CASCADE,
    correct_answer_text TEXT NOT NULL,
    created_at TIMESTAMPTZ NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE UNIQUE INDEX IF NOT EXISTS uq_question_audio_answers_question_id
    ON question_audio_answers(question_id);