-- Shared spelling curriculum and per-user familiarity tracking.

CREATE TABLE IF NOT EXISTS spelling_words (
  id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  canonical_word  TEXT NOT NULL UNIQUE,
  active          BOOLEAN NOT NULL DEFAULT true
);

CREATE TABLE IF NOT EXISTS spelling_items (
  id                    UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  spelling_word_id      UUID NOT NULL REFERENCES spelling_words (id) ON DELETE CASCADE,
  displayed_word        TEXT NOT NULL,
  is_correctly_spelled  BOOLEAN NOT NULL,
  correct_answer        NUMERIC NOT NULL,
  active                BOOLEAN NOT NULL DEFAULT true,
  UNIQUE (spelling_word_id, displayed_word)
);

CREATE INDEX IF NOT EXISTS spelling_items_active_idx
  ON spelling_items (spelling_word_id)
  WHERE active = true;

CREATE TABLE IF NOT EXISTS user_spelling_progress (
  firebase_uid        TEXT NOT NULL REFERENCES users (firebase_uid) ON DELETE CASCADE,
  spelling_item_id    UUID NOT NULL REFERENCES spelling_items (id) ON DELETE CASCADE,
  familiarity_score   INTEGER NOT NULL DEFAULT 0,
  attempt_count       INTEGER NOT NULL DEFAULT 0,
  correct_count       INTEGER NOT NULL DEFAULT 0,
  last_attempted_at   TIMESTAMPTZ,
  last_outcome        TEXT,
  PRIMARY KEY (firebase_uid, spelling_item_id)
);

CREATE INDEX IF NOT EXISTS user_spelling_progress_uid_idx
  ON user_spelling_progress (firebase_uid);