CREATE EXTENSION IF NOT EXISTS pgcrypto;

CREATE TABLE IF NOT EXISTS users (
  id uuid PRIMARY KEY DEFAULT gen_random_uuid(), openid text UNIQUE NOT NULL, unionid text,
  nickname text NOT NULL DEFAULT '微信用户', avatar_url text,
  created_at timestamptz NOT NULL DEFAULT now(), updated_at timestamptz NOT NULL DEFAULT now()
);
CREATE TABLE IF NOT EXISTS exhibitions (
  id uuid PRIMARY KEY DEFAULT gen_random_uuid(), name text NOT NULL, venue text NOT NULL,
  address text NOT NULL DEFAULT '', starts_at timestamptz NOT NULL, ends_at timestamptz NOT NULL,
  description text NOT NULL DEFAULT '', cover_url text, created_at timestamptz NOT NULL DEFAULT now(),
  CHECK (ends_at > starts_at)
);
CREATE TABLE IF NOT EXISTS tags (
  id uuid PRIMARY KEY DEFAULT gen_random_uuid(), name text UNIQUE NOT NULL, color text NOT NULL DEFAULT '#7C5CFC'
);
CREATE TABLE IF NOT EXISTS activities (
  id uuid PRIMARY KEY DEFAULT gen_random_uuid(), exhibition_id uuid NOT NULL REFERENCES exhibitions(id) ON DELETE CASCADE,
  title text NOT NULL, description text NOT NULL DEFAULT '', location text NOT NULL DEFAULT '',
  starts_at timestamptz NOT NULL, ends_at timestamptz, capacity integer CHECK (capacity IS NULL OR capacity > 0),
  published boolean NOT NULL DEFAULT false, created_at timestamptz NOT NULL DEFAULT now(), updated_at timestamptz NOT NULL DEFAULT now(),
  CHECK (ends_at IS NULL OR ends_at > starts_at)
);
CREATE TABLE IF NOT EXISTS activity_images (
  id uuid PRIMARY KEY DEFAULT gen_random_uuid(), activity_id uuid NOT NULL REFERENCES activities(id) ON DELETE CASCADE,
  url text NOT NULL, sort_order integer NOT NULL DEFAULT 0
);
CREATE TABLE IF NOT EXISTS activity_tags (
  activity_id uuid NOT NULL REFERENCES activities(id) ON DELETE CASCADE,
  tag_id uuid NOT NULL REFERENCES tags(id) ON DELETE CASCADE, PRIMARY KEY (activity_id, tag_id)
);
CREATE TABLE IF NOT EXISTS participations (
  activity_id uuid NOT NULL REFERENCES activities(id) ON DELETE CASCADE,
  user_id uuid NOT NULL REFERENCES users(id) ON DELETE CASCADE, purpose text NOT NULL DEFAULT '',
  joined_at timestamptz NOT NULL DEFAULT now(), updated_at timestamptz NOT NULL DEFAULT now(), PRIMARY KEY (activity_id, user_id)
);
DO $$ BEGIN CREATE TYPE group_review_status AS ENUM ('pending', 'approved', 'rejected'); EXCEPTION WHEN duplicate_object THEN null; END $$;
CREATE TABLE IF NOT EXISTS activity_groups (
  id uuid PRIMARY KEY DEFAULT gen_random_uuid(), activity_id uuid NOT NULL REFERENCES activities(id) ON DELETE CASCADE,
  submitted_by uuid REFERENCES users(id) ON DELETE SET NULL, name text NOT NULL, qr_image_url text NOT NULL,
  note text NOT NULL DEFAULT '', status group_review_status NOT NULL DEFAULT 'pending', review_note text NOT NULL DEFAULT '',
  reviewed_at timestamptz, created_at timestamptz NOT NULL DEFAULT now()
);
CREATE INDEX IF NOT EXISTS idx_activities_exhibition_start ON activities(exhibition_id, starts_at);
CREATE INDEX IF NOT EXISTS idx_activities_published_start ON activities(published, starts_at);
CREATE INDEX IF NOT EXISTS idx_participations_activity ON participations(activity_id, joined_at);
CREATE INDEX IF NOT EXISTS idx_groups_review ON activity_groups(status, created_at);