-- users 加两列
ALTER TABLE users ADD COLUMN invite_code TEXT;
ALTER TABLE users ADD COLUMN first_paid_at DATETIME;
CREATE UNIQUE INDEX ux_users_invite_code ON users(invite_code);

-- 邀请关系(一对一绑定)
CREATE TABLE referrals (
  id INTEGER PRIMARY KEY AUTOINCREMENT,
  inviter_id INTEGER NOT NULL,
  invitee_id INTEGER NOT NULL UNIQUE,
  device_uuid TEXT,
  status TEXT NOT NULL DEFAULT 'bound'
    CHECK (status IN ('bound','reg_rewarded','paid_rewarded','rejected')),
  reg_rewarded_at DATETIME,
  paid_rewarded_at DATETIME,
  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
  FOREIGN KEY (inviter_id) REFERENCES users(id),
  FOREIGN KEY (invitee_id) REFERENCES users(id)
);
CREATE INDEX ix_referrals_inviter ON referrals(inviter_id, created_at);

-- 通用一次性任务领取
CREATE TABLE reward_claims (
  id INTEGER PRIMARY KEY AUTOINCREMENT,
  user_id INTEGER NOT NULL,
  task_key TEXT NOT NULL,
  external_ref TEXT NOT NULL DEFAULT '',
  granted_days INTEGER NOT NULL,
  granted_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
  FOREIGN KEY (user_id) REFERENCES users(id)
);
CREATE UNIQUE INDEX ux_claim_user_task ON reward_claims(user_id, task_key);
CREATE UNIQUE INDEX ux_claim_task_ref ON reward_claims(task_key, external_ref);

-- subscriptions.source 扩容(SQLite 需重建表)
CREATE TABLE subscriptions_new (
  id INTEGER PRIMARY KEY AUTOINCREMENT,
  user_id INTEGER NOT NULL,
  plan_id INTEGER NOT NULL,
  expires_at DATETIME NOT NULL,
  source TEXT NOT NULL CHECK (source IN ('trial','code','pay','invite','task')),
  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
  FOREIGN KEY (user_id) REFERENCES users(id),
  FOREIGN KEY (plan_id) REFERENCES plans(id)
);
INSERT INTO subscriptions_new (id,user_id,plan_id,expires_at,source,created_at)
  SELECT id,user_id,plan_id,expires_at,source,created_at FROM subscriptions;
DROP TABLE subscriptions;
ALTER TABLE subscriptions_new RENAME TO subscriptions;
CREATE INDEX idx_subs_user_exp ON subscriptions (user_id, expires_at);