-- Telegram Bot Rolling Summary Schema
-- D1 Database for Cloudflare Workers

-- 사용자 테이블
CREATE TABLE IF NOT EXISTS users (
  id INTEGER PRIMARY KEY AUTOINCREMENT,
  telegram_id TEXT UNIQUE NOT NULL,
  username TEXT,
  first_name TEXT,
  created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
  updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
);

-- 메시지 버퍼 (요약 전 임시 저장)
CREATE TABLE IF NOT EXISTS message_buffer (
  id INTEGER PRIMARY KEY AUTOINCREMENT,
  user_id INTEGER NOT NULL,
  chat_id TEXT NOT NULL,
  role TEXT NOT NULL CHECK(role IN ('user', 'bot')),
  message TEXT NOT NULL,
  created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
  FOREIGN KEY (user_id) REFERENCES users(id)
);

-- 요약 저장 테이블 (슬라이딩 윈도우: 최대 3개만 유지)
CREATE TABLE IF NOT EXISTS summaries (
  id INTEGER PRIMARY KEY AUTOINCREMENT,
  user_id INTEGER NOT NULL,
  chat_id TEXT NOT NULL,
  generation INTEGER NOT NULL DEFAULT 1,
  summary TEXT NOT NULL,
  message_count INTEGER NOT NULL,
  created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
  FOREIGN KEY (user_id) REFERENCES users(id)
);

-- 인덱스
CREATE INDEX IF NOT EXISTS idx_buffer_user ON message_buffer(user_id);
CREATE INDEX IF NOT EXISTS idx_buffer_chat ON message_buffer(user_id, chat_id);
CREATE INDEX IF NOT EXISTS idx_summary_user ON summaries(user_id, chat_id);
CREATE INDEX IF NOT EXISTS idx_summary_latest ON summaries(user_id, chat_id, generation DESC);
CREATE INDEX IF NOT EXISTS idx_users_telegram ON users(telegram_id);