/**
 * SessionService 游标分页测试（v0.8.1 P2-3）
 *
 * 契约：无 limit 全量；limit 无游标 = 尾部窗口（最后 N 条，升序返回）；
 * limit + beforeRowid = 游标之前的更早 N 条（升序返回）；完整性判定
 * （返回条数 < limit 即到会话开头）由调用方依据长度比较。
 */

import { describe, it, expect, beforeAll, afterAll, vi } from 'vitest';

vi.mock('electron-log', () => ({
  default: { info: vi.fn(), warn: vi.fn(), error: vi.fn(), debug: vi.fn() },
}));

let dbAvailable = true;
let Database: typeof import('better-sqlite3');
try {
  // eslint-disable-next-line @typescript-eslint/no-require-imports
  Database = require('better-sqlite3');
  const probe = new Database(':memory:');
  probe.close();
} catch {
  dbAvailable = false;
}

import { SessionService } from '../session.service';

describe.skipIf(!dbAvailable)('SessionService — 游标分页（v0.8.1 P2-3）', () => {
  let db: InstanceType<typeof Database>;
  let svc: SessionService;
  const sessionId = 's_page';

  beforeAll(() => {
    if (!dbAvailable) return;
    db = new Database(':memory:');
    db.exec(`
      CREATE TABLE sessions (
        id TEXT PRIMARY KEY,
        title TEXT NOT NULL DEFAULT '',
        created_at INTEGER,
        updated_at INTEGER,
        message_count INTEGER DEFAULT 0,
        total_tokens INTEGER DEFAULT 0,
        pinned INTEGER DEFAULT 0,
        archived INTEGER DEFAULT 0,
        deleted_at INTEGER,
        metadata TEXT DEFAULT '{}'
      );
      CREATE TABLE messages (
        id TEXT PRIMARY KEY,
        session_id TEXT NOT NULL,
        role TEXT,
        content TEXT,
        reasoning_content TEXT,
        tool_calls TEXT,
        tool_result TEXT,
        attachments TEXT,
        iteration INTEGER,
        created_at INTEGER
      );
      CREATE TABLE session_summaries (
        session_id TEXT PRIMARY KEY,
        summary TEXT,
        summarized_until_rowid INTEGER,
        updated_at INTEGER
      );
      CREATE TABLE tasks (
        id TEXT PRIMARY KEY,
        session_id TEXT,
        title TEXT,
        description TEXT,
        status TEXT,
        priority TEXT,
        parent_id TEXT,
        assigned_to TEXT,
        order_idx INTEGER,
        created_at INTEGER,
        updated_at INTEGER,
        completed_at INTEGER
      );
    `);
    db.prepare('INSERT INTO sessions (id) VALUES (?)').run(sessionId);
    svc = new SessionService(() => db);
    for (let i = 1; i <= 10; i++) {
      svc.saveMessage({ sessionId, role: 'user', content: `msg-${i}` });
    }
  });
  afterAll(() => {
    if (db) db.close();
  });

  it('无 limit → 全量（向后兼容）', () => {
    expect(svc.getMessages(sessionId)).toHaveLength(10);
  });

  it('limit 无游标 → 尾部窗口（最后 N 条，升序返回）', () => {
    const tail = svc.getMessages(sessionId, { limit: 3 });
    expect(tail.map((m) => m.content)).toEqual(['msg-8', 'msg-9', 'msg-10']);
  });

  it('limit + beforeRowid → 游标之前 N 条（升序返回）', () => {
    const full = svc.getMessages(sessionId);
    const cursorRowId = full[6].rowId!; // msg-7 的 rowid
    const older = svc.getMessages(sessionId, { limit: 3, beforeRowid: cursorRowId });
    expect(older.map((m) => m.content)).toEqual(['msg-4', 'msg-5', 'msg-6']);
  });

  it('游标翻到开头：返回条数 < limit 表示已完整', () => {
    const full = svc.getMessages(sessionId);
    const first = full[0].rowId!;
    const older = svc.getMessages(sessionId, { limit: 3, beforeRowid: first });
    expect(older).toHaveLength(0);
  });
});