/**
 * Parser 边缘场景测试
 *
 * v0.8.0 强化说明：
 *  1. 此前 12 处断言写着 `expect(ast.where).toBeDefined()` —— 既没有验证结构也没有验证
 *     值，属于"空断言"。审计（AUDIT-query-layer / SQL 层）指出：`parser.test.ts` 无一处
 *     断言混合 AND/OR 的**结构**，这正是 AND/OR 无优先级缺陷（总账第 11 项）能长期存活的原因。
 *  2. 本文件此前 `parse()` 的返回类型是联合类型 `Statement`，直接访问 `.where` / `.columns`
 *     在类型上不成立（tests 从不做类型检查，所以没人发现）。现在用类型收窄辅助函数显式
 *     区分语句种类 —— 收窄失败即测试失败，而不是静默读到一个 undefined。
 */

import { parse } from '../../src/sql/parser';
import type {
  SelectStatement,
  InsertStatement,
  UpdateStatement,
  DeleteStatement,
  CreateTableStatement,
} from '../../src/query/ast';

// ---------------------------------------------------------------------------
//  类型收窄辅助：断言语句种类并返回收窄后的类型
//  （替代 `as any` —— 收窄失败会立刻让测试失败，而不是让断言落空）
// ---------------------------------------------------------------------------

function asSelect(stmt: ReturnType<typeof parse>): SelectStatement {
  expect(stmt.type).toBe('SELECT');
  if (stmt.type !== 'SELECT') throw new Error(`expected SELECT, got ${stmt.type}`);
  return stmt;
}

function asInsert(stmt: ReturnType<typeof parse>): InsertStatement & { values: unknown[][] } {
  expect(stmt.type).toBe('INSERT');
  if (stmt.type !== 'INSERT') throw new Error(`expected INSERT, got ${stmt.type}`);
  if (!stmt.values) throw new Error('INSERT statement is missing values');
  return stmt as InsertStatement & { values: unknown[][] };
}

function asUpdate(stmt: ReturnType<typeof parse>): UpdateStatement {
  expect(stmt.type).toBe('UPDATE');
  if (stmt.type !== 'UPDATE') throw new Error(`expected UPDATE, got ${stmt.type}`);
  return stmt;
}

function asDelete(stmt: ReturnType<typeof parse>): DeleteStatement {
  expect(stmt.type).toBe('DELETE');
  if (stmt.type !== 'DELETE') throw new Error(`expected DELETE, got ${stmt.type}`);
  return stmt;
}

function asCreateTable(stmt: ReturnType<typeof parse>): CreateTableStatement {
  expect(stmt.type).toBe('CREATE_TABLE');
  if (stmt.type !== 'CREATE_TABLE') throw new Error(`expected CREATE_TABLE, got ${stmt.type}`);
  return stmt;
}

describe('Parser 边缘场景', () => {
  // ---- SELECT 扩展 ----

  describe('SELECT 扩展', () => {
    it('WHERE 多条件 AND', () => {
      const ast = asSelect(parse("SELECT * FROM users WHERE age > 18 AND name LIKE 'A%'"));
      // v0.8.0: 断言真实结构而非 toBeDefined()
      expect(ast.where).toEqual({
        $and: [{ age: { $gt: 18 } }, { name: { $like: 'A%' } }],
      });
    });

    it('WHERE IN 列表', () => {
      const ast = asSelect(parse('SELECT * FROM users WHERE id IN (1, 2, 3)'));
      expect(ast.where).toEqual({ id: { $in: [1, 2, 3] } });
    });

    it('WHERE IS NULL', () => {
      const ast = asSelect(parse('SELECT * FROM users WHERE bio IS NULL'));
      expect(ast.where).toEqual({ bio: { $eq: null } });
    });

    it('WHERE IS NOT NULL', () => {
      const ast = asSelect(parse('SELECT * FROM users WHERE bio IS NOT NULL'));
      expect(ast.where).toEqual({ bio: { $ne: null } });
    });

    it('WHERE NOT', () => {
      const ast = asSelect(parse('SELECT * FROM users WHERE NOT age = 18'));
      expect(ast.where).toEqual({ $not: { age: { $eq: 18 } } });
    });

    it('WHERE 括号分组', () => {
      const ast = asSelect(parse('SELECT * FROM users WHERE (age > 18 OR age < 10) AND active = TRUE'));
      expect(ast.where).toEqual({
        $and: [{ $or: [{ age: { $gt: 18 } }, { age: { $lt: 10 } }] }, { active: { $eq: true } }],
      });
    });

    // v0.8.0 新增：AND 优先级必须高于 OR（SQL 标准），此前是纯左折叠
    it('AND 优先级高于 OR（SQL 标准）', () => {
      const ast = asSelect(parse('SELECT * FROM t WHERE a = 1 OR a = 2 AND b = 3'));
      expect(ast.where).toEqual({
        $or: [{ a: { $eq: 1 } }, { $and: [{ a: { $eq: 2 } }, { b: { $eq: 3 } }] }],
      });
    });

    it('显式括号可覆盖默认优先级', () => {
      const ast = asSelect(parse('SELECT * FROM t WHERE (a = 1 OR a = 2) AND b = 3'));
      expect(ast.where).toEqual({
        $and: [{ $or: [{ a: { $eq: 1 } }, { a: { $eq: 2 } }] }, { b: { $eq: 3 } }],
      });
    });

    it('NOT 优先级高于 AND/OR', () => {
      const ast = asSelect(parse('SELECT * FROM t WHERE NOT a = 1 OR b = 2'));
      expect(ast.where).toEqual({
        $or: [{ $not: { a: { $eq: 1 } } }, { b: { $eq: 2 } }],
      });
    });

    it('多层 AND/OR 交替的结合性', () => {
      const ast = asSelect(parse('SELECT * FROM t WHERE a = 1 AND b = 2 OR c = 3 AND d = 4'));
      expect(ast.where).toEqual({
        $or: [
          { $and: [{ a: { $eq: 1 } }, { b: { $eq: 2 } }] },
          { $and: [{ c: { $eq: 3 } }, { d: { $eq: 4 } }] },
        ],
      });
    });

    it('ORDER BY 多列', () => {
      const ast = asSelect(parse('SELECT * FROM users ORDER BY age DESC, name ASC'));
      expect(ast.orderBy).toHaveLength(2);
      expect(ast.orderBy![0]).toEqual({ column: 'age', direction: 'desc' });
      expect(ast.orderBy![1]).toEqual({ column: 'name', direction: 'asc' });
    });

    it('只有 LIMIT 没有 OFFSET', () => {
      const ast = asSelect(parse('SELECT * FROM users LIMIT 5'));
      expect(ast.limit).toBe(5);
      expect(ast.offset).toBeUndefined();
    });

    it('只有 OFFSET 没有 LIMIT', () => {
      const ast = asSelect(parse('SELECT * FROM users OFFSET 10'));
      expect(ast.offset).toBe(10);
      expect(ast.limit).toBeUndefined();
    });

    it('不带 WHERE 的 SELECT', () => {
      const ast = asSelect(parse('SELECT id, name FROM users ORDER BY id LIMIT 5'));
      expect(ast.where).toEqual({});
    });
  });

  // ---- INSERT 扩展 ----

  describe('INSERT 扩展', () => {
    it('不带列名的 INSERT', () => {
      const ast = asInsert(parse("INSERT INTO users VALUES ('1', 'Alice', 30)"));
      expect(ast.columns).toBeUndefined();
      expect(ast.values).toEqual([['1', 'Alice', 30]]);
    });

    it('INSERT 布尔值和 NULL', () => {
      const ast = asInsert(parse('INSERT INTO users VALUES (TRUE, FALSE, NULL)'));
      expect(ast.values[0]).toEqual([true, false, null]);
    });

    it('INSERT 负数和浮点数', () => {
      const ast = asInsert(parse('INSERT INTO scores VALUES (-1, 3.14)'));
      expect(ast.values[0]).toEqual([-1, 3.14]);
    });
  });

  // ---- UPDATE 扩展 ----

  describe('UPDATE 扩展', () => {
    it('UPDATE 多列', () => {
      const ast = asUpdate(parse("UPDATE users SET name = 'Bob', age = 26 WHERE id = '1'"));
      expect(ast.sets).toEqual({ name: 'Bob', age: 26 });
      expect(ast.where).toEqual({ id: { $eq: '1' } });
    });

    it('UPDATE 不带 WHERE', () => {
      const ast = asUpdate(parse('UPDATE users SET active = FALSE'));
      expect(ast.where).toEqual({});
    });
  });

  // ---- DELETE 扩展 ----

  describe('DELETE 扩展', () => {
    it('DELETE 不带 WHERE', () => {
      const ast = asDelete(parse('DELETE FROM users'));
      expect(ast.where).toEqual({});
    });

    it('DELETE 带复杂 WHERE', () => {
      const ast = asDelete(parse("DELETE FROM users WHERE age < 18 OR status = 'inactive'"));
      expect(ast.where).toEqual({
        $or: [{ age: { $lt: 18 } }, { status: { $eq: 'inactive' } }],
      });
    });
  });

  // ---- DDL 扩展 ----

  describe('DDL 扩展', () => {
    it('CREATE TABLE 完整修饰符', () => {
      const ast = asCreateTable(parse("CREATE TABLE products (id STRING PRIMARY KEY, name STRING NOT NULL UNIQUE, price NUMBER DEFAULT 0, active BOOLEAN DEFAULT TRUE)"));
      expect(ast.columns).toHaveLength(4);
      expect(ast.columns[0]).toMatchObject({ name: 'id', primaryKey: true });
      expect(ast.columns[1]).toMatchObject({ name: 'name', required: true, unique: true });
      expect(ast.columns[2]).toMatchObject({ name: 'price', default: 0 });
      expect(ast.columns[3]).toMatchObject({ name: 'active', default: true });
    });

    it('支持 DROP TABLE IF EXISTS 语法', () => {
      const ast = parse('DROP TABLE IF EXISTS users');
      expect(ast).toMatchObject({ type: 'DROP_TABLE', name: 'users', ifExists: true });
    });

    it('DROP TABLE 不带 IF EXISTS', () => {
      const ast = parse('DROP TABLE users');
      expect(ast).toMatchObject({ type: 'DROP_TABLE', name: 'users' });
    });
  });

  // ---- 值类型 ----

  describe('常量值解析', () => {
    it('布尔值 TRUE/FALSE', () => {
      const ast = asSelect(parse('SELECT * FROM users WHERE active = TRUE'));
      expect(ast.where).toEqual({ active: { $eq: true } });
    });

    it('NULL 值', () => {
      const ast = asSelect(parse('SELECT * FROM users WHERE bio IS NULL'));
      expect(ast.where).toEqual({ bio: { $eq: null } });
    });
  });
});