/* tslint:disable:no-unused-expression */
import { expect } from "chai";

import Error, { isError } from "../src/error";
import Lexer from "../src/lexer";
import Token, { TokenKind } from "../src/token";

const scan = (source: string): Token[] | Error => {
  return new Lexer(source).scan();
};

describe("Lexer", () => {
  it("scans uppercase keywords", () => {
    const tokens = scan("SELECT FROM WHERE");
    expect(tokens).to.deep.equal([
      new Token(TokenKind.SELECT, null, 1),
      new Token(TokenKind.FROM, null, 1),
      new Token(TokenKind.WHERE, null, 1),
      new Token(TokenKind.EOF, null, 1),
    ]);
  });

  it("scans lowercase keywords", () => {
    const tokens = scan("select from where");
    expect(tokens).to.deep.equal([
      new Token(TokenKind.SELECT, null, 1),
      new Token(TokenKind.FROM, null, 1),
      new Token(TokenKind.WHERE, null, 1),
      new Token(TokenKind.EOF, null, 1),
    ]);
  });

  it("scans symbols", () => {
    const tokens = scan("*=,`;.");
    expect(tokens).to.deep.equal([
      new Token(TokenKind.STAR, null, 1),
      new Token(TokenKind.EQUALS, null, 1),
      new Token(TokenKind.COMMA, null, 1),
      new Token(TokenKind.BACKTICK, null, 1),
      new Token(TokenKind.SEMICOLON, null, 1),
      new Token(TokenKind.DOT, null, 1),
      new Token(TokenKind.EOF, null, 1),
    ]);
  });

  it("scans identifiers", () => {
    const tokens = scan("ident ident_ifier Ident");
    expect(tokens).to.deep.equal([
      new Token(TokenKind.IDENTIFIER, "ident", 1),
      new Token(TokenKind.IDENTIFIER, "ident_ifier", 1),
      new Token(TokenKind.IDENTIFIER, "Ident", 1),
      new Token(TokenKind.EOF, null, 1),
    ]);
  });

  it("scans numbers", () => {
    const tokens = scan("1 123.45 .123");
    expect(tokens).to.deep.equal([
      new Token(TokenKind.NUMBER, "1", 1),
      new Token(TokenKind.NUMBER, "123.45", 1),
      new Token(TokenKind.NUMBER, ".123", 1),
      new Token(TokenKind.EOF, null, 1),
    ]);
  });

  it("keeps track of line numbers", () => {
    const tokens = scan("foo\nbar");
    expect(tokens).to.deep.equal([
      new Token(TokenKind.IDENTIFIER, "foo", 1),
      new Token(TokenKind.IDENTIFIER, "bar", 2),
      new Token(TokenKind.EOF, null, 2),
    ]);
  });

  it("returns an error for an unrecognized character", () => {
    const error = scan("~");
    expect(isError(error)).to.be.ok;
    if (isError(error)) {
      expect(error.message).to.equal("Unrecognized character ~");
    }
  });
});