using CanonSharp.Combinator;
using CanonSharp.Combinator.Abstractions;
using CanonSharp.Combinator.Extensions;
using CanonSharp.Tests.Utils;
using static CanonSharp.Combinator.ParserBuilder;

namespace CanonSharp.Tests.CombinatorsTests;

public class BasicParsersTests : ParserTestsBase
{
    [Fact]
    public void AlternativeTest()
    {
        IParser<char, char> parser = Token('a') | Token('b');

        ValidateSuccessfulResult(parser, 'a', "abc");
        ValidateSuccessfulResult(parser, 'b', "bcd");
        ValidateFailedResult(parser, "cde");

        parser = Token('a').Alternative(_ => Token('b'));
        ValidateSuccessfulResult(parser, 'a', "abc");
        ValidateSuccessfulResult(parser, 'b', "bcd");
        ValidateFailedResult(parser, "cde");
    }

    [Fact]
    public void BindTest()
    {
        IParser<char, char> parser = Token('a').Bind(_ => Token('b')).Bind(_ => Token('c'));
        ValidateSuccessfulResult(parser, 'c', "abc");
        ValidateFailedResult(parser, "acd");

        ValidateFailedResult(parser, "ab");
    }

    [Fact]
    public void MapTest()
    {
        IParser<char, string> parser = Token('a').Map(c => $"{c}");
        ValidateSuccessfulResult(parser, "a", "abc");

        parser = Token('a').Map("test");
        ValidateSuccessfulResult(parser, "test", "abc");
    }

    [Fact]
    public void NextTest()
    {
        IParser<char, char> parser = Token('a').Next(_ => Token('a'), _ => Token('b'));
        ValidateSuccessfulResult(parser, 'a', "aaa");
        ValidateSuccessfulResult(parser, 'b', "bbb");

        parser = Token('a').Next(_ => Token('a'), _ => 'b');
        ValidateSuccessfulResult(parser, 'b', "bbb");

        parser = Token('a').Next(_ => Pure<char, char>('1'), '2');
        ValidateSuccessfulResult(parser, '1', "aaa");
        ValidateSuccessfulResult(parser, '2', "bbb");
    }

    [Fact]
    public void NextTest2()
    {
        IParser<char, string> parser = Token('a').Next(_ => "123", _ => Pure<char, string>("456"));
        ValidateSuccessfulResult(parser, "123", "aaa");
        ValidateSuccessfulResult(parser, "456", "bbb");

        parser = Token('a').Next(_ => "123", _ => "456");
        ValidateSuccessfulResult(parser, "123", "aaa");
        ValidateSuccessfulResult(parser, "456", "bbb");

        parser = Token('a').Next(_ => "123", "456");
        ValidateSuccessfulResult(parser, "123", "aaa");
        ValidateSuccessfulResult(parser, "456", "bbb");
    }

    [Fact]
    public void FixTest()
    {
        IParser<char, char> parser = Fix<char, Unit>(self => Token('a').Next(_ => self, Unit.Instance))
            .Bind(_ => Token('b'));
        ValidateSuccessfulResult(parser, 'b', "aaaaab");
    }
}