using API.Helpers;
using System.Collections.Generic;
using System.Linq;
using Xunit;
using API.DTOs.SeriesDetail;

namespace API.Tests.Helpers;

public class ReviewHelperTests
{
    #region SelectSpectrumOfReviews Tests

    [Fact]
    public void SelectSpectrumOfReviews_WhenLessThan10Reviews_ReturnsAllReviews()
    {
        // Arrange
        var reviews = CreateReviewList(8);

        // Act
        var result = ReviewHelper.SelectSpectrumOfReviews(reviews).ToList();

        // Assert
        Assert.Equal(8, result.Count);
        Assert.Equal(reviews, result.OrderByDescending(r => r.Score));
    }

    [Fact]
    public void SelectSpectrumOfReviews_WhenMoreThan10Reviews_Returns10Reviews()
    {
        // Arrange
        var reviews = CreateReviewList(20);

        // Act
        var result = ReviewHelper.SelectSpectrumOfReviews(reviews).ToList();

        // Assert
        Assert.Equal(10, result.Count);
        Assert.Equal(reviews[0], result.First());
        Assert.Equal(reviews[19], result.Last());
    }

    [Fact]
    public void SelectSpectrumOfReviews_WithExactly10Reviews_ReturnsAllReviews()
    {
        // Arrange
        var reviews = CreateReviewList(10);

        // Act
        var result = ReviewHelper.SelectSpectrumOfReviews(reviews).ToList();

        // Assert
        Assert.Equal(10, result.Count);
    }

    [Fact]
    public void SelectSpectrumOfReviews_WithLargeNumberOfReviews_ReturnsCorrectSpectrum()
    {
        // Arrange
        var reviews = CreateReviewList(100);

        // Act
        var result = ReviewHelper.SelectSpectrumOfReviews(reviews).ToList();

        // Assert
        Assert.Equal(10, result.Count);
        Assert.Contains(reviews[0], result);
        Assert.Contains(reviews[1], result);
        Assert.Contains(reviews[98], result);
        Assert.Contains(reviews[99], result);
    }

    [Fact]
    public void SelectSpectrumOfReviews_WithEmptyList_ReturnsEmptyList()
    {
        // Arrange
        var reviews = new List<UserReviewDto>();

        // Act
        var result = ReviewHelper.SelectSpectrumOfReviews(reviews).ToList();

        // Assert
        Assert.Empty(result);
    }

    [Fact]
    public void SelectSpectrumOfReviews_ResultsOrderedByScoreDescending()
    {
        // Arrange
        var reviews = new List<UserReviewDto>
        {
            new UserReviewDto { Tagline = "1", Score = 3 },
            new UserReviewDto { Tagline = "2", Score = 5 },
            new UserReviewDto { Tagline = "3", Score = 1 },
            new UserReviewDto { Tagline = "4", Score = 4 },
            new UserReviewDto { Tagline = "5", Score = 2 }
        };

        // Act
        var result = ReviewHelper.SelectSpectrumOfReviews(reviews).ToList();

        // Assert
        Assert.Equal(5, result.Count);
        Assert.Equal(5, result[0].Score);
        Assert.Equal(4, result[1].Score);
        Assert.Equal(3, result[2].Score);
        Assert.Equal(2, result[3].Score);
        Assert.Equal(1, result[4].Score);
    }

    #endregion

    #region GetCharacters Tests

    [Fact]
    public void GetCharacters_WithNullBody_ReturnsNull()
    {
        // Arrange
        string body = null;

        // Act
        var result = ReviewHelper.GetCharacters(body);

        // Assert
        Assert.Null(result);
    }

    [Fact]
    public void GetCharacters_WithEmptyBody_ReturnsEmptyString()
    {
        // Arrange
        var body = string.Empty;

        // Act
        var result = ReviewHelper.GetCharacters(body);

        // Assert
        Assert.Equal(string.Empty, result);
    }

    [Fact]
    public void GetCharacters_WithNoTextNodes_ReturnsEmptyString()
    {
        // Arrange
        const string body = "<div></div>";

        // Act
        var result = ReviewHelper.GetCharacters(body);

        // Assert
        Assert.Equal(string.Empty, result);
    }

    [Fact]
    public void GetCharacters_WithLessCharactersThanLimit_ReturnsFullText()
    {
        // Arrange
        var body = "<p>This is a short review.</p>";

        // Act
        var result = ReviewHelper.GetCharacters(body);

        // Assert
        Assert.Equal("This is a short review.…", result);
    }

    [Fact]
    public void GetCharacters_WithMoreCharactersThanLimit_TruncatesText()
    {
        // Arrange
        var body = "<p>" + new string('a', 200) + "</p>";

        // Act
        var result = ReviewHelper.GetCharacters(body);

        // Assert
        Assert.Equal(new string('a', 175) + "…", result);
        Assert.Equal(176, result.Length); // 175 characters + ellipsis
    }

    [Fact]
    public void GetCharacters_IgnoresScriptTags()
    {
        // Arrange
        const string body = "<p>Visible text</p><script>console.log('hidden');</script>";

        // Act
        var result = ReviewHelper.GetCharacters(body);

        // Assert
        Assert.Equal("Visible text…", result);
        Assert.DoesNotContain("hidden", result);
    }

    [Fact]
    public void GetCharacters_RemovesMarkdownSymbols()
    {
        // Arrange
        const string body = "<p>This is **bold** and _italic_ text with [link](url).</p>";

        // Act
        var result = ReviewHelper.GetCharacters(body);

        // Assert
        Assert.Equal("This is bold and italic text with link.…", result);
    }

    [Fact]
    public void GetCharacters_HandlesComplexMarkdownAndHtml()
    {
        // Arrange
        const string body = """

                                        <div>
                                            <h1># Header</h1>
                                            <p>This is ~~strikethrough~~ and __underlined__ text</p>
                                            <p>~~~code block~~~</p>
                                            <p>+++highlighted+++</p>
                                            <p>img123(image.jpg)</p>
                                        </div>
                            """;

        // Act
        var result = ReviewHelper.GetCharacters(body);

        // Assert
        Assert.DoesNotContain("~~", result);
        Assert.DoesNotContain("__", result);
        Assert.DoesNotContain("~~~", result);
        Assert.DoesNotContain("+++", result);
        Assert.DoesNotContain("img123(", result);
        Assert.Contains("Header", result);
        Assert.Contains("strikethrough", result);
        Assert.Contains("underlined", result);
        Assert.Contains("code block", result);
        Assert.Contains("highlighted", result);
    }

    #endregion

    #region Helper Methods

    private static List<UserReviewDto> CreateReviewList(int count)
    {
        var reviews = new List<UserReviewDto>();
        for (var i = 0; i < count; i++)
        {
            reviews.Add(new UserReviewDto
            {
                Tagline = $"{i + 1}",
                Score = count - i // This makes them ordered by score descending initially
            });
        }
        return reviews;
    }

    #endregion
}