using FsCheck;
using FsCheck.Xunit;
using WorkCameraExport.Forms;
using Xunit;

namespace WorkCameraExport.Tests
{
    /// <summary>
    /// 图片显示数量属性测试
    /// Feature: work-camera-2.0.1, Property 1: 图片显示数量限制
    /// Validates: Requirements 3.1, 3.2
    /// </summary>
    public class ImageDisplayPropertyTests
    {
        private const int MaxThumbnailsToShow = 3;

        /// <summary>
        /// Property 1: 图片显示数量限制
        /// For any 工作记录，如果图片数量大于 3，则列表中显示的缩略图数量应等于 3，
        /// 且徽章显示的数字应等于总图片数减 3。
        /// </summary>
        [Property(MaxTest = 100)]
        public Property ImageDisplayCount_WhenMoreThanThree_ShouldShowThreeWithBadge()
        {
            return Prop.ForAll(
                Gen.Choose(4, 100).ToArbitrary(), // 4-100 张图片
                (totalImages) =>
                {
                    var (displayCount, badgeCount) = WorkRecordForm.CalculateImageDisplayInfo(totalImages);
                    
                    var displayCountCorrect = displayCount == MaxThumbnailsToShow;
                    var badgeCountCorrect = badgeCount == totalImages - MaxThumbnailsToShow;
                    
                    return (displayCountCorrect && badgeCountCorrect)
                        .Label($"For {totalImages} images: displayCount={displayCount} (expected {MaxThumbnailsToShow}), " +
                               $"badgeCount={badgeCount} (expected {totalImages - MaxThumbnailsToShow})");
                });
        }

        /// <summary>
        /// Property 1 扩展: 图片数量小于等于 3 时，显示全部图片，无徽章
        /// </summary>
        [Property(MaxTest = 100)]
        public Property ImageDisplayCount_WhenThreeOrLess_ShouldShowAllWithoutBadge()
        {
            return Prop.ForAll(
                Gen.Choose(1, 3).ToArbitrary(), // 1-3 张图片
                (totalImages) =>
                {
                    var (displayCount, badgeCount) = WorkRecordForm.CalculateImageDisplayInfo(totalImages);
                    
                    var displayCountCorrect = displayCount == totalImages;
                    var badgeCountCorrect = badgeCount == 0;
                    
                    return (displayCountCorrect && badgeCountCorrect)
                        .Label($"For {totalImages} images: displayCount={displayCount} (expected {totalImages}), " +
                               $"badgeCount={badgeCount} (expected 0)");
                });
        }

        /// <summary>
        /// Property 1 扩展: 无图片时，显示数量和徽章数量都为 0
        /// </summary>
        [Fact]
        public void ImageDisplayCount_WhenZero_ShouldReturnZeros()
        {
            var (displayCount, badgeCount) = WorkRecordForm.CalculateImageDisplayInfo(0);
            
            Assert.Equal(0, displayCount);
            Assert.Equal(0, badgeCount);
        }

        /// <summary>
        /// Property 1 扩展: 负数图片数量应返回 0
        /// </summary>
        [Property(MaxTest = 100)]
        public Property ImageDisplayCount_WhenNegative_ShouldReturnZeros()
        {
            return Prop.ForAll(
                Gen.Choose(-100, -1).ToArbitrary(), // 负数
                (totalImages) =>
                {
                    var (displayCount, badgeCount) = WorkRecordForm.CalculateImageDisplayInfo(totalImages);
                    
                    return (displayCount == 0 && badgeCount == 0)
                        .Label($"For {totalImages} images: displayCount={displayCount}, badgeCount={badgeCount} (both should be 0)");
                });
        }

        /// <summary>
        /// Property 1 扩展: 显示数量 + 徽章数量 应等于总图片数（当总数 > 0 时）
        /// </summary>
        [Property(MaxTest = 100)]
        public Property ImageDisplayCount_DisplayPlusBadge_ShouldEqualTotal()
        {
            return Prop.ForAll(
                Gen.Choose(1, 1000).ToArbitrary(), // 1-1000 张图片
                (totalImages) =>
                {
                    var (displayCount, badgeCount) = WorkRecordForm.CalculateImageDisplayInfo(totalImages);
                    
                    // 当图片数 <= 3 时，displayCount = totalImages, badgeCount = 0
                    // 当图片数 > 3 时，displayCount = 3, badgeCount = totalImages - 3
                    // 两种情况下，displayCount + badgeCount 都应该等于 totalImages
                    var sum = displayCount + badgeCount;
                    
                    return (sum == totalImages)
                        .Label($"For {totalImages} images: displayCount({displayCount}) + badgeCount({badgeCount}) = {sum} (expected {totalImages})");
                });
        }

        /// <summary>
        /// Property 1 扩展: 显示数量应始终在 [0, 3] 范围内
        /// </summary>
        [Property(MaxTest = 100)]
        public Property ImageDisplayCount_DisplayCount_ShouldBeInValidRange()
        {
            return Prop.ForAll(
                Arb.From<int>(),
                (totalImages) =>
                {
                    var (displayCount, _) = WorkRecordForm.CalculateImageDisplayInfo(totalImages);
                    
                    return (displayCount >= 0 && displayCount <= MaxThumbnailsToShow)
                        .Label($"For {totalImages} images: displayCount={displayCount} should be in [0, {MaxThumbnailsToShow}]");
                });
        }

        /// <summary>
        /// Property 1 扩展: 徽章数量应始终 >= 0
        /// </summary>
        [Property(MaxTest = 100)]
        public Property ImageDisplayCount_BadgeCount_ShouldBeNonNegative()
        {
            return Prop.ForAll(
                Arb.From<int>(),
                (totalImages) =>
                {
                    var (_, badgeCount) = WorkRecordForm.CalculateImageDisplayInfo(totalImages);
                    
                    return (badgeCount >= 0)
                        .Label($"For {totalImages} images: badgeCount={badgeCount} should be >= 0");
                });
        }

        /// <summary>
        /// Property 1 扩展: 边界值测试 - 恰好 3 张图片
        /// </summary>
        [Fact]
        public void ImageDisplayCount_ExactlyThree_ShouldShowAllWithoutBadge()
        {
            var (displayCount, badgeCount) = WorkRecordForm.CalculateImageDisplayInfo(3);
            
            Assert.Equal(3, displayCount);
            Assert.Equal(0, badgeCount);
        }

        /// <summary>
        /// Property 1 扩展: 边界值测试 - 恰好 4 张图片
        /// </summary>
        [Fact]
        public void ImageDisplayCount_ExactlyFour_ShouldShowThreeWithBadgeOne()
        {
            var (displayCount, badgeCount) = WorkRecordForm.CalculateImageDisplayInfo(4);
            
            Assert.Equal(3, displayCount);
            Assert.Equal(1, badgeCount);
        }

        /// <summary>
        /// Property 1 扩展: 大量图片测试
        /// </summary>
        [Property(MaxTest = 100)]
        public Property ImageDisplayCount_LargeNumbers_ShouldHandleCorrectly()
        {
            return Prop.ForAll(
                Gen.Choose(1000, 100000).ToArbitrary(), // 大量图片
                (totalImages) =>
                {
                    var (displayCount, badgeCount) = WorkRecordForm.CalculateImageDisplayInfo(totalImages);
                    
                    var displayCountCorrect = displayCount == MaxThumbnailsToShow;
                    var badgeCountCorrect = badgeCount == totalImages - MaxThumbnailsToShow;
                    var sumCorrect = displayCount + badgeCount == totalImages;
                    
                    return (displayCountCorrect && badgeCountCorrect && sumCorrect)
                        .Label($"For {totalImages} images: displayCount={displayCount}, badgeCount={badgeCount}");
                });
        }
    }
}