using System.Collections.Generic;
using System.Linq;
using System.Text.Json;
using FsCheck;
using FsCheck.Fluent;
using FsCheck.Xunit;
using XplorePlane.Models;

namespace XplorePlane.Tests.Models
{
    /// <summary>
    /// FsCheck property-based tests for BatchCaptureResult JSON serialization round-trip.
    /// Property 10: 摘要 JSON 序列化往返
    /// </summary>
    public class SummarySerializationPropertyTests
    {
        // ── Generators ───────────────────────────────────────────────────

        /// <summary>
        /// Generates a non-null string (FsCheck may generate nulls by default).
        /// </summary>
        private static Gen<string> NonNullStringGen =>
            ArbMap.Default.GeneratorFor<NonEmptyString>()
                .Select(s => s.Get)
                .Or(Gen.Constant(string.Empty));

        /// <summary>
        /// Generates a nullable string (either null or a non-empty string).
        /// </summary>
        private static Gen<string> NullableStringGen =>
            Gen.OneOf(
                Gen.Constant<string>(null),
                ArbMap.Default.GeneratorFor<NonEmptyString>().Select(s => s.Get));

        /// <summary>
        /// Generates a random PositionResult with valid field values.
        /// </summary>
        private static Gen<PositionResult> PositionResultGen =>
            from nodeName in NonNullStringGen
            from nodeIndex in Gen.Choose(0, 1000)
            from status in Gen.Elements("Success", "Failed")
            from errorMessage in NullableStringGen
            from imagePath in NullableStringGen
            select new PositionResult
            {
                NodeName = nodeName,
                NodeIndex = nodeIndex,
                Status = status,
                ErrorMessage = errorMessage,
                ImagePath = imagePath
            };

        /// <summary>
        /// Generates a random BatchCaptureResult with valid field values.
        /// </summary>
        private static Gen<BatchCaptureResult> BatchCaptureResultGen =>
            from programName in NonNullStringGen
            from startTime in NonNullStringGen
            from durationSeconds in Gen.Choose(0, 100000).Select(i => i / 100.0)
            from totalPositions in Gen.Choose(0, 50)
            from succeededPositions in Gen.Choose(0, 50)
            from failedPositions in Gen.Choose(0, 50)
            from savedImageCount in Gen.Choose(0, 100)
            from status in Gen.Elements("Completed", "Cancelled")
            from completedBeforeCancel in Gen.OneOf(
                Gen.Constant<int?>(null),
                Gen.Choose(0, 50).Select(i => (int?)i))
            from notExecutedAfterCancel in Gen.OneOf(
                Gen.Constant<int?>(null),
                Gen.Choose(0, 50).Select(i => (int?)i))
            from positionCount in Gen.Choose(0, 5)
            from positions in Gen.ListOf<PositionResult>(PositionResultGen, positionCount)
            select new BatchCaptureResult
            {
                ProgramName = programName,
                StartTime = startTime,
                DurationSeconds = durationSeconds,
                TotalPositions = totalPositions,
                SucceededPositions = succeededPositions,
                FailedPositions = failedPositions,
                SavedImageCount = savedImageCount,
                Status = status,
                CompletedBeforeCancel = completedBeforeCancel,
                NotExecutedAfterCancel = notExecutedAfterCancel,
                Positions = positions.ToList()
            };

        // ── Property 10 ─────────────────────────────────────────────────

        /// <summary>
        /// **Validates: Requirements 4.3**
        ///
        /// For any valid BatchCaptureResult object, serializing to JSON and
        /// deserializing back produces an object with identical field values.
        /// </summary>
        [Property(MaxTest = 100)]
        public Property BatchCaptureResult_JsonRoundTrip_PreservesAllFields()
        {
            return Prop.ForAll(
                BatchCaptureResultGen.ToArbitrary(),
                original =>
                {
                    // Serialize to JSON
                    var json = JsonSerializer.Serialize(original);

                    // Deserialize back
                    var deserialized = JsonSerializer.Deserialize<BatchCaptureResult>(json);

                    // Verify all scalar properties
                    bool scalarFieldsMatch =
                        deserialized.ProgramName == original.ProgramName &&
                        deserialized.StartTime == original.StartTime &&
                        deserialized.DurationSeconds == original.DurationSeconds &&
                        deserialized.TotalPositions == original.TotalPositions &&
                        deserialized.SucceededPositions == original.SucceededPositions &&
                        deserialized.FailedPositions == original.FailedPositions &&
                        deserialized.SavedImageCount == original.SavedImageCount &&
                        deserialized.Status == original.Status;

                    // Verify nullable int properties
                    bool nullableFieldsMatch =
                        deserialized.CompletedBeforeCancel == original.CompletedBeforeCancel &&
                        deserialized.NotExecutedAfterCancel == original.NotExecutedAfterCancel;

                    // Verify list property count
                    bool listCountMatch =
                        deserialized.Positions.Count == original.Positions.Count;

                    // Verify each position in the list
                    bool positionsMatch = true;
                    for (int i = 0; i < original.Positions.Count; i++)
                    {
                        var orig = original.Positions[i];
                        var deser = deserialized.Positions[i];
                        if (deser.NodeName != orig.NodeName ||
                            deser.NodeIndex != orig.NodeIndex ||
                            deser.Status != orig.Status ||
                            deser.ErrorMessage != orig.ErrorMessage ||
                            deser.ImagePath != orig.ImagePath)
                        {
                            positionsMatch = false;
                            break;
                        }
                    }

                    return scalarFieldsMatch && nullableFieldsMatch &&
                           listCountMatch && positionsMatch;
                });
        }
    }
}