using Core.Entities;
using Core.Validation;
using Core.Validation.Rules.StudentAssignmentRules;
using Tests.Builders;

namespace Tests.Validation.Rules;

[TestFixture]
public class StudentAssignmentRulesTests
{
    private Student _testStudent;

    [SetUp]
    public void SetUp()
    {
        BuilderExtensions.ResetAllBuilders();
        _testStudent = StudentBuilder.Default().WithName("Test", "Student").Build();
    }

    #region TooFewEventsRule Tests

    [Test]
    public void TooFewEventsRule_AboveMinimum_ReturnsNull()
    {
        // Arrange
        var config = new ValidationConfiguration { MinRecommendedEvents = 2 };
        var rule = new TooFewEventsRule();

        var stats = new StudentEventStatistics
        {
            Student = _testStudent,
            Events = new List<EventDefinition>
            {
                EventDefinitionBuilder.Individual("Flight").Build(),
                EventDefinitionBuilder.Individual("Coding").Build(),
                EventDefinitionBuilder.Individual("Speech").Build()
            }
        };

        // Act
        var warning = rule.Validate(stats, config);

        // Assert
        Assert.That(warning, Is.Null);
    }

    [Test]
    public void TooFewEventsRule_BelowMinimum_ReturnsWarning()
    {
        // Arrange
        var config = new ValidationConfiguration
        {
            MinRecommendedEvents = 3,
            MinCriticalEvents = 1,
            EventCountSeverity = ValidationSeverity.Warning
        };
        var rule = new TooFewEventsRule();

        var stats = new StudentEventStatistics
        {
            Student = _testStudent,
            Events = new List<EventDefinition>
            {
                EventDefinitionBuilder.Individual("Flight").Build()
            }
        };

        // Act
        var warning = rule.Validate(stats, config);

        // Assert
        Assert.That(warning, Is.Not.Null);
        Assert.That(warning!.Code, Is.EqualTo("TOO_FEW_EVENTS"));
        Assert.That(warning.Message, Does.Contain("1 events"));
        Assert.That(warning.Message, Does.Contain("min recommended: 3"));
        Assert.That(warning.Severity, Is.EqualTo(ValidationSeverity.Warning));
    }

    [Test]
    public void TooFewEventsRule_BelowCritical_EscalatesToError()
    {
        // Arrange
        var config = new ValidationConfiguration
        {
            MinRecommendedEvents = 3,
            MinCriticalEvents = 2,
            EventCountSeverity = ValidationSeverity.Warning
        };
        var rule = new TooFewEventsRule();

        var stats = new StudentEventStatistics
        {
            Student = _testStudent,
            Events = new List<EventDefinition>
            {
                EventDefinitionBuilder.Individual("Flight").Build()
            }
        };

        // Act
        var warning = rule.Validate(stats, config);

        // Assert
        Assert.That(warning, Is.Not.Null);
        Assert.That(warning!.Severity, Is.EqualTo(ValidationSeverity.Error),
            "Should escalate to Error when below critical threshold");
    }

    #endregion

    #region TooManyEventsRule Tests

    [Test]
    public void TooManyEventsRule_BelowMaximum_ReturnsNull()
    {
        // Arrange
        var config = new ValidationConfiguration { MaxRecommendedEvents = 4 };
        var rule = new TooManyEventsRule();

        var stats = new StudentEventStatistics
        {
            Student = _testStudent,
            Events = new List<EventDefinition>
            {
                EventDefinitionBuilder.Individual("Event1").Build(),
                EventDefinitionBuilder.Individual("Event2").Build(),
                EventDefinitionBuilder.Individual("Event3").Build()
            }
        };

        // Act
        var warning = rule.Validate(stats, config);

        // Assert
        Assert.That(warning, Is.Null);
    }

    [Test]
    public void TooManyEventsRule_AboveMaximum_ReturnsWarning()
    {
        // Arrange
        var config = new ValidationConfiguration
        {
            MaxRecommendedEvents = 3,
            MaxCriticalEvents = 6,
            EventCountSeverity = ValidationSeverity.Warning
        };
        var rule = new TooManyEventsRule();

        var events = new List<EventDefinition>();
        for (int i = 0; i < 5; i++)
        {
            events.Add(EventDefinitionBuilder.Individual($"Event{i}").Build());
        }
        var stats = new StudentEventStatistics
        {
            Student = _testStudent,
            Events = events
        };

        // Act
        var warning = rule.Validate(stats, config);

        // Assert
        Assert.That(warning, Is.Not.Null);
        Assert.That(warning!.Code, Is.EqualTo("TOO_MANY_EVENTS"));
        Assert.That(warning.Message, Does.Contain("5 events"));
        Assert.That(warning.Message, Does.Contain("max recommended: 3"));
        Assert.That(warning.Severity, Is.EqualTo(ValidationSeverity.Warning));
    }

    [Test]
    public void TooManyEventsRule_AboveCritical_EscalatesToError()
    {
        // Arrange
        var config = new ValidationConfiguration
        {
            MaxRecommendedEvents = 4,
            MaxCriticalEvents = 6,
            EventCountSeverity = ValidationSeverity.Warning
        };
        var rule = new TooManyEventsRule();

        var events = new List<EventDefinition>();
        for (int i = 0; i < 7; i++)
        {
            events.Add(EventDefinitionBuilder.Individual($"Event{i}").Build());
        }
        var stats = new StudentEventStatistics
        {
            Student = _testStudent,
            Events = events
        };

        // Act
        var warning = rule.Validate(stats, config);

        // Assert
        Assert.That(warning, Is.Not.Null);
        Assert.That(warning!.Severity, Is.EqualTo(ValidationSeverity.Error),
            "Should escalate to Error when above critical threshold");
    }

    [Test]
    public void TooManyEventsRule_ContainsMetadata()
    {
        // Arrange
        var config = new ValidationConfiguration
        {
            MaxRecommendedEvents = 2,
            MaxCriticalEvents = 5
        };
        var rule = new TooManyEventsRule();

        var events = new List<EventDefinition>();
        for (int i = 0; i < 4; i++)
        {
            events.Add(EventDefinitionBuilder.Individual($"Event{i}").Build());
        }
        var stats = new StudentEventStatistics
        {
            Student = _testStudent,
            Events = events
        };

        // Act
        var warning = rule.Validate(stats, config);

        // Assert
        Assert.That(warning, Is.Not.Null);
        Assert.That(warning!.Metadata, Contains.Key("MaxRecommended"));
        Assert.That(warning.Metadata, Contains.Key("MaxCritical"));
        Assert.That(warning.Metadata["MaxRecommended"], Is.EqualTo(2));
        Assert.That(warning.Metadata["MaxCritical"], Is.EqualTo(5));
    }

    #endregion

    #region NoRegionalEventAssignmentRule Tests

    [Test]
    public void NoRegionalEventAssignmentRule_HasRegionalEvent_ReturnsNull()
    {
        // Arrange
        var config = new ValidationConfiguration { RequireRegionalEvent = true };
        var rule = new NoRegionalEventAssignmentRule();

        var stats = new StudentEventStatistics
        {
            Student = _testStudent,
            Events = new List<EventDefinition>
            {
                EventDefinitionBuilder.Individual("Flight").AsRegionalEvent().Build()
            }
        };

        // Act
        var warning = rule.Validate(stats, config);

        // Assert
        Assert.That(warning, Is.Null);
    }

    [Test]
    public void NoRegionalEventAssignmentRule_LacksRegionalEvent_ReturnsWarning()
    {
        // Arrange
        var config = new ValidationConfiguration
        {
            RequireRegionalEvent = true,
            NoRegionalEventSeverity = ValidationSeverity.Warning
        };
        var rule = new NoRegionalEventAssignmentRule();

        var stats = new StudentEventStatistics
        {
            Student = _testStudent,
            Events = new List<EventDefinition>
            {
                EventDefinitionBuilder.Individual("Coding").Build()
            }
        };

        // Act
        var warning = rule.Validate(stats, config);

        // Assert
        Assert.That(warning, Is.Not.Null);
        Assert.That(warning!.Code, Is.EqualTo("NO_REGIONAL_EVENT_ASSIGNED"));
        Assert.That(warning.Context, Is.EqualTo(ValidationContext.StudentAssignment));
    }

    #endregion

    #region NoOnSiteActivityAssignmentRule Tests

    [Test]
    public void NoOnSiteActivityAssignmentRule_HasOnSiteActivity_ReturnsNull()
    {
        // Arrange
        var config = new ValidationConfiguration { RequireOnSiteActivity = true };
        var rule = new NoOnSiteActivityAssignmentRule();

        var stats = new StudentEventStatistics
        {
            Student = _testStudent,
            Events = new List<EventDefinition>
            {
                EventDefinitionBuilder.Individual("Speech").AsOnSite().Build()
            }
        };

        // Act
        var warning = rule.Validate(stats, config);

        // Assert
        Assert.That(warning, Is.Null);
    }

    [Test]
    public void NoOnSiteActivityAssignmentRule_LacksOnSiteActivity_ReturnsWarning()
    {
        // Arrange
        var config = new ValidationConfiguration
        {
            RequireOnSiteActivity = true,
            NoOnSiteActivitySeverity = ValidationSeverity.Error
        };
        var rule = new NoOnSiteActivityAssignmentRule();

        var stats = new StudentEventStatistics
        {
            Student = _testStudent,
            Events = new List<EventDefinition>
            {
                EventDefinitionBuilder.Individual("Flight").Build()
            }
        };

        // Act
        var warning = rule.Validate(stats, config);

        // Assert
        Assert.That(warning, Is.Not.Null);
        Assert.That(warning!.Code, Is.EqualTo("NO_ONSITE_ACTIVITY_ASSIGNED"));
        Assert.That(warning.Severity, Is.EqualTo(ValidationSeverity.Error));
    }

    #endregion

    #region TooManyRegionalEventsAssignmentRule Tests

    [Test]
    public void TooManyRegionalEventsAssignmentRule_WithinLimit_ReturnsNull()
    {
        // Arrange
        var config = new ValidationConfiguration { MaxRegionalEvents = 3 };
        var rule = new TooManyRegionalEventsAssignmentRule();

        var stats = new StudentEventStatistics
        {
            Student = _testStudent,
            Events = new List<EventDefinition>
            {
                EventDefinitionBuilder.Individual("Flight").AsRegionalEvent().Build(),
                EventDefinitionBuilder.Individual("Coding").AsRegionalEvent().Build()
            }
        };

        // Act
        var warning = rule.Validate(stats, config);

        // Assert
        Assert.That(warning, Is.Null);
    }

    [Test]
    public void TooManyRegionalEventsAssignmentRule_ExceedsLimit_ReturnsWarning()
    {
        // Arrange
        var config = new ValidationConfiguration
        {
            MaxRegionalEvents = 2,
            TooManyRegionalEventsSeverity = ValidationSeverity.Warning
        };
        var rule = new TooManyRegionalEventsAssignmentRule();

        var stats = new StudentEventStatistics
        {
            Student = _testStudent,
            Events = new List<EventDefinition>
            {
                EventDefinitionBuilder.Individual("Flight").AsRegionalEvent().Build(),
                EventDefinitionBuilder.Individual("Coding").AsRegionalEvent().Build(),
                EventDefinitionBuilder.Individual("Essays").AsRegionalEvent().Build()
            }
        };

        // Act
        var warning = rule.Validate(stats, config);

        // Assert
        Assert.That(warning, Is.Not.Null);
        Assert.That(warning!.Code, Is.EqualTo("TOO_MANY_REGIONAL_EVENTS"));
        Assert.That(warning.Message, Does.Contain("3 regional events"));
    }

    #endregion

    #region AppliesTo Tests

    [Test]
    public void AssignmentRules_ApplyToCorrectContexts()
    {
        // Arrange
        var rules = new IValidationRule<StudentEventStatistics>[]
        {
            new TooFewEventsRule(),
            new TooManyEventsRule(),
            new NoRegionalEventAssignmentRule(),
            new NoOnSiteActivityAssignmentRule(),
            new TooManyRegionalEventsAssignmentRule()
        };

        // Act & Assert - all assignment rules should apply to these contexts
        foreach (var rule in rules)
        {
            Assert.That(rule.AppliesTo(ValidationContext.StudentAssignment), Is.True,
                $"{rule.GetType().Name} should apply to StudentAssignment");
            Assert.That(rule.AppliesTo(ValidationContext.StudentRegistration), Is.True,
                $"{rule.GetType().Name} should apply to StudentRegistration");
            Assert.That(rule.AppliesTo(ValidationContext.StudentRanking), Is.False,
                $"{rule.GetType().Name} should not apply to StudentRanking");
            Assert.That(rule.AppliesTo(ValidationContext.Team), Is.False,
                $"{rule.GetType().Name} should not apply to Team");
        }
    }

    #endregion
}