using System.Text;
using Core.Notes;
using Core.Parsers;
using Tests.Builders;

namespace Tests.Parsers;

[TestFixture]
public class StudentNotesFieldParser_Tests
{
    [SetUp]
    public void SetUp()
    {
        BuilderExtensions.ResetAllBuilders();
    }

    [Test]
    public void Parse_MatchesStudentAndReportsUnmatched()
    {
        var aria = StudentBuilder.Create("Aria", "Chittenden").Build();
        const string csv = """
            Student Name,Interview Time,Application
            "Chittenden, Aria",3:20-3:35,x
            Nobody Here,1:00-1:15,x
            """;

        var result = Parse(csv, [aria]);

        Assert.That(result.IsSuccess, Is.True);
        Assert.That(result.Matches, Has.Count.EqualTo(1));
        Assert.That(result.Matches[0].Student, Is.SameAs(aria));
        Assert.That(result.Matches[0].Merge.Changed, Is.True);
        Assert.That(result.Issues, Has.Count.EqualTo(1));
        Assert.That(result.Issues[0].RawStudentName, Is.EqualTo("Nobody Here"));
    }

    [Test]
    public void Parse_SameExistingNote_HasNoChanges()
    {
        var aria = StudentBuilder.Create("Aria", "Chittenden").Build();
        var existing = ImportedFieldsTable.Merge(null,
        [
            new ImportedField("Interview Time", "3:20-3:35"),
            new ImportedField("Application", "Yes")
        ]).Markdown;

        const string csv = """
            Student Name,Interview Time,Application
            Aria Chittenden,3:20-3:35,x
            """;

        var result = Parse(csv, [aria], new Dictionary<int, string?> { [aria.Id] = existing });

        Assert.That(result.Matches, Has.Count.EqualTo(1));
        Assert.That(result.Matches[0].Merge.Changed, Is.False);
        Assert.That(result.StudentsWithChanges, Is.EqualTo(0));
    }

    [Test]
    public void Parse_MissingStudentNameColumn_IsError()
    {
        var aria = StudentBuilder.Create("Aria", "Chittenden").Build();
        const string csv = """
            Name,Interview Time
            Aria Chittenden,3:20-3:35
            """;

        var result = Parse(csv, [aria]);

        Assert.That(result.IsSuccess, Is.False);
        Assert.That(result.Errors, Has.Some.Contains("Student Name"));
        Assert.That(result.Matches, Is.Empty);
    }

    [Test]
    public void Parse_PreservesFieldsNotInCsv()
    {
        var aria = StudentBuilder.Create("Aria", "Chittenden").Build();
        var existing = ImportedFieldsTable.Merge(null,
        [
            new ImportedField("Interview Time", "1:00-1:15"),
            new ImportedField("Teacher Rec 1", "Fuqua")
        ]).Markdown;

        const string csv = """
            Student Name,Interview Time
            Aria Chittenden,3:20-3:35
            """;

        var result = Parse(csv, [aria], new Dictionary<int, string?> { [aria.Id] = existing });
        var fields = ImportedFieldsTable.ParseFields(result.Matches[0].Merge.Markdown);

        Assert.That(result.Matches[0].Merge.Changed, Is.True);
        Assert.That(fields.Single(f => f.Name == "Interview Time").Value, Is.EqualTo("3:20-3:35"));
        Assert.That(fields.Single(f => f.Name == "Teacher Rec 1").Value, Is.EqualTo("Fuqua"));
    }

    [Test]
    public void Parse_X_BecomesYes_AndBlankFieldsRoundTrip()
    {
        var aria = StudentBuilder.Create("Aria", "Chittenden").Build();
        const string csv = """
            Student Name,Application,Teacher Rec 3
            Aria Chittenden,x,
            """;

        var first = Parse(csv, [aria]);
        var markdown = first.Matches[0].Merge.Markdown;

        Assert.That(ImportedFieldsTable.GetFieldValue(markdown, "Application"), Is.EqualTo("Yes"));
        Assert.That(ImportedFieldsTable.GetFieldValue(markdown, "Teacher Rec 3"), Is.EqualTo(string.Empty));

        var second = Parse(csv, [aria], new Dictionary<int, string?> { [aria.Id] = markdown });
        Assert.That(second.Matches[0].Merge.Changed, Is.False);
        Assert.That(second.StudentsWithChanges, Is.EqualTo(0));
    }

    [Test]
    public void Parse_DuplicateStudentRows_LastValueWins_OneMatch()
    {
        var aria = StudentBuilder.Create("Aria", "Chittenden").Build();
        const string csv = """
            Student Name,Interview Time,Teacher Rec 1
            Aria Chittenden,1:00-1:15,Fuqua
            "Chittenden, Aria",3:20-3:35,Young
            """;

        var result = Parse(csv, [aria]);
        var fields = ImportedFieldsTable.ParseFields(result.Matches[0].Merge.Markdown);

        Assert.That(result.Matches, Has.Count.EqualTo(1));
        Assert.That(fields.Single(f => f.Name == "Interview Time").Value, Is.EqualTo("3:20-3:35"));
        Assert.That(fields.Single(f => f.Name == "Teacher Rec 1").Value, Is.EqualTo("Young"));
    }

    [Test]
    public void Parse_NameOnlyCsv_WarnsAndMatchesWithoutFieldChanges()
    {
        var aria = StudentBuilder.Create("Aria", "Chittenden").Build();
        const string csv = """
            Student Name
            Aria Chittenden
            """;

        var result = Parse(csv, [aria]);

        Assert.That(result.IsSuccess, Is.True);
        Assert.That(result.Warnings, Has.Some.Contains("No leftover field columns"));
        Assert.That(result.Matches, Has.Count.EqualTo(1));
        Assert.That(result.Matches[0].Merge.Changed, Is.False);
    }

    [Test]
    public void Parse_ExcludesRosterAndRankingColumns()
    {
        var aria = StudentBuilder.Create("Aria", "Chittenden").Build();
        const string csv = """
            Student Name,Grade,TSA year,State ID,Regional ID,National ID,Officer,1,2,TOTAL # OF EVENTS,Interview Time,Application
            Aria Chittenden,6,1st,,,,,Coding,JSS,2,3:20-3:35,x
            """;

        var result = Parse(csv, [aria]);
        var fields = ImportedFieldsTable.ParseFields(result.Matches[0].Merge.Markdown);

        Assert.That(result.FieldNames, Is.EquivalentTo(["Interview Time", "Application"]));
        Assert.That(fields.Select(f => f.Name), Is.EquivalentTo(["Interview Time", "Application"]));
        Assert.That(fields.Single(f => f.Name == "Application").Value, Is.EqualTo("Yes"));
        Assert.That(fields.Any(f => f.Name is "Grade" or "1" or "Officer"), Is.False);
    }

    [Test]
    public void Parse_RosterOnlyCsv_HasNoLeftoverFields()
    {
        var aria = StudentBuilder.Create("Aria", "Chittenden").Build();
        const string csv = """
            Student Name,Grade,TSA year,State ID,Regional ID,National ID
            Aria Chittenden,6,1st,,,
            """;

        var result = Parse(csv, [aria]);

        Assert.That(result.FieldNames, Is.Empty);
        Assert.That(result.Matches[0].Merge.Changed, Is.False);
        Assert.That(result.Warnings, Has.Some.Contains("No leftover field columns"));
    }

    private static Core.Models.StudentNotesImportResult Parse(
        string csv,
        ICollection<Core.Entities.Student> students,
        IReadOnlyDictionary<int, string?>? notes = null)
    {
        using var reader = new StreamReader(new MemoryStream(Encoding.UTF8.GetBytes(csv)));
        using var parser = new StudentNotesFieldParser(reader);
        return parser.Parse(students, notes ?? new Dictionary<int, string?>());
    }
}