using System.Data;
using JdeScoping.DataAccess.Interfaces;
using JdeScoping.DataSync.Contracts;
using JdeScoping.DataSync.Exceptions;
using JdeScoping.DataSync.Models;
using JdeScoping.DataSync.Services;
using Microsoft.Data.SqlClient;
using Microsoft.Extensions.Logging;
using NSubstitute;

namespace JdeScoping.DataSync.Tests.Services;

public class BulkMergeHelperTests
{
    private readonly IDbConnectionFactory _connectionFactory;
    private readonly IDataReaderFactory _dataReaderFactory;
    private readonly ISchemaValidator _schemaValidator;
    private readonly ILogger<BulkMergeHelper> _logger;
    private readonly BulkMergeHelper _helper;

    private class TestEntity
    {
        public int Id { get; set; }
        public string Name { get; set; } = string.Empty;
        public decimal Amount { get; set; }
    }

    public BulkMergeHelperTests()
    {
        _connectionFactory = Substitute.For<IDbConnectionFactory>();
        _dataReaderFactory = Substitute.For<IDataReaderFactory>();
        _schemaValidator = Substitute.For<ISchemaValidator>();
        _logger = Substitute.For<ILogger<BulkMergeHelper>>();

        // Setup default mock returns
        _dataReaderFactory.GetColumnNames<TestEntity>()
            .Returns(new List<string> { "Id", "Name", "Amount" });

        _helper = new BulkMergeHelper(
            _connectionFactory,
            _dataReaderFactory,
            _schemaValidator,
            _logger);
    }

    #region Constructor Tests

    [Fact]
    public void Constructor_NullConnectionFactory_ThrowsArgumentNullException()
    {
        Assert.Throws<ArgumentNullException>(() =>
            new BulkMergeHelper(null!, _dataReaderFactory, _schemaValidator, _logger));
    }

    [Fact]
    public void Constructor_NullDataReaderFactory_ThrowsArgumentNullException()
    {
        Assert.Throws<ArgumentNullException>(() =>
            new BulkMergeHelper(_connectionFactory, null!, _schemaValidator, _logger));
    }

    [Fact]
    public void Constructor_NullSchemaValidator_ThrowsArgumentNullException()
    {
        Assert.Throws<ArgumentNullException>(() =>
            new BulkMergeHelper(_connectionFactory, _dataReaderFactory, null!, _logger));
    }

    [Fact]
    public void Constructor_NullLogger_ThrowsArgumentNullException()
    {
        Assert.Throws<ArgumentNullException>(() =>
            new BulkMergeHelper(_connectionFactory, _dataReaderFactory, _schemaValidator, null!));
    }

    #endregion

    #region MergeAsync Parameter Validation Tests

    [Fact]
    public async Task MergeAsync_NullData_ThrowsArgumentNullException()
    {
        await Assert.ThrowsAsync<ArgumentNullException>(() =>
            _helper.MergeAsync<TestEntity>(
                null!,
                "TestTable",
                x => x.Id));
    }

    [Fact]
    public async Task MergeAsync_NullDestinationTable_ThrowsArgumentNullException()
    {
        var data = AsyncEnumerable.Empty<TestEntity>();

        await Assert.ThrowsAsync<ArgumentNullException>(() =>
            _helper.MergeAsync(
                data,
                null!,
                x => x.Id));
    }

    [Fact]
    public async Task MergeAsync_EmptyDestinationTable_ThrowsArgumentException()
    {
        var data = AsyncEnumerable.Empty<TestEntity>();

        await Assert.ThrowsAsync<ArgumentException>(() =>
            _helper.MergeAsync(
                data,
                "",
                x => x.Id));
    }

    [Fact]
    public async Task MergeAsync_NullMatchOn_ThrowsArgumentNullException()
    {
        var data = AsyncEnumerable.Empty<TestEntity>();

        await Assert.ThrowsAsync<ArgumentNullException>(() =>
            _helper.MergeAsync<TestEntity>(
                data,
                "TestTable",
                null!));
    }

    #endregion

    #region Column Expression Tests

    [Fact]
    public void GetColumnNames_CalledWithMatchOn_ReturnsCorrectColumns()
    {
        // The ExpressionParser is tested separately, this just verifies it's being called
        var columns = ExpressionParser.GetColumnNames<TestEntity>(x => x.Id);

        Assert.Single(columns);
        Assert.Equal("Id", columns[0]);
    }

    [Fact]
    public void GetColumnNames_CalledWithMultipleColumns_ReturnsCorrectColumns()
    {
        var columns = ExpressionParser.GetColumnNames<TestEntity>(x => new { x.Id, x.Name });

        Assert.Equal(2, columns.Count);
        Assert.Equal("Id", columns[0]);
        Assert.Equal("Name", columns[1]);
    }

    #endregion

    #region TempTableName Generation Tests

    [Fact]
    public void TempTableName_WithDots_ReplacesWithUnderscores()
    {
        // This is implicitly tested by how temp table names are generated
        var tableName = "dbo.TestTable";

        // The actual generation happens inside MergeAsync, so we verify the pattern
        var cleaned = tableName.Replace(".", "_").Replace("[", "").Replace("]", "");
        Assert.Equal("dbo_TestTable", cleaned);
    }

    [Fact]
    public void TempTableName_WithBrackets_RemovesBrackets()
    {
        var tableName = "[dbo].[TestTable]";
        var cleaned = tableName.Replace(".", "_").Replace("[", "").Replace("]", "");
        Assert.Equal("dbo_TestTable", cleaned);
    }

    #endregion

    #region MergeResult Tests

    [Fact]
    public void MergeResult_TotalRowsAffected_ReturnsSum()
    {
        var result = new MergeResult(100, 60, 40, 10, TimeSpan.FromSeconds(5));

        Assert.Equal(100, result.TotalRowsAffected);
    }

    [Fact]
    public void MergeResult_RecordProperties_AreCorrect()
    {
        var elapsed = TimeSpan.FromSeconds(5);
        var result = new MergeResult(100, 60, 40, 10, elapsed);

        Assert.Equal(100, result.TotalRowsProcessed);
        Assert.Equal(60, result.RowsInserted);
        Assert.Equal(40, result.RowsUpdated);
        Assert.Equal(10, result.BatchCount);
        Assert.Equal(elapsed, result.Elapsed);
    }

    #endregion

    #region MassInsertAsync Tests

    [Fact]
    public async Task MassInsertAsync_NullData_ThrowsArgumentNullException()
    {
        // Act & Assert
        await Assert.ThrowsAsync<ArgumentNullException>(
            () => _helper.MassInsertAsync<TestEntity>(null!, "TestTable"));
    }

    [Fact]
    public async Task MassInsertAsync_NullDestination_ThrowsArgumentNullException()
    {
        // Arrange
        var data = AsyncEnumerable.Empty<TestEntity>();

        // Act & Assert
        // ArgumentException.ThrowIfNullOrWhiteSpace throws ArgumentNullException for null values
        await Assert.ThrowsAsync<ArgumentNullException>(
            () => _helper.MassInsertAsync(data, null!));
    }

    [Fact]
    public async Task MassInsertAsync_EmptyDestination_ThrowsArgumentException()
    {
        // Arrange
        var data = AsyncEnumerable.Empty<TestEntity>();

        // Act & Assert
        await Assert.ThrowsAsync<ArgumentException>(
            () => _helper.MassInsertAsync(data, ""));
    }

    #endregion

    #region Exception Tests

    [Fact]
    public void BulkMergeException_PropertiesAreSet()
    {
        var ex = new BulkMergeException("Test error")
        {
            TableName = "TestTable",
            BatchNumber = 5,
            RowsInBatch = 1000,
            SqlStatement = "MERGE INTO..."
        };

        Assert.Equal("TestTable", ex.TableName);
        Assert.Equal(5, ex.BatchNumber);
        Assert.Equal(1000, ex.RowsInBatch);
        Assert.Equal("MERGE INTO...", ex.SqlStatement);
    }

    [Fact]
    public void BulkMergeValidationException_ContainsErrors()
    {
        var errors = new List<ValidationError>
        {
            new(0, "Name", "TooLong", "Exceeds max length"),
            new(1, "Amount", 999999m, "Overflow")
        };

        var ex = new BulkMergeValidationException("Validation failed", errors);

        Assert.Equal(2, ex.Errors.Count);
        Assert.Equal("Name", ex.Errors[0].ColumnName);
        Assert.Equal("Amount", ex.Errors[1].ColumnName);
    }

    #endregion
}