using System.Linq.Expressions;
using JdeScoping.DataSync.Services;

namespace JdeScoping.DataSync.Tests.Services;

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

    #region GetColumnNames Tests

    [Fact]
    public void GetColumnNames_SingleProperty_ReturnsSingleColumn()
    {
        // Arrange
        Expression<Func<TestEntity, object>> expr = x => x.Id;

        // Act
        var columns = ExpressionParser.GetColumnNames(expr);

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

    [Fact]
    public void GetColumnNames_SingleStringProperty_ReturnsSingleColumn()
    {
        // Arrange
        Expression<Func<TestEntity, object>> expr = x => x.Name;

        // Act
        var columns = ExpressionParser.GetColumnNames(expr);

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

    [Fact]
    public void GetColumnNames_AnonymousType_ReturnsAllColumns()
    {
        // Arrange
        Expression<Func<TestEntity, object>> expr = x => new { x.Id, x.Name };

        // Act
        var columns = ExpressionParser.GetColumnNames(expr);

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

    [Fact]
    public void GetColumnNames_AnonymousTypeWithMultipleProperties_ReturnsAllColumns()
    {
        // Arrange
        Expression<Func<TestEntity, object>> expr = x => new { x.Id, x.Name, x.Amount, x.LastUpdateDt };

        // Act
        var columns = ExpressionParser.GetColumnNames(expr);

        // Assert
        Assert.Equal(4, columns.Count);
        Assert.Equal("Id", columns[0]);
        Assert.Equal("Name", columns[1]);
        Assert.Equal("Amount", columns[2]);
        Assert.Equal("LastUpdateDt", columns[3]);
    }

    [Fact]
    public void GetColumnNames_NullExpression_ThrowsArgumentNullException()
    {
        // Act & Assert
        Assert.Throws<ArgumentNullException>(() =>
            ExpressionParser.GetColumnNames<TestEntity>(null!));
    }

    #endregion

    #region BuildUpdateWhenSql Tests

    [Fact]
    public void BuildUpdateWhenSql_NullExpression_ReturnsNull()
    {
        // Act
        var result = ExpressionParser.BuildUpdateWhenSql<TestEntity>(null);

        // Assert
        Assert.Null(result);
    }

    [Fact]
    public void BuildUpdateWhenSql_GreaterThan_ReturnsSqlCondition()
    {
        // Arrange
        Expression<Func<TestEntity, TestEntity, bool>> expr = (src, tgt) => src.LastUpdateDt > tgt.LastUpdateDt;

        // Act
        var result = ExpressionParser.BuildUpdateWhenSql(expr);

        // Assert
        Assert.Equal("source.[LastUpdateDt] > target.[LastUpdateDt]", result);
    }

    [Fact]
    public void BuildUpdateWhenSql_GreaterThanOrEqual_ReturnsSqlCondition()
    {
        // Arrange
        Expression<Func<TestEntity, TestEntity, bool>> expr = (src, tgt) => src.Id >= tgt.Id;

        // Act
        var result = ExpressionParser.BuildUpdateWhenSql(expr);

        // Assert
        Assert.Equal("source.[Id] >= target.[Id]", result);
    }

    [Fact]
    public void BuildUpdateWhenSql_Equal_ReturnsSqlCondition()
    {
        // Arrange
        Expression<Func<TestEntity, TestEntity, bool>> expr = (src, tgt) => src.Name == tgt.Name;

        // Act
        var result = ExpressionParser.BuildUpdateWhenSql(expr);

        // Assert
        Assert.Equal("source.[Name] = target.[Name]", result);
    }

    [Fact]
    public void BuildUpdateWhenSql_NotEqual_ReturnsSqlCondition()
    {
        // Arrange
        Expression<Func<TestEntity, TestEntity, bool>> expr = (src, tgt) => src.Amount != tgt.Amount;

        // Act
        var result = ExpressionParser.BuildUpdateWhenSql(expr);

        // Assert
        Assert.Equal("source.[Amount] <> target.[Amount]", result);
    }

    [Fact]
    public void BuildUpdateWhenSql_AndCondition_ReturnsSqlCondition()
    {
        // Arrange
        Expression<Func<TestEntity, TestEntity, bool>> expr =
            (src, tgt) => src.LastUpdateDt > tgt.LastUpdateDt && src.Id == tgt.Id;

        // Act
        var result = ExpressionParser.BuildUpdateWhenSql(expr);

        // Assert
        Assert.Equal("(source.[LastUpdateDt] > target.[LastUpdateDt] AND source.[Id] = target.[Id])", result);
    }

    [Fact]
    public void BuildUpdateWhenSql_OrCondition_ReturnsSqlCondition()
    {
        // Arrange
        Expression<Func<TestEntity, TestEntity, bool>> expr =
            (src, tgt) => src.LastUpdateDt > tgt.LastUpdateDt || src.Amount > tgt.Amount;

        // Act
        var result = ExpressionParser.BuildUpdateWhenSql(expr);

        // Assert
        Assert.Equal("(source.[LastUpdateDt] > target.[LastUpdateDt] OR source.[Amount] > target.[Amount])", result);
    }

    [Fact]
    public void BuildUpdateWhenSql_CustomAliases_UsesProvidedAliases()
    {
        // Arrange
        Expression<Func<TestEntity, TestEntity, bool>> expr = (src, tgt) => src.Id > tgt.Id;

        // Act
        var result = ExpressionParser.BuildUpdateWhenSql(expr, "s", "t");

        // Assert
        Assert.Equal("s.[Id] > t.[Id]", result);
    }

    #endregion
}