using Microsoft.EntityFrameworkCore;
using PoweredSoft.DynamicQuery.Core;
using PoweredSoft.DynamicQuery.Test.Mock;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Xunit;

namespace PoweredSoft.DynamicQuery.Test
{
    
    public class AggregateTests
    {
        [Fact]
        public void WithoutGrouping()
        {
            MockContextFactory.SeedAndTestContextFor("AggregateTests_WithoutGrouping", TestSeeders.SimpleSeedScenario, ctx =>
            {
                var shouldResult = ctx.OrderItems
                    .GroupBy(t => true)
                    .Select(t => new
                    {
                        Count = t.Count(),

                        ItemQuantityMin = t.Min(t2 => t2.Quantity),
                        ItemQuantityMax = t.Min(t2 => t2.Quantity),
                        ItemQuantityAverage = t.Average(t2 => t2.Quantity),
                        ItemQuantitySum = t.Sum(t2 => t2.Quantity),
                        AvgOfPrice = t.Average(t2 => t2.PriceAtTheTime),
                        /* not supported by ef core 3.0
                        First = t.First(),
                        FirstOrDefault = t.FirstOrDefault(),
                        Last = t.Last(),
                        LastOrDefault = t.LastOrDefault()*/
                    })
                    .First();

                // query handler that is empty should be the same as running to list.
                var criteria = new QueryCriteria()
                {
                    Aggregates = new List<Core.IAggregate>
                    {
                        new Aggregate { Type = AggregateType.Count },
                        new Aggregate { Type = AggregateType.Avg, Path = "Quantity" },
                        new Aggregate { Type = AggregateType.Sum, Path = "Quantity" },
                        new Aggregate { Type = AggregateType.Avg, Path = "PriceAtTheTime"},
                        new Aggregate { Type = AggregateType.Min, Path = "Quantity"},
                        new Aggregate { Type = AggregateType.Max, Path = "Quantity" },
                        /*not support by ef core 3.0
                        new Aggregate { Type = AggregateType.First },
                        new Aggregate { Type = AggregateType.FirstOrDefault },
                        new Aggregate { Type = AggregateType.Last },
                        new Aggregate { Type = AggregateType.LastOrDefault },
                        */
                    }
                };

                var queryHandler = new QueryHandler(Enumerable.Empty<IQueryInterceptorProvider>());
                var result = queryHandler.Execute(ctx.OrderItems, criteria, new QueryExecutionOptions
                {
                    GroupByInMemory = true
                });

                var aggCount = result.Aggregates.First(t => t.Type == AggregateType.Count);

                /*
                var aggFirst = result.Aggregates.First(t => t.Type == AggregateType.First);
                var aggFirstOrDefault = result.Aggregates.First(t => t.Type == AggregateType.FirstOrDefault);
                var aggLast = result.Aggregates.First(t => t.Type == AggregateType.Last);
                var aggLastOrDefault = result.Aggregates.First(t => t.Type == AggregateType.LastOrDefault);*/

                var aggItemQuantityMin  = result.Aggregates.First(t => t.Type == AggregateType.Min && t.Path == "Quantity");
                var aggItemQuantityMax = result.Aggregates.First(t => t.Type == AggregateType.Max && t.Path == "Quantity");
                var aggItemQuantityAverage  = result.Aggregates.First(t => t.Type == AggregateType.Avg && t.Path == "Quantity");
                var aggItemQuantitySum = result.Aggregates.First(t => t.Type == AggregateType.Sum && t.Path == "Quantity");
                var aggAvgOfPrice = result.Aggregates.First(t => t.Type == AggregateType.Avg && t.Path == "PriceAtTheTime");

                Assert.Equal(shouldResult.Count, aggCount.Value);
                /*
                Assert.Equal(shouldResult.First?.Id, (aggFirst.Value as OrderItem)?.Id);
                Assert.Equal(shouldResult.FirstOrDefault?.Id, (aggFirstOrDefault.Value as OrderItem)?.Id);
                Assert.Equal(shouldResult.Last?.Id, (aggLast.Value as OrderItem)?.Id);
                Assert.Equal(shouldResult.LastOrDefault?.Id, (aggLastOrDefault.Value as OrderItem)?.Id);*/

                Assert.Equal(shouldResult.ItemQuantityAverage, aggItemQuantityAverage.Value);
                Assert.Equal(shouldResult.ItemQuantitySum, aggItemQuantitySum.Value);
                Assert.Equal(shouldResult.AvgOfPrice, aggAvgOfPrice.Value);
            });
        }

        [Fact]
        public void WithGrouping()
        {
            MockContextFactory.SeedAndTestContextFor("AggregateTests_WithGrouping", TestSeeders.SimpleSeedScenario, ctx =>
            {
                var shouldResults = ctx.OrderItems
                    .GroupBy(t => t.Order.CustomerId)
                    .Select(t => new
                    {
                        GroupValue = t.Key,
                        Count = t.Count(),
                        ItemQuantityAverage = t.Average(t2 => t2.Quantity),
                        ItemQuantitySum = t.Sum(t2 => t2.Quantity),
                        AvgOfPrice = t.Average(t2 => t2.PriceAtTheTime)
                    })
                    .ToList();

                // query handler that is empty should be the same as running to list.
                var criteria = new QueryCriteria()
                {
                    Groups = new List<IGroup>
                    {
                        new Group { Path = "Order.CustomerId" }
                    },
                    Aggregates = new List<Core.IAggregate>
                    {
                        new Aggregate { Type = AggregateType.Count },
                        new Aggregate { Type = AggregateType.Avg, Path = "Quantity" },
                        new Aggregate { Type = AggregateType.Sum, Path = "Quantity" },
                        new Aggregate { Type = AggregateType.Avg, Path = "PriceAtTheTime"}
                    }
                };

                var queryHandler = new QueryHandler(Enumerable.Empty<IQueryInterceptorProvider>());
                var queryable = ctx.OrderItems.Include(t => t.Order);
                var result = queryHandler.Execute(queryable, criteria, new QueryExecutionOptions
                {
                    GroupByInMemory = true
                });

                var groupedResult = result as IQueryExecutionGroupResult<OrderItem>;
                Assert.NotNull(groupedResult);

                var groups = groupedResult.Groups;

                // validate group and aggregates of groups.
                Assert.Equal(groups.Count, shouldResults.Count);
                Assert.All(groups, g =>
                {
                    var index = groups.IndexOf(g);
                    var shouldResult = shouldResults[index];

                    // validate the group value.
                    Assert.Equal(g.GroupValue, shouldResult.GroupValue);

                    // validate the group aggregates.
                    var aggCount = g.Aggregates.First(t => t.Type == AggregateType.Count);
                    var aggItemQuantityAverage = g.Aggregates.First(t => t.Type == AggregateType.Avg && t.Path == "Quantity");
                    var aggItemQuantitySum = g.Aggregates.First(t => t.Type == AggregateType.Sum && t.Path == "Quantity");
                    var aggAvgOfPrice = g.Aggregates.First(t => t.Type == AggregateType.Avg && t.Path == "PriceAtTheTime");
                    Assert.Equal(shouldResult.Count, aggCount.Value);
                    Assert.Equal(shouldResult.ItemQuantityAverage, aggItemQuantityAverage.Value);
                    Assert.Equal(shouldResult.ItemQuantitySum, aggItemQuantitySum.Value);
                    Assert.Equal(shouldResult.AvgOfPrice, aggAvgOfPrice.Value);
                });
            });
        }
    }
}