unit Myc.Test.Trade.DataPoint;

interface

uses
    System.SysUtils,
    System.Classes,
    DUnitX.TestFramework,
    Myc.Trade.DataPoint;

type

    [TestFixture]
    TTestTDataSeries = class(TObject)
    private
        FSeries: TDataSeries<TAskBidItem>;
        procedure SetupSeriesWithData(ItemCount: Integer = 10; MaxLookBack: Int64 = 0);
    public
        [Setup]
        procedure Setup;
        [Teardown]
        procedure Teardown;

        [Test]
        procedure TestSetupSeriesWithDataVerification;
        [Test]
        procedure TestAddAndCount;
        [Test]
        [IgnoreMemoryLeaks]
        procedure TestAddOrderAssertion;
        [Test]
        procedure TestGetItemsIndexing;
        [Test]
        procedure TestIndexOfExistingTimeStamp;
        [Test]
        procedure TestIndexOfNonExistingBetween;
        [Test]
        procedure TestIndexOfBeforeFirstItem;
        [Test]
        procedure TestIndexOfAfterLastItem;
        [Test]
        procedure TestIndexOfExactOldestItem;
        [Test]
        procedure TestIndexOfExactNewestItem;
        [Test]
        procedure TestIndexOfEmptySeries;
        [Test]
        procedure TestIndexOfSingleItemSeries;

        // Tests for MaxLookback
        [Test]
        procedure TestCountIsCappedByMaxLookback_NoTrim;
        [Test]
        procedure TestCountIsCappedByMaxLookback_WithTrim;
        [Test]
        [IgnoreMemoryLeaks]
        procedure TestLoopIsSafeWithMaxLookback;
        [Test]
        procedure TestIndexOfRespectsMaxLookback;

        // Tests for bulk Add
        [Test]
        procedure TestBulkAddIncreasesCount;
        [Test]
        [IgnoreMemoryLeaks]
        procedure TestBulkAddChronologicalAssertion_Internal;
        [Test]
        [IgnoreMemoryLeaks]
        procedure TestBulkAddChronologicalAssertion_External;
        [Test]
        procedure TestBulkAddSpanningMultipleChunks;
        [Test]
        procedure TestBulkAddWithMaxLookback;

        // Tests for TotalCount
        [Test]
        procedure TestTotalCountIncrementsCorrectly;
        [Test]
        procedure TestTotalCountIgnoresTrimming;
        [Test]
        procedure TestTotalCountResetsOnClear;
    end;

implementation

{ TTestTDataSeries }

procedure TTestTDataSeries.Setup;
begin
    // Managed record is implicitly initialized.
end;

procedure TTestTDataSeries.Teardown;
begin
    // Ensure managed record is finalized to prevent false leak reports.
    FSeries := Default(TDataSeries<TAskBidItem>);
end;

procedure TTestTDataSeries.SetupSeriesWithData(ItemCount: Integer = 10; MaxLookBack: Int64 = 0);
var
    i: Integer;
    DataPoint: TDataPoint<TAskBidItem>;
    baseTime: TDateTime;
begin
    FSeries := TDataSeries<TAskBidItem>.Create( MaxLookBack );
    baseTime := EncodeDate(2020, 7, 7);

    // Add data points with increasing timestamps.
    for i := 0 to ItemCount - 1 do
    begin
        DataPoint := TDataPoint<TAskBidItem>.Create(baseTime + i, TAskBidItem.Create(i * 1.0, i * 1.0 + 0.1));
        FSeries.Add(DataPoint);
    end;
end;

// Verifies that the test data setup helper works as expected.
procedure TTestTDataSeries.TestSetupSeriesWithDataVerification;
var
    i: Integer;
    baseTime, expectedTime: TDateTime;
    expectedAsk: Single;
begin
    SetupSeriesWithData;
    baseTime := EncodeDate(2020, 7, 7);

    Assert.AreEqual(Int64(10), FSeries.Count, 'Setup should create exactly 10 items');

    // Check all items to ensure correct reverse chronological order.
    for i := 0 to FSeries.Count - 1 do
    begin
        expectedTime := baseTime + (9 - i);
        expectedAsk := Single(9 - i);
        Assert.AreEqual(expectedTime, FSeries[i].Time, 'Item at logical index should have correct reversed timestamp');
        Assert.AreEqual(expectedAsk, FSeries[i].Data.Ask, 'Item at logical index should have correct reversed data');
    end;
end;

// Tests adding new items and the resulting count.
procedure TTestTDataSeries.TestAddAndCount;
var
    DataPoint: TDataPoint<TAskBidItem>;
    newTime: TDateTime;
begin
    SetupSeriesWithData;
    newTime := EncodeDate(2020, 7, 17);

    Assert.AreEqual(Int64(10), FSeries.Count, 'Initial count should be 10');

    DataPoint := TDataPoint<TAskBidItem>.Create(newTime, TAskBidItem.Create(100.0, 100.1));
    FSeries.Add(DataPoint);

    Assert.AreEqual(Int64(11), FSeries.Count, 'Count should be 11 after adding one more');
    Assert.AreEqual(newTime, FSeries.Items[0].Time, 'Newest item should be at index 0');
end;

// Ensures that adding an item with an older timestamp raises an assertion.
procedure TTestTDataSeries.TestAddOrderAssertion;
var
    olderTime: TDateTime;
begin
    SetupSeriesWithData; // Newest item is at 2020-07-16
    olderTime := EncodeDate(2020, 7, 15);

    Assert.WillRaise(
        procedure
        begin
            var DataPoint := TDataPoint<TAskBidItem>.Create(olderTime, TAskBidItem.Create(0.0, 0.0));
            FSeries.Add(DataPoint);
        end,
        EAssertionFailed,
        'Adding item with older timestamp should raise an assert error'
    );
end;

// Verifies that the logical-to-physical index mapping is correct.
procedure TTestTDataSeries.TestGetItemsIndexing;
var
    i: Integer;
    expectedTime: TDateTime;
    baseTime: TDateTime;
begin
    SetupSeriesWithData;
    baseTime := EncodeDate(2020, 7, 7);

    for i := 0 to 9 do
    begin
        expectedTime := baseTime + (9 - i);
        Assert.AreEqual(expectedTime, FSeries.Items[i].Time, 'Item at logical index should have reversed chronological time');
        Assert.AreEqual(Single(9 - i), FSeries.Items[i].Data.Ask, 'Item data at logical index should match reversed insertion order');
    end;
end;

// Tests finding an existing item (in this case, the oldest).
procedure TTestTDataSeries.TestIndexOfExistingTimeStamp;
var
    ATimeStamp: TDateTime;
    expectedIndex: Int64;
begin
    SetupSeriesWithData;
    ATimeStamp := EncodeDate(2020, 7, 7); // Oldest item
    expectedIndex := 9;

    Assert.AreEqual(
        expectedIndex,
        FSeries.IndexOf(ATimeStamp),
        'IndexOf for the oldest existing item timestamp should return its correct index'
    );
end;

// Tests finding the index for a timestamp that falls between two existing items.
procedure TTestTDataSeries.TestIndexOfNonExistingBetween;
var
    ATimeStamp: TDateTime;
    expectedIndex: Int64;
begin
    SetupSeriesWithData;
    ATimeStamp := EncodeDate(2020, 7, 7) + 0.5; // 12:00 on the day of the oldest item
    expectedIndex := Int64(9); // Should find the item from 00:00

    Assert.AreEqual(
        expectedIndex,
        FSeries.IndexOf(ATimeStamp),
        'IndexOf for a non-existing timestamp should return the index of the immediately preceding item'
    );
end;

// Tests finding a timestamp that is older than any item in the series.
procedure TTestTDataSeries.TestIndexOfBeforeFirstItem;
var
    ATimeStamp: TDateTime;
    baseTime: TDateTime;
begin
    SetupSeriesWithData;
    baseTime := EncodeDate(2020, 7, 7);
    ATimeStamp := baseTime - 1; // A day before the oldest item

    Assert.AreEqual(Int64(-1), FSeries.IndexOf(ATimeStamp), 'IndexOf for a timestamp before the oldest item should return -1');
end;

// Tests finding a timestamp that is newer than any item in the series.
procedure TTestTDataSeries.TestIndexOfAfterLastItem;
var
    ATimeStamp: TDateTime;
    baseTime: TDateTime;
begin
    SetupSeriesWithData;
    baseTime := EncodeDate(2020, 7, 7);
    ATimeStamp := baseTime + 10; // A day after the newest item

    Assert.AreEqual(
        Int64(0),
        FSeries.IndexOf(ATimeStamp),
        'IndexOf for a timestamp after the newest item should return the index of the newest item'
    );
end;

// Specifically tests finding the exact oldest item.
procedure TTestTDataSeries.TestIndexOfExactOldestItem;
var
    ATimeStamp: TDateTime;
begin
    SetupSeriesWithData;
    ATimeStamp := EncodeDate(2020, 7, 7);

    Assert.AreEqual(Int64(9), FSeries.IndexOf(ATimeStamp), 'IndexOf for the exact oldest timestamp should return the last index');
end;

// Specifically tests finding the exact newest item.
procedure TTestTDataSeries.TestIndexOfExactNewestItem;
var
    ATimeStamp: TDateTime;
begin
    SetupSeriesWithData;
    ATimeStamp := EncodeDate(2020, 7, 16);

    Assert.AreEqual(Int64(0), FSeries.IndexOf(ATimeStamp), 'IndexOf for the exact newest timestamp should return index 0');
end;

// Tests IndexOf on an empty series.
procedure TTestTDataSeries.TestIndexOfEmptySeries;
begin
    FSeries := Default(TDataSeries<TAskBidItem>);
    Assert.AreEqual(Int64(0), FSeries.Count);
    Assert.AreEqual(Int64(-1), FSeries.IndexOf(Now), 'IndexOf on empty series should return -1');
end;

// Tests IndexOf on a series with only one item.
procedure TTestTDataSeries.TestIndexOfSingleItemSeries;
var
    DataPoint: TDataPoint<TAskBidItem>;
    testTime: TDateTime;
begin
    FSeries := Default(TDataSeries<TAskBidItem>);
    testTime := EncodeDate(2025, 1, 1);
    DataPoint := TDataPoint<TAskBidItem>.Create(testTime, TAskBidItem.Create(1.0, 2.0));
    FSeries.Add(DataPoint);

    Assert.AreEqual(Int64(1), FSeries.Count);
    Assert.AreEqual(Int64(0), FSeries.IndexOf(testTime), 'IndexOf for exact single item should be 0');
    Assert.AreEqual(Int64(0), FSeries.IndexOf(testTime + 0.5), 'IndexOf for time after single item should be 0');
    Assert.AreEqual(Int64(-1), FSeries.IndexOf(testTime - 1), 'IndexOf for time before single item should be -1');
end;

procedure TTestTDataSeries.TestCountIsCappedByMaxLookback_NoTrim;
begin
    SetupSeriesWithData(500, 400); // Less than one chunk

    // The public Count must now be the MaxLookback value, even though
    // no chunk was freed and FCount is still 500 internally.
    Assert.AreEqual(Int64(400), FSeries.Count, 'Public count should be capped by MaxLookback even if no chunk is freed');
end;

procedure TTestTDataSeries.TestCountIsCappedByMaxLookback_WithTrim;
const
    ITEMS_TO_ADD = 2000;
    LOOKBACK_LIMIT = 900;
begin
    SetupSeriesWithData(ITEMS_TO_ADD, LOOKBACK_LIMIT);

    // Internally, FCount will be 976 after one chunk is freed.
    // The public Count should still be capped at the lookback limit.
    Assert.AreEqual(Int64(LOOKBACK_LIMIT), FSeries.Count, 'Public count should be capped by MaxLookback after trimming');
end;

procedure TTestTDataSeries.TestLoopIsSafeWithMaxLookback;
var
    dummy: TDataPoint<TAskBidItem>;
begin
    SetupSeriesWithData(500, 400);
    Assert.AreEqual(Int64(400), FSeries.Count, 'Pre-condition: Count must be capped at 400');

    // This test proves that a standard loop based on the public Count is safe
    // and will not access an invalid index.
    Assert.WillNotRaise(
        procedure
        begin
            for var i := 0 to FSeries.Count - 1 do
            begin
                dummy := FSeries[i];
            end;
        end,
        nil,
        'Looping up to the public Count should not raise an exception'
    );

    // Also test the assert when going one item beyond the public count
    Assert.WillRaise(
        procedure begin dummy := FSeries[400]; end,
        EAssertionFailed,
        'Accessing index at the limit of MaxLookback should raise an exception'
    );
end;

procedure TTestTDataSeries.TestIndexOfRespectsMaxLookback;
var
    baseTime, searchTime: TDateTime;
begin
    SetupSeriesWithData(500, 400); // Items from baseTime+0 to baseTime+499
    baseTime := EncodeDate(2020, 7, 7);

    Assert.AreEqual(Int64(400), FSeries.Count, 'Pre-condition: Count must be 400');

    // The oldest *physically present* item has a timestamp of baseTime+0.
    // This item is at logical index 499, which is outside the MaxLookback range.
    // IndexOf must not find it.
    searchTime := baseTime; // Time of oldest physical item.
    Assert.AreEqual(Int64(-1), FSeries.IndexOf(searchTime), 'IndexOf should not find items outside the MaxLookback range');

    // The oldest *logically valid* item is at index 399.
    // Its physical index is 500 - 399 - 1 = 100.
    // Its timestamp is baseTime + 100.
    searchTime := baseTime + 100;
    Assert.AreEqual(Int64(399), FSeries.IndexOf(searchTime), 'IndexOf should find the oldest valid item at the edge of MaxLookback');
end;

procedure TTestTDataSeries.TestBulkAddIncreasesCount;
var
    newData: TArray<TDataPoint<TAskBidItem>>;
    baseTime, newTime: TDateTime;
    i: Integer;
begin
    SetupSeriesWithData(10);
    baseTime := EncodeDate(2020, 7, 7);

    SetLength(newData, 5);
    for i := 0 to High(newData) do
    begin
        newTime := baseTime + 10 + i;
        newData[i] := TDataPoint<TAskBidItem>.Create(newTime, TAskBidItem.Create(i, i));
    end;

    FSeries.Add(newData);

    Assert.AreEqual(Int64(15), FSeries.Count, 'Count should be increased by the number of items in the bulk add');
    Assert.AreEqual(baseTime + 10 + High(newData), FSeries.Time[0], 'Newest item should be the last item from the added array');
end;

procedure TTestTDataSeries.TestBulkAddChronologicalAssertion_Internal;
var
    newData: TArray<TDataPoint<TAskBidItem>>;
begin
    SetupSeriesWithData(10);
    SetLength(newData, 2);
    newData[0] := TDataPoint<TAskBidItem>.Create(Now + 1, TAskBidItem.Create(1, 1));
    newData[1] := TDataPoint<TAskBidItem>.Create(Now, TAskBidItem.Create(2, 2)); // Not sorted

    Assert.WillRaise(
        procedure begin FSeries.Add(newData); end,
        EAssertionFailed,
        'Bulk Add should fail if the input array is not chronologically sorted'
    );
end;

procedure TTestTDataSeries.TestBulkAddChronologicalAssertion_External;
var
    newData: TArray<TDataPoint<TAskBidItem>>;
    olderTime: TDateTime;
begin
    SetupSeriesWithData(10); // Newest is baseTime + 9
    olderTime := EncodeDate(2020, 7, 7) + 8;

    SetLength(newData, 1);
    newData[0] := TDataPoint<TAskBidItem>.Create(olderTime, TAskBidItem.Create(1, 1));

    Assert.WillRaise(
        procedure begin FSeries.Add(newData); end,
        EAssertionFailed,
        'Bulk Add should fail if its first item is older than the series last item'
    );
end;

procedure TTestTDataSeries.TestBulkAddSpanningMultipleChunks;
const
    CHUNK_SIZE = 1024;
var
    newData: TArray<TDataPoint<TAskBidItem>>;
    lastTimeBeforeAdd, firstNewTime, lastNewTime: TDateTime;
    i: Integer;
begin
    SetupSeriesWithData(CHUNK_SIZE - 4); // Almost fill the first chunk
    lastTimeBeforeAdd := FSeries.Time[0];

    SetLength(newData, 8); // Add 8 items, which will span the chunk boundary
    for i := 0 to High(newData) do
    begin
        newData[i] := TDataPoint<TAskBidItem>.Create(lastTimeBeforeAdd + 1 + i, TAskBidItem.Create(i, i));
    end;

    firstNewTime := newData[0].Time;
    lastNewTime := newData[High(newData)].Time;

    FSeries.Add(newData);
    Assert.AreEqual(Int64(CHUNK_SIZE + 4), FSeries.Count, 'Count should be correct after spanning a chunk');
    Assert.AreEqual(lastNewTime, FSeries.Time[0], 'Newest item should be correct');
    Assert.AreEqual(firstNewTime, FSeries.Time[7], 'Oldest of the new items should be at the correct logical index');
end;

procedure TTestTDataSeries.TestBulkAddWithMaxLookback;
var
    newData: TArray<TDataPoint<TAskBidItem>>;
    i: Integer;
    baseTime: TDateTime;
begin
    SetupSeriesWithData(400, 500);
    baseTime := FSeries.Time[0];

    SetLength(newData, 200);
    for i := 0 to High(newData) do
    begin
        newData[i] := TDataPoint<TAskBidItem>.Create(baseTime + 1 + i, TAskBidItem.Create(i, i));
    end;

    FSeries.Add(newData);

    // Total items would be 600, but MaxLookback is 500.
    // Trim does not free chunks (100 to remove < 1024).
    // The public Count must be capped at 500.
    Assert.AreEqual(Int64(500), FSeries.Count, 'Count should be capped by MaxLookback after bulk add');
end;

procedure TTestTDataSeries.TestTotalCountIncrementsCorrectly;
var
    newData: TArray<TDataPoint<TAskBidItem>>;
    i: Integer;
begin
    FSeries := TDataSeries<TAskBidItem>.Create( 0 );
    Assert.AreEqual(Int64(0), FSeries.TotalCount, 'TotalCount should be 0 on creation');

    // Test single add
    FSeries.Add(TDataPoint<TAskBidItem>.Create(Now, TAskBidItem.Create(1,1)));
    Assert.AreEqual(Int64(1), FSeries.TotalCount, 'TotalCount should be 1 after single add');

    // Test bulk add
    SetLength(newData, 10);
    for i := 0 to High(newData) do
        newData[i] := TDataPoint<TAskBidItem>.Create(Now + 1 + i, TAskBidItem.Create(i,i));

    FSeries.Add(newData);
    Assert.AreEqual(Int64(11), FSeries.TotalCount, 'TotalCount should be 11 after bulk add');
end;

procedure TTestTDataSeries.TestTotalCountIgnoresTrimming;
begin
    // Create series with a lookback that will cause trimming
    SetupSeriesWithData(20, 10);

    // The visible count is capped by MaxLookback
    Assert.AreEqual(Int64(10), FSeries.Count, 'Count should be capped by MaxLookback');
    // The total count should reflect all items that were ever added
    Assert.AreEqual(Int64(20), FSeries.TotalCount, 'TotalCount must not be affected by trimming');
end;

procedure TTestTDataSeries.TestTotalCountResetsOnClear;
begin
    SetupSeriesWithData(15);
    Assert.IsTrue(FSeries.TotalCount > 0, 'Pre-condition: TotalCount should be greater than 0');

    FSeries.Clear;

    Assert.AreEqual(Int64(0), FSeries.TotalCount, 'TotalCount should be 0 after Clear');
    Assert.AreEqual(Int64(0), FSeries.Count, 'Count should be 0 after Clear');
end;

initialization
    TDUnitX.RegisterTestFixture(TTestTDataSeries);
end.