// Copyright 2021 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package storage

import (
	"testing"

	"github.com/stretchr/testify/require"

	"github.com/prometheus/prometheus/model/labels"
	"github.com/prometheus/prometheus/tsdb/chunkenc"
	"github.com/prometheus/prometheus/tsdb/tsdbutil"
)

func TestListSeriesIterator(t *testing.T) {
	it := NewListSeriesIterator(samples{
		sample{0, 0, nil, nil},
		sample{1, 1, nil, nil},
		sample{1, 1.5, nil, nil},
		sample{2, 2, nil, nil},
		sample{3, 3, nil, nil},
	})

	// Seek to the first sample with ts=1.
	require.Equal(t, chunkenc.ValFloat, it.Seek(1))
	ts, v := it.At()
	require.Equal(t, int64(1), ts)
	require.Equal(t, 1., v)

	// Seek one further, next sample still has ts=1.
	require.Equal(t, chunkenc.ValFloat, it.Next())
	ts, v = it.At()
	require.Equal(t, int64(1), ts)
	require.Equal(t, 1.5, v)

	// Seek again to 1 and make sure we stay where we are.
	require.Equal(t, chunkenc.ValFloat, it.Seek(1))
	ts, v = it.At()
	require.Equal(t, int64(1), ts)
	require.Equal(t, 1.5, v)

	// Another seek.
	require.Equal(t, chunkenc.ValFloat, it.Seek(3))
	ts, v = it.At()
	require.Equal(t, int64(3), ts)
	require.Equal(t, 3., v)

	// And we don't go back.
	require.Equal(t, chunkenc.ValFloat, it.Seek(2))
	ts, v = it.At()
	require.Equal(t, int64(3), ts)
	require.Equal(t, 3., v)

	// Seek beyond the end.
	require.Equal(t, chunkenc.ValNone, it.Seek(5))
	// And we don't go back. (This exposes issue #10027.)
	require.Equal(t, chunkenc.ValNone, it.Seek(2))
}

// TestSeriesSetToChunkSet test the property of SeriesSet that says
// returned series should be iterable even after Next is called.
func TestChunkSeriesSetToSeriesSet(t *testing.T) {
	series := []struct {
		lbs     labels.Labels
		samples []tsdbutil.Sample
	}{
		{
			lbs: labels.Labels{
				{Name: "__name__", Value: "up"},
				{Name: "instance", Value: "localhost:8080"},
			},
			samples: []tsdbutil.Sample{
				sample{t: 1, v: 1},
				sample{t: 2, v: 2},
				sample{t: 3, v: 3},
				sample{t: 4, v: 4},
			},
		}, {
			lbs: labels.Labels{
				{Name: "__name__", Value: "up"},
				{Name: "instance", Value: "localhost:8081"},
			},
			samples: []tsdbutil.Sample{
				sample{t: 1, v: 2},
				sample{t: 2, v: 3},
				sample{t: 3, v: 4},
				sample{t: 4, v: 5},
				sample{t: 5, v: 6},
				sample{t: 6, v: 7},
			},
		},
	}
	var chunkSeries []ChunkSeries
	for _, s := range series {
		chunkSeries = append(chunkSeries, NewListChunkSeriesFromSamples(s.lbs, s.samples))
	}
	css := NewMockChunkSeriesSet(chunkSeries...)

	ss := NewSeriesSetFromChunkSeriesSet(css)
	var ssSlice []Series
	for ss.Next() {
		ssSlice = append(ssSlice, ss.At())
	}
	require.Len(t, ssSlice, 2)
	var iter chunkenc.Iterator
	for i, s := range ssSlice {
		require.EqualValues(t, series[i].lbs, s.Labels())
		iter = s.Iterator(iter)
		j := 0
		for iter.Next() == chunkenc.ValFloat {
			ts, v := iter.At()
			require.EqualValues(t, series[i].samples[j], sample{t: ts, v: v})
			j++
		}
	}
}