package loki

import (
	"fmt"
	"testing"
	"time"

	"github.com/prometheus/common/model"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"github.com/lixh00/loki-client-go/pkg/logproto"
)

func TestBatch_add(t *testing.T) {
	t.Parallel()

	tests := map[string]struct {
		inputEntries      []entry
		expectedSizeBytes int
	}{
		"empty batch": {
			inputEntries:      []entry{},
			expectedSizeBytes: 0,
		},
		"single stream with single log entry": {
			inputEntries: []entry{
				{"tenant", model.LabelSet{}, logEntries[0].Entry},
			},
			expectedSizeBytes: len(logEntries[0].Entry.Line),
		},
		"single stream with multiple log entries": {
			inputEntries: []entry{
				{"tenant", model.LabelSet{}, logEntries[0].Entry},
				{"tenant", model.LabelSet{}, logEntries[1].Entry},
			},
			expectedSizeBytes: len(logEntries[0].Entry.Line) + len(logEntries[1].Entry.Line),
		},
		"multiple streams with multiple log entries": {
			inputEntries: []entry{
				{"tenant", model.LabelSet{"type": "a"}, logEntries[0].Entry},
				{"tenant", model.LabelSet{"type": "a"}, logEntries[1].Entry},
				{"tenant", model.LabelSet{"type": "b"}, logEntries[2].Entry},
			},
			expectedSizeBytes: len(logEntries[0].Entry.Line) + len(logEntries[1].Entry.Line) + len(logEntries[2].Entry.Line),
		},
	}

	for testName, testData := range tests {
		testData := testData

		t.Run(testName, func(t *testing.T) {
			b := newBatch()

			for _, entry := range testData.inputEntries {
				b.add(entry)
			}

			assert.Equal(t, testData.expectedSizeBytes, b.sizeBytes())
		})
	}
}

func TestBatch_encode(t *testing.T) {
	t.Parallel()

	tests := map[string]struct {
		inputBatch           *batch
		expectedEntriesCount int
	}{
		"empty batch": {
			inputBatch:           newBatch(),
			expectedEntriesCount: 0,
		},
		"single stream with single log entry": {
			inputBatch: newBatch(
				entry{"tenant", model.LabelSet{}, logEntries[0].Entry},
			),
			expectedEntriesCount: 1,
		},
		"single stream with multiple log entries": {
			inputBatch: newBatch(
				entry{"tenant", model.LabelSet{}, logEntries[0].Entry},
				entry{"tenant", model.LabelSet{}, logEntries[1].Entry},
			),
			expectedEntriesCount: 2,
		},
		"multiple streams with multiple log entries": {
			inputBatch: newBatch(
				entry{"tenant", model.LabelSet{"type": "a"}, logEntries[0].Entry},
				entry{"tenant", model.LabelSet{"type": "a"}, logEntries[1].Entry},
				entry{"tenant", model.LabelSet{"type": "b"}, logEntries[2].Entry},
			),
			expectedEntriesCount: 3,
		},
	}

	for testName, testData := range tests {
		testData := testData

		t.Run(testName, func(t *testing.T) {
			t.Parallel()

			_, entriesCount, err := testData.inputBatch.encode()
			require.NoError(t, err)
			assert.Equal(t, testData.expectedEntriesCount, entriesCount)
		})
	}
}

func TestHashCollisions(t *testing.T) {
	b := newBatch()

	ls1 := model.LabelSet{"app": "l", "uniq0": "0", "uniq1": "1"}
	ls2 := model.LabelSet{"app": "m", "uniq0": "1", "uniq1": "1"}

	require.False(t, ls1.Equal(ls2))
	require.Equal(t, ls1.FastFingerprint(), ls2.FastFingerprint())

	const entriesPerLabel = 10

	for i := 0; i < entriesPerLabel; i++ {
		b.add(entry{labels: ls1, Entry: logproto.Entry{Timestamp: time.Now(), Line: fmt.Sprintf("line %d", i)}})
		b.add(entry{labels: ls2, Entry: logproto.Entry{Timestamp: time.Now(), Line: fmt.Sprintf("line %d", i)}})
	}

	// make sure that colliding labels are stored properly as independent streams
	req, entries := b.createPushRequest()
	assert.Len(t, req.Streams, 2)
	assert.Equal(t, 2*entriesPerLabel, entries)

	if req.Streams[0].Labels == ls1.String() {
		assert.Equal(t, ls1.String(), req.Streams[0].Labels)
		assert.Equal(t, ls2.String(), req.Streams[1].Labels)
	} else {
		assert.Equal(t, ls2.String(), req.Streams[0].Labels)
		assert.Equal(t, ls1.String(), req.Streams[1].Labels)
	}
}