package wal

import (
	"math/rand"
	"sync"
	"testing"
	"time"
)

func TestDeleteBefore(t *testing.T) {
	t.Parallel()
	firstSeqNum := rand.Int63n(9288389)
	tmpDir := t.TempDir()

	wal, err := Create(tmpDir, firstSeqNum, Config{
		SegMinCount:  10,
		SegMaxAgeSec: 1,
	})
	if err != nil {
		t.Fatal(err)
	}
	defer wal.Close()

	wg := sync.WaitGroup{}
	wg.Add(1)
	go func() {
		defer wg.Done()
		err := writeRandomWithEOF(wal, 8*time.Second)
		if err != nil {
			panic(err)
		}
	}()

	wg.Wait()

	info := wal.Info()
	if info.FirstSeqNum != firstSeqNum {
		t.Fatal(info)
	}

	lastSeqNum := info.LastSeqNum
	lastTimestampMS := info.LastTimestampMS

	err = wal.DeleteBefore((info.LastTimestampMS/1000)-4, lastSeqNum+100)
	if err != nil {
		t.Fatal(err)
	}

	info = wal.Info()
	if info.FirstSeqNum == firstSeqNum || info.LastSeqNum != lastSeqNum || info.LastTimestampMS != lastTimestampMS {
		t.Fatal(info)
	}

	header := wal.header
	if header.FirstSegmentID >= header.LastSegmentID {
		t.Fatal(header)
	}
}

func TestDeleteBeforeOnlyOneSegment(t *testing.T) {
	t.Parallel()
	firstSeqNum := rand.Int63n(9288389)
	tmpDir := t.TempDir()

	wal, err := Create(tmpDir, firstSeqNum, Config{
		SegMinCount:  10,
		SegMaxAgeSec: 10,
	})
	if err != nil {
		t.Fatal(err)
	}
	defer wal.Close()

	if err := writeRandomWithEOF(wal, time.Second); err != nil {
		t.Fatal(err)
	}

	header := wal.header
	if header.FirstSegmentID != header.LastSegmentID {
		t.Fatal(header)
	}

	lastSeqNum := wal.Info().LastSeqNum

	err = wal.DeleteBefore(time.Now().Unix()+1, lastSeqNum+100)
	if err != nil {
		t.Fatal(err)
	}

	header = wal.header
	if header.FirstSegmentID != header.LastSegmentID {
		t.Fatal(header)
	}
}