package deploy

import (
	"strings"
	"testing"

	"github.com/klauspost/reedsolomon"
)

func TestErasureParamsNormalizeDefaults(t *testing.T) {
	p := erasureParams{}
	got, err := p.normalize()
	if err != nil {
		t.Fatal(err)
	}
	if got.DataShards != erasureDefaultDataShards || got.ParityShards != erasureDefaultParityShards {
		t.Fatalf("defaults=%+v", got)
	}
	if got.minShards() != erasureDefaultDataShards {
		t.Fatalf("minShards=%d", got.minShards())
	}
	if got.totalShards() != erasureDefaultDataShards+erasureDefaultParityShards {
		t.Fatalf("totalShards=%d", got.totalShards())
	}
}

func TestDecodeErasureShardsInsufficientPresent(t *testing.T) {
	payload := []byte("codec-insufficient")
	p := erasureParams{DataShards: 2, ParityShards: 2}
	enc, err := reedsolomon.New(p.DataShards, p.ParityShards)
	if err != nil {
		t.Fatal(err)
	}
	shards, err := enc.Split(payload)
	if err != nil {
		t.Fatal(err)
	}
	if err := enc.Encode(shards); err != nil {
		t.Fatal(err)
	}
	shards[0] = nil
	shards[1] = nil
	shards[2] = nil
	_, err = decodeErasureShards(shards, len(payload), p)
	if err == nil || !strings.Contains(err.Error(), "need 2 shards") {
		t.Fatalf("err=%v", err)
	}
}

func TestDecodeErasureShardsSliceTooShort(t *testing.T) {
	_, err := decodeErasureShards([][]byte{{1}, {2}}, 4, erasureParams{DataShards: 2, ParityShards: 2})
	if err == nil || !strings.Contains(err.Error(), "shard slice too short") {
		t.Fatalf("err=%v", err)
	}
}

func TestDecodeErasureShardsVerificationFailed(t *testing.T) {
	payload := []byte("codec-bad-shard")
	p := erasureParams{DataShards: 2, ParityShards: 1}
	enc, err := reedsolomon.New(p.DataShards, p.ParityShards)
	if err != nil {
		t.Fatal(err)
	}
	shards, err := enc.Split(payload)
	if err != nil {
		t.Fatal(err)
	}
	if err := enc.Encode(shards); err != nil {
		t.Fatal(err)
	}
	shards[2][0] ^= 0xff
	_, err = decodeErasureShards(shards, len(payload), p)
	if err == nil || !strings.Contains(err.Error(), "verification failed") {
		t.Fatalf("err=%v", err)
	}
}