package blake2x_test

import (
	"bytes"
	"encoding/base64"
	"encoding/hex"
	"errors"
	"os"
	"path/filepath"
	"strings"
	"testing"

	"code.yun.ink/pkg/encryptx/blake2x"
)

// 测试向量来源：RFC 7693 / BLAKE2 官方测试向量，并经 Python 3 hashlib 独立复算确认。
var vectors = []struct {
	name    string
	newHash func() (hashLike, error)
	sum     func([]byte) []byte
	hex     func([]byte) string
	b64     func([]byte) string
	size    int
	empty   string
	abc     string
}{
	{
		name:    "BLAKE2b-512",
		newHash: func() (hashLike, error) { return blake2x.New512() },
		sum:     blake2x.Sum512,
		hex:     blake2x.Hex512,
		b64:     blake2x.Base64Sum512,
		size:    blake2x.SizeB512,
		empty:   "786a02f742015903c6c6fd852552d272912f4740e15847618a86e217f71f5419d25e1031afee585313896444934eb04b903a685b1448b755d56f701afe9be2ce",
		abc:     "ba80a53f981c4d0d6a2797b69f12f6e94c212f14685ac4b74b12bb6fdbffa2d17d87c5392aab792dc252d5de4533cc9518d38aa8dbf1925ab92386edd4009923",
	},
	{
		name:    "BLAKE2b-384",
		newHash: func() (hashLike, error) { return blake2x.New384() },
		sum:     blake2x.Sum384,
		hex:     blake2x.Hex384,
		b64:     blake2x.Base64Sum384,
		size:    blake2x.SizeB384,
		empty:   "b32811423377f52d7862286ee1a72ee540524380fda1724a6f25d7978c6fd3244a6caf0498812673c5e05ef583825100",
		abc:     "6f56a82c8e7ef526dfe182eb5212f7db9df1317e57815dbda46083fc30f54ee6c66ba83be64b302d7cba6ce15bb556f4",
	},
	{
		name:    "BLAKE2b-256",
		newHash: func() (hashLike, error) { return blake2x.New256B() },
		sum:     blake2x.Sum256B,
		hex:     blake2x.Hex256B,
		b64:     blake2x.Base64Sum256B,
		size:    blake2x.SizeB256,
		empty:   "0e5751c026e543b2e8ab2eb06099daa1d1e5df47778f7787faab45cdf12fe3a8",
		abc:     "bddd813c634239723171ef3fee98579b94964e3bb1cb3e427262c8c068d52319",
	},
	{
		name:    "BLAKE2s-256",
		newHash: func() (hashLike, error) { return blake2x.New256S() },
		sum:     blake2x.Sum256S,
		hex:     blake2x.Hex256S,
		b64:     blake2x.Base64Sum256S,
		size:    blake2x.SizeS256,
		empty:   "69217a3079908094e11121d042354a7c1f55b6482ca1a51e1b250dfd1ed0eef9",
		abc:     "508c5e8c327c14e2e1a72ba34eeb452f37458b209ed63a294d999b4c86675982",
	},
}

type hashLike interface {
	Write([]byte) (int, error)
	Sum([]byte) []byte
	Size() int
}

type failingReader struct{}

func (failingReader) Read([]byte) (int, error) { return 0, errors.New("模拟读取失败") }

func TestConstants(t *testing.T) {
	if blake2x.BlockSizeB != 128 || blake2x.BlockSizeS != 64 {
		t.Errorf("BlockSizeB/BlockSizeS = %d/%d, 期望 128/64", blake2x.BlockSizeB, blake2x.BlockSizeS)
	}
	if blake2x.SizeB512 != 64 || blake2x.SizeB384 != 48 || blake2x.SizeB256 != 32 || blake2x.SizeS256 != 32 {
		t.Errorf("摘要长度常量错误: %d/%d/%d/%d", blake2x.SizeB512, blake2x.SizeB384, blake2x.SizeB256, blake2x.SizeS256)
	}
	if blake2x.MinSizeB != 1 || blake2x.MaxSizeB != 64 {
		t.Errorf("MinSizeB/MaxSizeB = %d/%d, 期望 1/64", blake2x.MinSizeB, blake2x.MaxSizeB)
	}
}

func TestVectors(t *testing.T) {
	for _, v := range vectors {
		t.Run(v.name, func(t *testing.T) {
			cases := []struct {
				name  string
				input string
				want  string
			}{
				{"空串", "", v.empty},
				{"abc", "abc", v.abc},
			}
			for _, tc := range cases {
				t.Run(tc.name, func(t *testing.T) {
					data := []byte(tc.input)
					sum := v.sum(data)
					if len(sum) != v.size {
						t.Fatalf("Sum 长度 = %d, 期望 %d", len(sum), v.size)
					}
					if got := hex.EncodeToString(sum); got != tc.want {
						t.Errorf("Sum = %s, 期望 %s", got, tc.want)
					}
					if got := v.hex(data); got != tc.want {
						t.Errorf("Hex = %s, 期望 %s", got, tc.want)
					}
					if want := base64.StdEncoding.EncodeToString(sum); v.b64(data) != want {
						t.Errorf("Base64 = %s, 期望 %s", v.b64(data), want)
					}
					h, err := v.newHash()
					if err != nil {
						t.Fatalf("创建哈希失败: %v", err)
					}
					if h.Size() != v.size {
						t.Errorf("Size() = %d, 期望 %d", h.Size(), v.size)
					}
					if _, err := h.Write(data); err != nil {
						t.Fatalf("Write 失败: %v", err)
					}
					if got := hex.EncodeToString(h.Sum(nil)); got != tc.want {
						t.Errorf("New+Write = %s, 期望 %s", got, tc.want)
					}
				})
			}
		})
	}
}

func TestDefaultAliasesMatch512(t *testing.T) {
	data := []byte("encryptx blake2 alias check")
	if !bytes.Equal(blake2x.Sum(data), blake2x.Sum512(data)) {
		t.Error("Sum 应等价于 Sum512")
	}
	if blake2x.Hex(data) != blake2x.Hex512(data) {
		t.Error("Hex 应等价于 Hex512")
	}
	if blake2x.Base64(data) != blake2x.Base64Sum512(data) {
		t.Error("Base64 应等价于 Base64Sum512")
	}
	h, err := blake2x.New()
	if err != nil {
		t.Fatalf("New 失败: %v", err)
	}
	if h.Size() != blake2x.SizeB512 {
		t.Errorf("New().Size() = %d, 期望 %d", h.Size(), blake2x.SizeB512)
	}
}

func TestVariant256BAnd256SDiffer(t *testing.T) {
	data := []byte("abc")
	if blake2x.Hex256B(data) == blake2x.Hex256S(data) {
		t.Error("BLAKE2b-256 与 BLAKE2s-256 的摘要不应相同")
	}
}

func TestSumBSizes(t *testing.T) {
	data := []byte("arbitrary length blake2b")
	for size := blake2x.MinSizeB; size <= blake2x.MaxSizeB; size++ {
		sum, err := blake2x.SumB(size, data)
		if err != nil {
			t.Fatalf("SumB(%d) 失败: %v", size, err)
		}
		if len(sum) != size {
			t.Errorf("SumB(%d) 长度 = %d", size, len(sum))
		}
		h, err := blake2x.NewB(size)
		if err != nil {
			t.Fatalf("NewB(%d) 失败: %v", size, err)
		}
		if h.Size() != size {
			t.Errorf("NewB(%d).Size() = %d", size, h.Size())
		}
		if _, err := h.Write(data); err != nil {
			t.Fatalf("Write 失败: %v", err)
		}
		if !bytes.Equal(h.Sum(nil), sum) {
			t.Errorf("SumB(%d) 与 NewB(%d) 结果不一致", size, size)
		}
		hexStr, err := blake2x.HexB(size, data)
		if err != nil {
			t.Fatalf("HexB(%d) 失败: %v", size, err)
		}
		if hexStr != hex.EncodeToString(sum) {
			t.Errorf("HexB(%d) 与 SumB(%d) 结果不一致", size, size)
		}
	}

	if got, err := blake2x.SumB(blake2x.SizeB512, data); err != nil {
		t.Fatalf("SumB(64) 失败: %v", err)
	} else if !bytes.Equal(got, blake2x.Sum512(data)) {
		t.Error("SumB(64) 应等于 Sum512")
	}
	if got, err := blake2x.SumB(blake2x.SizeB384, data); err != nil {
		t.Fatalf("SumB(48) 失败: %v", err)
	} else if !bytes.Equal(got, blake2x.Sum384(data)) {
		t.Error("SumB(48) 应等于 Sum384")
	}
	if got, err := blake2x.SumB(blake2x.SizeB256, data); err != nil {
		t.Fatalf("SumB(32) 失败: %v", err)
	} else if !bytes.Equal(got, blake2x.Sum256B(data)) {
		t.Error("SumB(32) 应等于 Sum256B")
	}
}

func TestInvalidSizes(t *testing.T) {
	for _, size := range []int{-1, 0, 65, 128, 1 << 20} {
		if _, err := blake2x.NewB(size); err == nil {
			t.Errorf("NewB(%d) 应返回 error", size)
		}
		if _, err := blake2x.SumB(size, []byte("x")); err == nil {
			t.Errorf("SumB(%d) 应返回 error", size)
		}
		if _, err := blake2x.HexB(size, []byte("x")); err == nil {
			t.Errorf("HexB(%d) 应返回 error", size)
		}
	}
}

func TestStreamingMatchesSum(t *testing.T) {
	data := []byte(strings.Repeat("encryptx-blake2-", 128))
	for _, v := range vectors {
		t.Run(v.name, func(t *testing.T) {
			h, err := v.newHash()
			if err != nil {
				t.Fatalf("创建哈希失败: %v", err)
			}
			for i := 0; i < len(data); i += 23 {
				end := i + 23
				if end > len(data) {
					end = len(data)
				}
				if _, err := h.Write(data[i:end]); err != nil {
					t.Fatalf("Write 失败: %v", err)
				}
			}
			if got, want := h.Sum(nil), v.sum(data); !bytes.Equal(got, want) {
				t.Errorf("分块写入 = %x, 期望 %x", got, want)
			}
		})
	}
}

func TestReaderConsistency(t *testing.T) {
	const s = "encryptx blake2 reader"
	sum, err := blake2x.SumReader(strings.NewReader(s))
	if err != nil {
		t.Fatalf("SumReader 失败: %v", err)
	}
	if want := blake2x.Sum512([]byte(s)); !bytes.Equal(sum, want) {
		t.Errorf("SumReader = %x, 期望 %x", sum, want)
	}
	hexStr, err := blake2x.HexReader(strings.NewReader(s))
	if err != nil {
		t.Fatalf("HexReader 失败: %v", err)
	}
	if want := blake2x.Hex512([]byte(s)); hexStr != want {
		t.Errorf("HexReader = %s, 期望 %s", hexStr, want)
	}
}

func TestReaderErrors(t *testing.T) {
	if _, err := blake2x.SumReader(nil); err == nil {
		t.Fatal("nil 读取器应返回 error")
	}
	if _, err := blake2x.HexReader(nil); err == nil {
		t.Fatal("nil 读取器应返回 error")
	}
	if _, err := blake2x.SumReader(failingReader{}); err == nil {
		t.Fatal("读取失败时应返回 error")
	}
}

func TestHexFile(t *testing.T) {
	dir := t.TempDir()
	content := []byte("文件内容 file content\n")
	path := filepath.Join(dir, "sample.bin")
	if err := os.WriteFile(path, content, 0o600); err != nil {
		t.Fatalf("写入测试文件失败: %v", err)
	}
	got, err := blake2x.HexFile(path)
	if err != nil {
		t.Fatalf("HexFile 失败: %v", err)
	}
	if want := blake2x.Hex512(content); got != want {
		t.Errorf("HexFile = %s, 期望 %s", got, want)
	}
}

func TestHexFileErrors(t *testing.T) {
	if _, err := blake2x.HexFile(filepath.Join(t.TempDir(), "不存在.bin")); err == nil {
		t.Fatal("不存在的文件应返回 error")
	}
	if _, err := blake2x.HexFile(""); err == nil {
		t.Fatal("空路径应返回 error")
	}
	if _, err := blake2x.HexFile(t.TempDir()); err == nil {
		t.Fatal("目录路径应返回 error")
	}
}

func TestLargeInput(t *testing.T) {
	data := largeData(1 << 20)
	for _, v := range vectors {
		t.Run(v.name, func(t *testing.T) {
			want := v.hex(data)
			if got := v.hex(data); got != want {
				t.Errorf("重复计算结果不一致: %s vs %s", got, want)
			}
			h, err := v.newHash()
			if err != nil {
				t.Fatalf("创建哈希失败: %v", err)
			}
			if _, err := h.Write(data[:1<<19]); err != nil {
				t.Fatalf("Write 失败: %v", err)
			}
			if _, err := h.Write(data[1<<19:]); err != nil {
				t.Fatalf("Write 失败: %v", err)
			}
			if got := hex.EncodeToString(h.Sum(nil)); got != want {
				t.Errorf("1MiB 分块 = %s, 期望 %s", got, want)
			}
		})
	}
	got, err := blake2x.HexReader(bytes.NewReader(data))
	if err != nil {
		t.Fatalf("HexReader 失败: %v", err)
	}
	if want := blake2x.Hex512(data); got != want {
		t.Errorf("1MiB HexReader = %s, 期望 %s", got, want)
	}
}

// largeData 生成确定性的 n 字节数据。
func largeData(n int) []byte {
	b := make([]byte, n)
	for i := range b {
		b[i] = byte(i*31 + i/7)
	}
	return b
}