package nnet

import (
	"context"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestNNetVersionIdentifier_Identify(t *testing.T) {
	// 创建版本识别器
	identifier := NewNNetVersionIdentifier(map[byte]string{
		1: "1.0",
		2: "2.0",
		3: "3.0",
	})

	// 测试版本1识别
	t.Run("Identify version 1.0", func(t *testing.T) {
		// 创建版本1的数据包（Magic + Version(1) + Length(4) + Data + Checksum）
		data := []byte("NNET")
		data = append(data, byte(1)) // version
		data = append(data, []byte{0, 0, 0, 5}...) // length
		data = append(data, []byte("hello")...) // data
		data = append(data, []byte{0, 0}...) // checksum (简化)

		version, err := identifier.Identify(data, context.Background())
		require.NoError(t, err)
		assert.Equal(t, "1.0", version)
	})

	// 测试版本2识别
	t.Run("Identify version 2.0", func(t *testing.T) {
		data := []byte("NNET")
		data = append(data, byte(2)) // version
		data = append(data, []byte{0, 0, 0, 5}...) // length
		data = append(data, []byte("hello")...) // data
		data = append(data, []byte{0, 0}...) // checksum (简化)

		version, err := identifier.Identify(data, context.Background())
		require.NoError(t, err)
		assert.Equal(t, "2.0", version)
	})

	// 测试数据不足
	t.Run("Data too short", func(t *testing.T) {
		data := []byte("NNE") // 只有3字节，不足5字节

		version, err := identifier.Identify(data, context.Background())
		require.Error(t, err)
		assert.Empty(t, version)
	})

	// 测试无效Magic
	t.Run("Invalid magic", func(t *testing.T) {
		data := []byte("BAD!")
		data = append(data, byte(1)) // version

		version, err := identifier.Identify(data, context.Background())
		require.Error(t, err)
		assert.Empty(t, version)
	})

	// 测试未知版本
	t.Run("Unknown version", func(t *testing.T) {
		data := []byte("NNET")
		data = append(data, byte(99)) // unknown version
		data = append(data, []byte{0, 0, 0, 5}...) // length

		version, err := identifier.Identify(data, context.Background())
		require.Error(t, err)
		assert.Empty(t, version)
	})
}

func TestNNetVersionIdentifier_DefaultMapping(t *testing.T) {
	// 测试默认映射
	identifier := NewNNetVersionIdentifier(nil)

	data := []byte("NNET")
	data = append(data, byte(1)) // version
	data = append(data, []byte{0, 0, 0, 5}...) // length
	data = append(data, []byte("hello")...) // data
	data = append(data, []byte{0, 0}...) // checksum (简化)

	version, err := identifier.Identify(data, context.Background())
	require.NoError(t, err)
	assert.Equal(t, "1.0", version)
}