package model

import (
	"encoding/json"
	"testing"

	"with_you/internal/pkg/crypto"
)

const testKey = "12345678901234567890123456789012"

// initEnc 初始化（幂等，因 crypto 用 sync.Once）加密器。
func initEnc(t *testing.T) {
	t.Helper()
	if err := crypto.InitMessageEncryptor(testKey, 1); err != nil {
		t.Fatalf("InitMessageEncryptor: %v", err)
	}
	if crypto.GetMessageEncryptor() == nil {
		t.Fatal("encryptor not initialized")
	}
}

// TestMessage_EncryptDecryptRoundTrip 验证：BeforeCreate 加密落库 →
// 清空内存 Segments → Decrypt 还原 → 内容与原文一致。
func TestMessage_EncryptDecryptRoundTrip(t *testing.T) {
	initEnc(t)

	original := MessageSegments{
		{Type: "text", Data: MessageSegmentData{"content": "你好世界"}},
		{Type: "image", Data: MessageSegmentData{"url": "https://example.com/a.png"}},
	}

	msg := &Message{Segments: original}

	// 模拟 GORM 创建钩子：加密
	if err := msg.BeforeCreate(nil); err != nil {
		t.Fatalf("BeforeCreate (encrypt) failed: %v", err)
	}

	// 加密后应写入 SegmentsEncrypted，且不应是明文 JSON（除非降级）
	if msg.SegmentsEncrypted == "" {
		t.Fatal("SegmentsEncrypted should be populated after BeforeCreate")
	}
	// 校验确实加密了：明文 JSON 中应包含 "content"，密文 base64 中不应直接出现该明文
	if contains(msg.SegmentsEncrypted, "你好世界") {
		t.Errorf("SegmentsEncrypted appears to contain plaintext: %q", msg.SegmentsEncrypted)
	}
	if msg.SegmentsKeyVersion != crypto.GetMessageEncryptor().GetKeyVersion() {
		t.Errorf("SegmentsKeyVersion = %d, want %d",
			msg.SegmentsKeyVersion, crypto.GetMessageEncryptor().GetKeyVersion())
	}

	// 模拟从 DB 取回后清空内存段（仅 SegmentsEncrypted 落库）
	msg.Segments = nil
	msg.decrypted = false

	// 解密还原
	if err := msg.Decrypt(); err != nil {
		t.Fatalf("Decrypt failed: %v", err)
	}

	if len(msg.Segments) != len(original) {
		t.Fatalf("after Decrypt, len(Segments) = %d, want %d", len(msg.Segments), len(original))
	}
	for i, seg := range msg.Segments {
		if seg.Type != original[i].Type {
			t.Errorf("segment[%d].Type = %q, want %q", i, seg.Type, original[i].Type)
		}
		if seg.Data["content"] != original[i].Data["content"] {
			t.Errorf("segment[%d].content mismatch: got %v, want %v",
				i, seg.Data["content"], original[i].Data["content"])
		}
	}
}

// TestMessage_EncryptEmptySegments 验证：空 Segments 时加密为 no-op。
func TestMessage_EncryptEmptySegments(t *testing.T) {
	initEnc(t)

	msg := &Message{}
	if err := msg.BeforeCreate(nil); err != nil {
		t.Fatalf("BeforeCreate failed: %v", err)
	}
	if msg.SegmentsEncrypted != "" {
		t.Errorf("empty Segments should not produce ciphertext, got %q", msg.SegmentsEncrypted)
	}
}

// TestBatchDecryptMessagesParallel_RoundTrip 验证批量解密路径与单条一致。
func TestBatchDecryptMessagesParallel_RoundTrip(t *testing.T) {
	initEnc(t)

	contents := []string{"消息A", "消息B", "消息C"}
	msgs := make([]*Message, len(contents))
	for i, c := range contents {
		m := &Message{
			Segments: MessageSegments{
				{Type: "text", Data: MessageSegmentData{"content": c}},
			},
		}
		if err := m.BeforeCreate(nil); err != nil {
			t.Fatalf("BeforeCreate[%d]: %v", i, err)
		}
		m.Segments = nil // 模拟从 DB 取回
		msgs[i] = m
	}

	BatchDecryptMessagesParallel(msgs)

	for i, m := range msgs {
		if !m.decrypted {
			t.Errorf("msg[%d] not marked decrypted", i)
		}
		if len(m.Segments) != 1 {
			t.Errorf("msg[%d] segments len = %d, want 1", i, len(m.Segments))
			continue
		}
		if got := m.Segments[0].Data["content"]; got != contents[i] {
			t.Errorf("msg[%d].content = %v, want %q", i, got, contents[i])
		}
	}
}

// contains 简单子串判断（避免引入 strings 仅为此）。
func contains(s, sub string) bool {
	return len(s) >= len(sub) && (indexOf(s, sub) >= 0)
}

func indexOf(s, sub string) int {
	bs := []byte(s)
	for i := 0; i+len(sub) <= len(bs); i++ {
		if string(bs[i:i+len(sub)]) == sub {
			return i
		}
	}
	return -1
}

// 编译期保证 json 被使用（兼容路径用到）。
var _ = json.Marshal