# CSP Script Injection Improvements

## Vấn đề ban đầu

Extension gặp lỗi CSP khi inject script trên các website có Content Security Policy nghiêm ngặt:

```
Refused to load the script 'blob:...' because it violates the following Content Security Policy directive: "script-src 'self' 'wasm-unsafe-eval'..."
```

## Giải pháp đã implement

### 1. CSP Detection Logic

```typescript
private static detectStrictCSP(): boolean {
  // Check CSP meta tags
  // Check known strict domains (midjourney.com, github.com, etc.)
}
```

**Domains được detect:**
- midjourney.com ✅
- openai.com
- github.com  
- google.com
- googletagmanager.com
- facebook.com
- twitter.com
- linkedin.com

### 2. Smart Injection Order

**Cho sites có CSP nghiêm ngặt:**
1. 🎯 **Background Injection** (chrome.scripting với world: 'MAIN')
2. 🔧 **Eval Method** (direct execution trong content script)
3. 💬 **PostMessage Bridge** 
4. 🎈 **Blob URL** (sẽ fail nhưng vẫn thử)
5. 📄 **Data URL** (sẽ fail nhưng vẫn thử)

**Cho sites bình thường:**
1. 🎈 **Blob URL** (fastest)
2. 📄 **Data URL**
3. 🎯 **Background Injection**
4. 🔧 **Eval Method**
5. 💬 **PostMessage Bridge**

### 3. Enhanced Logging

```
Injecting script for MAIN (Strict CSP: true)
Trying Background injection...
✅ Script injection successful via Background for MAIN
```

### 4. New Eval Method

```typescript
static injectViaEval(script: string, actionType: string): Promise<boolean> {
  // Direct eval trong isolated function context
  // Fallback khi tất cả methods khác fail
}
```

## Kết quả Test

### Trước khi cải thiện:
```
❌ Blob injection failed: CSP violation
❌ Data URL injection failed: CSP violation  
✅ Background injection successful (nhưng có nhiều errors)
```

### Sau khi cải thiện:
```
✅ CSP detected: midjourney.com (Strict CSP: true)
✅ Background injection successful (no errors)
✅ Clean console output
```

## Performance Impact

| Build Type | Controller Size | Methods Available |
|------------|----------------|-------------------|
| Development | 73.7KB | 5 injection methods |
| Production | 11.1KB | 5 injection methods |

## Browser Compatibility

| Method | Chrome | Edge | Firefox | Safari |
|--------|--------|------|---------|--------|
| Background | ✅ | ✅ | ❌ | ❌ |
| Blob URL | ✅ | ✅ | ✅ | ✅ |
| Data URL | ✅ | ✅ | ✅ | ✅ |
| Eval | ✅ | ✅ | ✅ | ✅ |
| PostMessage | ✅ | ✅ | ✅ | ✅ |

## Test Cases

### ✅ Passed
- midjourney.com (strict CSP)
- googletagmanager.com (strict CSP)
- Normal websites without CSP
- Extension test page với simulated CSP

### 🧪 Recommended Tests
- github.com
- openai.com  
- facebook.com
- twitter.com
- linkedin.com

## Usage

Extension tự động detect CSP và chọn method phù hợp:

```javascript
// Automatic usage
await ScriptInjector.injectScript(scriptCode, 'MAIN');

// Manual method selection (nếu cần)
await ScriptInjector.injectViaBackground(scriptCode, 'MAIN');
```

## Monitoring

Check console logs để xem method nào được sử dụng:

```
Injecting script for MAIN (Strict CSP: true)
Trying Background injection...
✅ Script injection successful via Background for MAIN
```

## Future Improvements

1. **Dynamic CSP Detection**: Parse actual CSP headers từ network requests
2. **Method Caching**: Cache successful methods per domain
3. **Performance Metrics**: Track injection success rates
4. **Fallback Strategies**: More sophisticated fallback logic

## Deployment Notes

- Extension size tăng minimal (11.1KB minified)
- Backward compatible với tất cả existing functionality
- No breaking changes
- Ready for Chrome Web Store deployment
