# Implementation Summary: Per-Provider API Key Management

## What Was Implemented

### 1. ✅ PHP Backend Updated for Per-Provider Storage
**File:** `/Users/rbutare/downloads/api/finnhub-key.php`

- Added `provider` query parameter support (default: 'twelve')
- Provider name sanitization function (`sanitizeProvider()`)
- Per-provider key files: `apiKey_twelve.txt`, `apiKey_finnhub.txt`, etc.
- Key validation (10-500 character requirement)
- Secure file permissions (0600 for keys, 0700 for directory)

**Endpoints:**
```
GET  /downloads/api/finnhub-key.php?action=get&provider=twelve
POST /downloads/api/finnhub-key.php?action=set&provider=twelve
GET  /downloads/api/finnhub-key.php?action=delete&provider=twelve
```

### 2. ✅ JavaScript Functions Created in dash.html

**Server Communication Functions:**
- `serverKeyGet(provider = null)` - Retrieve key from server for provider
- `serverKeySet(value, provider = null)` - Save key to server for provider
- `serverKeyDelete(provider = null)` - Delete key from server for provider

**Per-Provider Key Management:**
- `getProviderKey(provider)` - Get key from preferences
- `setProviderKey(provider, key)` - Save key to preferences
- `editProviderKey(provider)` - Interactive prompt to set key for provider
- `updateKeyDisplay()` - Update preference UI with masked keys
- `switchApiProvider(provider)` - Change active provider and load its key

**Supporting Function:**
- `updateProviderInfo()` - Update UI display for current provider

### 3. ✅ Preferences Storage Structure
Keys stored in `prefs` object:
```javascript
prefs.apiKey_twelve      // Twelve Data API key
prefs.apiKey_finnhub     // Finnhub API key  
prefs.apiProvider        // Currently selected provider
```

### 4. ✅ Preferences UI Updated
- Separate fields for Twelve Data and Finnhub API keys
- Each field shows masked key (first 4 + dots + last 4 chars)
- "Set" button for each provider triggers `editProviderKey(provider)`
- Feature descriptions for each provider

### 5. ✅ Initialization Flow Updated
**DOMContentLoaded handler now:**
1. Loads API provider from preferences (default: 'twelve')
2. Attempts to load provider-specific key from server
3. Falls back to local preferences if server key not found
4. Prompts for key if none exists
5. Saves to both server and preferences
6. Updates preferences display with both provider keys

### 6. ✅ Provider Switching Logic
When user switches providers via `switchApiProvider(provider)`:
1. Updates global `API_PROVIDER` variable
2. Loads provider-specific key via `getProviderKey(provider)`
3. Updates provider info display
4. Clears quote cache
5. Refreshes watchlist data (if key available)

## Key Features

### Security
✅ Keys stored server-side only (never in browser storage)
✅ File permissions: 0600 (user-only)
✅ Directory permissions: 0700 (user-only)
✅ Provider name sanitization
✅ Key length validation

### User Experience
✅ Per-provider preferences UI
✅ Masked key display (safe to show in preferences)
✅ Separate "Set" buttons for each provider
✅ Provider descriptions with feature differences
✅ Automatic key loading on provider switch
✅ Automatic key loading on app initialization

### Flexibility
✅ User can set only Twelve Data key
✅ User can set only Finnhub key
✅ User can set both keys
✅ Can switch between providers without losing keys
✅ Keys persist across browser sessions

## Files Modified

1. **`/Users/rbutare/downloads/api/finnhub-key.php`**
   - Added per-provider support
   - Provider sanitization
   - Per-provider file naming

2. **`/Users/rbutare/downloads/dash.html`**
   - Added 6 new JavaScript functions
   - Updated preferences UI section
   - Updated initialization handler
   - Enhanced `serverKeyGet()` with provider param

## Testing Files Created

1. **`/Users/rbutare/downloads/API_KEY_MANAGEMENT.md`**
   - Architecture documentation
   - Flow diagrams
   - Function reference
   - Security features

2. **`/Users/rbutare/downloads/API_KEY_TESTING.md`**
   - Step-by-step test procedures
   - cURL examples for server testing
   - Browser testing guide
   - Debugging tips
   - Success criteria

## File Structure on Disk

After testing, users will have:
```
~/.downloads/.finnhub/
├── apiKey_twelve.txt      # 0600 permissions
└── apiKey_finnhub.txt     # 0600 permissions
```

## Integration with Existing Systems

### API Provider Selection
```javascript
const API_PROVIDERS = {
  'twelve': { ... },
  'finnhub': { ... }
};
```

Existing dual API support works seamlessly with per-provider keys.

### Preference Loading
Keys loaded during `loadPrefs()` call, stored in prefs object structure.

### API Fetching
`fhFetch()` uses `API_PROVIDER` global to determine which key to use from `API_KEY` variable.

## Backward Compatibility

- Old system (single key file): `api-key.txt`
- New system (per-provider): `apiKey_[provider].txt`
- Migration: Manual migration by copying old key to provider-specific file and setting via preferences

## What Users Can Now Do

1. ✅ Set Twelve Data API key in preferences
2. ✅ Set Finnhub API key in preferences (independently)
3. ✅ Switch between providers without losing either key
4. ✅ Update keys via preferences UI anytime
5. ✅ Keys automatically load when switching providers
6. ✅ Keys persist across browser refreshes
7. ✅ Keys stored securely on server (0600 permissions)
8. ✅ See masked keys in preferences (safe display)

## Configuration Examples

### Use Twelve Data (with indices support)
1. Open preferences
2. Click "Set" for Twelve Data
3. Paste API key
4. Select "Twelve Data" in API Provider dropdown
5. Watchlist loads with index data

### Use Finnhub (stocks/ETFs only)
1. Open preferences
2. Click "Set" for Finnhub
3. Paste API key
4. Select "Finnhub" in API Provider dropdown
5. Watchlist loads with stock data only

### Switch Between Providers
1. Have both keys set in preferences
2. Click provider dropdown
3. Select different provider
4. Key automatically loads
5. Watchlist refreshes with new provider's data

## Next Steps (Optional Enhancements)

- [ ] Add "Clear Key" button to preferences for each provider
- [ ] Show last-used provider on app startup
- [ ] Add key validation before saving (test API call)
- [ ] Show API call count/usage for each provider
- [ ] Auto-retry with fallback provider on API failure
- [ ] Add "Import key from localStorage" migration tool for old users