# Version Control Implementation Summary

## 🎯 **What We Built**

A complete version control system for the Insertr CMS with user attribution, rollback functionality, and modern database architecture using sqlc.

## 🏗️ **Architecture Changes**

### **Database Layer (sqlc + Modern Schema)**
- **sqlc Integration**: Type-safe Go database code generated from SQL
- **Clean Schema**: `content` + `content_versions` tables with proper indexing  
- **User Attribution**: Track who made each change with timestamps
- **Version History**: Complete edit history preserved automatically

### **API Enhancements**
- **Version Endpoints**: `GET /{id}/versions`, `POST /{id}/rollback`
- **User Attribution**: `X-User-ID` header support for all operations
- **Automatic Versioning**: Current content archived before any update
- **Clean Error Handling**: Proper HTTP status codes and error messages

### **Frontend Version Control UI**
- **History Button**: Added to all edit forms
- **Version Modal**: Professional GitHub-style version history display
- **One-Click Rollback**: Restore any previous version instantly
- **User Attribution**: Display who made each change and when
- **Version Comparison**: Preview content changes before restoring

## 🔧 **Technical Implementation**

### **ID Generation System (Fixed)**
- **Deterministic IDs**: Same content always generates same ID
- **CLI ↔ JS Consistency**: Both systems use identical SHA-1 based algorithm
- **Content-Based Versioning**: Content changes create new IDs naturally
- **Developer Override**: HTML `id` attribute takes precedence over generated IDs

### **Database Schema**
```sql
-- Current content (latest versions only)
CREATE TABLE content (
    id TEXT NOT NULL,
    site_id TEXT NOT NULL, 
    value TEXT NOT NULL,
    type TEXT NOT NULL,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    updated_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    last_edited_by TEXT,
    PRIMARY KEY (id, site_id)
);

-- Complete version history
CREATE TABLE content_versions (
    version_id INTEGER PRIMARY KEY AUTOINCREMENT,
    content_id TEXT NOT NULL,
    site_id TEXT NOT NULL,
    value TEXT NOT NULL,
    type TEXT NOT NULL,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    created_by TEXT
);
```

### **API Workflow Example**
```bash
# 1. Create content
POST /api/content
{"id": "hero-title", "value": "Original", "type": "text"}

# 2. Update (auto-archives current version)
PUT /api/content/hero-title?site_id=demo
{"value": "Updated content"}

# 3. View history
GET /api/content/hero-title/versions?site_id=demo
# Returns: [{"version_id": 1, "value": "Original", "created_by": "user"}]

# 4. Rollback 
POST /api/content/hero-title/rollback?site_id=demo
{"version_id": 1}
```

## 🎮 **User Experience**

### **Content Editor Workflow**
1. **Click Edit** on any `class="insertr"` element
2. **Professional Modal** opens with current content
3. **View History** button shows version timeline
4. **Version Modal** displays all changes with timestamps and authors
5. **One-Click Restore** to any previous version
6. **All Changes Tracked** automatically with user attribution

### **Developer Experience**
- **Zero Configuration**: Still just add `class="insertr"`
- **Hidden Complexity**: Version control happens transparently
- **Full Control**: HTML `id` attribute overrides system-generated IDs
- **Type Safety**: sqlc provides compile-time SQL validation
- **Modern Tooling**: Professional database migration workflow

## 📊 **Features Delivered**

### ✅ **Core Version Control**
- **Complete Edit History**: Every change preserved permanently
- **User Attribution**: Track who made each change
- **One-Click Rollback**: Restore any previous version instantly
- **Automatic Versioning**: No manual intervention required

### ✅ **Professional UI**
- **GitHub-Style History**: Familiar version control interface
- **Version Comparison**: See what changed between versions
- **User-Friendly Timestamps**: "2h ago", "yesterday", etc.
- **Responsive Design**: Works on mobile and desktop

### ✅ **Developer Tools**
- **sqlc Integration**: Type-safe database operations
- **Clean Database Schema**: Proper indexing and relationships
- **Development Commands**: `just server-generate`, `just server-clean-db`
- **API Documentation**: Complete endpoint reference

### ✅ **Production Ready**
- **SQLite → PostgreSQL**: Easy database migration path
- **Proper Error Handling**: Informative error messages
- **CORS Configured**: Multi-origin support for development
- **Health Checks**: Monitoring and debugging endpoints

## 🚀 **What's Different Now**

### **Before: Basic CMS**
- Simple content editing
- No version history
- Temporal ID conflicts
- No user tracking

### **After: Professional CMS**
- Complete version control with rollback
- User attribution for all changes  
- Deterministic ID system (CLI ↔ JS consistent)
- Modern database architecture (sqlc)
- Professional editing UI with history
- Production-ready API with proper error handling

## 📋 **Development Workflow Enhanced**

### **New Commands**
```bash
# Generate database code from SQL
just server-generate

# Clean development database  
just server-clean-db

# Full version control development
just dev  # Now includes version history UI
```

### **Updated Files**
- **Database**: `insertr-server/db/` - Complete sqlc setup
- **API**: `internal/api/handlers.go` - Version control endpoints
- **Frontend**: `lib/src/ui/form-renderer.js` - History modal UI
- **Docs**: Updated README.md with version control features

## 🎯 **Result**

Insertr now provides **WordPress-style version control** with:
- **Professional editing experience** 
- **Complete change tracking**
- **Easy rollback functionality**
- **Modern database architecture**
- **Type-safe backend code**

All while maintaining the **"zero configuration"** philosophy - developers still just add `class="insertr"` and get a complete CMS with version control.