# GORM → sqlc + pgx Migration Complete ✅

## Summary

Successfully migrated TraceRTM backend from GORM to **sqlc + pgx** for better performance and complex query support. The core handlers and database layer are now fully migrated.

## What Was Completed

### ✅ Core Infrastructure
1. **Database Layer** (`internal/database/database.go`)
   - Migrated from GORM to pgxpool
   - Updated connection pooling (25 max, 5 min)
   - Migration system now reads from schema.sql

2. **Main Application** (`main.go`)
   - Updated to use pgxpool
   - Added graceful shutdown with context timeout
   - Proper signal handling

3. **Server** (`internal/server/server.go`)
   - Updated to accept pgxpool instead of GORM
   - All handlers now initialized with pgxpool

### ✅ Handlers Migrated
1. **Project Handler** (`internal/handlers/handlers.go`)
   - ✅ CreateProject
   - ✅ ListProjects (with pagination)
   - ✅ GetProject
   - ✅ UpdateProject
   - ✅ DeleteProject

2. **Item Handler** (`internal/handlers/item_handler.go`)
   - ✅ CreateItem
   - ✅ ListItems (with pagination)
   - ✅ GetItem
   - ✅ UpdateItem
   - ✅ DeleteItem

3. **Link Handler** (`internal/handlers/link_handler.go`)
   - ✅ CreateLink
   - ✅ ListLinks (by source/target)
   - ✅ GetLink
   - ⚠️ UpdateLink (not implemented - not in queries.sql)
   - ✅ DeleteLink

4. **Agent Handler** (`internal/handlers/agent_handler.go`)
   - ✅ CreateAgent
   - ✅ ListAgents
   - ✅ GetAgent
   - ✅ UpdateAgent
   - ✅ DeleteAgent
   - ⚠️ Coordinator methods (still use GORM - needs separate migration)

5. **Graph Handler** (`internal/handlers/graph_handler.go`)
   - ⚠️ All methods return 501 Not Implemented
   - Graph service still uses GORM - needs separate migration
   - All methods have proper nil checks

### ✅ Utilities Created
- **UUID Utilities** (`internal/utils/uuid.go`)
  - StringToUUID - converts string to pgtype.UUID
  - UUIDToString - converts pgtype.UUID to string

## Build Status

```
✅ Build: SUCCESS
✅ Compilation: 0 errors
✅ Dependencies: Resolved
```

## What Remains (Future Work)

### 🔄 Services Needing Migration

1. **Graph Service** (`internal/graph/graph.go`)
   - Currently uses GORM
   - Needs migration to use sqlc queries
   - Graph handler is ready but returns 501 until service is migrated

2. **Agent Coordinator** (`internal/agents/coordinator.go`)
   - Currently uses GORM
   - Agent CRUD operations work, but coordination features need migration

3. **Agent Queue** (`internal/agents/queue.go`)
   - Currently uses GORM
   - Task queue operations need migration

4. **Repository Layer** (`internal/repository/repository.go`)
   - Currently uses GORM
   - Can be removed or migrated if still needed

### 📝 Additional Queries Needed

Add to `queries.sql`:
- UpdateLink query (for link updates)
- Graph traversal queries (recursive CTEs)
- Agent task queries (for coordinator)

## Migration Pattern

### Before (GORM)
```go
type ProjectHandler struct {
    db *gorm.DB
}

func (h *ProjectHandler) CreateProject(c echo.Context) error {
    var project models.Project
    if err := c.Bind(&project); err != nil {
        return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
    }
    if err := h.db.Create(&project).Error; err != nil {
        return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
    }
    return c.JSON(http.StatusCreated, project)
}
```

### After (sqlc + pgx)
```go
type ProjectHandler struct {
    queries *db.Queries
}

func (h *ProjectHandler) CreateProject(c echo.Context) error {
    var req struct {
        Name        string          `json:"name"`
        Description string          `json:"description"`
        Metadata    json.RawMessage `json:"metadata"`
    }
    if err := c.Bind(&req); err != nil {
        return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
    }
    
    metadata := []byte("{}")
    if req.Metadata != nil {
        metadata = req.Metadata
    }
    
    project, err := h.queries.CreateProject(c.Request().Context(), db.CreateProjectParams{
        Name:        req.Name,
        Description: pgtype.Text{String: req.Description, Valid: req.Description != ""},
        Metadata:    metadata,
    })
    if err != nil {
        return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
    }
    return c.JSON(http.StatusCreated, project)
}
```

## Key Benefits Achieved

✅ **Type Safety**: Compile-time verification of all queries
✅ **Performance**: Direct pgx driver, no ORM overhead
✅ **Explicit SQL**: All queries visible and auditable
✅ **Better Error Handling**: Proper context propagation
✅ **Scalability**: Connection pooling configured

## Files Modified

- ✅ `backend/internal/database/database.go` - pgxpool migration
- ✅ `backend/main.go` - pgxpool integration
- ✅ `backend/internal/server/server.go` - pgxpool support
- ✅ `backend/internal/handlers/handlers.go` - Project handler
- ✅ `backend/internal/handlers/item_handler.go` - Item handler
- ✅ `backend/internal/handlers/link_handler.go` - Link handler
- ✅ `backend/internal/handlers/agent_handler.go` - Agent handler (CRUD only)
- ✅ `backend/internal/handlers/graph_handler.go` - Graph handler (stubbed)

## Files Created

- ✅ `backend/internal/utils/uuid.go` - UUID conversion utilities

## Next Steps

1. **Migrate Graph Service** - Update `internal/graph/graph.go` to use sqlc
2. **Migrate Agent Coordinator** - Update `internal/agents/coordinator.go` to use sqlc
3. **Add Missing Queries** - Add UpdateLink and graph queries to `queries.sql`
4. **Remove GORM Dependencies** - Clean up go.mod (some may still be needed for tests)
5. **Update Tests** - Migrate tests to use pgxpool instead of GORM

---

**Status**: ✅ Core migration complete, ready for service-level migrations
**Build**: ✅ Successful
**Date**: 2024-11-29
