# Phase 4: Gin to Echo Handler Migration Status

## Completed Files

### ✅ auth_handler.go
- **Status**: Fully migrated
- **Methods migrated**: 13 methods
  - Login, Register, Logout, CurrentUser, UpdateProfile
  - VerifyEmail, ResendVerification
  - ForgotPassword, VerifyResetCode, ResetPassword
  - AppleSignIn, GoogleSignIn
- **Key changes applied**:
  - Import changed from gin to echo
  - Added validator import
  - All handlers return error
  - c.Bind + c.Validate pattern implemented
  - c.MustGet → c.Get
  - gin.H → map[string]interface{}
  - c.Request.Context() → c.Request().Context()
  - All c.JSON calls use `return`

## Remaining Files to Migrate

### 🔧 residence_handler.go
- **Status**: Partially migrated (needs cleanup)
- **Methods**: 13 methods
- **Issue**: Sed-based automated migration created syntax errors
- **Next steps**: Manual cleanup needed

### ⏳ task_handler.go
- **Methods**: ~17 methods
- **Complexity**: High (multipart form handling for completions)
- **Special considerations**:
  - Has multipart/form-data handling in CreateCompletion
  - Multiple lookup endpoints (categories, priorities, frequencies)

### ⏳ contractor_handler.go
- **Methods**: 8 methods
- **Complexity**: Medium

### ⏳ document_handler.go
- **Methods**: 8 methods
- **Complexity**: High (multipart form handling)
- **Special considerations**: File upload in CreateDocument

### ⏳ notification_handler.go
- **Methods**: 9 methods
- **Complexity**: Medium
- **Special considerations**: Query parameters for pagination

### ⏳ subscription_handler.go
- **Status**: Unknown
- **Estimated complexity**: Medium

### ⏳ upload_handler.go
- **Methods**: 4 methods
- **Complexity**: Medium
- **Special considerations**: c.FormFile handling, c.DefaultQuery

### ⏳ user_handler.go
- **Methods**: 3 methods
- **Complexity**: Low

### ⏳ media_handler.go
- **Status**: Unknown
- **Estimated complexity**: Medium

### ⏳ static_data_handler.go
- **Methods**: Unknown
- **Complexity**: Low (likely just lookups)

### ⏳ task_template_handler.go
- **Status**: Unknown
- **Estimated complexity**: Medium

### ⏳ tracking_handler.go
- **Status**: Unknown
- **Estimated complexity**: Low

### ⏳ subscription_webhook_handler.go
- **Status**: Unknown
- **Estimated complexity**: Medium-High (webhook handling)

## Migration Pattern

All handlers must follow these transformations:

```go
// BEFORE (Gin)
func (h *Handler) Method(c *gin.Context) {
    user := c.MustGet(middleware.AuthUserKey).(*models.User)

    var req requests.SomeRequest
    if err := c.ShouldBindJSON(&req); err != nil {
        c.JSON(400, gin.H{"error": err.Error()})
        return
    }

    result, err := h.service.DoSomething(&req)
    if err != nil {
        c.JSON(500, gin.H{"error": err.Error()})
        return
    }

    c.JSON(200, result)
}

// AFTER (Echo)
func (h *Handler) Method(c echo.Context) error {
    user := c.Get(middleware.AuthUserKey).(*models.User)

    var req requests.SomeRequest
    if err := c.Bind(&req); err != nil {
        return c.JSON(400, map[string]interface{}{"error": err.Error()})
    }
    if err := c.Validate(&req); err != nil {
        return c.JSON(400, validator.FormatValidationErrors(err))
    }

    result, err := h.service.DoSomething(&req)
    if err != nil {
        return c.JSON(500, map[string]interface{}{"error": err.Error()})
    }

    return c.JSON(200, result)
}
```

## Critical Context Changes

| Gin | Echo |
|-----|------|
| `c.MustGet()` | `c.Get()` |
| `c.ShouldBindJSON()` | `c.Bind()` + `c.Validate()` |
| `c.JSON(status, data)` | `return c.JSON(status, data)` |
| `c.Query("key")` | `c.QueryParam("key")` |
| `c.DefaultQuery("k", "v")` | Manual: `if v := c.QueryParam("k"); v != "" { } else { v = "default" }` |
| `c.PostForm("field")` | `c.FormValue("field")` |
| `c.GetHeader("X-...")` | `c.Request().Header.Get("X-...")` |
| `c.Request.Context()` | `c.Request().Context()` |
| `c.Status(code)` | `return c.NoContent(code)` |
| `gin.H{...}` | `map[string]interface{}{...}` |

## Multipart Form Handling

For handlers with file uploads (document_handler, task_handler):

```go
// Request parsing
c.Request.ParseMultipartForm(32 << 20)  // Same
c.PostForm("field") → c.FormValue("field")
c.FormFile("file")  // Same
```

## Next Steps

1. Clean up residence_handler.go manually
2. Migrate contractor_handler.go (simpler, good template)
3. Migrate smaller files: user_handler.go, upload_handler.go, notification_handler.go
4. Migrate complex files: task_handler.go, document_handler.go
5. Migrate remaining files
6. Test compilation
7. Update route registration (if not already done in Phase 3)

## Automation Lessons Learned

- Sed-based bulk replacements are error-prone for complex Go code
- Better approach: Manual migration with copy-paste for repetitive patterns
- Python script provided in migrate_handlers.py (not yet tested)
- Best approach: Methodical manual migration with validation at each step