refactor(api): restructured API for type safety, maintainability and docs generation

- These changes makes the API incombatible with previous versions
- Added new types for error handling, success responses, and health checks.
- Updated health check logic to utilize the new types for better clarity and structure.
- Refactored existing handlers to improve response consistency and error handling.
- Updated Makefile to include a new target for generating API types from Swagger.
- Updated "new agent" API to respond an encrypted cert pair

internal/api/types/error.go

@@ -0,0 +1,42 @@
+package apitypes
+
+type ErrorResponse struct {
+	Message string `json:"message"`
+	Error   string `json:"error,omitempty" extensions:"x-nullable"`
+} // @name ErrorResponse
+
+type serverError struct {
+	Message string
+	Err     error
+}
+
+// Error returns a generic error response
+func Error(message string, err ...error) ErrorResponse {
+	if len(err) > 0 {
+		return ErrorResponse{
+			Message: message,
+			Error:   err[0].Error(),
+		}
+	}
+	return ErrorResponse{
+		Message: message,
+	}
+}
+
+func InternalServerError(err error, message string) error {
+	return serverError{
+		Message: message,
+		Err:     err,
+	}
+}
+
+func (e serverError) Error() string {
+	if e.Err != nil {
+		return e.Message + ": " + e.Err.Error()
+	}
+	return e.Message
+}
+
+func (e serverError) Unwrap() error {
+	return e.Err
+}

internal/api/types/error_code.go

@@ -0,0 +1,17 @@
+package apitypes
+
+type ErrorCode int
+
+const (
+	ErrorCodeUnauthorized ErrorCode = iota + 1
+	ErrorCodeNotFound
+	ErrorCodeInternalServerError
+)
+
+func (e ErrorCode) String() string {
+	return []string{
+		"Unauthorized",
+		"Not Found",
+		"Internal Server Error",
+	}[e]
+}

internal/api/types/query.go

@@ -0,0 +1,29 @@
+package apitypes
+
+type QueryOptions struct {
+	Limit   int                 `binding:"required,min=1,max=20" form:"limit"`
+	Offset  int                 `binding:"omitempty,min=0" form:"offset"`
+	OrderBy QueryOrder          `binding:"omitempty,oneof=created_at updated_at" form:"order_by"`
+	Order   QueryOrderDirection `binding:"omitempty,oneof=asc desc" form:"order"`
+}
+
+type QueryOrder string
+
+const (
+	QueryOrderCreatedAt QueryOrder = "created_at"
+	QueryOrderUpdatedAt QueryOrder = "updated_at"
+)
+
+type QueryOrderDirection string
+
+const (
+	QueryOrderDirectionAsc  QueryOrderDirection = "asc"
+	QueryOrderDirectionDesc QueryOrderDirection = "desc"
+)
+
+type QueryResponse struct {
+	Total   int64 `json:"total"`
+	Limit   int   `json:"limit"`
+	Offset  int   `json:"offset"`
+	HasMore bool  `json:"has_more"`
+}

internal/api/types/success.go

@@ -0,0 +1,18 @@
+package apitypes
+
+type SuccessResponse struct {
+	Message string         `json:"message"`
+	Details map[string]any `json:"details,omitempty" extensions:"x-nullable"`
+} // @name SuccessResponse
+
+func Success(message string, extra ...map[string]any) SuccessResponse {
+	if len(extra) > 0 {
+		return SuccessResponse{
+			Message: message,
+			Details: extra[0],
+		}
+	}
+	return SuccessResponse{
+		Message: message,
+	}
+}