K.I.S.S Refactoring Summary

Applied Principles

1. Modularization (Keep It Simple, Keep It Small)

Before: Large monolithic modules (138+ lines)
After: Small focused modules (each under 50 lines)
Example: SSH module split into 5 specialized modules

2. Single Responsibility Principle (UNIX Philosophy: Do One Thing Well)

connection-test.scm: Only SSH connectivity testing
remote-command.scm: Only remote command execution
file-copy.scm: Only file transfer operations
retry.scm: Only retry logic
context.scm: Only connection context management

3. Functional Programming Patterns

Pure Functions First: All core logic implemented as pure functions
Immutable Data: Configuration and data structures remain immutable
Separation of Concerns: Pure functions separated from side effects

4. Function-Level Modularity

Each module exports both:

Pure functions: For testing, composition, and functional programming
Impure wrappers: For convenience and logging

Module Structure

utils/
├── ssh/
│   ├── connection-test.scm    # Pure SSH connectivity testing
│   ├── remote-command.scm     # Pure command execution logic
│   ├── file-copy.scm          # Pure file transfer operations
│   ├── retry.scm              # Pure retry logic with backoff
│   └── context.scm            # Connection context management
├── config/
│   ├── defaults.scm           # Pure data: default configuration
│   ├── loader.scm             # File I/O operations
│   ├── accessor.scm           # Pure configuration access functions
│   └── state.scm              # Mutable state management
├── logging/
│   ├── format.scm             # Pure formatting and color codes
│   ├── level.scm              # Pure log level management
│   ├── state.scm              # Mutable log level state
│   ├── output.scm             # Pure output formatting
│   ├── core.scm               # Main logging functions
│   └── spinner.scm            # Progress indication
└── json/
    ├── parse.scm              # Pure JSON parsing
    ├── serialize.scm          # Pure JSON serialization
    ├── file-io.scm            # File I/O with pure/impure versions
    ├── validation.scm         # Pure schema validation
    ├── manipulation.scm       # Pure object manipulation
    └── pretty-print.scm       # Output formatting

Benefits Achieved

1. Testability

Pure functions can be tested in isolation
No side effects to mock or manage
Clear input/output contracts

2. Composability

Small functions can be easily combined
Pure functions enable functional composition
Reusable building blocks

3. Maintainability

Single responsibility makes modules easy to understand
Changes are localized to specific modules
Clear separation between pure and impure code

4. Code Reuse

Pure functions can be reused across different contexts
Both pure and impure versions available
Facade modules provide convenient interfaces

Usage Examples

Pure Function Composition

;; Test connection and get config in one go
(let ((ssh-config (get-ssh-config-pure config "machine-name")))
  (if (test-ssh-connection-pure ssh-config)
      (run-remote-command-pure ssh-config "uptime" '())
      #f))

Convenient Impure Wrappers

;; Same operation with logging and error handling
(with-ssh-connection "machine-name"
  (lambda () (run-remote-command "machine-name" "uptime")))

Functional Pipeline

;; Pure validation pipeline
(let* ((config (load-config-from-file "config.json"))
       (valid? (validate-json-schema config machine-schema))
       (machines (if valid? (get-all-machines-pure config) '())))
  machines)

This refactoring transforms the codebase from monolithic modules into a collection of small, focused, composable functions that follow functional programming principles while maintaining practical usability.

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