Add Theme/Configuration Support for UserOutput

[Copilot]

Extracts hardcoded emoji symbols from UserOutput methods into a configurable Theme struct, enabling support for different output styles (emoji, plain text, ASCII) based on environment or user preferences.

Changes

Theme System

• Added Theme struct with three predefined themes:
  • emoji() - Unicode symbols (⏳ ✅ ⚠️ ❌) for interactive terminals (default)
  • plain() - Text labels ([INFO] [OK] [WARN] [ERROR]) for CI/CD pipelines
  • ascii() - ASCII characters (=> [+] [!] [x]) for limited terminal support
• Implements Default trait returning emoji theme for backward compatibility

UserOutput Integration

• Added theme: Theme field to UserOutput
• Added UserOutput::with_theme(verbosity, theme) constructor
• Updated all output methods (progress(), success(), warn(), error()) to use self.theme.X_symbol()
• Removed hardcoded symbols from method implementations

Testing

• Added TestUserOutput::with_theme() for theme injection in tests
• 11 new tests covering theme creation, accessors, and integration

Usage

use torrust_tracker_deployer_lib::presentation::user_output::{UserOutput, VerbosityLevel, Theme};

// Default emoji theme (existing behavior)
let mut output = UserOutput::new(VerbosityLevel::Normal);

// Plain text for CI/CD
let mut output = UserOutput::with_theme(VerbosityLevel::Normal, Theme::plain());
output.success("Deployment complete"); // [OK] Deployment complete

// ASCII for limited terminals
let mut output = UserOutput::with_theme(VerbosityLevel::Normal, Theme::ascii());
output.success("Deployment complete"); // [+] Deployment complete

All existing code continues to work without modifications.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• 192.0.2.1
  • Triggering command: ssh -i /nonexistent/key -p 22 -o ConnectTimeout=5 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no testuser@192.0.2.1 echo 'SSH connected' (packet block)
  • Triggering command: ssh -i /nonexistent/key -p 22 -o UserKnownHostsFile=/dev/null -o ConnectTimeout=5 -o StrictHostKeyChecking=no testuser@192.0.2.1 echo 'SSH connected' (packet block)
  • Triggering command: ssh -i /nonexistent/key -p 22 -o ConnectTimeout=5 -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null testuser@192.0.2.1 echo 'SSH connected' (packet block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

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This section details on the original issue you should resolve

<issue_title>Add Theme/Configuration Support for UserOutput</issue_title>
<issue_description>## Overview

Extract emoji symbols from UserOutput methods into a configurable Theme struct. This enables support for different output styles (emoji, plain text, ASCII) based on environment or user preferences, making the application more accessible and CI/CD-friendly.

Specification

See detailed specification: docs/issues/124-add-theme-configuration-support.md

🏗️ Architecture Requirements

DDD Layer: Presentation
Module Path: src/presentation/user_output.rs
Pattern: Configuration/Theme Pattern

Module Structure Requirements

• Create Theme struct within user_output.rs module
• Implement predefined theme constructors (emoji(), plain(), ascii())
• Implement Default trait for Theme (emoji theme)
• Update UserOutput to use Theme for all symbol formatting
• Follow module organization conventions (see docs/contributing/module-organization.md)

Architectural Constraints

• No breaking changes: Existing code using default constructor continues to work
• Backward compatibility: Default theme uses emoji (current behavior)
• Extensibility: Easy to add new themes without modifying output methods
• Type safety: Theme fields are strongly typed
• Immutability: Theme is set at construction, not modified during runtime

Anti-Patterns to Avoid

• ❌ Global mutable theme - Don't use static mutable for theme configuration
• ❌ Runtime theme switching - Theme is set at construction, not changed afterward
• ❌ Hardcoded symbols in methods - All symbols must come from Theme

Implementation Plan

Phase 1: Create Theme Struct (1-2 hours)

• Create Theme struct with symbol fields
• Implement Theme::emoji(), Theme::plain(), Theme::ascii()
• Implement accessor methods and Default trait
• Add comprehensive documentation

Phase 2: Add Unit Tests for Theme (1 hour)

• Test all predefined themes
• Test accessor methods
• Test theme cloning and equality

Phase 3: Integrate Theme into UserOutput (2-3 hours)

• Add theme: Theme field to UserOutput
• Create UserOutput::with_theme() constructor
• Update all output methods to use self.theme.X_symbol()
• Remove hardcoded symbols

Phase 4: Update Tests (2-3 hours)

• Update test infrastructure to support themes
• Add tests for each theme variant
• Verify all existing tests pass

Phase 5: Documentation and Verification (1 hour)

• Add module documentation
• Add usage examples
• Run pre-commit checks: ./scripts/pre-commit.sh

Acceptance Criteria

Note for Contributors: These criteria define what the PR reviewer will check. Use this as your pre-review checklist before submitting the PR to minimize back-and-forth iterations.

Quality Checks:

• Pre-commit checks pass: ./scripts/pre-commit.sh

Theme Implementation Checks:

• Theme struct exists with all symbol fields
• All predefined themes implemented: emoji(), plain(), ascii()
• Default trait returns emoji theme
• All accessor methods implemented

Integration Checks:

• UserOutput has theme: Theme field
• UserOutput::with_theme() constructor exists
• All output methods use theme symbols (no hardcoded symbols)

Testing Checks:

• Theme unit tests cover all variants
• Test infrastructure supports theme injection
• All existing tests pass

Backward Compatibility Checks:

• Default UserOutput::new() uses emoji theme
• No breaking changes to public API

Documentation Checks:

• Theme system fully documented
• Usage examples for each theme
• Each theme variant documented with use case

Related

• Parent: [EPIC] User Output Architecture Improvements #102 (Epic: User Output Architecture Improvements)
• Roadmap: N/A (Code quality improvement)
• Specification: docs/issues/124-add-theme-configuration-support.md</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Add Theme/Configuration Support for UserOutput #124

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[josecelano]

ACK 2835384