Refactor handle_environment_creation() using Steps Pattern

[Copilot]

The handle_environment_creation() function mixed configuration loading, command execution, and result display in a single 58-line function, violating SRP and making individual steps untestable.

Changes

Main function refactored to orchestration-only (21 lines):

pub fn handle_environment_creation(
    env_file: &Path,
    working_dir: &Path,
) -> Result<(), CreateSubcommandError> {
    let mut ctx = CommandContext::new(working_dir.to_path_buf());

    // Step 1: Load configuration
    let config = load_configuration(ctx.output(), env_file)?;

    // Step 2: Execute command
    let environment = {
        let repository = ctx.repository().clone();
        let clock = ctx.clock().clone();
        execute_create_command(ctx.output(), config, repository, clock)?
    };

    // Step 3: Display results
    display_creation_results(ctx.output(), &environment);

    Ok(())
}

Extracted three focused helper functions:

• load_configuration() - Config loading and validation
• execute_create_command() - Command handler creation and execution
• display_creation_results() - Success message formatting

Added unit tests for each helper function:

• 3 tests for configuration loading (valid config, missing file, invalid JSON)
• 2 tests for command execution (success, duplicate environment)
• 1 test for result display
• All 5 existing integration tests remain unchanged and passing

No behavioral changes. Each step is now independently testable while maintaining the same user-facing behavior.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Refactor handle_environment_creation() Using Steps Pattern</issue_title>
<issue_description>Parent Issue: #63
Type: 🔨 Structural Improvement
Impact: 🟢🟢🟢 High
Effort: 🔵🔵🔵 High
Priority: P1
Depends On: #67 (Proposal 4)

Problem

The handle_environment_creation() function is 110+ lines and does too much:

fn handle_environment_creation(env_file: &Path, working_dir: &Path)
    -> Result<(), CreateSubcommandError>
{
    // 1. Create user output
    // 2. Load configuration
    // 3. Validate configuration
    // 4. Create repository
    // 5. Create clock
    // 6. Create command handler
    // 7. Execute command
    // 8. Display results
    // All in one function! 110+ lines
}

This violates SRP and makes the function hard to test and understand.

Proposed Solution

Break down into focused step functions:

pub fn handle_environment_creation(
    env_file: &Path,
    working_dir: &Path,
) -> Result<(), CreateSubcommandError> {
    let mut output = output::create_default();

    // Step 1: Load configuration
    let config = load_configuration(&mut output, env_file)?;

    // Step 2: Create dependencies
    let context = CommandContext::new(working_dir.to_path_buf());

    // Step 3: Execute command
    let environment = execute_create_command(&mut output, config, &context)?;

    // Step 4: Display results
    display_creation_results(&mut output, &environment);

    Ok(())
}

fn load_configuration(output: &mut UserOutput, env_file: &Path) 
    -> Result<EnvironmentCreationConfig, CreateSubcommandError> 
{
    // Focused on configuration loading only
}

fn execute_create_command(
    output: &mut UserOutput,
    config: EnvironmentCreationConfig,
    context: &CommandContext,
) -> Result<Environment, CreateSubcommandError> 
{
    // Focused on command execution only
}

fn display_creation_results(output: &mut UserOutput, environment: &Environment) {
    // Focused on result display only
}

Benefits

• ✅ Main function reduced from 110+ to ~25 lines
• ✅ Each step is self-contained and testable
• ✅ Clear orchestration flow
• ✅ Easier to modify individual steps
• ✅ Better error handling with clear error context

Implementation Checklist

• Create helper function load_configuration()
• Create helper function execute_create_command()
• Create helper function display_creation_results()
• Refactor main handle_environment_creation() to orchestrate steps
• Add comprehensive documentation to each function
• Write unit tests for each helper function
• Update integration tests to verify end-to-end behavior
• Verify all existing tests still pass
• Run linter and fix issues

Acceptance Criteria

• handle_environment_creation() is orchestration-only (~25 lines)
• Each step has its own focused function
• All steps have unit tests
• Integration tests verify end-to-end flow
• No behavioral changes from user perspective
• All tests pass: cargo test create::subcommands::environment
• Pre-commit checks pass: ./scripts/pre-commit.sh
• Code follows project conventions

Related Documentation

• Module Organization Guide
• Refactor Plan</issue_description>

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

• Fixes Refactor handle_environment_creation() Using Steps Pattern #69

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

[josecelano]

ACK c8931b0