Feature: Plan correction diff command
  As a developer using the v3 plan lifecycle
  I want to view a structured diff for a correction attempt
  So that I can understand what changes a correction will introduce

  # ---------- All 4 output formats ----------

  Scenario: correction diff returns rich format output
    Given correction-diff a mocked apply service returning rich correction diff
    When correction-diff I run plan diff for "PLAN-001" with correction "CORR-001" format "rich"
    Then correction-diff the exit code should be 0
    And correction-diff the output should contain "Correction Diff"
    And correction-diff the output should contain "CORR-001"

  Scenario: correction diff returns plain format output
    Given correction-diff a mocked apply service returning plain correction diff
    When correction-diff I run plan diff for "PLAN-002" with correction "CORR-002" format "plain"
    Then correction-diff the exit code should be 0
    And correction-diff the output should contain "Correction Diff"
    And correction-diff the output should contain "CORR-002"

  Scenario: correction diff returns json format output
    Given correction-diff a mocked apply service returning json correction diff for "CORR-003"
    When correction-diff I run plan diff for "PLAN-003" with correction "CORR-003" format "json"
    Then correction-diff the exit code should be 0
    And correction-diff the output should contain "correction_diff"
    And correction-diff the output should contain "CORR-003"
    And correction-diff the service was called with format "json"

  Scenario: correction diff returns yaml format output
    Given correction-diff a mocked apply service returning yaml correction diff for "CORR-004"
    When correction-diff I run plan diff for "PLAN-004" with correction "CORR-004" format "yaml"
    Then correction-diff the exit code should be 0
    And correction-diff the output should contain "correction_diff"
    And correction-diff the output should contain "CORR-004"
    And correction-diff the service was called with format "yaml"

  # ---------- Error paths ----------

  Scenario: correction diff raises PlanError when plan not found
    Given correction-diff the apply service correction_diff raises PlanError "Plan PLAN-999 not found"
    When correction-diff I run plan diff for "PLAN-999" with correction "CORR-999" format "rich"
    Then correction-diff the exit code should be nonzero
    And correction-diff the output should contain "Diff Error"
    And correction-diff the output should contain "Plan PLAN-999 not found"

  Scenario: correction diff raises PlanError when correction not found
    Given correction-diff the apply service correction_diff raises PlanError "Correction attempt CORR-404 not found"
    When correction-diff I run plan diff for "PLAN-001" with correction "CORR-404" format "rich"
    Then correction-diff the exit code should be nonzero
    And correction-diff the output should contain "Diff Error"
    And correction-diff the output should contain "Correction attempt CORR-404 not found"

  Scenario: correction diff raises PlanError when attempt does not belong to the plan
    Given correction-diff the apply service correction_diff raises PlanError "Correction attempt CORR-001 does not belong to plan PLAN-999"
    When correction-diff I run plan diff for "PLAN-999" with correction "CORR-001" format "rich"
    Then correction-diff the exit code should be nonzero
    And correction-diff the output should contain "Diff Error"
    And correction-diff the output should contain "does not belong to plan"

  Scenario: correction diff raises error when plan_id is empty
    Given correction-diff the apply service correction_diff raises ValidationError "plan_id must not be empty"
    When correction-diff I run plan diff for "" with correction "CORR-001" format "rich"
    Then correction-diff the exit code should be nonzero
    And correction-diff the output should contain "Error"
    And correction-diff the output should contain "plan_id must not be empty"

  Scenario: correction diff raises error when correction_attempt_id is empty (service guard)
    # The CLI passes --correction through to correction_diff() only when it is non-empty.
    # The service-level ValidationError guard for empty correction_attempt_id is tested
    # here by mocking the service to raise the error and asserting the CLI surfaces it.
    Given correction-diff the apply service correction_diff raises ValidationError "correction_attempt_id must not be empty"
    When correction-diff I run plan diff for "PLAN-001" with correction "CORR-001" format "rich"
    Then correction-diff the exit code should be nonzero
    And correction-diff the output should contain "Error"
    And correction-diff the output should contain "correction_attempt_id must not be empty"