Feature: Plan Domain Model
  As a developer
  I want a plan domain model that supports the lifecycle
  So that I can track plans through Strategize -> Execute -> Apply phases

  # NamespacedName Tests

  Scenario: Parse simple name defaults to local namespace
    When I parse the namespaced name "my-action"
    Then the parsed namespace should be "local"
    And the parsed item name should be "my-action"
    And the parsed server should be empty

  Scenario: Parse name with explicit local namespace
    When I parse the namespaced name "local/my-action"
    Then the parsed namespace should be "local"
    And the parsed item name should be "my-action"

  Scenario: Parse name with organization namespace
    When I parse the namespaced name "myorg/my-action"
    Then the parsed namespace should be "myorg"
    And the parsed item name should be "my-action"

  Scenario: Parse name with server qualifier
    When I parse the namespaced name "prod:myorg/my-action"
    Then the parsed server should be "prod"
    And the parsed namespace should be "myorg"
    And the parsed item name should be "my-action"

  Scenario: NamespacedName string representation
    Given I have a namespaced name with server "prod" namespace "myorg" and name "my-action"
    Then the namespaced string representation should be "prod:myorg/my-action"

  Scenario: NamespacedName without server
    Given I have a namespaced name with namespace "local" and name "test-plan"
    Then the namespaced string representation should be "local/test-plan"

  Scenario: Invalid namespace with special characters fails
    When I try to create a namespaced name with namespace "my@org" and name "test"
    Then a validation error should be raised

  Scenario: Empty namespace defaults to local
    Given I create a namespaced name with an empty namespace and name "test-plan"
    Then the parsed namespace should be "local"

  # PlanPhase Tests

  Scenario: Plan phases are in correct order
    Then the plan phases should be in order "action, strategize, execute, apply"

  Scenario: STRATEGIZE phase is the starting phase
    Given I create a new plan
    Then the plan phase should be "strategize"

  # PlanState Tests

  Scenario: New plan starts in STRATEGIZE with QUEUED processing state
    Given I create a plan in strategize phase
    Then the plan phase should be "strategize"
    And the plan processing state should be "queued"

  Scenario: Strategize phase uses ProcessingState
    Given I create a plan in strategize phase
    Then the plan processing state should be "queued"

  Scenario: Plan in strategize phase defaults to QUEUED processing state
    Given I create a plan in strategize phase
    Then the plan processing state should be "queued"
    And the plan state should be "queued"

  Scenario: Strategize phase defaults processing_state to QUEUED
    Given I create a plan in strategize phase
    Then the plan processing state should be "queued"

  # Plan Identity Tests

  Scenario: Plan requires valid ULID
    When I try to create a plan identity with invalid ULID "not-a-ulid"
    Then a validation error should be raised

  Scenario: Plan identity with valid ULID succeeds
    When I create a plan identity with ULID "01ARZ3NDEKTSV4RRFFQ69G5FAV"
    Then the plan identity should be valid

  Scenario: Plan identity supports parent and root plan IDs
    When I create a plan identity with parent "01ARZ3NDEKTSV4RRFFQ69G5FAV" and root "01ARZ3NDEKTSV4RRFFQ69G5FAW"
    Then the parent plan ID should be "01ARZ3NDEKTSV4RRFFQ69G5FAV"
    And the root plan ID should be "01ARZ3NDEKTSV4RRFFQ69G5FAW"

  # Plan Lifecycle Tests

  Scenario: New plan starts in STRATEGIZE phase with QUEUED state
    Given I create a new plan with description "Test plan"
    Then the plan phase should be "strategize"
    And the plan processing state should be "queued"
    And the plan should not be terminal

  Scenario: Plan in STRATEGIZE with QUEUED cannot transition
    Given I create a plan in strategize phase
    Then the plan cannot transition to next phase

  Scenario: New plan in STRATEGIZE with QUEUED cannot transition
    Given I create a plan in strategize phase
    Then the plan cannot transition to next phase

  Scenario: Processing complete allows transition
    Given I create a plan in execute phase with complete processing state
    Then the plan can transition to next phase

  Scenario: Get next phase from STRATEGIZE is EXECUTE
    Given I create a new plan
    Then the next phase should be "execute"

  Scenario: Get next phase from APPLY is None (terminal phase)
    Given I create a plan in apply phase as terminal
    Then the next phase should be empty

  Scenario: Unknown phase returns no next phase
    Given I create a plan with an unknown phase value
    Then the next phase should be empty

  # Phase Transition Validation Tests

  Scenario: Valid transition from STRATEGIZE to EXECUTE
    Then transition from "strategize" to "execute" should be valid

  Scenario: Valid transition from EXECUTE to APPLY
    Then transition from "execute" to "apply" should be valid

  Scenario: Valid transition from APPLY to STRATEGIZE (revert via constrained)
    Then transition from "apply" to "strategize" should be valid

  Scenario: Invalid transition from STRATEGIZE to APPLY
    Then transition from "strategize" to "apply" should be invalid

  Scenario: Valid transition from ACTION to STRATEGIZE
    Then transition from "action" to "strategize" should be valid

  # Error State Tests

  Scenario: Plan in errored state is_errored returns True
    Given I create a plan in strategize phase with errored state
    Then the plan should be errored

  Scenario: Plan in processing state is_errored returns False
    Given I create a plan in strategize phase with processing state
    Then the plan should not be errored

  Scenario: Cancelled plan is terminal
    Given I create a plan in strategize phase with cancelled state
    Then the plan should be terminal

  # Model Validation Tests

  Scenario: Plan requires description
    When I try to create a plan without description
    Then a validation error should be raised

  Scenario: Plan description cannot be empty
    When I try to create a plan with empty description
    Then a validation error should be raised

  Scenario: Invalid phase value raises validation error
    When I try to create a plan with invalid phase value
    Then a validation error should be raised

  Scenario: Apply phase cannot transition to next phase
    Given I create a plan in apply phase as terminal
    Then the plan cannot transition to next phase