Feature: ChangeSet Models and Invocation Tracking
  As a developer
  I want ChangeSet models with deterministic ordering and invocation tracking
  So that all tool executions and their changes are auditable

  # ---- ChangeType Alias ----

  Scenario: ChangeType is an alias for ChangeOperation
    Given I import ChangeType and ChangeOperation
    Then ChangeType should be the same class as ChangeOperation
    And ChangeType CREATE should equal "create"

  # ---- ChangeEntry Validators ----

  Scenario: CREATE entry rejects before_hash
    When I create a ChangeEntry with CREATE and before_hash "abc"
    Then a validation error should be raised mentioning "before_hash"

  Scenario: DELETE entry rejects after_hash
    When I create a ChangeEntry with DELETE and after_hash "abc"
    Then a validation error should be raised mentioning "after_hash"

  Scenario: CREATE entry accepts after_hash only
    When I create a valid CREATE ChangeEntry with after_hash "abc123"
    Then the change entry operation should be "create"
    And the change entry after_hash should be "abc123"

  Scenario: MODIFY entry accepts both hashes
    When I create a valid MODIFY ChangeEntry with both hashes
    Then the change entry operation should be "modify"
    And the change entry has_integrity_hashes should be true

  Scenario: RENAME entry without hashes is valid
    When I create a RENAME ChangeEntry without hashes
    Then the change entry operation should be "rename"
    And the change entry has_integrity_hashes should be true

  Scenario: CREATE entry without after_hash has no integrity
    When I create a CREATE ChangeEntry without any hashes
    Then the change entry has_integrity_hashes should be false

  # ---- Path Normalization ----

  Scenario: Normalize absolute path with repo root
    Given a repo root "/home/user/project"
    When I normalize the path "/home/user/project/src/main.py"
    Then the normalized path should be "src/main.py"

  Scenario: Normalize relative path stays unchanged
    Given an empty repo root
    When I normalize the path "src/main.py"
    Then the normalized path should be "src/main.py"

  Scenario: Normalize path outside repo root is unchanged
    Given a repo root "/other/project"
    When I normalize the path "/home/user/project/src/main.py"
    Then the normalized path should be "home/user/project/src/main.py"

  # ---- SpecChangeSet Ordering ----

  Scenario: sorted_entries returns deterministic order
    Given a SpecChangeSet with entries in random order
    When I call sorted_entries
    Then entries should be sorted by resource_id then path then timestamp

  Scenario: grouped_by_resource groups correctly
    Given a SpecChangeSet with entries for multiple resources
    When I call grouped_by_resource
    Then entries should be grouped by resource_id
    And each group should be sorted by path and timestamp

  Scenario: add_change appends to entries
    Given an empty SpecChangeSet
    When I add a change entry to it
    Then the spec changeset should contain 1 entry

  # ---- ToolInvocation Model ----

  Scenario: Create a ToolInvocation with minimal fields
    When I create a ToolInvocation for plan "plan-1" and tool "builtin/file-write"
    Then the invocation should have a ULID invocation_id
    And the invocation plan_id should be "plan-1"
    And the invocation tool_name should be "builtin/file-write"
    And the invocation success should be true

  Scenario: Create a failed ToolInvocation
    When I create a failed ToolInvocation with error "file not found"
    Then the invocation success should be false
    And the invocation error should be "file not found"

  Scenario: ToolInvocation with change_ids
    When I create a ToolInvocation with change_ids
    Then the invocation should have 2 change_ids

  Scenario: ToolInvocation with provider metadata
    When I create a ToolInvocation with provider metadata
    Then the invocation provider_metadata should contain model name

  # ---- InMemoryInvocationTracker ----

  Scenario: Track invocations and retrieve by plan
    Given an InMemoryInvocationTracker
    When I track 3 invocations for plan "plan-A"
    And I track 2 invocations for plan "plan-B"
    Then get_invocations for "plan-A" should return 3
    And get_invocations for "plan-B" should return 2

  Scenario: Retrieve invocations for a specific skill
    Given an InMemoryInvocationTracker
    When I track invocations for different skills
    Then get_invocations_for_skill should filter correctly

  Scenario: Get change IDs across invocations
    Given an InMemoryInvocationTracker
    When I track invocations with change_ids
    Then get_changes should return all change_ids for the plan

  Scenario: Invocations are ordered by sequence number
    Given an InMemoryInvocationTracker
    When I track invocations out of order
    Then get_invocations should return them in sequence order

  # ---- SpecChangeSet summary ----

  Scenario: summary returns correct counts for mixed operations
    Given a SpecChangeSet with mixed operation entries
    When I call summary on the changeset
    Then the summary total should be 4
    And the summary creates should be 1
    And the summary modifies should be 1
    And the summary deletes should be 1
    And the summary renames should be 1
    And the summary paths_changed should be 4
    And the summary resources_involved should be 2

  # ---- add_change plan_id validation ----

  Scenario: add_change rejects entry with mismatched plan_id
    Given an empty SpecChangeSet
    When I add a change entry with a different plan_id
    Then a validation error should be raised mentioning "plan_id"

  # ---- Empty tracker queries ----

  Scenario: get_invocations returns empty for unknown plan
    Given an InMemoryInvocationTracker
    Then get_invocations for "nonexistent-plan" should return 0

  Scenario: get_changes returns empty for unknown plan
    Given an InMemoryInvocationTracker
    Then get_changes for "nonexistent-plan" should return 0 ids

  Scenario: get_invocations_for_skill returns empty for unknown skill
    Given an InMemoryInvocationTracker
    When I track 1 invocations for plan "plan-X"
    Then get_invocations_for_skill "plan-X" "no-such-skill" should return 0

  # ---- get_changes ordering proof ----

  Scenario: get_changes respects sequence order not insertion order
    Given an InMemoryInvocationTracker
    When I track change invocations in reverse sequence order
    Then get_changes should return change_ids in sequence order

  # ---- Path normalization edge cases ----

  Scenario: Normalize path that equals repo root returns dot
    Given a repo root "/home/user/project"
    When I normalize the path "/home/user/project"
    Then the normalized path should be "."

  Scenario: Normalize path with dot-dot components preserves them
    Given a repo root "/repo"
    When I normalize the path "/repo/foo/../bar/file.py"
    Then the normalized path should be "foo/../bar/file.py"

  Scenario: Normalize empty path returns dot
    Given an empty repo root
    When I normalize the path "."
    Then the normalized path should be "."