use oa_core::{
    references,
    transitions::*,
    validation::{self, Severity},
    *,
};

fn add_occurrence(p: &mut Project, owner: Id, name: &str, body: OccurrenceBody) -> Id {
    let mut e = p
        .make_element(
            Kind::Occurrence,
            p.elements[&owner].layer(),
            name,
            Some(owner),
        )
        .unwrap();
    *e.shared_mut().unwrap() = SharedBody::Occurrence {
        body,
        precondition: String::new(),
        postcondition: String::new(),
    };
    let id = e.id;
    p.elements.insert(id, e);
    p.elements
        .get_mut(&owner)
        .unwrap()
        .steps_mut()
        .unwrap()
        .push(id);
    id
}
fn line(p: &mut Project, scenario: Id, represented: Id, name: &str) -> Id {
    let id = p
        .add_element(
            Kind::Lifeline,
            p.elements[&scenario].layer(),
            name,
            Some(scenario),
        )
        .unwrap();
    *p.elements.get_mut(&id).unwrap().shared_mut().unwrap() = SharedBody::Lifeline {
        represented: Some(represented),
    };
    id
}
fn message(
    exchange: Option<Id>,
    sender: Id,
    receiver: Option<Id>,
    kind: MessageKind,
    call: Option<Id>,
) -> OccurrenceBody {
    OccurrenceBody::Exchange {
        operation: None,
        exchange,
        sender: Some(sender),
        receiver,
        message_kind: kind,
        reply_to: call,
        values: vec![],
    }
}
struct Fixture {
    p: Project,
    scenario: Id,
    a: Id,
    b: Id,
    call: Id,
    reply: Id,
    exchange: Id,
    field: Id,
}
fn fixture(layer: Layer) -> Fixture {
    let mut p = Project::empty();
    let work_kind = if layer == Layer::Oa {
        Kind::Activity
    } else {
        Kind::Function
    };
    let client = p
        .add_element(work_kind, layer, "Request service", None)
        .unwrap();
    let server = p
        .add_element(work_kind, layer, "Provide service", None)
        .unwrap();
    let scenario = p
        .add_element(Kind::Scenario, layer, "Service conversation", None)
        .unwrap();
    let a = line(&mut p, scenario, client, "Client");
    let b = line(&mut p, scenario, server, "Provider");
    let item = p
        .add_element(Kind::ExchangeItem, layer, "Service request", None)
        .unwrap();
    let record = p
        .add_element(Kind::DataType, layer, "Request record", None)
        .unwrap();
    *p.elements.get_mut(&record).unwrap().shared_mut().unwrap() = SharedBody::DataType {
        definition: DataTypeDefinition::Record { supertype: None },
        default: None,
        unit: String::new(),
    };
    let field = p
        .add_element(Kind::DataField, layer, "Requested level", Some(record))
        .unwrap();
    let payload = p
        .add_element(Kind::DataField, layer, "Payload", Some(item))
        .unwrap();
    if let Some(SharedBody::DataField { type_ref, .. }) =
        p.elements.get_mut(&payload).unwrap().shared_mut()
    {
        *type_ref = TypeRef::Named(record);
    }
    let exchange = p.relate(
        if layer == Layer::Oa {
            RelationKind::Interaction
        } else {
            RelationKind::FunctionalExchange
        },
        "Service invocation",
        client,
        server,
    );
    match &mut p.relations.get_mut(&exchange).unwrap().body {
        RelationBody::Interaction { items, .. }
        | RelationBody::FunctionalExchange { items, .. } => items.push(item),
        _ => unreachable!(),
    }
    if let RelationBody::FunctionalExchange {
        source_port,
        target_port,
        ..
    } = p.relations[&exchange].body
    {
        for port in [source_port, target_port] {
            match p.elements.get_mut(&port).unwrap().shared_mut() {
                Some(SharedBody::Port {
                    contract: PortContract::FunctionInput { incoming_items },
                    ..
                }) => incoming_items.push(item),
                Some(SharedBody::Port {
                    contract: PortContract::FunctionOutput { outgoing_items },
                    ..
                }) => outgoing_items.push(item),
                _ => unreachable!(),
            }
        }
    }
    let call = add_occurrence(
        &mut p,
        scenario,
        "Request service",
        message(Some(exchange), a, Some(b), MessageKind::Call, None),
    );
    let reply = add_occurrence(
        &mut p,
        scenario,
        "Return result",
        message(Some(exchange), b, Some(a), MessageKind::Reply, Some(call)),
    );
    if let Some(SharedBody::Occurrence {
        body: OccurrenceBody::Exchange { values, .. },
        ..
    }) = p.elements.get_mut(&call).unwrap().shared_mut()
    {
        values.push(MessageValue {
            path: vec![payload],
            field,
            expression: "requested_level".into(),
        });
    }
    Fixture {
        p,
        scenario,
        a,
        b,
        call,
        reply,
        exchange,
        field,
    }
}
fn valid(p: &Project) {
    let errors: Vec<_> = validation::validate(p)
        .into_iter()
        .filter(|i| i.severity == Severity::Error)
        .collect();
    assert!(errors.is_empty(), "{errors:?}");
}
fn edit_message(p: &Project, id: Id, edit: impl FnOnce(&mut OccurrenceBody)) -> Element {
    let mut element = p.elements[&id].clone();
    if let Some(SharedBody::Occurrence { body, .. }) = element.shared_mut() {
        edit(body);
    }
    element
}

#[test]
fn calls_and_replies_have_real_direction_correlation_and_order() {
    for layer in [Layer::Oa, Layer::Sa] {
        let Fixture {
            p,
            scenario,
            a,
            b,
            call,
            reply,
            exchange,
            ..
        } = fixture(layer);
        valid(&p);
        let mut session = Session::new(p.clone());
        assert!(
            session
                .execute(Command::MoveStep(scenario, 1, 0))
                .unwrap_err()
                .0
                .contains("reply_order")
        );
        assert_eq!(session.project(), &p);
        for edit in [
            edit_message(&p, reply, |body| {
                if let OccurrenceBody::Exchange {
                    sender, receiver, ..
                } = body
                {
                    *sender = Some(a);
                    *receiver = Some(b);
                }
            }),
            edit_message(&p, reply, |body| {
                if let OccurrenceBody::Exchange { reply_to, .. } = body {
                    *reply_to = Some(reply);
                }
            }),
        ] {
            assert!(session.execute(Command::EditElement(reply, edit)).is_err());
            assert_eq!(session.project(), &p);
        }
        let mut duplicate = p.clone();
        add_occurrence(
            &mut duplicate,
            scenario,
            "Second return",
            message(Some(exchange), b, Some(a), MessageKind::Reply, Some(call)),
        );
        assert!(
            validate_candidate(&duplicate)
                .unwrap_err()
                .0
                .contains("duplicate_reply")
        );
        let mut reverse = p.clone();
        let original = &p.relations[&exchange];
        let reverse_exchange = reverse.relate(
            original.kind(),
            "Explicit return contract",
            original.target(),
            original.source(),
        );
        let edited = edit_message(&reverse, reply, |body| {
            if let OccurrenceBody::Exchange { exchange, .. } = body {
                *exchange = Some(reverse_exchange);
            }
        });
        reverse.elements.insert(reply, edited);
        valid(&reverse);
        assert_eq!(reverse.relations[&exchange], p.relations[&exchange]);
    }
}

#[test]
fn reused_scenarios_bind_existing_roles_and_transition_the_reference_closure() {
    for direction in [TransitionDirection::OaToSa, TransitionDirection::SaToOa] {
        let Fixture {
            mut p,
            scenario,
            a,
            b,
            ..
        } = fixture(direction.source_layer());
        let represented = |p: &Project, id| match p.elements[&id].shared().unwrap() {
            SharedBody::Lifeline {
                represented: Some(id),
            } => *id,
            _ => unreachable!(),
        };
        let client = represented(&p, a);
        let provider = represented(&p, b);
        let mut callers = vec![];
        for name in ["Nominal service", "Degraded service"] {
            let caller = p
                .add_element(Kind::Scenario, direction.source_layer(), name, None)
                .unwrap();
            let local_a = line(&mut p, caller, client, "Caller client");
            let local_b = line(&mut p, caller, provider, "Caller provider");
            let use_id = add_occurrence(
                &mut p,
                caller,
                "Reuse service conversation",
                OccurrenceBody::ScenarioUse {
                    scenario: Some(scenario),
                    bindings: vec![
                        LifelineBinding {
                            referenced: a,
                            local: local_a,
                        },
                        LifelineBinding {
                            referenced: b,
                            local: local_b,
                        },
                    ],
                },
            );
            callers.push((caller, use_id));
        }
        valid(&p);
        let request = {
            let mut r =
                TransitionRequest::new(direction, callers.iter().map(|(id, _)| *id).collect());
            r.scope = DependencyScope::Required;
            r
        };
        let plan = plan_transition(&p, &request).unwrap();
        assert!(plan.conflicts.is_empty(), "{:?}", plan.conflicts);
        let mapped = |id| plan.changes.iter().find(|c| c.source == id).unwrap().target;
        let target = apply_transition(&p, &plan).unwrap();
        valid(&target);
        for (caller, use_id) in &callers {
            assert!(
                references::element_references(&target.elements[&mapped(*use_id)])
                    .contains(&mapped(scenario))
            );
            assert_eq!(
                target.elements[&mapped(*caller)].layer(),
                direction.target_layer()
            );
            assert!(
                matches!(target.elements[&mapped(*use_id)].shared(),Some(SharedBody::Occurrence{body:OccurrenceBody::ScenarioUse{scenario:Some(id),..},..})if *id==mapped(scenario))
            );
        }
        let mut session = Session::new(p.clone());
        session
            .execute(Command::Rename(
                scenario,
                "Reviewed shared conversation".into(),
            ))
            .unwrap();
        for (_, use_id) in callers {
            assert_eq!(session.project().elements[&use_id], p.elements[&use_id]);
        }
        session.undo();
        assert_eq!(session.project(), &p);
        let reverse = {
            let mut r = TransitionRequest::new(
                if direction == TransitionDirection::OaToSa {
                    TransitionDirection::SaToOa
                } else {
                    TransitionDirection::OaToSa
                },
                vec![mapped(scenario)],
            );
            r.scope = DependencyScope::Required;
            r
        };
        let repeat = plan_transition(&target, &reverse).unwrap();
        assert!(repeat.conflicts.is_empty());
        assert!(repeat.commands.is_empty());
    }
}
#[test]
fn reuse_rejects_wrong_bindings_recursive_calls_and_wrong_viewpoints() {
    let Fixture {
        mut p,
        scenario,
        a,
        b,
        ..
    } = fixture(Layer::Sa);
    let caller = p
        .add_element(Kind::Scenario, Layer::Sa, "Caller", None)
        .unwrap();
    let wrong_work = p
        .add_element(Kind::Function, Layer::Sa, "Different function", None)
        .unwrap();
    let wrong = line(&mut p, caller, wrong_work, "Wrong role");
    let use_id = add_occurrence(
        &mut p,
        caller,
        "Bad role binding",
        OccurrenceBody::ScenarioUse {
            scenario: Some(scenario),
            bindings: vec![LifelineBinding {
                referenced: a,
                local: wrong,
            }],
        },
    );
    assert!(
        validate_candidate(&p)
            .unwrap_err()
            .0
            .contains("scenario_binding_identity")
    );
    let correct = match p.elements[&a].shared().unwrap() {
        SharedBody::Lifeline {
            represented: Some(id),
        } => *id,
        _ => unreachable!(),
    };
    *p.elements.get_mut(&wrong).unwrap().shared_mut().unwrap() = SharedBody::Lifeline {
        represented: Some(correct),
    };
    valid(&p);
    assert!(
        validation::validate(&p)
            .iter()
            .any(|i| i.element == Some(use_id) && i.code == "missing_lifeline_binding")
    );
    let mut cycle = p.clone();
    add_occurrence(
        &mut cycle,
        scenario,
        "Recursive caller",
        OccurrenceBody::ScenarioUse {
            scenario: Some(caller),
            bindings: vec![],
        },
    );
    assert!(
        validation::validate(&cycle)
            .iter()
            .any(|i| i.code == "recursive_scenario_use" && i.severity == Severity::Error)
    );
    let mut wrong_context = p.clone();
    let edited = edit_message(&wrong_context, use_id, |body| {
        if let OccurrenceBody::ScenarioUse { bindings, .. } = body {
            bindings[0].local = b;
        }
    });
    wrong_context.elements.insert(use_id, edited);
    assert!(
        validation::validate(&wrong_context)
            .iter()
            .any(|i| i.code == "scenario_binding_context")
    );
    if let Some(SharedBody::Scenario { viewpoint, .. }) =
        p.elements.get_mut(&caller).unwrap().shared_mut()
    {
        *viewpoint = ScenarioViewpoint::BoundaryInterface;
    }
    assert!(
        validation::validate(&p)
            .iter()
            .any(|i| i.code == "scenario_use_viewpoint")
    );
}

#[test]
fn create_delete_and_local_timer_messages_enforce_lifetime_rules() {
    let Fixture {
        mut p,
        scenario,
        a,
        b,
        exchange,
        ..
    } = fixture(Layer::Sa);
    let create = add_occurrence(
        &mut p,
        scenario,
        "Create provider",
        message(Some(exchange), a, Some(b), MessageKind::Create, None),
    );
    let steps = p.elements.get_mut(&scenario).unwrap().steps_mut().unwrap();
    steps.pop();
    steps.insert(0, create);
    let timer = add_occurrence(
        &mut p,
        scenario,
        "Wait for completion",
        message(
            None,
            b,
            None,
            MessageKind::Timer {
                expression: "after 5 s".into(),
            },
            None,
        ),
    );
    let delete = add_occurrence(
        &mut p,
        scenario,
        "Delete provider",
        message(Some(exchange), a, Some(b), MessageKind::Delete, None),
    );
    valid(&p);
    let mut session = Session::new(p.clone());
    for command in [
        Command::MoveStep(scenario, 0, 2),
        Command::MoveStep(scenario, 4, 1),
    ] {
        assert!(
            session
                .execute(command)
                .unwrap_err()
                .0
                .contains("lifeline_lifetime")
        );
        assert_eq!(session.project(), &p);
    }
    let bad = edit_message(&p, timer, |body| {
        if let OccurrenceBody::Exchange { receiver, .. } = body {
            *receiver = Some(a);
        }
    });
    assert!(
        session
            .execute(Command::EditElement(timer, bad))
            .unwrap_err()
            .0
            .contains("timer_contract")
    );
    let incomplete = edit_message(&p, timer, |body| {
        if let OccurrenceBody::Exchange { message_kind, .. } = body {
            *message_kind = MessageKind::Timer {
                expression: String::new(),
            };
        }
    });
    session
        .execute(Command::EditElement(timer, incomplete))
        .unwrap();
    assert!(
        validation::validate(session.project())
            .iter()
            .any(|i| i.element == Some(timer) && i.code == "missing_timer_expression")
    );
    assert_eq!(session.project().elements[&delete], p.elements[&delete]);
}

#[test]
fn value_annotations_are_bound_to_carried_fields_and_all_references_follow_identity_changes() {
    let Fixture { p, call, field, .. } = fixture(Layer::Oa);
    valid(&p);
    let mut duplicate = edit_message(&p, call, |body| {
        if let OccurrenceBody::Exchange { values, .. } = body {
            values.push(values[0].clone());
        }
    });
    let mut session = Session::new(p.clone());
    assert!(
        session
            .execute(Command::EditElement(call, duplicate.clone()))
            .unwrap_err()
            .0
            .contains("duplicate_message_value")
    );
    let mut unrelated = p.clone();
    let item = unrelated
        .add_element(Kind::ExchangeItem, Layer::Oa, "Unrelated item", None)
        .unwrap();
    let other = unrelated
        .add_element(Kind::DataField, Layer::Oa, "Unrelated field", Some(item))
        .unwrap();
    if let Some(SharedBody::Occurrence {
        body: OccurrenceBody::Exchange { values, .. },
        ..
    }) = duplicate.shared_mut()
    {
        values.truncate(1);
        values[0].field = other;
    }
    assert!(
        execute_batch(&unrelated, &[Command::EditElement(call, duplicate)])
            .unwrap_err()
            .0
            .contains("message_value_field")
    );
    for id in p.elements.keys().chain(p.relations.keys()).copied() {
        let mut session = Session::new(p.clone());
        let replacement = Id::new_v4();
        session
            .execute(Command::Reidentify(id, replacement))
            .unwrap();
        let renamed = session.project().clone();
        assert!(
            renamed
                .elements
                .values()
                .all(|e| !references::element_references(e).contains(&id))
        );
        session.execute(Command::Delete(replacement)).unwrap();
        valid(session.project());
        session.undo();
        assert_eq!(session.project(), &renamed);
        session.undo();
        assert_eq!(session.project(), &p);
    }
    session.execute(Command::Delete(field)).unwrap();
    assert!(
        matches!(session.project().elements[&call].shared(),Some(SharedBody::Occurrence{body:OccurrenceBody::Exchange{values,..},..})if values.is_empty())
    );
}

#[test]
fn loop_fragment_repetition_is_distinct_from_recursive_scenario_use() {
    let Fixture {
        mut p,
        scenario,
        a,
        b,
        call,
        reply,
        ..
    } = fixture(Layer::Oa);
    let mut fragment = p
        .make_element(Kind::Occurrence, Layer::Oa, "Retry service", Some(scenario))
        .unwrap();
    let fragment_id = fragment.id;
    *fragment.shared_mut().unwrap() = SharedBody::Occurrence {
        body: OccurrenceBody::Fragment {
            operator: FragmentOperator::Loop,
            branches: vec![],
        },
        precondition: String::new(),
        postcondition: String::new(),
    };
    let mut branch = p
        .make_element(
            Kind::Occurrence,
            Layer::Oa,
            "While needed",
            Some(fragment_id),
        )
        .unwrap();
    let branch_id = branch.id;
    *branch.shared_mut().unwrap() = SharedBody::Occurrence {
        body: OccurrenceBody::Branch {
            guard: "retry && count < 3".into(),
            occurrences: vec![call, reply],
        },
        precondition: String::new(),
        postcondition: String::new(),
    };
    if let Some(SharedBody::Occurrence {
        body: OccurrenceBody::Fragment { branches, .. },
        ..
    }) = fragment.shared_mut()
    {
        branches.push(branch_id);
    }
    p.elements.get_mut(&call).unwrap().parent = Some(branch_id);
    p.elements.get_mut(&reply).unwrap().parent = Some(branch_id);
    *p.elements.get_mut(&scenario).unwrap().steps_mut().unwrap() = vec![fragment_id];
    p.elements.insert(fragment_id, fragment);
    p.elements.insert(branch_id, branch);
    valid(&p);
    let exchange = p_exchange(&p, call);
    let outside = add_occurrence(
        &mut p,
        scenario,
        "Reply outside optional loop",
        message(Some(exchange), b, Some(a), MessageKind::Reply, Some(call)),
    );
    assert!(
        validation::validate(&p)
            .iter()
            .any(|i| i.element == Some(outside) && i.code == "reply_order")
    );
}
fn p_exchange(p: &Project, id: Id) -> Id {
    match p.elements[&id].shared().unwrap() {
        SharedBody::Occurrence {
            body: OccurrenceBody::Exchange {
                exchange: Some(id), ..
            },
            ..
        } => *id,
        _ => unreachable!(),
    }
}

#[test]
fn deleting_reused_scenarios_or_bound_lifelines_preserves_callers_and_undo() {
    let Fixture {
        mut p,
        scenario,
        a,
        b,
        ..
    } = fixture(Layer::Sa);
    let caller = p
        .add_element(Kind::Scenario, Layer::Sa, "Caller", None)
        .unwrap();
    let client = match p.elements[&a].shared().unwrap() {
        SharedBody::Lifeline {
            represented: Some(id),
        } => *id,
        _ => unreachable!(),
    };
    let provider = match p.elements[&b].shared().unwrap() {
        SharedBody::Lifeline {
            represented: Some(id),
        } => *id,
        _ => unreachable!(),
    };
    let local_a = line(&mut p, caller, client, "Local client");
    let local_b = line(&mut p, caller, provider, "Local provider");
    let use_id = add_occurrence(
        &mut p,
        caller,
        "Shared conversation",
        OccurrenceBody::ScenarioUse {
            scenario: Some(scenario),
            bindings: vec![
                LifelineBinding {
                    referenced: a,
                    local: local_a,
                },
                LifelineBinding {
                    referenced: b,
                    local: local_b,
                },
            ],
        },
    );
    valid(&p);
    for id in [scenario, a, b, local_a, local_b, use_id] {
        let mut session = Session::new(p.clone());
        let replacement = Id::new_v4();
        session
            .execute(Command::Reidentify(id, replacement))
            .unwrap();
        assert!(
            session
                .project()
                .elements
                .values()
                .all(|e| !references::element_references(e).contains(&id))
        );
        let renamed = session.project().clone();
        session.execute(Command::Delete(replacement)).unwrap();
        valid(session.project());
        assert!(session.project().elements.contains_key(&caller));
        if id == scenario {
            assert!(
                matches!(session.project().elements[&use_id].shared(),Some(SharedBody::Occurrence{body:OccurrenceBody::ScenarioUse{scenario:None,bindings},..})if bindings.is_empty())
            );
            assert!(session.project().elements.contains_key(&local_a));
        }
        session.undo();
        assert_eq!(session.project(), &renamed);
        session.undo();
        assert_eq!(session.project(), &p);
    }
}

fn scenario_branch(p: &mut Project, owner: Id, operator: FragmentOperator) -> (Id, Id) {
    let fragment = add_occurrence(
        p,
        owner,
        "Conditional fragment",
        OccurrenceBody::Fragment {
            operator,
            branches: vec![],
        },
    );
    let branch = additional_branch(p, fragment);
    (fragment, branch)
}
fn additional_branch(p: &mut Project, fragment: Id) -> Id {
    let mut branch = p
        .make_element(
            Kind::Occurrence,
            p.elements[&fragment].layer(),
            "Operand",
            Some(fragment),
        )
        .unwrap();
    let id = branch.id;
    *branch.shared_mut().unwrap() = SharedBody::Occurrence {
        body: OccurrenceBody::Branch {
            guard: "condition".into(),
            occurrences: vec![],
        },
        precondition: String::new(),
        postcondition: String::new(),
    };
    p.elements.insert(id, branch);
    if let Some(SharedBody::Occurrence {
        body: OccurrenceBody::Fragment { branches, .. },
        ..
    }) = p.elements.get_mut(&fragment).unwrap().shared_mut()
    {
        branches.push(id);
    }
    id
}

#[test]
fn conditional_and_parallel_replies_cannot_answer_one_call_twice_but_alternatives_can() {
    for operator in [FragmentOperator::Optional, FragmentOperator::Alternative] {
        let Fixture {
            mut p,
            scenario,
            a,
            b,
            call,
            reply,
            exchange,
            ..
        } = fixture(Layer::Sa);
        p.elements.remove(&reply);
        p.elements
            .get_mut(&scenario)
            .unwrap()
            .steps_mut()
            .unwrap()
            .retain(|id| *id != reply);
        let (_, operand) = scenario_branch(&mut p, scenario, operator);
        add_occurrence(
            &mut p,
            operand,
            "Conditional return",
            message(Some(exchange), b, Some(a), MessageKind::Reply, Some(call)),
        );
        valid(&p);
        let before = p.clone();
        add_occurrence(
            &mut p,
            scenario,
            "Later return",
            message(Some(exchange), b, Some(a), MessageKind::Reply, Some(call)),
        );
        let mut session = Session::new(before.clone());
        assert!(
            session
                .execute(Command::Replace(p))
                .unwrap_err()
                .0
                .contains("duplicate_reply")
        );
        assert_eq!(session.project(), &before);
    }
    for operator in [FragmentOperator::Alternative, FragmentOperator::Parallel] {
        let Fixture {
            mut p,
            scenario,
            a,
            b,
            call,
            reply,
            exchange,
            ..
        } = fixture(Layer::Sa);
        p.elements.remove(&reply);
        p.elements
            .get_mut(&scenario)
            .unwrap()
            .steps_mut()
            .unwrap()
            .retain(|id| *id != reply);
        let (fragment, left) = scenario_branch(&mut p, scenario, operator);
        let right = additional_branch(&mut p, fragment);
        for operand in [left, right] {
            add_occurrence(
                &mut p,
                operand,
                "Branch return",
                message(Some(exchange), b, Some(a), MessageKind::Reply, Some(call)),
            );
        }
        if operator == FragmentOperator::Alternative {
            valid(&p);
        } else {
            assert!(
                validate_candidate(&p)
                    .unwrap_err()
                    .0
                    .contains("duplicate_reply")
            );
        }
    }
}

#[test]
fn conditional_lifetime_changes_conflict_with_later_or_parallel_use_not_exclusive_use() {
    for operator in [FragmentOperator::Optional, FragmentOperator::Alternative] {
        let Fixture {
            mut p,
            scenario,
            a,
            b,
            exchange,
            ..
        } = fixture(Layer::Sa);
        let (_, operand) = scenario_branch(&mut p, scenario, operator);
        add_occurrence(
            &mut p,
            operand,
            "Conditional deletion",
            message(Some(exchange), a, Some(b), MessageKind::Delete, None),
        );
        valid(&p);
        add_occurrence(
            &mut p,
            scenario,
            "Use after fragment",
            message(Some(exchange), a, Some(b), MessageKind::Asynchronous, None),
        );
        assert!(
            validate_candidate(&p)
                .unwrap_err()
                .0
                .contains("lifeline_lifetime")
        );
    }
    for operator in [FragmentOperator::Alternative, FragmentOperator::Parallel] {
        let Fixture {
            mut p,
            scenario,
            a,
            b,
            exchange,
            ..
        } = fixture(Layer::Sa);
        let (fragment, left) = scenario_branch(&mut p, scenario, operator);
        let right = additional_branch(&mut p, fragment);
        add_occurrence(
            &mut p,
            left,
            "Delete in one operand",
            message(Some(exchange), a, Some(b), MessageKind::Delete, None),
        );
        add_occurrence(
            &mut p,
            right,
            "Use in another operand",
            message(Some(exchange), a, Some(b), MessageKind::Asynchronous, None),
        );
        if operator == FragmentOperator::Alternative {
            valid(&p);
        } else {
            assert!(
                validate_candidate(&p)
                    .unwrap_err()
                    .0
                    .contains("lifeline_lifetime")
            );
        }
    }
}

#[test]
fn role_lifelines_require_explicit_work_assignment_not_just_a_shared_realizing_entity() {
    let Fixture {
        mut p,
        scenario,
        a,
        b,
        exchange,
        ..
    } = fixture(Layer::Oa);
    let work = p.relations[&exchange].source();
    let target = p.relations[&exchange].target();
    let entity = p
        .add_element(Kind::Entity, Layer::Oa, "Controller", None)
        .unwrap();
    let other = p
        .add_element(Kind::Entity, Layer::Oa, "Recipient", None)
        .unwrap();
    let role = p
        .add_element(Kind::Role, Layer::Oa, "Coordinator", None)
        .unwrap();
    let wrong_role = p
        .add_element(Kind::Role, Layer::Oa, "Unassigned role", None)
        .unwrap();
    let allocation = p.relate(
        RelationKind::Allocation,
        "Controller performs",
        entity,
        work,
    );
    p.relate(
        RelationKind::Allocation,
        "Recipient performs",
        other,
        target,
    );
    p.relate(
        RelationKind::RoleRealization,
        "Controller realizes coordinator",
        entity,
        role,
    );
    p.relate(
        RelationKind::RoleRealization,
        "Controller also realizes unassigned role",
        entity,
        wrong_role,
    );
    p.relate(
        RelationKind::RoleAssignment,
        "Coordinator assignment",
        role,
        work,
    );
    if let Some(SharedBody::Scenario { viewpoint, .. }) =
        p.elements.get_mut(&scenario).unwrap().shared_mut()
    {
        *viewpoint = ScenarioViewpoint::ParticipantInteraction;
    }
    *p.elements.get_mut(&a).unwrap().shared_mut().unwrap() = SharedBody::Lifeline {
        represented: Some(role),
    };
    *p.elements.get_mut(&b).unwrap().shared_mut().unwrap() = SharedBody::Lifeline {
        represented: Some(other),
    };
    valid(&p);
    assert_eq!(
        validation::lifeline_matches_endpoint(&p, a, work),
        Some(true)
    );
    assert_eq!(
        validation::semantic_representation_compatible(&p, wrong_role, work),
        Some(false)
    );
    assert_eq!(
        validation::semantic_representation_compatible(&p, work, work),
        Some(true)
    );
    assert_eq!(
        validation::semantic_representation_compatible(&p, target, work),
        Some(false)
    );
    let port = Id::new_v4();
    p.elements.insert(
        port,
        Element {
            id: port,
            alias: "legacy_controller_port".into(),
            name: "Controller port".into(),
            description: String::new(),
            parent: Some(entity),
            body: ElementBody::shared_in(
                Layer::Oa,
                SharedBody::Port {
                    contract: PortContract::Legacy,
                    legacy: Some(LegacyPortContract {
                        direction: PortDirection::InOut,
                        interface: None,
                    }),
                },
            ),
        },
    );
    assert_eq!(
        validation::semantic_representation_compatible(&p, entity, port),
        Some(true)
    );
    assert_eq!(
        validation::semantic_representation_compatible(&p, role, port),
        Some(true)
    );
    assert_eq!(
        validation::semantic_representation_compatible(&p, other, port),
        Some(false)
    );
    let mut wrong = p.clone();
    *wrong.elements.get_mut(&a).unwrap().shared_mut().unwrap() = SharedBody::Lifeline {
        represented: Some(wrong_role),
    };
    assert!(
        validation::validate(&wrong)
            .iter()
            .any(|i| i.code == "scenario_endpoint" && i.severity == Severity::Error)
    );
    p.relations.remove(&allocation);
    let additional = p
        .add_element(Kind::Entity, Layer::Oa, "Alternative coordinator", None)
        .unwrap();
    p.relate(
        RelationKind::RoleRealization,
        "Another coordinator realization",
        additional,
        role,
    );
    assert_eq!(validation::effective_performer(&p, work), None);
    assert_eq!(
        validation::lifeline_matches_endpoint(&p, a, work),
        Some(true)
    );
    assert_eq!(
        validation::semantic_representation_compatible(&p, entity, work),
        None
    );
    valid(&p);
}

#[test]
fn effective_message_endpoints_are_shared_for_forward_and_reverse_reply_choices() {
    let Fixture {
        mut p,
        a,
        b,
        call,
        reply,
        exchange,
        ..
    } = fixture(Layer::Sa);
    let body = |p: &Project, id| match p.elements[&id].shared().unwrap() {
        SharedBody::Occurrence { body, .. } => body.clone(),
        _ => unreachable!(),
    };
    let (source, target) = p.relations[&exchange].body.endpoints();
    assert_eq!(
        validation::message_endpoints(&p, &body(&p, call)),
        Some((source, target))
    );
    let reversed = validation::message_endpoints(&p, &body(&p, reply)).unwrap();
    assert_eq!(reversed, (target, source));
    assert_eq!(
        validation::lifeline_matches_endpoint(&p, b, reversed.0),
        Some(true)
    );
    assert_eq!(
        validation::lifeline_matches_endpoint(&p, a, reversed.0),
        Some(false)
    );
    let reverse = p.relate(
        RelationKind::FunctionalExchange,
        "Explicit reply exchange",
        target,
        source,
    );
    let explicit = message(Some(reverse), b, Some(a), MessageKind::Reply, Some(call));
    assert_eq!(
        validation::message_endpoints(&p, &explicit),
        Some((target, source))
    );
    assert_eq!(
        validation::message_endpoints(
            &p,
            &message(Some(exchange), b, Some(a), MessageKind::Reply, None)
        ),
        None
    );
    assert_eq!(
        validation::message_endpoints(
            &p,
            &message(
                None,
                b,
                None,
                MessageKind::Timer {
                    expression: "5 s".into()
                },
                None
            )
        ),
        None
    );
}

fn move_into_operand(p: &mut Project, id: Id, operand: Id) {
    let old = p.elements[&id].parent.unwrap();
    p.elements
        .get_mut(&old)
        .unwrap()
        .steps_mut()
        .unwrap()
        .retain(|step| *step != id);
    p.elements.get_mut(&id).unwrap().parent = Some(operand);
    p.elements
        .get_mut(&operand)
        .unwrap()
        .steps_mut()
        .unwrap()
        .push(id);
}

#[test]
fn replies_repeated_without_their_call_warn_in_each_extra_loop_scope() {
    let Fixture {
        mut p,
        scenario,
        call,
        reply,
        ..
    } = fixture(Layer::Sa);
    let (_, outer) = scenario_branch(&mut p, scenario, FragmentOperator::Loop);
    move_into_operand(&mut p, reply, outer);
    valid(&p);
    assert!(
        validation::validate(&p)
            .iter()
            .any(|i| i.element == Some(reply)
                && i.code == "reply_repetition"
                && i.severity == Severity::Warning)
    );
    // Moving both into the same loop gives each iteration its own call and reply.
    move_into_operand(&mut p, call, outer);
    p.elements
        .get_mut(&outer)
        .unwrap()
        .steps_mut()
        .unwrap()
        .swap(0, 1);
    valid(&p);
    assert!(
        !validation::validate(&p)
            .iter()
            .any(|i| i.code == "reply_repetition")
    );
    // An inner loop can still repeat the reply more often than the outer call.
    let (_, inner) = scenario_branch(&mut p, outer, FragmentOperator::Loop);
    move_into_operand(&mut p, reply, inner);
    valid(&p);
    assert_eq!(
        validation::validate(&p)
            .iter()
            .filter(|i| i.code == "reply_repetition")
            .count(),
        1
    );
    move_into_operand(&mut p, call, inner);
    p.elements
        .get_mut(&inner)
        .unwrap()
        .steps_mut()
        .unwrap()
        .swap(0, 1);
    valid(&p);
    assert!(
        !validation::validate(&p)
            .iter()
            .any(|i| i.code == "reply_repetition")
    );
}

#[test]
fn repeated_lifecycle_requires_per_iteration_balance_without_prohibiting_balanced_loops() {
    for starts_with_creation in [false, true] {
        let Fixture {
            mut p,
            scenario,
            a,
            b,
            call,
            reply,
            exchange,
            ..
        } = fixture(Layer::Sa);
        for id in [call, reply] {
            p.elements.remove(&id);
        }
        p.elements
            .get_mut(&scenario)
            .unwrap()
            .steps_mut()
            .unwrap()
            .clear();
        let (_, operand) = scenario_branch(&mut p, scenario, FragmentOperator::Loop);
        let lifecycle = if starts_with_creation {
            add_occurrence(
                &mut p,
                operand,
                "Create each iteration",
                message(Some(exchange), a, Some(b), MessageKind::Create, None),
            )
        } else {
            Id::nil()
        };
        add_occurrence(
            &mut p,
            operand,
            "Use provider",
            message(Some(exchange), a, Some(b), MessageKind::Asynchronous, None),
        );
        let lifecycle = if starts_with_creation {
            lifecycle
        } else {
            add_occurrence(
                &mut p,
                operand,
                "Delete each iteration",
                message(Some(exchange), a, Some(b), MessageKind::Delete, None),
            )
        };
        valid(&p);
        assert!(
            validation::validate(&p)
                .iter()
                .any(|i| i.element == Some(lifecycle)
                    && i.code == "lifeline_repetition"
                    && i.severity == Severity::Warning)
        );
        if starts_with_creation {
            add_occurrence(
                &mut p,
                operand,
                "Complete lifetime",
                message(Some(exchange), a, Some(b), MessageKind::Delete, None),
            );
        } else {
            add_occurrence(
                &mut p,
                operand,
                "Start lifetime",
                message(Some(exchange), a, Some(b), MessageKind::Create, None),
            );
            p.elements
                .get_mut(&operand)
                .unwrap()
                .steps_mut()
                .unwrap()
                .rotate_right(1);
        }
        valid(&p);
        assert!(
            !validation::validate(&p)
                .iter()
                .any(|i| i.code == "lifeline_repetition")
        );
    }
}

#[test]
fn optional_cleanup_does_not_claim_a_repeated_lifetime_is_balanced() {
    let Fixture {
        mut p,
        scenario,
        a,
        b,
        call,
        reply,
        exchange,
        ..
    } = fixture(Layer::Sa);
    for id in [call, reply] {
        p.elements.remove(&id);
    }
    p.elements
        .get_mut(&scenario)
        .unwrap()
        .steps_mut()
        .unwrap()
        .clear();
    let (_, iteration) = scenario_branch(&mut p, scenario, FragmentOperator::Loop);
    let create = add_occurrence(
        &mut p,
        iteration,
        "Create provider",
        message(Some(exchange), a, Some(b), MessageKind::Create, None),
    );
    add_occurrence(
        &mut p,
        iteration,
        "Use provider",
        message(Some(exchange), a, Some(b), MessageKind::Asynchronous, None),
    );
    let (_, cleanup) = scenario_branch(&mut p, iteration, FragmentOperator::Optional);
    add_occurrence(
        &mut p,
        cleanup,
        "Optional deletion",
        message(Some(exchange), a, Some(b), MessageKind::Delete, None),
    );
    valid(&p);
    assert!(
        validation::validate(&p)
            .iter()
            .any(|i| i.element == Some(create) && i.code == "lifeline_repetition")
    );
}