//! Advisory presence of explicit behavior evidence, never inferred execution.
use super::*;

#[derive(Default)]
pub(super) struct Index {
    pub grouping: BTreeSet<Id>,
    pub supported_capabilities: BTreeSet<Id>,
    contextual_capabilities: BTreeSet<Id>,
    supported_missions: BTreeSet<Id>,
}

impl Index {
    pub fn new(p: &Project) -> Self {
        let mut index = Self::default();
        for element in p.elements.values() {
            if let Some(parent) = element.parent.and_then(|id| p.elements.get(&id))
                && parent.kind() == element.kind()
                && parent.layer() == element.layer()
            {
                index.grouping.insert(parent.id);
            }
            if let Some(SharedBody::Scenario {
                context: Some(id), ..
            }) = element.shared()
                && p.elements.get(id).is_some_and(|context| {
                    matches!(context.kind(), Kind::Capability | Kind::SystemCapability)
                        && context.layer() == element.layer()
                })
            {
                index.contextual_capabilities.insert(*id);
                index.supported_capabilities.insert(*id);
            }
        }
        for relation in p.relations.values() {
            let (Some(source), Some(target)) = (
                p.elements.get(&relation.source()),
                p.elements.get(&relation.target()),
            ) else {
                continue;
            };
            if source.layer() != target.layer()
                || !relation.kind().permits(source.kind(), target.kind())
            {
                continue;
            }
            match relation.kind() {
                RelationKind::CapabilityInvolvement => {
                    index.supported_capabilities.insert(target.id);
                }
                RelationKind::ChainInvolvement => {
                    index.supported_capabilities.insert(target.id);
                    index.contextual_capabilities.insert(target.id);
                }
                RelationKind::MissionCapability => {
                    index.supported_missions.insert(source.id);
                }
                _ => {}
            }
        }
        index
    }

    pub fn validate(&self, p: &Project, out: &mut Vec<Issue>) {
        let (work, exchanges) = included_evidence(p);
        for element in p.elements.values() {
            if element.kind().is_work()
                && !self.grouping.contains(&element.id)
                && !work.contains(&element.id)
            {
                warning(
                    out,
                    element.id,
                    "work_without_behavior_context",
                    "",
                    "Include this leaf activity/function in a process/chain or scenario through a work action or exchange occurrence.",
                );
            }
            if matches!(element.kind(), Kind::OperationalMission | Kind::Mission)
                && !self.supported_missions.contains(&element.id)
            {
                warning(
                    out,
                    element.id,
                    "mission_without_capability",
                    "",
                    "Connect this mission to a capability that delivers it.",
                );
            }
            if matches!(element.kind(), Kind::Capability | Kind::SystemCapability)
                && !self.grouping.contains(&element.id)
                && self.supported_capabilities.contains(&element.id)
                && !self.contextual_capabilities.contains(&element.id)
            {
                warning(
                    out,
                    element.id,
                    "capability_without_behavior_context",
                    "",
                    "Add an explicit behavior context: link a process/chain with Chain involvement, or set a scenario's Context to this capability.",
                );
            }
        }
        for relation in p.relations.values().filter(|r| work_exchange(r.kind())) {
            let mut non_leaf = false;
            for (field, endpoint) in [("source", relation.source()), ("target", relation.target())]
            {
                if self.grouping.contains(&endpoint) {
                    non_leaf = true;
                    warning(
                        out,
                        relation.id,
                        "non_leaf_work_exchange",
                        field,
                        "Choose the leaf activity/function responsible for this exchange; keep any typed port owned by that function.",
                    );
                }
            }
            if !non_leaf && !exchanges.contains(&relation.id) {
                warning(
                    out,
                    relation.id,
                    "exchange_without_behavior_context",
                    "",
                    "Use this exchange in a process/chain or scenario.",
                );
            }
        }
    }
}

fn work_exchange(kind: RelationKind) -> bool {
    matches!(
        kind,
        RelationKind::Interaction | RelationKind::FunctionalExchange
    )
}

/// Only ordered, owned occurrences contribute. Each identity is visited once,
/// including reused containers; this remains bounded even on malformed drafts.
fn included_evidence(p: &Project) -> (BTreeSet<Id>, BTreeSet<Id>) {
    let crate::view_options::BehaviorEvidence { work, exchanges } =
        crate::view_options::all_behavior_evidence(p);
    (work, exchanges)
}
#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn malformed_self_reuse_is_bounded_even_without_structural_gate() {
        let mut p = Project::empty();
        let scenario = p
            .add_element(Kind::Scenario, Layer::Oa, "Self reuse", None)
            .unwrap();
        let occurrence = p
            .add_element(Kind::Occurrence, Layer::Oa, "Cycle", Some(scenario))
            .unwrap();
        if let Some(SharedBody::Occurrence { body, .. }) =
            p.elements.get_mut(&occurrence).unwrap().shared_mut()
        {
            *body = OccurrenceBody::ScenarioUse {
                scenario: Some(scenario),
                bindings: vec![],
            };
        }
        p.elements
            .get_mut(&scenario)
            .unwrap()
            .steps_mut()
            .unwrap()
            .push(occurrence);
        assert_eq!(included_evidence(&p), (BTreeSet::new(), BTreeSet::new()));
    }
}