mant-engine 0.11.0

//! Application adapters join a loading report to a pure collection query.
use super::{LoadedDocumentScope, ScopeQueryError, ScopeQueryResult, SearchQuery};
use mant_protocol::{ScopeQueryRequest, ScopeQueryResponse, ScopeQuerySchema, ScopeQueryView};
use mant_query::QueryScopeView;

/// A complete scope query validated before local environment capture.
///
/// Preparation binds the immutable request, not loaded documents or a cached
/// search matcher. The same prepared request may use an explicit host snapshot.
pub struct PreparedScopeQuery<'request> {
    request: &'request ScopeQueryRequest,
}

impl<'request> PreparedScopeQuery<'request> {
    /// Validate roots, traversal and the projection without local IO.
    ///
    /// # Errors
    /// Returns scope, selector or query configuration failures.
    pub fn new(request: &'request ScopeQueryRequest) -> Result<Self, ScopeQueryError> {
        super::validate_scope_query_request(request)?;
        Ok(Self { request })
    }

    /// The immutable scope request whose roots and view were validated together.
    #[must_use]
    pub const fn request(&self) -> &'request ScopeQueryRequest {
        self.request
    }

    /// Load and query against the supplied snapshot using the shared pipeline.
    ///
    /// # Errors
    /// Returns scope loading, mapping or pure query execution failures.
    pub fn execute(
        &self,
        resolver: &crate::DocumentResolver,
    ) -> Result<ScopeQueryResponse, ScopeQueryError> {
        resolver.execute_validated_scope_query(self.request)
    }
}

/// Validate a complete scope query before capturing the local source environment.
///
/// # Errors
///
/// Returns invalid query input, scope-loading failure, or query-execution failure.
pub fn execute_scope_query(
    request: &ScopeQueryRequest,
) -> Result<ScopeQueryResponse, ScopeQueryError> {
    let (prepared, resolver) =
        validated_scope_resolver(request, crate::DocumentResolver::from_system)?;
    prepared.execute(&resolver)
}

fn validated_scope_resolver<T>(
    request: &ScopeQueryRequest,
    factory: impl FnOnce() -> T,
) -> Result<(PreparedScopeQuery<'_>, T), ScopeQueryError> {
    let prepared = PreparedScopeQuery::new(request)?;
    Ok((prepared, factory()))
}

impl crate::DocumentResolver {
    /// Resolve a scope and apply its closed multi-document projection.
    ///
    /// # Errors
    ///
    /// Returns request validation, resolution, or search errors. Ordinary
    /// per-document explanation misses do not fail the aggregate query.
    pub fn execute_scope_query(
        &self,
        request: &ScopeQueryRequest,
    ) -> Result<ScopeQueryResponse, ScopeQueryError> {
        PreparedScopeQuery::new(request)?.execute(self)
    }

    // Both public entry points validate the complete request exactly once before
    // this shared pipeline. Pure query APIs retain their own input validation.
    fn execute_validated_scope_query(
        &self,
        request: &ScopeQueryRequest,
    ) -> Result<ScopeQueryResponse, ScopeQueryError> {
        let loaded = self.resolve_scope(&request.scope)?;
        let result = match &request.view {
            ScopeQueryView::Explain { entry, options } => execute_scope_explain(
                &loaded,
                &mant_protocol::ExplanationQuery {
                    entry: entry.clone(),
                    options: *options,
                },
            )?,
            ScopeQueryView::Search {
                pattern,
                syntax,
                case,
                scope,
                word,
                context_lines,
                limit,
                offset,
            } => execute_scope_search(
                &loaded,
                &SearchQuery {
                    pattern: pattern.clone(),
                    syntax: *syntax,
                    case: *case,
                    scope: *scope,
                    word: *word,
                    context_lines: *context_lines,
                    limit: *limit,
                    offset: *offset,
                },
            )?,
        };
        Ok(ScopeQueryResponse {
            schema: ScopeQuerySchema::V0Dot11,
            scope: loaded.into_parts().0,
            result,
        })
    }
}

pub(super) fn execute_scope_explain(
    loaded: &LoadedDocumentScope,
    query: &mant_protocol::ExplanationQuery,
) -> Result<ScopeQueryResult, ScopeQueryError> {
    let input = QueryScopeView::new(loaded.scope(), loaded.documents())
        .map_err(ScopeQueryError::InvalidLoadedScope)?;
    mant_query::explain_scope(input, query)
        .map(|explanation| ScopeQueryResult::Explain { explanation })
        .map_err(ScopeQueryError::Execution)
}

pub(super) fn execute_scope_search(
    loaded: &LoadedDocumentScope,
    query: &SearchQuery,
) -> Result<ScopeQueryResult, ScopeQueryError> {
    let input = QueryScopeView::new(loaded.scope(), loaded.documents())
        .map_err(ScopeQueryError::InvalidLoadedScope)?;
    mant_query::search_scope(input, query)
        .map(|search| ScopeQueryResult::Search { search })
        .map_err(ScopeQueryError::Execution)
}

#[cfg(test)]
mod tests {
    use std::cell::Cell;

    use super::*;
    use mant_protocol::{
        DocumentScope, DocumentSelector, DocumentTraversal, ExplanationOptions,
        MAX_SEMANTIC_ENTRY_CHARS, ScopeRequestSchema, SearchCase, SearchScope, SearchSyntax,
    };

    fn request() -> ScopeQueryRequest {
        ScopeQueryRequest {
            schema: ScopeRequestSchema::V0Dot11,
            scope: DocumentScope {
                documents: vec![DocumentSelector {
                    selector: "root".to_owned(),
                    source: None,
                    manual_section: None,
                }],
                traversal: DocumentTraversal::default(),
            },
            view: ScopeQueryView::Explain {
                entry: "--help".to_owned(),
                options: ExplanationOptions::default(),
            },
        }
    }

    #[test]
    fn invalid_scope_views_and_roots_never_construct_the_environment() {
        let mut empty_roots = request();
        empty_roots.scope.documents.clear();
        let mut invalid_root = request();
        invalid_root.scope.documents[0].selector = "root\nother".to_owned();
        let mut invalid_entry = request();
        invalid_entry.view = ScopeQueryView::Explain {
            entry: "x".repeat(MAX_SEMANTIC_ENTRY_CHARS + 1),
            options: ExplanationOptions::default(),
        };
        let mut invalid_explanation_budget = request();
        invalid_explanation_budget.view = ScopeQueryView::Explain {
            entry: "--help".to_owned(),
            options: ExplanationOptions {
                content_bytes: 0,
                ..ExplanationOptions::default()
            },
        };
        let mut invalid_search = request();
        invalid_search.view = ScopeQueryView::Search {
            pattern: "needle".to_owned(),
            syntax: SearchSyntax::Literal,
            case: SearchCase::Sensitive,
            scope: SearchScope::Visible,
            word: false,
            context_lines: 101,
            limit: 10,
            offset: 0,
        };
        for invalid in [
            empty_roots,
            invalid_root,
            invalid_entry,
            invalid_explanation_budget,
            invalid_search,
        ] {
            let calls = Cell::new(0);
            let result = validated_scope_resolver(&invalid, || calls.set(calls.get() + 1));
            assert!(result.is_err());
            assert_eq!(
                calls.get(),
                0,
                "validation must precede environment discovery"
            );
        }
    }

    #[test]
    fn valid_scope_constructs_exactly_one_environment_after_validation() {
        let calls = Cell::new(0);
        let request = request();
        let (prepared, value) = validated_scope_resolver(&request, || {
            calls.set(calls.get() + 1);
            "snapshot"
        })
        .unwrap();
        assert_eq!(value, "snapshot");
        assert_eq!(calls.get(), 1);
        assert!(std::ptr::eq(prepared.request(), &raw const request));
    }
}