teaql_runtime/repository/

relation.rs

use std::collections::BTreeMap;
use std::slice;

use teaql_core::{
    Aggregate, Expr, ObjectGroupBy, Record, RelationAggregate, RelationLoad, SelectQuery, Value,
};
use teaql_sql::SqlDialect;

use crate::{RepositoryError, RuntimeError};

use super::{QueryExecutor, RelationLoadPlan, ResolvedRepository, helpers::*};

impl<'a, D, E> ResolvedRepository<'a, D, E>
where
    D: SqlDialect,
    E: QueryExecutor,
{
    pub fn relation_loads(&self) -> Vec<String> {
        self.behavior()
            .map(|behavior| behavior.relation_loads(self.repository.metadata.context))
            .unwrap_or_default()
    }

    pub fn relation_plans(&self) -> Result<Vec<RelationLoadPlan>, RuntimeError> {
        self.build_relation_plans(&self.entity, &self.relation_loads())
    }

    pub fn relation_query(
        &self,
        relation_name: &str,
        parent_rows: &[Record],
    ) -> Result<SelectQuery, RuntimeError> {
        let plan = self
            .relation_plans()?
            .into_iter()
            .find(|plan| plan.relation_name == relation_name)
            .ok_or_else(|| RuntimeError::MissingRelation {
                entity: self.entity.clone(),
                relation: relation_name.to_owned(),
            })?;
        Ok(self.query_for_plan(&plan, parent_rows))
    }

    pub fn enhance_relations(
        &self,
        parent_rows: &mut [Record],
    ) -> Result<(), RepositoryError<E::Error>> {
        let plans = self.relation_plans().map_err(RepositoryError::Runtime)?;
        for plan in plans {
            self.enhance_plan(parent_rows, &plan)?;
        }
        Ok(())
    }

    pub fn enhance_query_relations(
        &self,
        parent_rows: &mut [Record],
        query: &SelectQuery,
    ) -> Result<(), RepositoryError<E::Error>> {
        let plans = self
            .build_relation_plans_from_loads(&query.entity, &query.relations)
            .map_err(RepositoryError::Runtime)?;
        for plan in plans {
            self.enhance_plan(parent_rows, &plan)?;
        }
        Ok(())
    }

    pub fn enhance_relation_aggregates(
        &self,
        parent_rows: &mut [Record],
        relation_aggregates: &[RelationAggregate],
        parent_cache_options: Option<teaql_core::AggregationCacheOptions>,
    ) -> Result<(), RepositoryError<E::Error>> {
        for aggregate in relation_aggregates {
            self.enhance_relation_aggregate(parent_rows, aggregate, parent_cache_options)?;
        }
        Ok(())
    }

    pub fn enhance_object_group_bys(
        &self,
        rows: &mut [Record],
        object_group_bys: &[ObjectGroupBy],
    ) -> Result<(), RepositoryError<E::Error>> {
        for group_by in object_group_bys {
            let ids = rows
                .iter()
                .filter_map(|row| row.get(&group_by.storage_field).cloned())
                .collect::<Vec<_>>();
            if ids.is_empty() {
                continue;
            }
            let mut query = group_by.query.clone();
            ensure_projection(&mut query, "id");
            query = query.and_filter(Expr::in_list("id", ids));
            let object_rows = self
                .scoped_repository(query.entity.clone())
                .fetch_all(&query)?
                .into_iter()
                .filter_map(|row| {
                    row.get("id")
                        .cloned()
                        .map(|id| (graph_identity_key(&id), row))
                })
                .collect::<BTreeMap<_, _>>();
            for row in rows.iter_mut() {
                if let Some(key) = row.get(&group_by.storage_field).map(graph_identity_key) {
                    let value = object_rows
                        .get(&key)
                        .cloned()
                        .map(Value::object)
                        .unwrap_or(Value::Null);
                    row.insert(group_by.property_name.clone(), value);
                }
            }
        }
        Ok(())
    }

    pub fn enhance_child_queries(
        &self,
        rows: &mut [Record],
        child_queries: &[SelectQuery],
    ) -> Result<(), RepositoryError<E::Error>> {
        for child_query in child_queries {
            let ids = rows
                .iter()
                .filter_map(|row| row.get("id").cloned())
                .collect::<Vec<_>>();
            if ids.is_empty() {
                continue;
            }
            let mut query = child_query.clone();
            ensure_projection(&mut query, "id");
            query = query.and_filter(Expr::in_list("id", ids));
            let child_rows = self
                .scoped_repository(query.entity.clone())
                .fetch_all(&query)?
                .into_iter()
                .filter_map(|row| {
                    row.get("id")
                        .cloned()
                        .map(|id| (graph_identity_key(&id), row))
                })
                .collect::<BTreeMap<_, _>>();
            for row in rows.iter_mut() {
                if let Some(key) = row.get("id").map(graph_identity_key) {
                    if let Some(child) = child_rows.get(&key) {
                        row.extend(child.clone());
                    }
                }
            }
        }
        Ok(())
    }

    fn enhance_relation_aggregate(
        &self,
        parent_rows: &mut [Record],
        aggregate: &RelationAggregate,
        parent_cache_options: Option<teaql_core::AggregationCacheOptions>,
    ) -> Result<(), RepositoryError<E::Error>> {
        let plan = self
            .build_relation_plans_from_loads(
                &self.entity,
                &[RelationLoad::with_query(
                    aggregate.relation_name.clone(),
                    aggregate.query.clone(),
                )],
            )
            .map_err(RepositoryError::Runtime)?
            .into_iter()
            .next()
            .ok_or_else(|| {
                RepositoryError::Runtime(RuntimeError::MissingRelation {
                    entity: self.entity.clone(),
                    relation: aggregate.relation_name.clone(),
                })
            })?;

        let ids = parent_rows
            .iter()
            .filter_map(|row| row.get(&plan.local_key).cloned())
            .collect::<Vec<_>>();
        if ids.is_empty() {
            attach_empty_relation_aggregate(parent_rows, &aggregate.alias, aggregate.single_result);
            return Ok(());
        }

        let child_repo = self.scoped_repository(plan.target_entity.clone());
        let mut query = aggregate.query.clone();
        query.entity = plan.target_entity.clone();
        if query.aggregation_cache.is_none() {
            if let Some(options) = parent_cache_options.filter(|options| options.propagate) {
                query.aggregation_cache = Some(teaql_core::AggregationCacheOptions::enabled(
                    options.propagate_cache_expired_millis,
                ));
            }
        }
        query.projection.clear();
        query.expr_projection.clear();
        query.order_by.clear();
        query.slice = None;
        query.relations.clear();
        if query.aggregates.is_empty() {
            let alias = if aggregate.single_result {
                aggregate.alias.clone()
            } else {
                "count".to_owned()
            };
            query = query.aggregate(Aggregate::count(alias));
        }
        if !query
            .group_by
            .iter()
            .any(|field| field == &plan.foreign_key)
        {
            query = query.group_by(plan.foreign_key.clone());
        }
        query = query.and_filter(Expr::in_list(plan.foreign_key.clone(), ids));

        let mut aggregate_rows = child_repo.fetch_all(&query)?;
        let foreign_key_column = self
            .repository
            .metadata
            .context
            .entity(&plan.target_entity)
            .and_then(|descriptor| {
                descriptor
                    .properties
                    .iter()
                    .find(|property| property.name == plan.foreign_key)
                    .map(|property| property.column_name.clone())
            });
        if let Some(foreign_key_column) =
            foreign_key_column.filter(|column| column != &plan.foreign_key)
        {
            for row in &mut aggregate_rows {
                if !row.contains_key(&plan.foreign_key) {
                    if let Some(value) = row.remove(&foreign_key_column) {
                        row.insert(plan.foreign_key.clone(), value);
                    }
                }
            }
        }
        attach_relation_aggregate_rows(parent_rows, &plan, aggregate, aggregate_rows);
        Ok(())
    }

    fn build_relation_plans(
        &self,
        entity: &str,
        loads: &[String],
    ) -> Result<Vec<RelationLoadPlan>, RuntimeError> {
        let descriptor = self.repository.metadata.context.require_entity(entity)?;
        let mut grouped: BTreeMap<String, Vec<String>> = BTreeMap::new();
        for load in loads {
            if let Some((head, tail)) = load.split_once('.') {
                grouped
                    .entry(head.to_owned())
                    .or_default()
                    .push(tail.to_owned());
            } else {
                grouped.entry(load.clone()).or_default();
            }
        }

        grouped
            .into_iter()
            .map(|(name, child_loads)| {
                let relation = descriptor.relation_by_name(&name).ok_or_else(|| {
                    RuntimeError::MissingRelation {
                        entity: entity.to_owned(),
                        relation: name.clone(),
                    }
                })?;
                let child_repo = self.scoped_repository(relation.target_entity.clone());
                let children =
                    child_repo.build_relation_plans(&relation.target_entity, &child_loads)?;
                Ok(RelationLoadPlan {
                    parent_entity: entity.to_owned(),
                    relation_name: relation.name.clone(),
                    path: relation.name.clone(),
                    target_entity: relation.target_entity.clone(),
                    local_key: relation.local_key.clone(),
                    foreign_key: relation.foreign_key.clone(),
                    many: relation.many,
                    query: None,
                    children,
                })
            })
            .collect()
    }

    fn build_relation_plans_from_loads(
        &self,
        entity: &str,
        loads: &[RelationLoad],
    ) -> Result<Vec<RelationLoadPlan>, RuntimeError> {
        let descriptor = self.repository.metadata.context.require_entity(entity)?;
        loads
            .iter()
            .map(|load| {
                let relation = descriptor.relation_by_name(&load.name).ok_or_else(|| {
                    RuntimeError::MissingRelation {
                        entity: entity.to_owned(),
                        relation: load.name.clone(),
                    }
                })?;
                let relation_query = load.query.as_deref().cloned();
                let child_loads = relation_query
                    .as_ref()
                    .map(|query| query.relations.as_slice())
                    .unwrap_or_default();
                let child_repo = self.scoped_repository(relation.target_entity.clone());
                let children = child_repo
                    .build_relation_plans_from_loads(&relation.target_entity, child_loads)?;
                Ok(RelationLoadPlan {
                    parent_entity: entity.to_owned(),
                    relation_name: relation.name.clone(),
                    path: relation.name.clone(),
                    target_entity: relation.target_entity.clone(),
                    local_key: relation.local_key.clone(),
                    foreign_key: relation.foreign_key.clone(),
                    many: relation.many,
                    query: relation_query,
                    children,
                })
            })
            .collect()
    }
    fn enhance_plan(
        &self,
        parent_rows: &mut [Record],
        plan: &RelationLoadPlan,
    ) -> Result<(), RepositoryError<E::Error>> {
        let child_repo = self.scoped_repository(plan.target_entity.clone());
        let query = self.query_for_plan(plan, parent_rows);
        let child_rows = child_repo.fetch_all(&query)?;
        self.attach_relation_rows(parent_rows, plan, child_rows);

        if !plan.children.is_empty() {
            for parent in parent_rows.iter_mut() {
                match parent.get_mut(&plan.relation_name) {
                    Some(Value::Object(child)) => {
                        child_repo.enhance_child_record(child, &plan.children)?;
                    }
                    Some(Value::List(values)) => {
                        for value in values.iter_mut() {
                            if let Value::Object(child) = value {
                                child_repo.enhance_child_record(child, &plan.children)?;
                            }
                        }
                    }
                    _ => {}
                }
            }
        }
        Ok(())
    }

    fn enhance_child_record(
        &self,
        child: &mut Record,
        plans: &[RelationLoadPlan],
    ) -> Result<(), RepositoryError<E::Error>> {
        for plan in plans {
            self.enhance_plan(slice::from_mut(child), plan)?;
        }
        Ok(())
    }

    fn query_for_plan(&self, plan: &RelationLoadPlan, parent_rows: &[Record]) -> SelectQuery {
        let ids = parent_rows
            .iter()
            .filter_map(|row| row.get(&plan.local_key).cloned())
            .collect::<Vec<_>>();

        let mut query = plan
            .query
            .clone()
            .unwrap_or_else(|| SelectQuery::new(plan.target_entity.clone()));
        query.entity = plan.target_entity.clone();
        ensure_projection(&mut query, &plan.foreign_key);
        for child in &plan.children {
            ensure_projection(&mut query, &child.local_key);
        }
        if !ids.is_empty() {
            query = query.and_filter(Expr::in_list(plan.foreign_key.clone(), ids));
        }
        query
    }

    fn attach_relation_rows(
        &self,
        parent_rows: &mut [Record],
        plan: &RelationLoadPlan,
        child_rows: Vec<Record>,
    ) {
        let inverse_relation = self
            .repository
            .metadata
            .context
            .entity(&plan.target_entity)
            .and_then(|descriptor| {
                descriptor.relations.iter().find(|relation| {
                    relation.target_entity == plan.parent_entity
                        && relation.local_key == plan.foreign_key
                        && relation.foreign_key == plan.local_key
                })
            })
            .map(|relation| relation.name.clone());

        let mut buckets: BTreeMap<String, Vec<Record>> = BTreeMap::new();
        for child in child_rows {
            if let Some(key) = child.get(&plan.foreign_key) {
                buckets
                    .entry(graph_identity_key(key))
                    .or_default()
                    .push(child);
            }
        }

        for parent in parent_rows.iter_mut() {
            let Some(local_value) = parent.get(&plan.local_key) else {
                continue;
            };
            let bucket_key = graph_identity_key(local_value);
            let related = buckets.get(&bucket_key).cloned().unwrap_or_default();
            let related = if let Some(inverse_relation) = &inverse_relation {
                let mut parent_object = parent.clone();
                parent_object.remove(&plan.relation_name);
                related
                    .into_iter()
                    .map(|mut child| {
                        child
                            .entry(inverse_relation.clone())
                            .or_insert_with(|| Value::object(parent_object.clone()));
                        child
                    })
                    .collect::<Vec<_>>()
            } else {
                related
            };
            if plan.many {
                parent.insert(
                    plan.relation_name.clone(),
                    Value::List(related.into_iter().map(Value::object).collect()),
                );
            } else {
                let value = related
                    .into_iter()
                    .next()
                    .map(Value::object)
                    .unwrap_or(Value::Null);
                parent.insert(plan.relation_name.clone(), value);
            }
        }
    }
}