ggen-domain 5.1.3

//! Compose multiple ontologies into unified schema
//!
//! This module handles:
//! - Loading multiple ontology schemas
//! - Merging strategies (union, intersection, custom)
//! - Resolving namespace conflicts
//! - Validating composition compatibility
//! - Generating unified code

use ggen_core::ontology_pack::OntologySchema;
use ggen_utils::error::Result;
use std::path::PathBuf;

/// Input for ontology composition
#[derive(Debug, Clone)]
pub struct ComposeInput {
    /// Pack IDs to compose (e.g., ["schema-org", "foaf"])
    pub pack_ids: Vec<String>,

    /// Merge strategy (union, intersection)
    pub merge_strategy: MergeStrategy,

    /// Output language
    pub language: String,

    /// Output directory
    pub output_dir: PathBuf,
}

/// Merge strategy for composition
#[derive(Debug, Clone, serde::Serialize)]
pub enum MergeStrategy {
    /// Union - include all classes and properties
    Union,
    /// Intersection - only common elements
    Intersection,
}

/// Output from composition
#[derive(Debug, Clone, serde::Serialize)]
pub struct ComposeOutput {
    /// Composed schema
    pub schema: OntologySchema,

    /// Files generated
    pub files_generated: Vec<PathBuf>,

    /// Composition statistics
    pub stats: CompositionStats,
}

/// Statistics about composition
#[derive(Debug, Clone, serde::Serialize)]
pub struct CompositionStats {
    /// Number of ontologies composed
    pub ontologies_composed: usize,

    /// Total classes in result
    pub total_classes: usize,

    /// Total properties in result
    pub total_properties: usize,

    /// Number of conflicts resolved
    pub conflicts_resolved: usize,
}

/// Execute ontology composition
pub async fn execute_compose(input: &ComposeInput) -> Result<ComposeOutput> {
    // 1. Load all ontologies
    let mut schemas = Vec::new();

    for pack_id in &input.pack_ids {
        // Note: Schema loading from pack to be implemented
        schemas.push(OntologySchema {
            namespace: format!("https://{}", pack_id),
            classes: vec![],
            properties: vec![],
            relationships: vec![],
            prefixes: Default::default(),
        });
    }

    // 2. Apply merge strategy
    let merged = match input.merge_strategy {
        MergeStrategy::Union => merge_union(schemas),
        MergeStrategy::Intersection => merge_intersection(schemas),
    }?;

    // 3. Generate unified code
    tokio::fs::create_dir_all(&input.output_dir).await?;

    let stats = CompositionStats {
        ontologies_composed: input.pack_ids.len(),
        total_classes: merged.classes.len(),
        total_properties: merged.properties.len(),
        conflicts_resolved: 0,
    };

    Ok(ComposeOutput {
        schema: merged,
        files_generated: vec![],
        stats,
    })
}

fn merge_union(schemas: Vec<OntologySchema>) -> Result<OntologySchema> {
    let mut result = OntologySchema {
        namespace: "composed".to_string(),
        classes: vec![],
        properties: vec![],
        relationships: vec![],
        prefixes: Default::default(),
    };

    for schema in schemas {
        result.classes.extend(schema.classes);
        result.properties.extend(schema.properties);
        result.relationships.extend(schema.relationships);
        result.prefixes.extend(schema.prefixes);
    }

    Ok(result)
}

fn merge_intersection(schemas: Vec<OntologySchema>) -> Result<OntologySchema> {
    // Note: Intersection merge to be implemented (currently uses union)
    merge_union(schemas)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_merge_union() {
        let schema1 = OntologySchema {
            namespace: "schema1".to_string(),
            classes: vec![],
            properties: vec![],
            relationships: vec![],
            prefixes: Default::default(),
        };

        let schema2 = OntologySchema {
            namespace: "schema2".to_string(),
            classes: vec![],
            properties: vec![],
            relationships: vec![],
            prefixes: Default::default(),
        };

        let result = merge_union(vec![schema1, schema2]).unwrap();
        assert_eq!(result.namespace, "composed");
    }
}