components-rs 0.1.1

use std::collections::HashMap;
use std::path::{Path, PathBuf};

use crate::discovery::node_modules;
use crate::discovery::package_json::{self, PackageJson, get_module_iri};
use crate::error::Result;
use crate::fs::Fs;

/// Represents the fully-resolved state of all discoverable CJS modules.
/// Mirrors the TypeScript `IModuleState`.
#[derive(Debug, Clone)]
pub struct ModuleState {
    /// Path to the root project.
    pub main_module_path: PathBuf,
    /// All ancestor paths used for node_modules searching.
    pub node_module_import_paths: Vec<PathBuf>,
    /// All discovered node module directories.
    pub node_module_paths: Vec<PathBuf>,
    /// Parsed package.json by module path.
    pub package_jsons: HashMap<PathBuf, PackageJson>,
    /// Component modules: module IRI → (major version → absolute components.jsonld path).
    pub component_modules: HashMap<String, HashMap<u64, PathBuf>>,
    /// Contexts: context IRI → parsed JSON content of context file.
    pub contexts: HashMap<String, serde_json::Value>,
    /// Import paths: IRI prefix → absolute local directory path.
    pub import_paths: HashMap<String, PathBuf>,
}

impl ModuleState {
    /// Build the full module state from a project root path.
    pub async fn build(fs: &dyn Fs, main_module_path: &Path) -> Result<Self> {
        let main_module_path = fs
            .canonicalize(main_module_path)
            .await?;

        tracing::info!("Building module state from: {}", main_module_path.display());

        let node_module_import_paths =
            node_modules::build_node_module_import_paths(&main_module_path);
        let node_module_paths =
            node_modules::build_node_module_paths(fs, &node_module_import_paths).await?;

        tracing::info!("Discovered {} node module paths", node_module_paths.len());

        let mut package_jsons = package_json::read_package_jsons(fs, &node_module_paths).await?;
        package_json::preprocess_all(fs, &mut package_jsons).await;

        let component_modules = build_component_modules(&package_jsons)?;
        let contexts = build_component_contexts(fs, &package_jsons).await?;
        let import_paths = build_component_import_paths(&package_jsons)?;

        tracing::info!(
            "Found {} component modules, {} contexts, {} import paths",
            component_modules.len(),
            contexts.len(),
            import_paths.len()
        );

        Ok(ModuleState {
            main_module_path,
            node_module_import_paths,
            node_module_paths,
            package_jsons,
            component_modules,
            contexts,
            import_paths,
        })
    }
}

/// Build the component modules map: module IRI → (major version → absolute path to components.jsonld).
fn build_component_modules(
    package_jsons: &HashMap<PathBuf, PackageJson>,
) -> Result<HashMap<String, HashMap<u64, PathBuf>>> {
    let mut modules: HashMap<String, HashMap<u64, PathBuf>> = HashMap::new();
    let mut versions: HashMap<String, HashMap<u64, semver::Version>> = HashMap::new();

    for (module_path, pkg) in package_jsons {
        let Some(module_iri) = get_module_iri(pkg) else {
            continue;
        };
        let Some(components_rel) = &pkg.lsd_components else {
            continue;
        };
        let Ok(version) = semver::Version::parse(&pkg.version) else {
            continue;
        };

        let major = version.major;
        let absolute_path = module_path.join(components_rel);

        let entry = modules.entry(module_iri.clone()).or_default();
        let ver_entry = versions.entry(module_iri.clone()).or_default();

        if let Some(existing_ver) = ver_entry.get(&major) {
            if &version > existing_ver {
                entry.insert(major, absolute_path);
                ver_entry.insert(major, version);
            }
        } else {
            entry.insert(major, absolute_path);
            ver_entry.insert(major, version);
        }
    }

    Ok(modules)
}

/// Build the contexts map: context IRI → parsed JSON content.
async fn build_component_contexts(
    fs: &dyn Fs,
    package_jsons: &HashMap<PathBuf, PackageJson>,
) -> Result<HashMap<String, serde_json::Value>> {
    let mut contexts: HashMap<String, serde_json::Value> = HashMap::new();
    let mut ctx_versions: HashMap<String, semver::Version> = HashMap::new();

    for (module_path, pkg) in package_jsons {
        let Some(ctx_map) = &pkg.lsd_contexts else {
            continue;
        };
        let Ok(version) = semver::Version::parse(&pkg.version) else {
            continue;
        };

        for (ctx_iri, rel_path) in ctx_map {
            let file_path = module_path.join(rel_path);

            // Check version priority
            if let Some(existing_ver) = ctx_versions.get(ctx_iri) {
                if &version <= existing_ver {
                    continue;
                }
            }

            match fs.read_to_string(&file_path).await {
                Ok(contents) => match serde_json::from_str(&contents) {
                    Ok(parsed) => {
                        contexts.insert(ctx_iri.clone(), parsed);
                        ctx_versions.insert(ctx_iri.clone(), version.clone());
                    }
                    Err(e) => {
                        tracing::warn!(
                            "Failed to parse context file {}: {}",
                            file_path.display(),
                            e
                        );
                    }
                },
                Err(e) => {
                    tracing::warn!(
                        "Failed to read context file {}: {}",
                        file_path.display(),
                        e
                    );
                }
            }
        }
    }

    Ok(contexts)
}

/// Build the import paths map: IRI prefix → absolute directory path.
fn build_component_import_paths(
    package_jsons: &HashMap<PathBuf, PackageJson>,
) -> Result<HashMap<String, PathBuf>> {
    let mut import_paths: HashMap<String, PathBuf> = HashMap::new();
    let mut path_versions: HashMap<String, semver::Version> = HashMap::new();

    for (module_path, pkg) in package_jsons {
        let Some(ip_map) = &pkg.lsd_import_paths else {
            continue;
        };
        let Ok(version) = semver::Version::parse(&pkg.version) else {
            continue;
        };

        for (iri_prefix, rel_path) in ip_map {
            let abs_path = module_path.join(rel_path);

            if let Some(existing_ver) = path_versions.get(iri_prefix) {
                if &version <= existing_ver {
                    continue;
                }
            }

            import_paths.insert(iri_prefix.clone(), abs_path);
            path_versions.insert(iri_prefix.clone(), version.clone());
        }
    }

    Ok(import_paths)
}