/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

use std::collections::{BTreeSet, HashMap};

use crate::*;
use anyhow::{bail, Result};

pub type MetadataGroupMap = HashMap<String, MetadataGroup>;

// Create empty metadata groups based on the metadata items.
pub fn create_metadata_groups(items: &[Metadata]) -> MetadataGroupMap {
    // Map crate names to MetadataGroup instances
    items
        .iter()
        .filter_map(|i| match i {
            Metadata::Namespace(namespace) => {
                let group = MetadataGroup {
                    namespace: namespace.clone(),
                    namespace_docstring: None,
                    items: BTreeSet::new(),
                };
                Some((namespace.crate_name.clone(), group))
            }
            Metadata::UdlFile(udl) => {
                let namespace = NamespaceMetadata {
                    crate_name: udl.module_path.clone(),
                    name: udl.namespace.clone(),
                };
                let group = MetadataGroup {
                    namespace,
                    namespace_docstring: None,
                    items: BTreeSet::new(),
                };
                Some((udl.module_path.clone(), group))
            }
            _ => None,
        })
        .collect::<HashMap<_, _>>()
}

/// Consume the items into the previously created metadata groups.
pub fn group_metadata(group_map: &mut MetadataGroupMap, items: Vec<Metadata>) -> Result<()> {
    for item in items {
        if matches!(&item, Metadata::Namespace(_)) {
            continue;
        }

        let crate_name = crate_name(item.module_path()).to_owned();
        let group = match group_map.get_mut(&crate_name) {
            Some(ns) => ns,
            None => bail!("Unknown namespace for {item:?} ({crate_name})"),
        };
        if group.items.contains(&item) {
            bail!("Duplicate metadata item: {item:?}");
        }
        group.add_item(item);
    }
    Ok(())
}

#[derive(Debug)]
pub struct MetadataGroup {
    pub namespace: NamespaceMetadata,
    pub namespace_docstring: Option<String>,
    pub items: BTreeSet<Metadata>,
}

impl MetadataGroup {
    pub fn add_item(&mut self, item: Metadata) {
        self.items.insert(item);
    }
}