download package (badly)

src/resolve.rs

@@ -0,0 +1,79 @@
+use std::{
+    collections::HashMap,
+    sync::{Arc, RwLock},
+};
+
+use color_eyre::{eyre::bail, Result};
+use node_semver::Range;
+use tracing::{debug, info};
+
+use crate::{download::PackageMeta, NpmClient, WrapErr};
+
+pub struct ResolveContext {
+    meta_cache: Arc<RwLock<HashMap<String, Arc<PackageMeta>>>>,
+    client: NpmClient,
+}
+
+impl ResolveContext {
+    pub fn new() -> Self {
+        Self {
+            meta_cache: Arc::new(Default::default()),
+            client: NpmClient::default(),
+        }
+    }
+
+    async fn get_meta(&self, name: &str) -> Result<Arc<PackageMeta>> {
+        {
+            let cache_read = self.meta_cache.read().unwrap();
+            if let Some(meta) = cache_read.get(name) {
+                return Ok(Arc::clone(meta));
+            }
+        }
+
+        debug!("Fetching package info..");
+
+        // two futures might race here - who cares
+        let meta = self
+            .client
+            .fetch_package_meta(name)
+            .await
+            .wrap_err("fetching package metadata")?;
+
+        let meta = Arc::new(meta);
+
+        let mut cache_write = self.meta_cache.write().unwrap();
+        cache_write.insert(name.to_owned(), Arc::clone(&meta));
+
+        Ok(meta)
+    }
+
+    #[tracing::instrument(skip(self, requested_version), fields(requested_version = %requested_version))]
+    pub async fn download_package_and_deps(
+        &self,
+        name: &str,
+        requested_version: &Range,
+    ) -> Result<()> {
+        let meta = self.get_meta(name).await?;
+
+        info!(versions = ?meta.versions.keys().map(ToString::to_string).collect::<Vec<_>>());
+
+        let chosen = meta
+            .versions
+            .keys()
+            .filter(|version| version.satisfies(requested_version))
+            .max();
+
+        match chosen {
+            Some(version) => {
+                info!(%version, "Found version");
+                self.client
+                    .download_package(name, &meta.versions[version].dist.tarball)
+                    .await
+                    .wrap_err("downloading package")?;
+            }
+            None => bail!("could not find matching version for '{requested_version}'"),
+        }
+
+        Ok(())
+    }
+}