1 files changed, 58 insertions, 0 deletions
diff --git a/client/src/download.rs b/client/src/download.rs
new file mode 100644
index 0000000..256c25c
--- /dev/null
+++ b/client/src/download.rs
@@ -0,0 +1,58 @@
+use anyhow::Result;
+use std::collections::HashSet;
+use weareshared::{
+    packets::{Packet, Resource},
+    store::{ResourceStore, sha256},
+};
+
+use crate::network::Network;
+
+pub struct Downloader {
+    have: HashSet<Resource>,
+    need: HashSet<Resource>,
+    pending: HashSet<Resource>,
+    store: ResourceStore,
+}
+
+impl Downloader {
+    pub fn new(store: ResourceStore) -> Self {
+        Self {
+            have: HashSet::new(),
+            need: HashSet::new(),
+            pending: HashSet::new(),
+            store,
+        }
+    }
+    pub fn try_get(&mut self, hash: Resource) -> Result<Option<Vec<u8>>> {
+        if self.have.contains(&hash) {
+            self.store.get(hash)
+        } else {
+            self.need.insert(hash);
+            Ok(None)
+        }
+    }
+    pub fn packet(&mut self, p: &Packet) -> Result<()> {
+        match p {
+            Packet::RespondResource(d) => {
+                let key = Resource(sha256(&d));
+                self.store.set(&d)?;
+                self.need.remove(&key);
+                self.pending.remove(&key);
+                self.have.insert(key);
+            }
+            _ => (),
+        }
+        Ok(())
+    }
+    pub fn update(&mut self, network: &mut Network) {
+        let mut new_pending = Vec::new();
+        for n in self.need.difference(&self.pending) {
+            network
+                .packet_send
+                .send(Packet::RequestResource(*n))
+                .unwrap();
+            new_pending.push(*n);
+        }
+        self.pending.extend(new_pending);
+    }
+}