1 files changed, 66 insertions, 0 deletions
diff --git a/server/src/interaction.rs b/server/src/interaction.rs
new file mode 100644
index 00000000..5f8b0097
--- /dev/null
+++ b/server/src/interaction.rs
@@ -0,0 +1,66 @@
+use crate::{
+    protocol::{ItemIndex, TileIndex},
+    recipes::{Action, Gamedata},
+};
+use std::collections::BTreeSet;
+
+pub enum Out {
+    Take(usize),
+    Put,
+    Produce(ItemIndex),
+    Consume(usize),
+}
+use Out::*;
+
+pub fn interact(
+    data: &Gamedata,
+    edge: bool,
+    tile: TileIndex,
+    items: &[ItemIndex],
+    hand: &Option<ItemIndex>,
+    mut out: impl FnMut(Out),
+) {
+    let mut allowed = BTreeSet::new();
+    for r in &data.recipes {
+        if r.tile == tile {
+            allowed.extend(r.inputs.clone())
+        }
+    }
+    if !edge {
+        return;
+    }
+
+    let mut put_item = None;
+    if let Some(hand) = hand {
+        if allowed.contains(hand) {
+            out(Put);
+            put_item = Some(*hand);
+        }
+    }
+
+    for r in &data.recipes {
+        let ok = r
+            .inputs
+            .iter()
+            .all(|e| items.contains(e) || put_item == Some(*e))
+            && r.inputs.len() == items.len();
+        if ok {
+            match r.action {
+                Action::Passive(_) => todo!(),
+                Action::Active(_) => todo!(),
+                Action::Instant => {
+                    for i in 0..items.len() {
+                        out(Consume(i))
+                    }
+                    for i in &r.outputs {
+                        out(Produce(*i));
+                    }
+                    if !r.outputs.is_empty() {
+                        out(Take(r.outputs.len() - 1));
+                    }
+                }
+                Action::Never => (),
+            }
+        }
+    }
+}