1 files changed, 50 insertions, 0 deletions
diff --git a/tools/claim.js b/tools/claim.js
new file mode 100644
index 0000000..2e568f2
--- /dev/null
+++ b/tools/claim.js
@@ -0,0 +1,50 @@
+// A tool to manage land claims (i.e. a certain Space is delegated to only call a specific `call()` if a tileUpdate occurs differing from that Space)
+
+const ms = require('../utils/measurespace');
+const ri = require('../utils/rectintersect');
+const vec = require('../utils/vec');
+const comb = require('../utils/comb');
+
+module.exports = function(catchall){
+  // socket is a Socket() object to declare the hook on.
+  // catchall is called if tileUpdate occurs w/ no relevant claim on a part.
+  let claims = {};
+  let claimId = 0;
+  this.claim = function(space, call, excl=true){
+    // `space` is Space obj; `call` is callback function
+    // `exclusive` sets whether this callback will prevent other (incl. catchall) functions from seeing the space. Cannot be used with an exclusive callback, and does not guarantee order.
+    // If exclusive claim intersects another claim, behavior undefined.
+    claimId++;
+    claims[claimId] = {'space':space, 'call':call, 'excl':excl, 'area':ms(space)}
+    return claimId;
+  }
+
+  this.unclaim = function(id){
+    delete claims[id];
+  }
+
+  this.handle = function(send, tilespaces, locs){
+    // Because usually tilespaces is small, the inefficiency of an O(nk) rect match is acceptable
+    for (let id in claims){
+      claim = claims[id];
+      diffspace = {};
+      rellocs = [];
+      for (let loc of locs){
+        let tile = tilespaces[loc];
+        if (ri(claim.area, [vec.tileToChar(loc), vec.tileToChar(vec.add(loc, [1,1]))])){
+          let diff = claim.space.copy();
+          diff.comb(tile, comb.unmask);
+          rellocs.push(loc);
+          diffspace[loc] = diff;
+          if (claim.excl){
+            let newtile = claim.space.copy();
+            newtile.comb(tile, comb.mask);
+            tilespaces[loc] = newtile;
+          }
+        }
+      }
+      claim.call(send, diffspace, rellocs, id, claim.space, claim.area); // claim.space should not be modified by the function. it is only present to make functions easier to write
+    }
+    catchall(send, tilespaces, locs);
+  }
+}