areas implementation

src/areas.zig

@@ -3,27 +3,41 @@ const rl = @import("raylib");
 const spawn_area = @import("spawn-area.zig");
 const structures = @import("structures.zig");
 
-const Areas = struct {
-    areas: []spawn_area.SpawnArea,
+pub const Areas = struct {
     allocator: std.mem.Allocator,
+    areas: []spawn_area.SpawnArea,
 
     pub fn init(allocator: std.mem.Allocator, size: usize) !Areas {
         const values = std.enums.values(structures.AreaLocation);
-        if (size > values.len) size = values.len;
+        var max_areas = size;
+        if (size > values.len) max_areas = values.len;
 
         var used_areas = std.ArrayList(structures.AreaLocation).init(allocator);
         defer used_areas.deinit();
 
-        // here we generate size random AreaLocation enums that aren't in used_areas
-        // the random generator will only generate AreaLocation enums that are not in
-        //
-        // todo implement function which will subtract values from used_areas (after RANDOM)
-        // based on this we will fill data with 0..size data and return the final value
+        var prng = std.Random.DefaultPrng.init(blk: {
+            var seed: u64 = undefined;
+            try std.posix.getrandom(std.mem.asBytes(&seed));
+            break :blk seed;
+        });
+
+        const rand = prng.random();
+        const area_data = try allocator.alloc(spawn_area.SpawnArea, size);
+
+        for (area_data) |*area| {
+            // give us all valid values we can use for AreaLocation
+            const valid_values = try getEnumValuesMinusUsed(allocator, used_areas, values);
+            defer allocator.free(valid_values);
+
+            const num = rand.intRangeAtMost(usize, 0, valid_values.len - 1); // random number
+            // here we create new spawnarea
+            area.* = spawn_area.SpawnArea.init(valid_values[num]);
+            try used_areas.append(valid_values[num]);
+        }
 
-        const data = try allocator.alloc(structures.AreaLocation, size);
-        // todo data must be set before returned
         return Areas{
-            .areas = data,
+            .allocator = allocator,
+            .areas = area_data,
         };
     }
 
@@ -31,8 +45,28 @@ const Areas = struct {
         self.allocator.free(self.areas);
     }
 
-    pub fn draw(areas: *Areas) void {
-        // todo implement draw
-        _ = areas;
+    pub fn draw(self: *Areas) void {
+        for (self.areas) |area| {
+            area.draw();
+        }
+    }
+
+    fn getEnumValuesMinusUsed(allocator: std.mem.Allocator, used_values: std.ArrayList(structures.AreaLocation), values: []const structures.AreaLocation) ![]structures.AreaLocation {
+        var valuesToRandomise = try allocator.alloc(structures.AreaLocation, values.len - used_values.items.len);
+
+        var i: usize = 0;
+
+        outer: for (values) |value| {
+            for (used_values.items) |used_val| {
+                if (value == used_val) {
+                    continue :outer;
+                }
+            }
+            // this value is clean and can get put into values good for randomisation
+            valuesToRandomise[i] = value;
+            i += 1;
+        }
+
+        return valuesToRandomise;
     }
 };