Clocks can't go to 0?

Fixes #89

src/tracks/clock-file.ts

@@ -91,7 +91,6 @@ export class ClockIndexer extends BaseIndexer<ClockFileAdapter> {
     cache: CachedMetadata,
   ): ClockFileAdapter | undefined {
     // TODO: we should use our Either support now to handle this
-    // TODO: customize track image gen
     return ClockFileAdapter.create(cache.frontmatter).unwrap();
   }
 }

src/tracks/clock.test.ts

@@ -0,0 +1,52 @@
+import { Clock, ClockInput } from "./clock";
+
+const DEFAULT_CLOCK_INPUT = {
+  progress: 0,
+  segments: 6,
+  active: true,
+};
+
+function make_clock(input: Partial<ClockInput> = {}) {
+  return Clock.create({ ...DEFAULT_CLOCK_INPUT, ...input });
+}
+
+describe("Clock", () => {
+  describe("create", () => {
+    it("accepts clocks with 0 progress", () => {
+      expect(
+        Clock.create({ active: true, progress: 0, segments: 6 }).unwrap(),
+      ).toEqual({
+        progress: 0,
+        segments: 6,
+        active: true,
+      });
+    });
+  });
+
+  describe("withProgress", () => {
+    it("returns a new clock with updated progress", () => {
+      const clock = make_clock({ progress: 1 }).unwrap();
+      const newClock = clock.withProgress(2);
+      expect(clock.progress).toBe(1);
+      expect(newClock.progress).toBe(2);
+    });
+    it("constrains progress to be >= 0", () => {
+      expect(make_clock().unwrap().withProgress(-1).progress).toBe(0);
+    });
+
+    it("constrains progress to be < segments", () => {
+      expect(
+        make_clock({ segments: 6 }).unwrap().withProgress(7).progress,
+      ).toBe(6);
+    });
+  });
+
+  describe("tick", () => {
+    it("returns a new clock with updated progress", () => {
+      const clock = make_clock({ progress: 1 }).unwrap();
+      const newClock = clock.tick(2);
+      expect(clock.progress).toBe(1);
+      expect(newClock.progress).toBe(3);
+    });
+  });
+});

src/tracks/clock.ts

@@ -5,7 +5,7 @@ import { zodResultToEither } from "../utils/zodutils";
 export const clockValidator = z
   .object({
     /** Number of filled segments. */
-    progress: z.number().positive(),
+    progress: z.number().nonnegative(),
 
     /** Number of total segments */
     segments: z.number().positive(),
@@ -45,15 +45,7 @@ export class Clock implements ClockLike {
   }
 
   public tick(steps: number = 1): this {
-    if (!this.active) return this;
-
-    // TODO: should this give an error or something if we attempt to tick beyond the limit?
-    const newProgress = Math.max(
-      Math.min(this.segments, this.progress + steps),
-      0,
-    );
-    if (newProgress === this.progress) return this;
-    return new Clock(newProgress, this.segments, this.active) as this;
+    return this.withProgress(this.progress + steps);
   }
 
   public deactivate(): this {