1 files changed, 63 insertions, 0 deletions
diff --git a/src/state.ts b/src/state.ts
new file mode 100644
index 0000000..3b390c5
--- /dev/null
+++ b/src/state.ts
@@ -0,0 +1,63 @@
+import * as Config from 'config'
+
+export enum Step {
+  Prepare,
+  Work,
+  Rest,
+  End,
+}
+
+export function prettyPrintStep(step: Step): string {
+  if (step === Step.Prepare)
+    return "Prepare"
+  else if (step === Step.Work)
+    return "Work"
+  else if (step === Step.Rest)
+    return "Rest"
+  else
+    return "End"
+}
+
+export interface State {
+  step: Step,
+  remaining: number,
+  tabata: number,
+  cycle: number,
+}
+
+export function getAt(config: Config.Config, elapsed: number): State {
+  const cycleDuration = config.work + config.rest
+  const tabataDuration = config.prepare + (config.cycles * cycleDuration)
+  if (elapsed >= tabataDuration * config.tabatas) {
+    return {
+      step: Step.End,
+      remaining: 0,
+      tabata: config.tabatas,
+      cycle: config.cycles,
+    }
+  } else {
+    const currentTabataElapsed = elapsed % tabataDuration
+    let step, remaining
+    if (currentTabataElapsed < config.prepare) {
+      step = Step.Prepare
+      remaining = config.prepare - currentTabataElapsed
+    } else {
+      const currentCycleElapsed = (currentTabataElapsed - config.prepare) % cycleDuration
+      if (currentCycleElapsed < config.work) {
+        step = Step.Work
+        remaining = config.work - currentCycleElapsed
+      } else {
+        step = Step.Rest
+        remaining = config.work + config.rest - currentCycleElapsed
+      }
+    }
+
+    const tabata = Math.floor(elapsed / tabataDuration) + 1
+    const cycle =
+      currentTabataElapsed < config.prepare
+        ? 1
+        : Math.floor((currentTabataElapsed - config.prepare) / cycleDuration) + 1
+
+    return { step, remaining, tabata, cycle }
+  }
+}