feat(atlas): persist preferred task session reuse

src/features/boulder-state/top-level-task.ts

@@ -0,0 +1,77 @@
+import { existsSync, readFileSync } from "node:fs"
+
+import type { TopLevelTaskRef } from "./types"
+
+const TODO_HEADING_PATTERN = /^##\s+TODOs\b/i
+const FINAL_VERIFICATION_HEADING_PATTERN = /^##\s+Final Verification Wave\b/i
+const SECOND_LEVEL_HEADING_PATTERN = /^##\s+/
+const UNCHECKED_CHECKBOX_PATTERN = /^(\s*)[-*]\s*\[\s*\]\s*(.+)$/
+const TODO_TASK_PATTERN = /^(\d+)\.\s+(.+)$/
+const FINAL_WAVE_TASK_PATTERN = /^(F\d+)\.\s+(.+)$/i
+
+type PlanSection = "todo" | "final-wave" | "other"
+
+function buildTaskRef(
+  section: "todo" | "final-wave",
+  taskLabel: string,
+): TopLevelTaskRef | null {
+  const pattern = section === "todo" ? TODO_TASK_PATTERN : FINAL_WAVE_TASK_PATTERN
+  const match = taskLabel.match(pattern)
+  if (!match) {
+    return null
+  }
+
+  const rawLabel = match[1]
+  const title = match[2].trim()
+
+  return {
+    key: `${section}:${rawLabel.toLowerCase()}`,
+    section,
+    label: rawLabel,
+    title,
+  }
+}
+
+export function readCurrentTopLevelTask(planPath: string): TopLevelTaskRef | null {
+  if (!existsSync(planPath)) {
+    return null
+  }
+
+  try {
+    const content = readFileSync(planPath, "utf-8")
+    const lines = content.split(/\r?\n/)
+    let section: PlanSection = "other"
+
+    for (const line of lines) {
+      if (SECOND_LEVEL_HEADING_PATTERN.test(line)) {
+        section = TODO_HEADING_PATTERN.test(line)
+          ? "todo"
+          : FINAL_VERIFICATION_HEADING_PATTERN.test(line)
+            ? "final-wave"
+            : "other"
+      }
+
+      const uncheckedTaskMatch = line.match(UNCHECKED_CHECKBOX_PATTERN)
+      if (!uncheckedTaskMatch) {
+        continue
+      }
+
+      if (uncheckedTaskMatch[1].length > 0) {
+        continue
+      }
+
+      if (section !== "todo" && section !== "final-wave") {
+        continue
+      }
+
+      const taskRef = buildTaskRef(section, uncheckedTaskMatch[2].trim())
+      if (taskRef) {
+        return taskRef
+      }
+    }
+
+    return null
+  } catch {
+    return null
+  }
+}