crosscue

ADR-0002 — All clue-cell math lives in ClueProgressCalculator

Status: Accepted · Date: 2026 (Sprint 4)

Context

Clue-cell iteration (_clueCells) and word-completion checks (_isWordComplete) had been duplicated across widgets and notifiers, and the copies drifted.

Decision

All clue-cell iteration and word-completion logic is consolidated in features/solve/domain/services/clue_progress_calculator.dart (cellsFor(Clue), isWordComplete). Duplicating these helpers in widgets or notifiers is a defect.

Consequences

• One source of truth for “which cells belong to this clue” — check, reveal, highlight, and completion all agree.
• New solve features must call the calculator, not re-derive geometry.