analyse if we have covered all the review below If I were taking over this project, I would **freeze feature development for 1–2 weeks** and do nothing but architecture work. The code is at the point where every new feature will either become much easier or much harder depending on what you do next. This is the roadmap I'd follow. --- # Phase 1 — Establish a Real Domain (Highest Priority) ## Goal The application should revolve around an `Estimate`, not a screen. Today the execution flow is roughly: ```text User ↓ CostEstimateScreen ↓ EstimateStore ↓ Estimate ``` I want: ```text User ↓ Command ↓ Estimate ↓ Domain Event ↓ UI ``` The UI should never decide how an estimate changes. --- ## Create explicit commands Instead of: ```rust screen.set_region(...) screen.recalculate(...) ``` everything becomes: ```text SetRegion SetProperty AddRoom DeleteRoom UpdateRoomDimensions SetFloorCount ImportEstimate ExportEstimate ``` Every state change enters the system exactly one way. --- ## Estimate becomes the application Today Estimate still behaves like a data structure. It should become the application. It should own: ```text Estimate Rooms Selection Totals Floors Property Region Validation Calculations ``` Nothing outside Estimate should modify these. --- # Phase 2 — Remove UI Orchestration This is the biggest architectural problem today. Current pattern: ```text set property ↓ reload dropdown ↓ reload rooms ↓ update preview ↓ update totals ↓ emit action ``` That chain should disappear. --- Instead: ```text SetProperty Command ↓ Estimate updates ↓ EstimateChanged event ↓ UI redraws ``` The screen should become stupid. Its job should be: ```text Receive Event ↓ Refresh Widgets ``` That's it. --- # Phase 3 — Introduce Services Estimate is already growing. Don't let it become another monolith. Split responsibilities. ## RateService ```text lookup_rate() lookup_region() lookup_property() ``` --- ## RoomTemplateService ```text available_rooms() default_dimensions() room_generation() ``` --- ## CostService ```text calculate_room() calculate_total() floor_multiplier() ``` --- ## ExportService ```text PDF CSV JSON ``` --- Estimate coordinates them. It doesn't implement them. --- # Phase 4 — Eliminate Manual Synchronisation This is the smell I dislike most. Current code has many functions like: ```text refresh_property() refresh_header() refresh_dropdown() reload_rooms() sync_preview() ``` Instead introduce a ViewModel. ```text Estimate ↓ EstimateViewModel ↓ Widgets ``` Widgets bind to data. No widget should know another widget exists. --- # Phase 5 — Build a Proper State Machine Instead of scattered booleans ```text loading dirty editing calculating ``` make them explicit. ```rust enum EstimateState { Loading, Ready, Editing, Saving, Exporting, } ``` State machines eliminate entire categories of bugs. --- # Phase 6 — Introduce Immutable Snapshots Today changes happen directly. I'd rather have ```text Estimate ↓ clone ↓ modify ↓ replace ``` This immediately enables * Undo * Redo * Autosave * Time travel debugging * Change history --- # Phase 7 — Replace Nested Searches Current: ```text Category ↓ Region ↓ Property ↓ Room ↓ Rate ``` every lookup. After JSON loads build indices. ```text PropertyIndex RateIndex RoomIndex RegionIndex ``` Everything becomes O(1). --- # Phase 8 — UI Decomposition Current screen still owns too much. Split into ```text EstimateHeader EstimateSidebar RoomEditor TotalsPanel PropertyPanel RoomPanel StatusBar ``` Each owns only its widgets. --- # Phase 9 — Stronger Types I would remove lots of ```rust String ``` usage. Replace with ```rust PropertyId RegionId RoomId EstimateId ``` Compiler catches mistakes. --- # Phase 10 — Events Everywhere Instead of ```text screen ↓ store ↓ screen ↓ preview ``` everything communicates through events. Example: ```text RoomUpdated ↓ Estimate recalculates ↓ TotalsChanged ↓ Header redraw ↓ RoomUpdated ↓ Preview redraw ``` No direct widget calls. --- # Phase 11 — Testing Current testing is okay. I'd increase it dramatically. Test * property switching * room generation * totals * floor multiplier * imports * exports * region changes * invalid JSON * invalid rooms * duplicate rooms * undo UI tests are far less valuable than domain tests. --- # Phase 12 — Performance Do this last. Optimise * lookup indices * redraw batching * cached calculations Ignore * clone * Vec * HashMap They're not your bottleneck. --- # The Architecture I Would End Up With ```text UI │ EstimateViewModel │ Event Bus │ ┌─────────┴─────────┐ │ │ Commands Domain Events │ │ └─────────┬─────────┘ │ Estimate │ ┌────────────┼─────────────┐ │ │ │ RoomStore CostService RateService │ │ │ └────────────┴─────────────┘ │ Building Repository │ JSON ``` ## What I'd do first (in order) 1. **Move all business rules into `Estimate`.** Nothing outside it should calculate totals, update rooms, or apply property changes. 2. **Replace the screen's manual refresh chains with domain events.** A state change should naturally produce an event that the UI responds to. 3. **Extract calculation and lookup logic into dedicated services.** Keep `Estimate` as the coordinator rather than the implementation of every algorithm. 4. **Introduce lookup indices after loading configuration.** This simplifies logic and prepares the application for larger datasets. 5. **Split the screen into smaller presentation components** once the domain layer is stable. --- ## One thing I would **not** do I would **not** create more files just to reduce file size. Splitting a 600-line file into six 100-line files doesn't improve architecture if the responsibilities stay the same. Every extraction should answer one question: > **Does this give a single component clear ownership of a single responsibility?** If the answer is no, it's just moving code around. That's the principle I'd use to guide every refactor from here onward.