### FunkyJuice Recipes — Project Milestones

This document outlines the sequence of milestones to deliver the FunkyJuice Recipes desktop app using Toga, Peewee (SQLite), and Briefcase. Each milestone is scoped to be achievable in a short iteration and includes clear acceptance criteria.

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### Milestone 1 — Project skeleton and tooling
- Set up `src/funkyjuicerecipes/` package layout per README.
- Add minimal `app.py` with `FunkyJuiceRecipesApp` and `main()` returning the app.
- Configure `pyproject.toml` (already added) and ensure `briefcase dev` can start a blank window.
- Add `tests/` folder and test runner config.

Acceptance:
- `briefcase dev` launches an empty Toga window titled “FunkyJuice Recipes”.
- `pytest` runs (even with zero or smoke tests).

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### Milestone 2 — Database initialization and migrations framework
- Implement `data/db.py` using `app.paths.data` and Peewee pragmas (`foreign_keys=1`, WAL).
- Create migrations table and a simple migration runner that detects unapplied migration files by filename.
- Implement initial migrations for `flavor`, `recipe`, and `recipe_flavor` tables matching README DDL.

Acceptance:
- On first launch, DB file is created in the per‑user data directory, tables exist, and migrations table is populated.
- Subsequent launches do not re-run applied migrations.

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### Milestone 3 — Peewee models and DAOs
- Implement `Flavor`, `Recipe`, `RecipeFlavor` models reflecting constraints (UNIQUEs, FKs, CHECKs where applicable in logic).
- Provide DAO/helper functions for common ops (create/list/get/update/delete) with soft-delete semantics for flavors.
- Enable case-insensitive uniqueness for `Flavor(name, company)`.

Acceptance:
- Unit tests can create flavors (no duplicates ignoring case), recipes, and link ingredients; soft-deleted flavors are excluded by default queries.

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### Milestone 4 — Calculation engine
- Implement pure functions in `logic/calculations.py` to compute PG/VG/Nic and per-flavor mL from inputs (percents + size).
- Include validation (non-negative PG/VG; base_pg + base_vg = 100; percent totals ≈ 100 within tolerance).
- Define rounding/display policy (e.g., 1 decimal for View screen).

Acceptance:
- Tests cover the README example (120 mL case) and edge cases (nic in PG vs VG, excessive flavor %).

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### Milestone 5 — Main window and navigation shell
- Build `MainWindow`: menu bar (File/New Recipe/Exit; Help/About), buttons for Inventory, recipe list placeholder.
- Wire basic screens/routes (View Recipe, Add/Edit Recipe, Inventory) with placeholders.

Acceptance:
- App displays main list and can navigate to empty placeholder screens and back.

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### Milestone 6 — Inventory screen (CRUD + soft delete)
- Implement `FlavorsTable` with add/edit/delete.
- Enforce no duplicates; on delete, soft-delete if referenced by recipes; otherwise hard-delete.
- Provide toggle to view soft-deleted flavors and actions to undelete or hard-delete when safe.

Acceptance:
- Users can manage flavors per README, with correct soft/hard delete behavior.

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### Milestone 7 — Add/Edit Recipe screens
- Implement `RecipeForm` with PG/VG base, Nic % and base, size, and flavor lines (select existing flavors + percentage).
- Auto-maintain PG + VG = 100; prevent negatives.
- On save: validate, combine duplicate flavors (prompt as specified), persist recipe + ingredients.

Acceptance:
- Users can create and edit recipes meeting validation rules and duplicate-combine flow.

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### Milestone 8 — View Recipe screen
- Render computed components (PG, VG, Nic, flavors) using calculation engine, rounded to 1 decimal.
- Support view mode toggle: Individual Flavors vs Flavor Prep total.
- Provide action to open Edit, Delete confirmation, and Inventory.

Acceptance:
- A saved recipe displays correct amounts; toggle updates view accordingly.

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### Milestone 9 — Flavor Prep mixer utility
- Implement “Mix Flavor Prep” dialog/workflow computing batch amounts from recipe flavor ratios for selectable sizes (10/30/120 mL, etc.).
- No persistence for Flavor Prep (ephemeral), but support printing/exporting batch breakdown (optional CSV).

Acceptance:
- Users can choose a batch size and see per-flavor mL for the prep; closing returns to View Recipe.

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### Milestone 10 — Polishing, About, and edge behaviors
- Implement About dialog (app name, version, author).
- Confirm unsaved-changes prompts on screen change and app exit while editing.
- Empty states, error dialogs, and friendly validation messages.

Acceptance:
- UX polish complete; no obvious dead-ends; dialogs work across platforms.

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### Milestone 11 — Packaging and distribution
- Verify `briefcase dev` on target OS; add icons under `resources/`.
- Build installers with Briefcase for target platforms.
- Document install/run instructions and DB location.

Acceptance:
- Installers build successfully; smoke test of installed app passes.

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### Milestone 12 — Testing and CI (optional but recommended)
- Add unit tests for models/DAOs and calculations; UI smoke tests using Toga Dummy backend where feasible.
- Set up a simple CI (e.g., GitHub Actions) to run tests on push.

Acceptance:
- CI passes on main branch; coverage of calculation and DAO logic acceptable.