# Rust Tauri MVP Design

## Goal

Build a Windows desktop MVP for the building-material radioactivity judgment system. The first version covers manual entry of repeated Ra-226, Th-232, and K-40 measurements, Rust-side uncertainty calculation, and display of IRa, Ir, relative uncertainty, and the acceptance conclusion.

## Source Documents

- `temp/项目报价单.md`: original Rust + Tauri quotation scope.
- `temp/项目报价单_B方案.md`: C# alternative quotation.
- `temp/项目报价单_C方案.md`: Python alternative quotation.
- `temp/不确定度公式.pdf`: formula reference for calculation and judgment.

## Technology Choice

Use Rust + Tauri + React + TypeScript. Rust owns the formula engine and later storage/reporting commands. React owns data entry and presentation. Ant Design is the preferred UI library because this app is form-heavy and table-heavy.

## MVP Scope

Included:

- Manual entry of repeated measured values for Ra-226, Th-232, and K-40.
- Configurable calibration parameters with defaults from the PDF table 3:
  - Ra: `a = 0.916`, `U = 6.3%`, `k = 2`
  - Th: `a = 0.884`, `U = 6.9%`, `k = 2`
  - K: `a = 0.961`, `U = 6.7%`, `k = 2`
- A-type uncertainty:
  - `n >= 6`: sample standard deviation divided by `sqrt(n)`.
  - `2 <= n < 6`: range method using table 2 coefficients.
- B-type uncertainty:
  - `urB = U / k`
  - `uB = a * urB`
- Calibrated activity values:
  - `C = measured * calibration_factor`
- Indices:
  - `IRa = C_Ra / 200`
  - `Ir = C_Ra / 370 + C_Th / 260 + C_K / 4200`
- Combined nuclide uncertainty and index uncertainty.
- Relative uncertainty and three-state conclusion:
  - both relative uncertainties <= 20%: `OK`
  - otherwise, if sample count is below 6: `请增加试验次数至 6 次`
  - otherwise: `校准仪器后重新测量`

Excluded from first pass:

- SQLite history.
- Excel import/export.
- PDF report export.
- Installer packaging.

These are second-stage modules after the formula path is verified.

## Architecture

The repository root starts as a Rust library crate named `ceramic-radioactivity`. It exposes calculation data structures and a pure `calculate_sample` function. Tauri integration will call this function from a command, and the React UI will pass plain JSON data to the command.

Planned modules:

- `src/lib.rs`: public exports.
- `src/calculator.rs`: formula implementation.
- `src/domain.rs`: input, output, calibration parameters, and conclusion types.
- `tests/calculator_tests.rs`: formula behavior tests.

The front end will be added after Rust tests pass:

- `src-tauri`: Tauri application shell.
- `ui`: React + TypeScript + Ant Design UI.

## Error Handling

The calculator returns validation errors for:

- fewer than 2 measurements for any nuclide;
- unequal measurement counts across nuclides;
- non-finite numeric values;
- missing range coefficient for the `2 <= n < 6` range method.

The UI displays validation failures without saving or exporting anything.

## Testing

The Rust calculator is tested first. Tests cover:

- mean and calibrated activity calculation;
- A-type uncertainty for both standard-deviation and range methods;
- default B-type uncertainty;
- index calculation;
- conclusion switching between `OK`, `请增加试验次数至 6 次`, and `校准仪器后重新测量`.

The first implementation target is a deterministic unit test based on hand-computed small input values, then a sample-shaped test using the PDF table 1 data.