# Implementation Tasks

## 1. Backend API Changes

- [x] 1.1 Update `app/schemas/task.py` to add `layout_model` enum type
- [x] 1.2 Update `app/routers/tasks.py` to replace `pp_structure_params` with `layout_model` parameter
- [x] 1.3 Update `app/services/ocr_service.py` to map `layout_model` to `layout_detection_model_name`
- [x] 1.4 Remove custom PP-Structure engine creation logic (use model selection instead)
- [x] 1.5 Add backward compatibility: default to "chinese" if no model specified

## 2. Backend Configuration

- [x] 2.1 Keep `layout_detection_model_name` in `config.py` as fallback default
- [x] 2.2 Keep fine-tuning parameters in `config.py` (not exposed to API)
- [x] 2.3 Document available layout models in config comments

## 3. Frontend Changes

- [x] 3.1 Remove `PPStructureParams.tsx` component
- [x] 3.2 Update `src/types/apiV2.ts`:
  - Remove `PPStructureV3Params` interface
  - Add `LayoutModel` type: `"default" | "chinese" | "cdla"`
  - Update `ProcessingOptions` to use `layout_model` instead of `pp_structure_params`
- [x] 3.3 Create `LayoutModelSelector.tsx` component with:
  - Radio buttons or dropdown for model selection
  - Clear descriptions for each model option
  - Default selection: "chinese"
- [x] 3.4 Update task start form to use new `LayoutModelSelector`
- [x] 3.5 Update API calls to send `layout_model` instead of `pp_structure_params`

## 4. Internationalization

- [x] 4.1 Add i18n strings for layout model options:
  - `layoutModel.default`: "Standard Model (English documents)"
  - `layoutModel.chinese`: "Chinese Document Model (Recommended)"
  - `layoutModel.cdla`: "CDLA Model (Chinese layout analysis)"
- [x] 4.2 Add i18n strings for model descriptions

## 5. Testing

- [x] 5.1 Create new tests for `layout_model` parameter (`test_layout_model_api.py`, `test_layout_model.py`)
- [x] 5.2 Archive tests for `pp_structure_params` validation (moved to `tests/archived/`)
- [x] 5.3 Add tests for layout model selection (19 tests passing)
- [x] 5.4 Test backward compatibility (no model specified → use chinese default)

## 6. Documentation

- [ ] 6.1 Update API documentation for task start endpoint
- [ ] 6.2 Remove PP-Structure parameter documentation
- [ ] 6.3 Add layout model selection documentation

## 7. Cleanup

- [x] 7.1 Remove localStorage keys for PP-Structure params (`pp_structure_params_presets`, `pp_structure_params_last_used`)
- [x] 7.2 Remove any unused imports/types related to PP-Structure params
- [x] 7.3 Archive old PP-Structure params test files