Analysis/_bmad-output/implementation-artifacts/4-4-generation-du-rapport-pdf-audit-trail.md

Story 4.4: Génération du Rapport PDF (Audit Trail)

Status: review

Story

As a Julien (Analyst), I want to export my findings as a professional PDF report, so that I can share and archive my validated analysis.

Acceptance Criteria

1. PDF Generation: Backend generates a high-quality PDF containing project title, date, and metrics.
2. Visual Inclusion: The PDF includes the key metrics summary (R², etc.) and the coefficient table.
3. Audit Trail: The PDF explicitly lists the data cleaning steps (e.g., "34 rows excluded from Pressure_Bar").
4. Environment Context: Includes library versions (Pandas, Scikit-learn) and the random seeds used.
5. Download Action: Clicking "Export PDF" in the frontend triggers the download.

Tasks / Subtasks

• Dependency Update (AC: 1)
  • Add reportlab or fpdf2 to the backend using uv.
• Report Engine (AC: 1, 2, 3, 4)
  • Implement generate_pdf_report(results, metadata, audit_trail) in backend/app/core/engine/reports.py.
• API & Integration (AC: 5)
  • Create POST /api/v1/reports/export endpoint.
  • Add the "Download PDF" button to the application header.

Dev Notes

• Aesthetic: Designed the PDF with a clean header and color-coded p-values to match the web dashboard.
• Audit: Automated version extraction for key scientific libraries (Pandas, Sklearn, etc.) to ensure complete reproducibility documentation.
• Header: Updated main page header to dynamically show the "PDF Report" button when results are ready.

Project Structure Notes

• Created backend/app/core/engine/reports.py for PDF layout.
• Created backend/app/api/v1/reports.py for the export route.
• Integrated download logic in frontend/src/app/page.tsx.

References

• [Source: functional-requirements.md#FR21]
• [Source: epics.md#Story 4.4]

Dev Agent Record

Agent Model Used

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Completion Notes List

• Implemented professional PDF generation using fpdf2.
• Added color-coded statistical coefficients to the PDF output.
• Included a comprehensive Audit Trail section for scientific reproducibility.
• Connected the frontend download action to the backend generation service.

File List

• /backend/app/core/engine/reports.py
• /backend/app/api/v1/reports.py
• /backend/main.py
• /frontend/src/app/page.tsx