# Fox Fitt LabourPay

## Project Overview
Django payroll management system for Fox Fitt Construction, a civil works contractor specializing in solar farm foundation installations. Manages field worker attendance, payroll processing, employee loans, and business expenses for solar farm projects.

## Tech Stack
- Django 5.x, Python 3.11, MariaDB
- Bootstrap 5 with Material Design-inspired styling, vanilla JavaScript
- PDF generation for payslips and receipts
- SMTP email integration for automated document delivery
- Apache reverse proxy with systemd service management

## Project Structure
- `config/` — Django project settings, URLs, WSGI/ASGI entrypoints
- `core/` — Single main app containing ALL business logic, models, views, forms, templates, and migrations
- `ai/` — Local AI API integration module
- `media/workers/ids/` — Worker ID photo uploads
- `static/` — Source static files (custom CSS)
- `staticfiles/` — Collected static assets (Bootstrap, Popper.js, admin)

## Key Business Rules
- All business logic lives in the `core/` app — do not create additional apps
- Workers have a `day_rate` calculated automatically from monthly salary / 20 working days
- PIN authentication (4-digit) exists alongside password auth for quick field access
- Supervisors can only see their assigned projects and teams
- Admins have full access to payroll, adjustments, and resource management
- WorkLog is the central attendance record — links workers to projects on specific dates
- Attendance logging includes conflict detection to prevent double-logging
- Loans have automated repayment deductions during payroll processing
- Cascading deletes use SET_NULL for supervisors to preserve historical data

## Key Models
- **UserProfile** — extends User with PIN and is_admin flag
- **Project** — work sites/contracts with supervisor assignments
- **Worker** — profiles with salary, day_rate, employment details
- **Team** — groups of workers under a supervisor
- **WorkLog** — daily attendance records (worker + project + date)
- **PayrollRecord** — completed payments linked to WorkLog entries
- **PayrollAdjustment** — bonuses, deductions, overtime, loan repayments
- **Loan** — worker advances with balance tracking
- **ExpenseReceipt / ExpenseLineItem** — business expense records

## Commands
- `python manage.py runserver 0.0.0.0:8000` — run dev server
- `python manage.py migrate` — apply database migrations
- `python manage.py collectstatic` — collect static files for production
- `python manage.py setup_groups` — configure permission groups
- `python manage.py update_permission_names` — update permission display names
- `python manage.py check` — system check (ignore staticfiles warnings about missing `assets/` and `node_modules/` dirs — pre-existing, harmless)

## Development Workflow
- Active development branch: `ai-dev` (PR target: `master`)
- Admin check in views: `is_admin(request.user)` helper (imported at top of views.py)
- "Unpaid" adjustment = `payroll_record__isnull=True` (no linked PayrollRecord)
- POST-only mutation views pattern: check `request.method != 'POST'` → redirect, then process
- Template UI pattern: Bootstrap 5 modals with dynamic JS wiring, data-* attributes on clickable elements

## PayrollAdjustment Type Handling
- **BONUS / DEDUCTION** — standalone, no linked objects
- **LOAN** — links to `Loan` model via `adj.loan` FK; editing syncs loan amount/balance/reason; deleting cascades to Loan + unpaid repayments (blocked if paid repayments exist)
- **OVERTIME** — links to `WorkLog` via `adj.work_log` FK; deleting removes worker from `work_log.overtime_paid_to` M2M (un-prices the OT)
- **LOAN_REPAYMENT** — links to `Loan` via `adj.loan` FK; loan balance only changes during payment processing

## Important Context
- Read APP_DOCUMENTATION.md for detailed workflows (attendance, payroll, expenses)
- Environment variables loaded from `../.env`
- The owner (Konrad) is not a developer — explain changes clearly and avoid unnecessary complexity
- This system handles real payroll for 14 field workers — accuracy is critical