turash/bugulma/backend/internal/financial/irr_calculator.go
Damir Mukimov 000eab4740
Major repository reorganization and missing backend endpoints implementation
Repository Structure:
- Move files from cluttered root directory into organized structure
- Create archive/ for archived data and scraper results
- Create bugulma/ for the complete application (frontend + backend)
- Create data/ for sample datasets and reference materials
- Create docs/ for comprehensive documentation structure
- Create scripts/ for utility scripts and API tools

Backend Implementation:
- Implement 3 missing backend endpoints identified in gap analysis:
  * GET /api/v1/organizations/{id}/matching/direct - Direct symbiosis matches
  * GET /api/v1/users/me/organizations - User organizations
  * POST /api/v1/proposals/{id}/status - Update proposal status
- Add complete proposal domain model, repository, and service layers
- Create database migration for proposals table
- Fix CLI server command registration issue

API Documentation:
- Add comprehensive proposals.md API documentation
- Update README.md with Users and Proposals API sections
- Document all request/response formats, error codes, and business rules

Code Quality:
- Follow existing Go backend architecture patterns
- Add proper error handling and validation
- Match frontend expected response schemas
- Maintain clean separation of concerns (handler -> service -> repository)
2025-11-25 06:01:16 +01:00

54 lines
1.2 KiB
Go

package financial
import "math"
// IRRCalculatorImpl implements IRRCalculator interface
type IRRCalculatorImpl struct{}
// NewIRRCalculator creates a new IRR calculator
func NewIRRCalculator() IRRCalculator {
return &IRRCalculatorImpl{}
}
// CalculateIRR calculates Internal Rate of Return using Newton-Raphson method
// IRR is the discount rate where NPV = 0
func (irr *IRRCalculatorImpl) CalculateIRR(capex, annualCashFlow float64, years int) float64 {
if annualCashFlow <= 0 {
return 0.0 // No positive cash flow
}
// Newton-Raphson iteration
irrRate := 0.1 // Initial guess: 10%
tolerance := 0.0001
maxIterations := 100
for i := 0; i < maxIterations; i++ {
npv := -capex
derivative := 0.0
for year := 1; year <= years; year++ {
yearFloat := float64(year)
discountFactor := math.Pow(1+irrRate, yearFloat)
npv += annualCashFlow / discountFactor
derivative -= yearFloat * annualCashFlow / math.Pow(1+irrRate, yearFloat+1)
}
if math.Abs(npv) < tolerance {
return irrRate * 100 // Return as percentage
}
if derivative != 0 {
irrRate = irrRate - npv/derivative
} else {
break
}
// Prevent negative IRR
if irrRate < -0.99 {
irrRate = -0.99
}
}
return irrRate * 100 // Return as percentage
}