package financial

import "math"

// CapexEstimatorImpl implements CapexEstimator interface
type CapexEstimatorImpl struct {
	config *Config
}

// NewCapexEstimator creates a new CAPEX estimator
func NewCapexEstimator(config *Config) CapexEstimator {
	return &CapexEstimatorImpl{config: config}
}

// EstimateCapex estimates capital expenditure based on distance and resource type
func (ce *CapexEstimatorImpl) EstimateCapex(resourceType string, distanceKm float64, annualVolume float64) float64 {
	// Get base CAPEX per km from config
	baseCapex, exists := ce.config.CapexPerKm[resourceType]
	if !exists {
		baseCapex = 20000 // Default estimate
	}

	// Base infrastructure cost
	infrastructureCost := baseCapex * distanceKm

	// Add connection costs (heat exchangers, meters, etc.)
	connectionCost := 20000.0 // Fixed connection cost

	// Scale factor based on volume (larger volumes need larger equipment)
	scaleFactor := 1.0 + math.Log10(math.Max(1, annualVolume/1000))

	return (infrastructureCost + connectionCost) * scaleFactor
}