package calc

func ShipProductionCost(shipEmptyMass float64) float64 {
	return shipEmptyMass * 10.
}

func PlanetProduceShipMass(L, Mat, Res float64) float64 {
	result := L / 10
	if result <= Mat {
		return result
	}
	return (L + Mat/Res) / (10 + 1/Res)
}

// ShipBuildCost returns the total per-turn cost (production units) to
// build one ship of empty mass shipMass on a planet that currently
// holds material stockpile and has natural resources. The cost is the
// ship's production cost ([ShipProductionCost]) plus the cost of
// farming any missing material from the planet (the missing-material
// volume divided by the planet's resources rating).
//
// resources is expected to be positive in normal play; the helper
// guards against a non-positive value by collapsing the material-
// farming term to zero, which keeps callers numerically stable on
// pathological synthetic data. Mirrors the per-iteration math inside
// the engine's controller.ProduceShip so both surfaces — and the
// legacy-report-to-json dev tool that needs to derive prod_used from
// percent — share the same formula.
func ShipBuildCost(shipMass, material, resources float64) float64 {
	matNeed := shipMass - material
	if matNeed < 0 {
		matNeed = 0
	}
	matFarm := 0.
	if resources > 0 {
		matFarm = matNeed / resources
	}
	return ShipProductionCost(shipMass) + matFarm
}