package calc_test

import (
	"math"
	"testing"

	"galaxy/calc"
)

func TestBlockUpgradeCost(t *testing.T) {
	cases := []struct {
		name        string
		blockMass   float64
		currentTech float64
		targetTech  float64
		want        float64
	}{
		{"zero block mass returns zero", 0, 1.0, 2.0, 0},
		{"target equal to current returns zero", 5, 2.0, 2.0, 0},
		{"target below current returns zero", 5, 2.0, 1.0, 0},
		{"doubling tech on mass 5 costs 25", 5, 1.0, 2.0, 25},
		{"doubling tech on mass 10 costs 50", 10, 1.0, 2.0, 50},
		{"partial step from 2.0 to 2.5 on mass 5", 5, 2.0, 2.5, 10},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			got := calc.BlockUpgradeCost(tc.blockMass, tc.currentTech, tc.targetTech)
			if math.Abs(got-tc.want) > 1e-9 {
				t.Errorf("BlockUpgradeCost(%v, %v, %v) = %v, want %v",
					tc.blockMass, tc.currentTech, tc.targetTech, got, tc.want)
			}
		})
	}
}