package billing

import "testing"

func TestTokenPackMath(t *testing.T) {
	// Mirrors DebitAmount pack math: ceil(tokens/1000).
	cases := []struct {
		tokens int
		packs  int
	}{
		{0, 0},
		{1, 1},
		{1000, 1},
		{1001, 2},
		{2500, 3},
	}
	for _, c := range cases {
		packs := 0
		if c.tokens > 0 {
			packs = (c.tokens + 999) / 1000
		}
		got := DebitAmount(1, 1, c.tokens)
		want := 1 + packs
		if got != want {
			t.Fatalf("tokens=%d DebitAmount=%d want %d (packs=%d)", c.tokens, got, want, packs)
		}
	}
}

func TestEstimateDebitMath(t *testing.T) {
	// Pure pack math aligned with EstimateDebit / ConsumeCredits (costs=1).
	cases := []struct {
		featureTokens int
		want          int
	}{
		{0, 1}, // base feature cost only
		{1, 2},
		{1000, 2},
		{1001, 3},
	}
	for _, c := range cases {
		got := DebitAmount(1, 1, c.featureTokens)
		if got != c.want {
			t.Fatalf("tokens=%d debit=%d want %d", c.featureTokens, got, c.want)
		}
	}
}