package main

import (
	"testing"
	"time"
)

func TestCounterSeriesIsMonotonicAndDeterministic(t *testing.T) {
	start := time.Date(2026, 9, 1, 0, 0, 0, 0, time.UTC)
	a := counterSeries(patternDiurnal, start, 3*24*60, time.Minute, 1_000_000, 7)
	b := counterSeries(patternDiurnal, start, 3*24*60, time.Minute, 1_000_000, 7)
	for i := range a {
		if a[i] != b[i] {
			t.Fatalf("not deterministic at %d", i)
		}
		if i > 0 && a[i] < a[i-1] {
			t.Fatalf("decreased at %d", i)
		}
	}
	if a[0] != 0 {
		t.Fatalf("starts at %v, want 0", a[0])
	}
	meanRate := a[len(a)-1] / (float64(len(a)-1) * 60)
	if meanRate < 0.8e6 || meanRate > 1.4e6 {
		t.Fatalf("mean rate %.0f B/s drifted from 1e6", meanRate)
	}
}

func TestDiurnalEveningBusierThanNight(t *testing.T) {
	// Monday, so the weekend factor does not interfere. Averaged over many days the noise washes out.
	var night, evening float64
	for d := 0; d < 28; d++ {
		day := time.Date(2026, 9, 7, 0, 0, 0, 0, time.UTC).AddDate(0, 0, d)
		if wd := day.Weekday(); wd == time.Saturday || wd == time.Sunday {
			continue
		}
		night += rateFactor(patternDiurnal, day.Add(5*time.Hour), 1)
		evening += rateFactor(patternDiurnal, day.Add(20*time.Hour), 1)
	}
	if evening < 2*night {
		t.Fatalf("evening %.2f is not clearly busier than night %.2f", evening, night)
	}
}

func TestFlatPatternIsConstant(t *testing.T) {
	if f := rateFactor(patternFlat, time.Now(), 3); f != 1 {
		t.Fatalf("flat factor %v", f)
	}
}

func TestDefaultMeanIsStableAndBounded(t *testing.T) {
	m := defaultMeanBytesPerSec("01abc", 1)
	if m != defaultMeanBytesPerSec("01abc", 1) || m < 2*125_000 || m > 60*125_000 {
		t.Fatalf("mean %v", m)
	}
}