package store

import (
	"testing"
	"time"
)

func TestAddUpload_AverageOfOne(t *testing.T) {
	s := New(nil)
	id := DeviceID("device-1")
	d := 197331667813 * time.Nanosecond // ~3m17.331667813s

	s.AddUpload(id, d)

	if got := s.AverageUploadTime(id); got != d {
		t.Fatalf("avg = %v, want %v", got, d)
	}
}

func TestAddUpload_AverageOfMany(t *testing.T) {
	s := New(nil)
	id := DeviceID("device-1")

	s.AddUpload(id, 100*time.Nanosecond)
	s.AddUpload(id, 200*time.Nanosecond)
	s.AddUpload(id, 300*time.Nanosecond)

	// (100+200+300)/3 = 200
	if got := s.AverageUploadTime(id); got != 200*time.Nanosecond {
		t.Fatalf("avg = %v, want 200ns", got)
	}
}

func TestAverageUploadTime_UnknownDevice(t *testing.T) {
	s := New(nil)
	if got := s.AverageUploadTime(DeviceID("missing")); got != 0 {
		t.Fatalf("avg = %v, want 0", got)
	}
}

func TestAverageUploadTime_IsPerDevice(t *testing.T) {
	s := New(nil)
	a := DeviceID("device-1")
	b := DeviceID("device-2")

	s.AddUpload(a, 100*time.Nanosecond)
	s.AddUpload(a, 300*time.Nanosecond)
	s.AddUpload(b, 50*time.Nanosecond)

	if got := s.AverageUploadTime(a); got != 200*time.Nanosecond {
		t.Fatalf("device-1 avg = %v, want 200ns", got)
	}
	if got := s.AverageUploadTime(b); got != 50*time.Nanosecond {
		t.Fatalf("device-2 avg = %v, want 50ns", got)
	}
}

func TestAverageUploadTime_TruncatingDivision(t *testing.T) {
	s := New(nil)
	id := DeviceID("device-1")

	// 10+11 = 21; 21/2 = 10 in integer division
	s.AddUpload(id, 10*time.Nanosecond)
	s.AddUpload(id, 11*time.Nanosecond)

	if got := s.AverageUploadTime(id); got != 10*time.Nanosecond {
		t.Fatalf("avg = %v, want 10ns (truncating)", got)
	}
}