package profile

import (
	"context"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

// Defends novox/hq ADR 0255: a machine says whether a battery powers it and whether anything on it
// measures the power it draws, read from the kernel, so the controller composes a battery's or a power
// draw's block only where there is one.

func write(t *testing.T, path, content string) {
	t.Helper()
	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(path, []byte(content+"\n"), 0o644); err != nil {
		t.Fatal(err)
	}
}

// sysfs points every power source at a directory of its own, empty unless a case fills it.
func sysfs(t *testing.T) string {
	t.Helper()
	dir := t.TempDir()
	old := [4]string{PowerSupplySource, PowercapSource, SeatSource, NvidiaSource}
	PowerSupplySource = filepath.Join(dir, "power_supply")
	PowercapSource = filepath.Join(dir, "powercap")
	SeatSource = filepath.Join(dir, "drm")
	NvidiaSource = filepath.Join(dir, "nvidia")
	t.Cleanup(func() { PowerSupplySource, PowercapSource, SeatSource, NvidiaSource = old[0], old[1], old[2], old[3] })
	return dir
}

func TestALaptopHasABatteryAndAMeter(t *testing.T) {
	dir := sysfs(t)
	write(t, dir+"/power_supply/ACAD/type", "Mains")
	write(t, dir+"/power_supply/BAT1/type", "Battery")
	write(t, dir+"/power_supply/BAT1/scope", "System")
	write(t, dir+"/power_supply/BAT1/present", "1")
	write(t, dir+"/powercap/intel-rapl:0/name", "package-0")
	write(t, dir+"/powercap/intel-rapl:0/energy_uj", "1")

	b := battery{}.Detect(context.Background())
	if !b.Present || b.Detail != "BAT1" {
		t.Fatalf("battery: %+v", b)
	}
	m := powerMeter{}.Detect(context.Background())
	if !m.Present || m.Detail != "battery BAT1, processor package-0" {
		t.Fatalf("power meter: %+v", m)
	}
}

func TestADevicesBatteryIsNotTheMachines(t *testing.T) {
	// The case worth a test: a desktop with a wireless mouse reports a Battery, and a battery block
	// composed for it would show the mouse's charge as the machine's.
	dir := sysfs(t)
	write(t, dir+"/power_supply/hidpp_battery_0/type", "Battery")
	write(t, dir+"/power_supply/hidpp_battery_0/scope", "Device")
	write(t, dir+"/power_supply/BAT0/type", "Battery")
	write(t, dir+"/power_supply/BAT0/present", "0")

	if b := (battery{}).Detect(context.Background()); b.Present {
		t.Fatalf("a mouse's battery, or an empty bay, was taken for the machine's: %+v", b)
	}
	if m := (powerMeter{}).Detect(context.Background()); m.Present {
		t.Fatalf("a device's battery was taken for a meter: %+v", m)
	}
}

func TestADesktopMeasuresItsProcessorAndItsGraphics(t *testing.T) {
	dir := sysfs(t)
	write(t, dir+"/powercap/intel-rapl:0/name", "package-0")
	write(t, dir+"/powercap/intel-rapl:0/energy_uj", "1")
	// A sub-domain is part of the package, not a second meter.
	write(t, dir+"/powercap/intel-rapl:0:0/name", "core")
	write(t, dir+"/powercap/intel-rapl:0:0/energy_uj", "1")
	write(t, dir+"/drm/card1/device/hwmon/hwmon4/power1_average", "8000000")
	write(t, dir+"/drm/card1/device/mem_info_vram_vendor", "samsung")
	write(t, dir+"/nvidia/0000:01:00.0/information", "x")

	if b := (battery{}).Detect(context.Background()); b.Present {
		t.Fatalf("a desktop has a battery: %+v", b)
	}
	m := powerMeter{}.Detect(context.Background())
	if !m.Present || m.Detail != "processor package-0, graphics card1, graphics nvidia" {
		t.Fatalf("power meter: %+v", m)
	}
}

func TestAMachineWithNothingToReadHasNeither(t *testing.T) {
	sysfs(t)
	b, m := battery{}.Detect(context.Background()), powerMeter{}.Detect(context.Background())
	if b.Present || m.Present || b.How == "" || m.How == "" || !strings.Contains(m.Detail, "nothing") {
		t.Fatalf("%+v %+v", b, m)
	}
}

func TestAPackageShownTwiceIsOneMeterAndIntegratedGraphicsAreNone(t *testing.T) {
	dir := sysfs(t)
	write(t, dir+"/powercap/intel-rapl:0/name", "package-0")
	write(t, dir+"/powercap/intel-rapl:0/energy_uj", "1")
	write(t, dir+"/powercap/intel-rapl-mmio:0/name", "package-0")
	write(t, dir+"/powercap/intel-rapl-mmio:0/energy_uj", "1")
	// An APU's graphics: power reported, no memory of its own.
	write(t, dir+"/drm/card1/device/hwmon/hwmon5/power1_average", "19000000")
	m := powerMeter{}.Detect(context.Background())
	if !m.Present || m.Detail != "processor package-0" {
		t.Fatalf("power meter: %+v", m)
	}
}

func TestOnlyIntegratedGraphicsMeasureNothing(t *testing.T) {
	dir := sysfs(t)
	write(t, dir+"/drm/card0/device/hwmon/hwmon1/power1_input", "5000000")
	if m := (powerMeter{}).Detect(context.Background()); m.Present {
		t.Fatalf("integrated graphics were taken for a meter: %+v", m)
	}
}

func TestABatteryOfUnknownScopeIsTheMachines(t *testing.T) {
	// Many laptops' firmware says nothing of scope; the kernel reports Unknown. Only Device is a
	// peripheral's.
	dir := sysfs(t)
	write(t, dir+"/power_supply/BAT0/type", "Battery")
	write(t, dir+"/power_supply/BAT0/scope", "Unknown")
	if b := (battery{}).Detect(context.Background()); !b.Present || b.Detail != "BAT0" {
		t.Fatalf("battery: %+v", b)
	}
}