package greenled

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

func TestSysfsControllerMapsSerialChannelsInOrder(t *testing.T) {
	root := t.TempDir()
	for channel := 1; channel <= ChannelCount; channel++ {
		state, err := stateForChannel(channel)
		if err != nil {
			t.Fatalf("map channel %d: %v", channel, err)
		}
		if err := os.MkdirAll(filepath.Join(root, state.LEDName), 0o755); err != nil {
			t.Fatalf("create %s: %v", state.LEDName, err)
		}
		if err := os.WriteFile(filepath.Join(root, state.LEDName, "brightness"), []byte("0\n"), 0o644); err != nil {
			t.Fatalf("seed %s: %v", state.LEDName, err)
		}
	}

	controller := NewSysfsController(root)
	states, err := controller.States(context.Background())
	if err != nil {
		t.Fatalf("list states: %v", err)
	}
	if len(states) != ChannelCount {
		t.Fatalf("state count = %d, want %d", len(states), ChannelCount)
	}
	for index, state := range states {
		channel := index + 1
		if state.Channel != "CH"+twoDigits(channel) || state.I2CBus != 3 || state.I2CAddress != expectedAddress(channel) || state.GPIOOffset != (channel-1)%8 || !state.Available || state.Forced {
			t.Fatalf("state for serial CH%02d = %#v", channel, state)
		}
	}
}

func TestSysfsControllerForcesAndPulsesThenReleases(t *testing.T) {
	root := t.TempDir()
	state, err := stateForChannel(9)
	if err != nil {
		t.Fatal(err)
	}
	if err := os.MkdirAll(filepath.Join(root, state.LEDName), 0o755); err != nil {
		t.Fatal(err)
	}
	brightnessPath := filepath.Join(root, state.LEDName, "brightness")
	if err := os.WriteFile(brightnessPath, []byte("0\n"), 0o644); err != nil {
		t.Fatal(err)
	}

	controller := NewSysfsController(root)
	forced, err := controller.SetForce(context.Background(), "ch09", true)
	if err != nil || !forced.Forced || forced.Channel != "CH09" {
		t.Fatalf("force CH09 = %#v, %v", forced, err)
	}
	if value, err := os.ReadFile(brightnessPath); err != nil || string(value) != "1\n" {
		t.Fatalf("brightness after force = %q, %v", value, err)
	}

	released, err := controller.Pulse(context.Background(), "CH09", MinPulseDuration)
	if err != nil || released.Forced {
		t.Fatalf("pulse CH09 = %#v, %v", released, err)
	}
	if value, err := os.ReadFile(brightnessPath); err != nil || string(value) != "0\n" {
		t.Fatalf("brightness after pulse = %q, %v", value, err)
	}
}

func TestSysfsControllerRejectsInvalidChannelAndPulseDuration(t *testing.T) {
	controller := NewSysfsController(t.TempDir())
	if _, err := controller.SetForce(context.Background(), "CH49", true); err == nil {
		t.Fatal("CH49 force unexpectedly succeeded")
	}
	if _, err := controller.Pulse(context.Background(), "CH01", 99*time.Millisecond); err == nil {
		t.Fatal("short pulse unexpectedly succeeded")
	}
}

func twoDigits(value int) string {
	if value < 10 {
		return "0" + string(rune('0'+value))
	}
	return string(rune('0'+value/10)) + string(rune('0'+value%10))
}

func expectedAddress(channel int) string {
	return "0x" + []string{"20", "21", "22", "23", "24", "25"}[(channel-1)/8]
}