package backend

import (
	"context"
	"log/slog"
	"testing"
)

func testLogger() *slog.Logger {
	return slog.New(slog.NewTextHandler(testDiscard{}, nil))
}

type testDiscard struct{}

func (testDiscard) Write(p []byte) (int, error) { return len(p), nil }

func TestResolveMonitorNamesSerial(t *testing.T) {
	current := []MonitorInfo{
		{Name: "eDP-1", Description: "Lenovo", Width: 1920, Height: 1200},
		{Name: "DP-12", Description: "Xiaomi Mi Monitor", Serial: "3342300033911", Width: 2560, Height: 1440},
		{Name: "DP-11", Description: "Xiaomi Mi Monitor", Serial: "", Width: 3440, Height: 1440},
	}
	getMonitors := func(context.Context) ([]MonitorInfo, error) { return current, nil }

	monitors := []MonitorConfig{
		{Name: "serial:3342300033911", Enabled: true},
		{Name: "eDP-1", Enabled: false},
	}
	resolved, err := resolveMonitorNames(context.Background(), monitors, getMonitors, testLogger())
	if err != nil {
		t.Fatalf("resolveMonitorNames: %v", err)
	}
	if resolved[0].Name != "DP-12" {
		t.Errorf("serial should resolve to DP-12, got %q", resolved[0].Name)
	}
	if resolved[1].Name != "eDP-1" {
		t.Errorf("plain name should pass through, got %q", resolved[1].Name)
	}
}

func TestResolveMonitorNamesSerialNoMatch(t *testing.T) {
	current := []MonitorInfo{
		{Name: "DP-12", Description: "Xiaomi", Serial: "3342300033911"},
	}
	getMonitors := func(context.Context) ([]MonitorInfo, error) { return current, nil }

	monitors := []MonitorConfig{{Name: "serial:9999999999", Enabled: true}}
	if _, err := resolveMonitorNames(context.Background(), monitors, getMonitors, testLogger()); err == nil {
		t.Error("unresolvable serial should return an error")
	}
}

func TestResolveMonitorNamesSerialMultipleMatches(t *testing.T) {
	current := []MonitorInfo{
		{Name: "DP-1", Serial: "SN-XYZ"},
		{Name: "DP-2", Serial: "SN-XYZ"},
	}
	getMonitors := func(context.Context) ([]MonitorInfo, error) { return current, nil }

	monitors := []MonitorConfig{{Name: "serial:SN-XYZ", Enabled: true}}
	if _, err := resolveMonitorNames(context.Background(), monitors, getMonitors, testLogger()); err == nil {
		t.Error("ambiguous serial match should return an error")
	}
}

func TestResolveMonitorNamesDescAlsoMatchesSerial(t *testing.T) {
	current := []MonitorInfo{
		{Name: "DP-12", Description: "Generic", Serial: "3342300033911"},
	}
	getMonitors := func(context.Context) ([]MonitorInfo, error) { return current, nil }

	monitors := []MonitorConfig{{Name: "desc:3342300033911", Enabled: true}}
	resolved, err := resolveMonitorNames(context.Background(), monitors, getMonitors, testLogger())
	if err != nil {
		t.Fatalf("resolveMonitorNames: %v", err)
	}
	if resolved[0].Name != "DP-12" {
		t.Errorf("desc should match via serial, got %q", resolved[0].Name)
	}
}