package example

import (
	"context"
	"fmt"
	"slices"

	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/yaml"

	"edge-infra.dev/pkg/sds/display/displaymanager/applier"
	examplereader "edge-infra.dev/pkg/sds/display/displaymanager/reader/example"
	v2 "edge-infra.dev/pkg/sds/display/k8s/apis/v2"
)

// Returns a new DisplayApplier which simply logs the display configuration to be applied.
func NewExampleDisplayApplier(withLogging bool) applier.DisplayApplier {
	return &exampleApplier{
		withLogging: withLogging,
	}
}

type exampleApplier struct {
	withLogging bool
}

func (a *exampleApplier) Apply(ctx context.Context, displayConfig *v2.DisplayConfig) (*v2.DisplayConfig, error) {
	log := ctrl.LoggerFrom(ctx)

	filterInputDeviceMappings(displayConfig, examplereader.HostInputDevices)

	bytes, err := yaml.Marshal(displayConfig)
	if err != nil {
		return nil, err
	}

	if a.withLogging {
		log.Info("applying display configuration", "DisplayConfig", displayConfig)
		fmt.Printf("\nApplying display configuration:\n\n%s\n", string(bytes))
	}

	return displayConfig, nil
}

// Removes mappings from the display config where a matching input device does not exist,
// or it was already mapped to another display.
func filterInputDeviceMappings(displayConfig *v2.DisplayConfig, inputDevices []v2.InputDeviceName) {
	for _, display := range displayConfig.Displays {
		displayInputDevices := []v2.InputDeviceName{}

		for _, inputDevice := range display.InputDeviceMappings {
			if slices.Contains(inputDevices, inputDevice) {
				displayInputDevices = append(displayInputDevices, inputDevice)
			}
		}

		display.InputDeviceMappings = displayInputDevices
		displayConfig.Displays.UpdateDisplay(display)
	}
}