package displayconfig

import (
	"context"
	"fmt"

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

var readerOpts = []reader.Option{
	reader.WithDefaultLayout(),
	reader.WithIgnoreRelativeInputDevices(),
	reader.WithIgnoreSupportedResolutions(),
}

// Apply applies the custom display configuration defined by customDisplayConfig.
//
// The current display configuration is read from the node. This is merged with the default configuration,
// then merged with the custom configuration. If the custom configuration is nil, the configuration
// remains as default.
//
// The resulting DisplayConfig is applied to the node and returned.
func Apply(ctx context.Context, customDisplayConfig *v2.DisplayConfig, displayManager manager.DisplayManager) (*v2.DisplayConfig, error) {
	// wait for display manager to become ready before applying configuration
	if err := displayManager.Wait(ctx); err != nil {
		return nil, fmt.Errorf("display manager did not become ready: %w", err)
	}

	// read displays and input devices from node
	displayConfig, inputDevices, err := displayManager.Read(ctx, readerOpts...)
	if err != nil {
		return nil, fmt.Errorf("unable to read display configuration from node: %w", err)
	}

	// apply the default configuration
	displayConfig, err = displayConfig.GenerateDefaultDisplayConfig(v2.Defaults, inputDevices)
	if err != nil {
		return nil, fmt.Errorf("unable to apply defaults to node display configuration: %w", err)
	}

	// merge in custom DisplayConfig (does nothing when nil)
	displayConfig, err = displayConfig.Merge(customDisplayConfig)
	if err != nil {
		return nil, fmt.Errorf("unable to merge node display configuration with NodeDisplayConfig: %w", err)
	}

	// apply the node display configuration
	displayConfig, err = displayManager.Apply(ctx, displayConfig)
	if err != nil {
		return nil, fmt.Errorf("unable to apply node display configuration: %w", err)
	}

	return displayConfig, nil
}