package packer

import (
	"context"
	"fmt"
	"log"

	"github.com/hashicorp/hcp-sdk-go/clients/cloud-packer-service/preview/2021-04-30/models"
	packersdk "github.com/hashicorp/packer-plugin-sdk/packer"
	registryimage "github.com/hashicorp/packer-plugin-sdk/packer/registry/image"
	packerregistry "github.com/hashicorp/packer/internal/registry"
	"github.com/mitchellh/mapstructure"
)

type RegistryBuilder struct {
	Name                      string
	ArtifactMetadataPublisher *packerregistry.Bucket
	packersdk.Builder
}

func (b *RegistryBuilder) Prepare(raws ...interface{}) ([]string, []string, error) {
	return b.Builder.Prepare(raws...)
}

// Run is where the actual build should take place. It takes a Build and a Ui.
func (b *RegistryBuilder) Run(ctx context.Context, ui packersdk.Ui, hook packersdk.Hook) (packersdk.Artifact, error) {

	if !b.ArtifactMetadataPublisher.IsExpectingBuildForComponent(b.Name) {
		ui.Error(fmt.Sprintf("The build for %q in iteration %q has already been marked as DONE; Skipping build to prevent drift.", b.Name, b.ArtifactMetadataPublisher.Iteration.ID))
		return nil, nil
	}

	runCompleted := make(chan struct{})
	go func() {
		for {
			select {
			case <-ctx.Done():
				log.Printf("[TRACE] marking build %q as cancelled in HCP Packer registry", b.Name)
				if err := b.ArtifactMetadataPublisher.UpdateBuildStatus(context.TODO(), b.Name, models.HashicorpCloudPackerBuildStatusCANCELLED); err != nil {
					log.Printf("[TRACE] failed to update HCP Packer registry status for %q: %s", b.Name, err)
				}
				return
			case <-runCompleted:
				return
			}
		}
	}()

	if err := b.ArtifactMetadataPublisher.UpdateBuildStatus(ctx, b.Name, models.HashicorpCloudPackerBuildStatusRUNNING); err != nil {
		log.Printf("[TRACE] failed to update HCP Packer registry status for %q: %s", b.Name, err)
	}

	ui.Say(fmt.Sprintf("Publishing build details for %s to the HCP Packer registry", b.Name))
	artifact, err := b.Builder.Run(ctx, ui, hook)
	if err != nil {
		if parErr := b.ArtifactMetadataPublisher.UpdateBuildStatus(ctx, b.Name, models.HashicorpCloudPackerBuildStatusFAILED); parErr != nil {
			log.Printf("[TRACE] failed to update HCP Packer registry status for %q: %s", b.Name, parErr)
		}
	}

	// close chan to mark completion
	close(runCompleted)

	if err != nil {
		return nil, err
	}

	if artifact == nil {
		return nil, nil
	}

	var images []registryimage.Image
	decoder, err := mapstructure.NewDecoder(&mapstructure.DecoderConfig{
		Result:           &images,
		WeaklyTypedInput: true,
		ErrorUnused:      false,
	})
	if err != nil {
		return artifact, fmt.Errorf("failed to create decoder for HCP Packer registry image: %w", err)
	}

	state := artifact.State(registryimage.ArtifactStateURI)
	err = decoder.Decode(state)
	if err != nil {
		return artifact, fmt.Errorf("failed to obtain HCP Packer registry image from build artifact: %w", err)
	}

	err = b.ArtifactMetadataPublisher.UpdateImageForBuild(b.Name, images...)
	if err != nil {
		return artifact, fmt.Errorf("failed to add image artifact for %q: %s", b.Name, err)
	}

	return artifact, nil
}
