package bootstrap

import (
	"bytes"
	"context"
	"isle/garage"
	"isle/nebula"
	"fmt"
	"path/filepath"
	"strings"

	"github.com/mediocregopher/mediocre-go-lib/v2/mctx"
	"github.com/mediocregopher/mediocre-go-lib/v2/mlog"
	"github.com/minio/minio-go/v7"
	"gopkg.in/yaml.v3"
)

// Paths within garage's global bucket
const (
	garageGlobalBucketBootstrapHostsDirPath = "bootstrap/hosts"
)

// PutGarageBoostrapHost places the <hostname>.yml.signed file for this host
// into garage so that other hosts are able to see relevant configuration for
// it.
func (b Bootstrap) PutGarageBoostrapHost(ctx context.Context) error {

	host := b.ThisHost()
	client := b.GlobalBucketS3APIClient()

	// the base Bootstrap has the public credentials signed by the CA, but we
	// need this to be presented in the data stored into garage, so other hosts
	// can verify that the stored host object is signed by the host public key,
	// and that the host public key is signed by the CA.
	host.Nebula.SignedPublicCredentials = b.Nebula.SignedPublicCredentials

	hostB, err := yaml.Marshal(host)
	if err != nil {
		return fmt.Errorf("yaml encoding host data: %w", err)
	}

	buf := new(bytes.Buffer)

	err = nebula.SignAndWrap(buf, b.Nebula.HostCredentials.SigningPrivateKeyPEM, hostB)
	if err != nil {
		return fmt.Errorf("signing encoded host data: %w", err)
	}

	filePath := filepath.Join(
		garageGlobalBucketBootstrapHostsDirPath,
		host.Name+".yml.signed",
	)

	_, err = client.PutObject(
		ctx, garage.GlobalBucket, filePath, buf, int64(buf.Len()),
		minio.PutObjectOptions{},
	)

	if err != nil {
		return fmt.Errorf("writing to %q in global bucket: %w", filePath, err)
	}

	return nil
}

// RemoveGarageBootstrapHost removes the <hostname>.yml.signed for the given
// host from garage.
//
// The given client should be for the global bucket.
func RemoveGarageBootstrapHost(
	ctx context.Context, client garage.S3APIClient, hostName string,
) error {

	filePath := filepath.Join(
		garageGlobalBucketBootstrapHostsDirPath,
		hostName+".yml.signed",
	)

	return client.RemoveObject(
		ctx, garage.GlobalBucket, filePath,
		minio.RemoveObjectOptions{},
	)
}

// GetGarageBootstrapHosts loads the <hostname>.yml.signed file for all hosts
// stored in garage.
func (b Bootstrap) GetGarageBootstrapHosts(
	ctx context.Context,
	logger *mlog.Logger,
) (
	map[string]Host, error,
) {

	client := b.GlobalBucketS3APIClient()

	hosts := map[string]Host{}

	objInfoCh := client.ListObjects(
		ctx, garage.GlobalBucket,
		minio.ListObjectsOptions{
			Prefix:    garageGlobalBucketBootstrapHostsDirPath,
			Recursive: true,
		},
	)

	for objInfo := range objInfoCh {

		ctx := mctx.Annotate(ctx, "objectKey", objInfo.Key)

		if objInfo.Err != nil {
			return nil, fmt.Errorf("listing objects: %w", objInfo.Err)
		}

		obj, err := client.GetObject(
			ctx, garage.GlobalBucket, objInfo.Key, minio.GetObjectOptions{},
		)

		if err != nil {
			return nil, fmt.Errorf("retrieving object %q: %w", objInfo.Key, err)
		}

		hostB, hostSig, err := nebula.Unwrap(obj)
		obj.Close()

		if err != nil {
			return nil, fmt.Errorf("unwrapping signature from %q: %w", objInfo.Key, err)
		}

		var host Host
		if err = yaml.Unmarshal(hostB, &host); err != nil {
			return nil, fmt.Errorf("yaml decoding object %q: %w", objInfo.Key, err)
		}

		hostPublicCredsB, hostPublicCredsSig, err := nebula.Unwrap(
			strings.NewReader(host.Nebula.SignedPublicCredentials),
		)

		if err != nil {
			logger.Warn(ctx, "unwrapping signed public creds", err)
			continue
		}

		err = nebula.ValidateSignature(
			b.Nebula.CAPublicCredentials.SigningKeyPEM,
			hostPublicCredsB,
			hostPublicCredsSig,
		)

		if err != nil {
			logger.Warn(ctx, "invalid signed public creds", err)
			continue
		}

		var hostPublicCreds nebula.HostPublicCredentials
		if err := yaml.Unmarshal(hostPublicCredsB, &hostPublicCreds); err != nil {
			logger.Warn(ctx, "yaml unmarshaling signed public creds", err)
			continue
		}

		err = nebula.ValidateSignature(hostPublicCreds.SigningKeyPEM, hostB, hostSig)

		if err != nil {
			logger.Warn(ctx, "invalid host data", err)
			continue
		}

		hosts[host.Name] = host
	}

	return hosts, nil
}