package jar

import (
	"crypto/rand"
	"encoding/hex"
	"errors"
	"fmt"
	"io"
	"net/http"
	"os"
	"strings"

	"flink-kube-operator/pkg"

	"github.com/google/go-containerregistry/pkg/authn"
	"github.com/google/go-containerregistry/pkg/name"
	"github.com/google/go-containerregistry/pkg/v1/remote"
	"github.com/google/go-containerregistry/pkg/v1/types"
	api "github.com/logi-camp/go-flink-client"
	"go.uber.org/zap"
)

type JarFile struct {
	ref               string
	filePath          string
	digest            string
	basicAuthUsername *string
	basicAuthPassword *string
	auth              authn.Authenticator
}

// NewJarFile creates a JarFile from an OCI reference, pulling the artifact.
// auth is the OCI authenticator (from pull secret or env vars). Use authn.Anonymous for public registries.
func NewJarFile(ref string, auth authn.Authenticator) (*JarFile, error) {
	jarFile := &JarFile{
		ref:  ref,
		auth: auth,
	}
	err := jarFile.Pull()
	if err != nil {
		return nil, err
	}
	return jarFile, nil
}

// NewJarFileFromURI creates a JarFile from an HTTP URI (deprecated path, kept for backward compat).
func NewJarFileFromURI(uri string, basicAuthUsername *string, basicAuthPassword *string) (*JarFile, error) {
	jarFile := &JarFile{
		ref:               uri,
		basicAuthUsername: basicAuthUsername,
		basicAuthPassword: basicAuthPassword,
	}
	err := jarFile.Download()
	if err != nil {
		return nil, err
	}
	return jarFile, nil
}

func (jarFile *JarFile) Upload(flinkClient *api.Client) (fileName string, err error) {
	resp, err := flinkClient.UploadJar(jarFile.filePath)
	if err != nil {
		pkg.Logger.Error("[jar] error uploading jar", zap.Error(err))
		return "", err
	}
	filePathParts := strings.Split(resp.FileName, "/")
	fileName = filePathParts[len(filePathParts)-1]
	if resp.Status != "success" {
		err = errors.New("jar upload was not success")
	}
	jarFile.delete()
	return
}

func (jarFile *JarFile) Digest() string {
	return jarFile.digest
}

func (jarFile *JarFile) Pull() error {
	randBytes := make([]byte, 16)
	rand.Read(randBytes)
	fileName := hex.EncodeToString(randBytes)
	jarFile.filePath = "/tmp/" + fileName + ".jar"

	ref, err := name.ParseReference(jarFile.ref)
	if err != nil {
		return fmt.Errorf("parsing OCI reference %q: %w", jarFile.ref, err)
	}

	img, err := remote.Image(ref, remote.WithAuth(jarFile.auth))
	if err != nil {
		return fmt.Errorf("fetching OCI image %q: %w", jarFile.ref, err)
	}

	d, err := img.Digest()
	if err != nil {
		return fmt.Errorf("getting image digest: %w", err)
	}
	jarFile.digest = d.String()

	layers, err := img.Layers()
	if err != nil {
		return fmt.Errorf("getting image layers: %w", err)
	}
	if len(layers) == 0 {
		return fmt.Errorf("OCI image %q has no layers", jarFile.ref)
	}

	layer := layers[0]
	mediaType, err := layer.MediaType()
	if err != nil {
		return fmt.Errorf("getting layer media type: %w", err)
	}
	if mediaType != types.OCILayer && mediaType != types.OCIUncompressedLayer && mediaType != types.DockerLayer && mediaType != types.DockerUncompressedLayer && string(mediaType) != "application/java-archive" {
		pkg.Logger.Warn("[jar] unexpected layer media type, expected application/java-archive or standard OCI layer",
			zap.String("got", string(mediaType)),
			zap.String("ref", jarFile.ref),
		)
	}

	blob, err := layer.Compressed()
	if err != nil {
		return fmt.Errorf("reading layer blob: %w", err)
	}
	defer blob.Close()

	out, err := os.Create(jarFile.filePath)
	if err != nil {
		return fmt.Errorf("creating temp file: %w", err)
	}
	defer out.Close()

	_, err = io.Copy(out, blob)
	if err != nil {
		jarFile.delete()
		return fmt.Errorf("writing layer to disk: %w", err)
	}

	pkg.Logger.Info("[jar] pulled OCI artifact",
		zap.String("ref", jarFile.ref),
		zap.String("digest", jarFile.digest),
		zap.String("path", jarFile.filePath),
	)
	return nil
}

func (jarFile *JarFile) Download() error {
	randBytes := make([]byte, 16)
	rand.Read(randBytes)
	fileName := hex.EncodeToString(randBytes)
	jarFile.filePath = "/tmp/" + fileName + ".jar"
	out, err := os.Create(jarFile.filePath)
	if err != nil {
		return err
	}

	defer out.Close()

	var resp *http.Response
	if jarFile.basicAuthPassword != nil && jarFile.basicAuthUsername != nil {
		req, err := http.NewRequest("GET", jarFile.ref, nil)
		if err != nil {
			jarFile.delete()
			return err
		}
		req.SetBasicAuth(*jarFile.basicAuthUsername, *jarFile.basicAuthPassword)
		resp, err = http.DefaultClient.Do(req)
	} else {
		resp, err = http.Get(jarFile.ref)
	}
	if err != nil {
		jarFile.delete()
		pkg.Logger.Error("error in downloading jar", zap.Error(err))
		return err
	}
	if resp.StatusCode > 299 {
		err = fmt.Errorf("download failed: status %s", resp.Status)
		pkg.Logger.Error("error in downloading jar", zap.Error(err))
		return err
	}

	defer resp.Body.Close()
	_, err = io.Copy(out, resp.Body)
	if err != nil {
		return err
	}
	return nil
}

func (jarFile *JarFile) delete() error {
	pkg.Logger.Info("[jar] [delete]", zap.String("path", jarFile.filePath))
	err := os.Remove(jarFile.filePath)
	if err != nil {
		pkg.Logger.Error("[jar] [delete]", zap.Error(err))
	}
	return err
}