package handler

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"

	"nf-repo/internal/controller"
	"nf-repo/internal/interfaces"
	"nf-repo/internal/model"
	"nf-repo/internal/tool/rerr"

	v1 "github.com/google/go-containerregistry/pkg/v1"
	"github.com/loveuer/nf"
	"github.com/loveuer/nf/nft/log"
)

func handleManifest(ctx *nf.Ctx, m interfaces.ManifestHandler, blobHandler interfaces.BlobHandler) error {
	elem := strings.Split(ctx.Path(), "/")
	elem = elem[1:]
	target := elem[len(elem)-1]
	repo := strings.Join(elem[1:len(elem)-2], "/")

	log.Debug("handleManifest: path = %s, method = %s, repo = %s, target = %s",
		ctx.Path(), ctx.Method(), repo, target)

	switch ctx.Method() {
	case http.MethodGet:
		var (
			err         error
			reader      io.ReadCloser
			contentType string
			re          *rerr.RepositoryError
			bs          []byte
		)

		if reader, contentType, re = m.Get(ctx.Request.Context(), repo, target); re != nil {
			if re.Status == 404 {
				log.Debug("handleManifest: repo not found, start pull, repo = %s, tag = %s", repo, target)
				var manifest *v1.Manifest
				if manifest, err = controller.PullRepo(ctx.Context(), repo, target, "", m, blobHandler); err != nil {
					return rerr.Error(ctx, &rerr.RepositoryError{
						Status:  http.StatusInternalServerError,
						Code:    "INTERNAL_SERVER_ERROR",
						Message: err.Error(),
					})
				}

				contentType = string(manifest.MediaType)
				bs, _ = json.Marshal(manifest)
				goto RETURN_GET
			}

			return rerr.Error(ctx, re)
		}

		if bs, err = io.ReadAll(reader); err != nil {
			return rerr.Error(ctx, &rerr.RepositoryError{
				Status:  http.StatusInternalServerError,
				Code:    "INTERNAL_SERVER_ERROR",
				Message: err.Error(),
			})
		}

	RETURN_GET:

		h, _, _ := model.SHA256(bytes.NewReader(bs))
		ctx.Set("Docker-Content-Digest", h.String())
		ctx.Set("Content-Type", contentType)
		ctx.Set("Content-Length", fmt.Sprint(len(bs)))
		ctx.Status(http.StatusOK)
		_, err = ctx.Write(bs)
		return err

	case http.MethodHead:
		var (
			err         error
			reader      io.ReadCloser
			contentType string
			re          *rerr.RepositoryError
			bs          []byte
		)

		if reader, contentType, re = m.Get(ctx.Request.Context(), repo, target); re != nil {
			return rerr.Error(ctx, re)
		}

		if bs, err = io.ReadAll(reader); err != nil {
			return rerr.Error(ctx, &rerr.RepositoryError{
				Status:  http.StatusInternalServerError,
				Code:    "INTERNAL_SERVER_ERROR",
				Message: err.Error(),
			})
		}

		h, _, _ := model.SHA256(bytes.NewReader(bs))
		ctx.Set("Docker-Content-Digest", h.String())
		ctx.Set("Content-Type", contentType)
		ctx.Set("Content-Length", fmt.Sprint(len(bs)))

		return ctx.SendStatus(http.StatusOK)

	case http.MethodPut:
		var (
			err  error
			buf  = &bytes.Buffer{}
			hash model.Hash
		)

		if _, err = io.Copy(buf, ctx.Request.Body); err != nil {
			return rerr.Error(ctx, rerr.ErrInternal(err))
		}

		if hash, _, err = model.SHA256(bytes.NewReader(buf.Bytes())); err != nil {
			return rerr.Error(ctx, rerr.ErrInternal(err))
		}

		digest := hash.String()

		mf := model.RepoSimpleManifest{
			Blob:        buf.Bytes(),
			ContentType: ctx.Get("Content-Type"),
		}

		log.Debug("handleManifest: path = %s, method = %s, repo = %s, target = %s, digest = %s, content-type = %s, content = %s",
			ctx.Path(), ctx.Method(), repo, target, digest, ctx.Get("Content-Type"), buf.String())

		if err := m.Put(ctx.Request.Context(), repo, target, digest, &mf); err != nil {
			return rerr.Error(ctx, err)
		}

		ctx.Set("Docker-Content-Digest", digest)
		return ctx.SendStatus(http.StatusCreated)

	case http.MethodDelete:
		return ctx.SendStatus(http.StatusAccepted)

	default:
		return rerr.Error(ctx, &rerr.RepositoryError{
			Status:  http.StatusBadRequest,
			Code:    "METHOD_UNKNOWN",
			Message: "We don't understand your method + url",
		})
	}
}