package handler

import (
	"bytes"
	"encoding/json"
	"fmt"
	"github.com/loveuer/nf"
	"io"
	"net/http"
	"nf-repo/internal/interfaces"
	"nf-repo/internal/model"
	"nf-repo/internal/model/types"
	"nf-repo/internal/util/rerr"
	"strings"
)

func handleReferrers(ctx *nf.Ctx, m interfaces.ManifestHandler) error {
	if ctx.Method() != "GET" {
		return rerr.Error(ctx, &rerr.RepositoryError{
			Status:  http.StatusBadRequest,
			Code:    "METHOD_UNKNOWN",
			Message: "We don't understand your method + url",
		})
	}

	elem := strings.Split(ctx.Path(), "/")
	elem = elem[1:]
	target := elem[len(elem)-1]
	repo := strings.Join(elem[1:len(elem)-2], "/")

	var (
		err error
		re  *rerr.RepositoryError
		im  *model.IndexManifest
	)

	// Validate that incoming target is a valid digest
	if _, err := model.NewHash(target); err != nil {
		return rerr.Error(ctx, &rerr.RepositoryError{
			Status:  http.StatusBadRequest,
			Code:    "UNSUPPORTED",
			Message: "Target must be a valid digest",
		})
	}

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

	msg, _ := json.Marshal(im)
	ctx.Set("Content-Length", fmt.Sprint(len(msg)))
	ctx.Set("Content-Type", string(types.OCIImageIndex))
	ctx.Status(http.StatusOK)
	_, err = io.Copy(ctx.RawWriter(), bytes.NewReader(msg))

	return err
}