package epom

import (
	"encoding/json"
	"fmt"
	"net/http"

	"github.com/prebid/openrtb/v20/openrtb2"
	"github.com/prebid/prebid-server/v4/adapters"
	"github.com/prebid/prebid-server/v4/config"
	"github.com/prebid/prebid-server/v4/errortypes"
	"github.com/prebid/prebid-server/v4/openrtb_ext"
	"github.com/prebid/prebid-server/v4/util/jsonutil"
)

type adapter struct {
	endpoint string
}

// Builder builds a new instance of the Epom adapter for the given bidder with the given config.
func Builder(bidderName openrtb_ext.BidderName, config config.Adapter, server config.Server) (adapters.Bidder, error) {
	bidder := &adapter{
		endpoint: config.Endpoint,
	}
	return bidder, nil
}

func (a *adapter) MakeRequests(request *openrtb2.BidRequest, reqInfo *adapters.ExtraRequestInfo) (requests []*adapters.RequestData, errors []error) {
	rq, errs := a.makeRequest(request)

	if len(errs) > 0 {
		return nil, errs
	}

	if rq != nil {
		requests = append(requests, rq)
	}

	return requests, nil
}

func (a *adapter) makeRequest(request *openrtb2.BidRequest) (*adapters.RequestData, []error) {
	if request.Device == nil || request.Device.IP == "" {
		return nil, []error{&errortypes.BadInput{
			Message: "ipv4 address is required field",
		}}
	}

	reqJSON, err := json.Marshal(request)
	if err != nil {
		return nil, []error{err}
	}

	headers := http.Header{}
	headers.Add("Content-Type", "application/json;charset=utf-8")
	headers.Add("Accept", "application/json")
	return &adapters.RequestData{
		Method:  "POST",
		Uri:     a.endpoint,
		Body:    reqJSON,
		Headers: headers,
		ImpIDs:  openrtb_ext.GetImpIDs(request.Imp),
	}, nil
}

func (a *adapter) MakeBids(internalRequest *openrtb2.BidRequest, externalRequest *adapters.RequestData, response *adapters.ResponseData) (*adapters.BidderResponse, []error) {
	if response.StatusCode == http.StatusNoContent {
		return nil, nil
	}

	if response.StatusCode >= http.StatusInternalServerError {
		return nil, []error{&errortypes.BadServerResponse{
			Message: fmt.Sprintf("Unexpected status code: %d. Dsp server internal error", response.StatusCode),
		}}
	}

	if response.StatusCode >= http.StatusBadRequest {
		return nil, []error{&errortypes.BadInput{
			Message: fmt.Sprintf("Unexpected status code: %d. Bad request to dsp", response.StatusCode),
		}}
	}

	if response.StatusCode != http.StatusOK {
		return nil, []error{&errortypes.BadServerResponse{
			Message: fmt.Sprintf("Unexpected status code: %d", response.StatusCode),
		}}
	}

	var bidResp openrtb2.BidResponse
	if err := jsonutil.Unmarshal(response.Body, &bidResp); err != nil {
		return nil, []error{err}
	}

	//additional no content check
	if len(bidResp.SeatBid) == 0 || len(bidResp.SeatBid[0].Bid) == 0 {
		return nil, []error{&errortypes.Warning{
			Message: "No bids in response",
		}}
	}

	bidResponse := adapters.NewBidderResponseWithBidsCapacity(len(bidResp.SeatBid[0].Bid))

	var errs []error
	for _, seatBid := range bidResp.SeatBid {
		for _, bid := range seatBid.Bid {
			b := &adapters.TypedBid{
				Bid:     &bid,
				BidType: getMediaTypeForImp(bid.ImpID, internalRequest.Imp),
			}
			bidResponse.Bids = append(bidResponse.Bids, b)
		}
	}
	return bidResponse, errs
}

func getMediaTypeForImp(impID string, imps []openrtb2.Imp) openrtb_ext.BidType {
	for _, imp := range imps {
		if imp.ID == impID {
			if imp.Banner != nil {
				return openrtb_ext.BidTypeBanner
			} else if imp.Video != nil {
				return openrtb_ext.BidTypeVideo
			} else if imp.Native != nil {
				return openrtb_ext.BidTypeNative
			}
		}
	}
	return openrtb_ext.BidTypeBanner
}