package aidem

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

	"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/macros"
	"github.com/prebid/prebid-server/v4/openrtb_ext"
	"github.com/prebid/prebid-server/v4/util/jsonutil"
)

type adapter struct {
	EndpointTemplate *template.Template
}

func (a *adapter) MakeRequests(request *openrtb2.BidRequest, reqInfo *adapters.ExtraRequestInfo) ([]*adapters.RequestData, []error) {

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

	impExt, err := getImpressionExt(&request.Imp[0])
	if err != nil {
		return nil, []error{err}
	}

	url, err := a.buildEndpointURL(impExt)
	if err != nil {
		return nil, []error{err}
	}

	headers := http.Header{}
	headers.Add("Content-Type", "application/json;charset=utf-8")

	return []*adapters.RequestData{{
		Method:  "POST",
		Uri:     url,
		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) {
	var errs []error

	if adapters.IsResponseStatusCodeNoContent(response) {
		return nil, nil
	}

	if err := adapters.CheckResponseStatusCodeForErrors(response); err != nil {
		return nil, []error{&errortypes.BadInput{
			Message: fmt.Sprintf("Unexpected status code: %d. Run with request.debug = 1 for more info", response.StatusCode),
		}}
	}

	var bidResp openrtb2.BidResponse
	if err := jsonutil.Unmarshal(response.Body, &bidResp); err != nil {
		return nil, []error{&errortypes.BadServerResponse{
			Message: fmt.Sprintf("JSON parsing error: %v", err),
		}}
	}

	if len(bidResp.SeatBid) == 0 {
		return nil, []error{&errortypes.BadServerResponse{
			Message: "Empty SeatBid array",
		}}
	}

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

	for _, seatBid := range bidResp.SeatBid {
		for i := range seatBid.Bid {
			bidType, err := getMediaTypeForBid(seatBid.Bid[i])
			if err != nil {
				errs = append(errs, err)
			} else {
				b := &adapters.TypedBid{
					Bid:     &seatBid.Bid[i],
					BidType: bidType,
				}
				bidResponse.Bids = append(bidResponse.Bids, b)
			}
		}
	}
	return bidResponse, errs
}

// Builder builds a new instance of the AIDEM adapter for the given bidder with the given config.
func Builder(bidderName openrtb_ext.BidderName, config config.Adapter, server config.Server) (adapters.Bidder, error) {
	urlTemplate, err := template.New("endpointTemplate").Parse(config.Endpoint)
	if err != nil {
		return nil, fmt.Errorf("unable to parse endpoint url template: %v", err)
	}

	bidder := &adapter{
		EndpointTemplate: urlTemplate,
	}
	return bidder, nil
}

func getMediaTypeForBid(bid openrtb2.Bid) (openrtb_ext.BidType, error) {
	switch bid.MType {
	case openrtb2.MarkupBanner:
		return openrtb_ext.BidTypeBanner, nil
	case openrtb2.MarkupVideo:
		return openrtb_ext.BidTypeVideo, nil
	default:
		return "", fmt.Errorf("Unable to fetch mediaType in multi-format: %s", bid.ImpID)
	}
}

func getImpressionExt(imp *openrtb2.Imp) (*openrtb_ext.ExtImpAidem, error) {
	var bidderExt adapters.ExtImpBidder
	if err := jsonutil.Unmarshal(imp.Ext, &bidderExt); err != nil {
		return nil, &errortypes.BadInput{
			Message: err.Error(),
		}
	}
	var AIDEMExt openrtb_ext.ExtImpAidem
	if err := jsonutil.Unmarshal(bidderExt.Bidder, &AIDEMExt); err != nil {
		return nil, &errortypes.BadInput{
			Message: err.Error(),
		}
	}
	return &AIDEMExt, nil
}

// Builds enpoint url based on adapter-specific pub settings from imp.ext
func (a *adapter) buildEndpointURL(params *openrtb_ext.ExtImpAidem) (string, error) {
	endpointParams := macros.EndpointTemplateParams{PublisherID: params.PublisherId}
	return macros.ResolveMacros(a.EndpointTemplate, endpointParams)
}