package datablocks

import (
	"encoding/json"
	"fmt"
	"net/http"
	"strconv"
	"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 DatablocksAdapter struct {
	EndpointTemplate *template.Template
}

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

	errs := make([]error, 0, len(request.Imp))
	headers := http.Header{
		"Content-Type": {"application/json"},
		"Accept":       {"application/json"},
	}

	// Pull the source ID info from the bidder params.
	reqImps, err := splitImpressions(request.Imp)

	if err != nil {
		errs = append(errs, err)
	}

	requests := []*adapters.RequestData{}

	for reqExt, reqImp := range reqImps {
		request.Imp = reqImp
		reqJson, err := json.Marshal(request)

		if err != nil {
			errs = append(errs, err)
			continue
		}

		urlParams := macros.EndpointTemplateParams{SourceId: strconv.Itoa(reqExt.SourceId)}
		url, err := macros.ResolveMacros(a.EndpointTemplate, urlParams)

		if err != nil {
			errs = append(errs, err)
			continue
		}

		request := adapters.RequestData{
			Method:  "POST",
			Uri:     url,
			Body:    reqJson,
			Headers: headers,
			ImpIDs:  openrtb_ext.GetImpIDs(request.Imp)}

		requests = append(requests, &request)
	}

	return requests, errs
}

/*
internal original request in OpenRTB, external = result of us having converted it (what comes out of MakeRequests)
*/
func (a *DatablocksAdapter) 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.StatusOK {
		return nil, []error{&errortypes.BadServerResponse{
			Message: fmt.Sprintf("ERR, response with status %d", response.StatusCode),
		}}
	}

	var bidResp openrtb2.BidResponse

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

	bidResponse := adapters.NewBidderResponse()
	bidResponse.Currency = bidResp.Cur

	for _, seatBid := range bidResp.SeatBid {
		for i := 0; i < len(seatBid.Bid); i++ {
			bid := seatBid.Bid[i]
			bidResponse.Bids = append(bidResponse.Bids, &adapters.TypedBid{
				Bid:     &bid,
				BidType: getMediaType(bid.ImpID, internalRequest.Imp),
			})
		}
	}

	return bidResponse, nil
}

func splitImpressions(imps []openrtb2.Imp) (map[openrtb_ext.ExtImpDatablocks][]openrtb2.Imp, error) {

	var m = make(map[openrtb_ext.ExtImpDatablocks][]openrtb2.Imp)

	for _, imp := range imps {
		bidderParams, err := getBidderParams(&imp)
		if err != nil {
			return nil, err
		}

		v, ok := m[*bidderParams]
		if ok {
			m[*bidderParams] = append(v, imp)
		} else {
			m[*bidderParams] = []openrtb2.Imp{imp}
		}
	}

	return m, nil
}

func getBidderParams(imp *openrtb2.Imp) (*openrtb_ext.ExtImpDatablocks, error) {
	var bidderExt adapters.ExtImpBidder
	if err := jsonutil.Unmarshal(imp.Ext, &bidderExt); err != nil {
		return nil, &errortypes.BadInput{
			Message: fmt.Sprintf("Missing bidder ext: %s", err.Error()),
		}
	}
	var datablocksExt openrtb_ext.ExtImpDatablocks
	if err := jsonutil.Unmarshal(bidderExt.Bidder, &datablocksExt); err != nil {
		return nil, &errortypes.BadInput{
			Message: fmt.Sprintf("Cannot Resolve sourceId: %s", err.Error()),
		}
	}

	if datablocksExt.SourceId < 1 {
		return nil, &errortypes.BadInput{
			Message: "Invalid/Missing SourceId",
		}
	}

	return &datablocksExt, nil
}

func getMediaType(impID string, imps []openrtb2.Imp) openrtb_ext.BidType {

	bidType := openrtb_ext.BidTypeBanner

	for _, imp := range imps {
		if imp.ID == impID {
			if imp.Video != nil {
				bidType = openrtb_ext.BidTypeVideo
				break
			} else if imp.Native != nil {
				bidType = openrtb_ext.BidTypeNative
				break
			} else {
				bidType = openrtb_ext.BidTypeBanner
				break
			}
		}
	}

	return bidType
}

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

	bidder := &DatablocksAdapter{
		EndpointTemplate: template,
	}
	return bidder, nil
}