package gamoshi

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

	"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 GamoshiAdapter struct {
	URI string
}

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

	errs := make([]error, 0, len(request.Imp))
	if len(request.Imp) == 0 {
		err := &errortypes.BadInput{
			Message: "No impressions in the bid request",
		}
		errs = append(errs, err)
		return nil, errs
	}

	// As of now, Gamoshi supports only banner and video impressions

	validImpExists := false
	for i := 0; i < len(request.Imp); i++ {
		if request.Imp[i].Banner != nil {
			bannerCopy := *request.Imp[i].Banner
			if bannerCopy.W == nil && bannerCopy.H == nil && len(bannerCopy.Format) > 0 {
				firstFormat := bannerCopy.Format[0]
				bannerCopy.W = &(firstFormat.W)
				bannerCopy.H = &(firstFormat.H)
			}
			request.Imp[i].Banner = &bannerCopy
			validImpExists = true
		} else if request.Imp[i].Video != nil {
			validImpExists = true
		} else {
			err := &errortypes.BadInput{
				Message: fmt.Sprintf("Gamoshi only supports banner and video media types. Ignoring imp id=%s", request.Imp[i].ID),
			}
			errs = append(errs, err)
			request.Imp = append(request.Imp[:i], request.Imp[i+1:]...)
			i--
		}
	}

	if !validImpExists {
		err := &errortypes.BadInput{
			Message: "No valid impression in the bid request",
		}
		errs = append(errs, err)
		return nil, errs
	}

	reqJSON, err := json.Marshal(request)
	if err != nil {
		errs = append(errs, err)
		return nil, errs
	}
	errors := make([]error, 0, 1)

	var bidderExt adapters.ExtImpBidder
	err = jsonutil.Unmarshal(request.Imp[0].Ext, &bidderExt)

	if err != nil {
		err = &errortypes.BadInput{
			Message: "ext.bidder not provided",
		}
		errors = append(errors, err)
		return nil, errors
	}
	var gamoshiExt openrtb_ext.ExtImpGamoshi
	err = jsonutil.Unmarshal(bidderExt.Bidder, &gamoshiExt)
	if err != nil {
		err = &errortypes.BadInput{
			Message: "ext.bidder.supplyPartnerId not provided",
		}
		errors = append(errors, err)
		return nil, errors
	}

	if gamoshiExt.SupplyPartnerId == "" {
		err = &errortypes.BadInput{
			Message: "supplyPartnerId is empty",
		}
		errors = append(errors, err)
		return nil, errors
	}

	thisURI := a.URI
	if len(thisURI) == 0 {
		thisURI = "https://rtb.gamoshi.io"
	}
	thisURI = thisURI + "/r/" + gamoshiExt.SupplyPartnerId + "/bidr?bidder=prebid-server"
	headers := http.Header{}
	headers.Add("Content-Type", "application/json;charset=utf-8")
	headers.Add("Accept", "application/json")
	headers.Add("x-openrtb-version", "2.4")

	if request.Device != nil {
		addHeaderIfNonEmpty(headers, "User-Agent", request.Device.UA)
		addHeaderIfNonEmpty(headers, "X-Forwarded-For", request.Device.IP)
		addHeaderIfNonEmpty(headers, "Accept-Language", request.Device.Language)
		if request.Device.DNT != nil {
			addHeaderIfNonEmpty(headers, "DNT", strconv.Itoa(int(*request.Device.DNT)))
		}
	}

	return []*adapters.RequestData{{
		Method:  "POST",
		Uri:     thisURI,
		Body:    reqJSON,
		Headers: headers,
		ImpIDs:  openrtb_ext.GetImpIDs(request.Imp),
	}}, errors
}

func (a *GamoshiAdapter) 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.StatusBadRequest {
		return nil, []error{&errortypes.BadInput{
			Message: fmt.Sprintf("Unexpected status code: %d. ", response.StatusCode),
		}}
	}

	if response.StatusCode != http.StatusOK {
		return nil, []error{&errortypes.BadServerResponse{
			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("bad server response: %v. ", err),
		}}
	}

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

// Adding header fields to request header
func addHeaderIfNonEmpty(headers http.Header, headerName string, headerValue string) {
	if len(headerValue) > 0 {
		headers.Add(headerName, headerValue)
	}
}

func getMediaType(impId string, imps []openrtb2.Imp) openrtb_ext.BidType {
	for _, imp := range imps {
		if imp.ID == impId {
			if imp.Video != nil {
				return openrtb_ext.BidTypeVideo
			}
			return openrtb_ext.BidTypeBanner
		}
	}
	return openrtb_ext.BidTypeBanner
}

// Builder builds a new instance of the Gamoshi 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 := &GamoshiAdapter{
		URI: config.Endpoint,
	}
	return bidder, nil
}