// monorepo/cloud/backend/internal/maplefile/interface/http/collection/create.go
package collection

import (
	"bytes"
	"context"
	"encoding/json"
	"io"
	"net/http"

	"go.uber.org/zap"

	"codeberg.org/mapleopentech/monorepo/cloud/maplefile-backend/config"
	"codeberg.org/mapleopentech/monorepo/cloud/maplefile-backend/internal/interface/http/middleware"
	svc_collection "codeberg.org/mapleopentech/monorepo/cloud/maplefile-backend/internal/service/collection"
	"codeberg.org/mapleopentech/monorepo/cloud/maplefile-backend/pkg/httperror"
)

type CreateCollectionHTTPHandler struct {
	config     *config.Configuration
	logger     *zap.Logger
	service    svc_collection.CreateCollectionService
	middleware middleware.Middleware
}

func NewCreateCollectionHTTPHandler(
	config *config.Configuration,
	logger *zap.Logger,
	service svc_collection.CreateCollectionService,
	middleware middleware.Middleware,
) *CreateCollectionHTTPHandler {
	logger = logger.Named("CreateCollectionHTTPHandler")
	return &CreateCollectionHTTPHandler{
		config:     config,
		logger:     logger,
		service:    service,
		middleware: middleware,
	}
}

func (*CreateCollectionHTTPHandler) Pattern() string {
	return "POST /api/v1/collections"
}

func (h *CreateCollectionHTTPHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	// Apply middleware before handling the request
	h.middleware.Attach(h.Execute)(w, req)
}

func (h *CreateCollectionHTTPHandler) unmarshalRequest(
	ctx context.Context,
	r *http.Request,
) (*svc_collection.CreateCollectionRequestDTO, error) {
	// Initialize our structure which will store the parsed request data
	var requestData svc_collection.CreateCollectionRequestDTO

	defer r.Body.Close()

	var rawJSON bytes.Buffer
	teeReader := io.TeeReader(r.Body, &rawJSON) // TeeReader allows you to read the JSON and capture it

	// Read the JSON string and convert it into our golang struct
	err := json.NewDecoder(teeReader).Decode(&requestData)
	if err != nil {
		h.logger.Error("Failed to decode create collection request",
			zap.Error(err),
			zap.String("json", rawJSON.String()),
		)
		return nil, httperror.NewBadRequestError("Invalid request payload. Please check your collection data.")
	}

	return &requestData, nil
}

func (h *CreateCollectionHTTPHandler) Execute(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()

	req, err := h.unmarshalRequest(ctx, r)
	if err != nil {
		h.logger.Error("Failed to unmarshal create collection request", zap.Error(err))
		httperror.RespondWithError(w, r, err)
		return
	}

	resp, err := h.service.Execute(ctx, req)
	if err != nil {
		h.logger.Error("Failed to create collection", zap.Error(err))
		// Service returns RFC 9457 errors, use RespondWithError to handle them
		httperror.RespondWithError(w, r, err)
		return
	}

	if resp == nil {
		h.logger.Error("No collection returned from service")
		problem := httperror.NewInternalServerError("Failed to create collection. Please try again.").
			WithInstance(r.URL.Path).
			WithTraceID(httperror.ExtractRequestID(r))
		httperror.RespondWithProblem(w, problem)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusCreated)
	if err := json.NewEncoder(w).Encode(resp); err != nil {
		h.logger.Error("Failed to encode collection response", zap.Error(err))
		// At this point headers are already sent, log the error but can't send RFC 9457 response
		return
	}
}