package main

import (
	"encoding/json"
	"io/ioutil"
	"log"
	"mime/multipart"
	"net/http"
	"runtime/debug"
)

func sendJSON(w http.ResponseWriter, jsonMessage interface{}) {
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(jsonMessage)
}

func sendError(w http.ResponseWriter, err YggError) {
	if config.DebugMode {
		log.Printf("Send error: %s\n", err.ErrorMessage)
	}
	w.WriteHeader(err.Code)
	sendJSON(w, err)
}

func unmarshalTo(r *http.Request, v any) error {
	body, err := ioutil.ReadAll(r.Body)
	if err != nil {
		return err
	}
	err = json.Unmarshal(body, &v)
	if err != nil {
		return err
	}
	return nil
}

func handleError(w http.ResponseWriter, err error) {
	sendError(w, YggError{Code: 500, Error: "Unspecified error", ErrorMessage: "An error has occured handling your request."})
	log.Println("error processing request:", err)
	if config.DebugMode {
		debug.PrintStack()
	}
}

func sendEmpty(w http.ResponseWriter) {
	w.WriteHeader(http.StatusNoContent)
}

func recievePNG(filename string, w http.ResponseWriter, r *http.Request) ([]byte, *multipart.FileHeader, error) {
	file, header, err := r.FormFile(filename)
	if err != nil {
		return []byte{}, header, err
	}

	bytes, err := ioutil.ReadAll(file)
	if err != nil {
		return bytes, header, err
	}

	if len(bytes) < 4 ||
		bytes[0] != 0x89 ||
		bytes[1] != 0x50 ||
		bytes[2] != 0x4e ||
		bytes[3] != 0x47 {
		return bytes, header, &InvalidDataError{}
	}

	return bytes, header, nil
}