package main

import (
	"encoding/json"
	"net/http"
)

const authProxyKeyIDHeader = "Auth-Proxy-Key-ID"

type apiError struct {
	Status      int
	Code        string
	Description string
}

func (e *apiError) Error() string {
	return e.Description
}

func invalidRequestError(description string) *apiError {
	return &apiError{
		Status:      http.StatusBadRequest,
		Code:        "invalid_request",
		Description: description,
	}
}

func upstreamRequestError(description string) *apiError {
	return &apiError{
		Status:      http.StatusBadGateway,
		Code:        "server_error",
		Description: description,
	}
}

func writeAPIError(w http.ResponseWriter, err error) {
	if apiErr, ok := err.(*apiError); ok {
		writeJSONError(w, apiErr.Status, apiErr.Code, apiErr.Description)
		return
	}

	writeJSONError(w, http.StatusInternalServerError, "server_error", "internal server error")
}

func writeJSONError(w http.ResponseWriter, status int, code string, description string) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(map[string]string{
		"error":             code,
		"error_description": description,
	})
}