package core

import (
	"fmt"
	"net/http"
)

type (
	ApiRoute struct {
		ServletRoute     *ServletRoute
		HttpMethodRoutes *map[HttpMethod]ServletHandleFunction
	}
)

type (
	HttpMethod int
)

const (
	GET HttpMethod = iota
	POST
	PUT
	PATCH
	DELETE
	UNDEFINED
)

func NewApiRoute(pattern string) *ApiRoute {
	functionMap := make(map[HttpMethod]ServletHandleFunction)
	ancestorRoute := NewServletRoute(pattern, createMethodHandler(&functionMap))
	route := ApiRoute{
		ancestorRoute,
		&functionMap,
	}
	return &route
}

func createMethodHandler(m *map[HttpMethod]ServletHandleFunction) ServletHandleFunction {
	return func(w http.ResponseWriter, req *http.Request) {
		method := getHttpMethod(req)
		fn, exists := (*m)[method]
		if exists {
			fn(w, req)
		} else {
			SendApiError(
				w,
				200,
				404,
				"Method ["+req.Method+"] does not exist for endpoint["+req.URL.Path+"].",
			)
		}
	}
}

func (api *ApiRoute) RegisterHttpMethodHandler(method HttpMethod, handler ServletHandleFunction) {
	(*api.HttpMethodRoutes)[method] = handler
}

func getHttpMethod(req *http.Request) HttpMethod {
	switch req.Method {
	case "GET":
		return GET
	case "POST":
		return POST
	case "PUT":
		return PUT
	case "PATCH":
		return PATCH
	case "DELETE":
		return DELETE
	case "UNDEFINED":
	default:
		return UNDEFINED
	}
	return UNDEFINED
}

func SendApiError(w http.ResponseWriter, httpCode int, messageCode int, message string) {
	respMessage := fmt.Sprintf("{\"code\":%d, \"message\":\"%s\"}", messageCode, message)
	w.WriteHeader(httpCode)

	_, err := w.Write([]byte(respMessage))
	if err != nil {
		panic(err)
	}
}