package helper

import (
	"image"
	"net/http"
)

// Checks if the subreact exists, responds with a bad status when false.
func IsValidSubreact(subreact string, writer http.ResponseWriter) bool {
	switch subreact {
	case "":
		fallthrough
	case "t":
		fallthrough
	case "g":
		fallthrough
	case "k":
		fallthrough
	case "p":
		fallthrough
	case "a":
		fallthrough
	case "pr":
		fallthrough
	case "m":
		break
	default:
		WriteErrorJson("invalid subreact", writer, http.StatusBadRequest)
		return false
	}
	return true
}

// Range checks the length of the argument, responds with a bad status when false.
func IsValidRange(str string, name string, min int, max int, writer http.ResponseWriter) bool {
	if len(str) < min {
		WriteErrorJson(name+" too short", writer, http.StatusBadRequest)
		return false
	}
	if len(str) > max {
		WriteErrorJson(name+" too long", writer, http.StatusBadRequest)
		return false
	}
	return true
}

// Checks that the image has supported properties, responds with a bad status when false.
func IsImageSupported(image image.Image, format string, writer http.ResponseWriter) bool {
	if bounds := image.Bounds(); bounds.Dx() > 4096 || bounds.Dy() > 4096 {
		WriteErrorJson("image dimensions too large", writer, http.StatusBadRequest)
		return false
	} else if bounds.Dx() < 256 || bounds.Dy() < 256 {
		WriteErrorJson("image dimensions too small", writer, http.StatusBadRequest)
		return false
	}

	switch format {
	case "png":
		fallthrough
	case "jpeg":
		fallthrough
	case "gif":
		break
	default:
		WriteErrorJson("image format no recognised", writer, http.StatusBadRequest)
		return false
	}

	return true
}