package restclient

import (
	"errors"
)

// FileExtension is the type of image on Discord's CDN
type FileExtension string

// The available FileExtension(s)
const (
	PNG   FileExtension = "png"
	JPEG  FileExtension = "jpg"
	WEBP  FileExtension = "webp"
	GIF   FileExtension = "gif"
	BLANK FileExtension = ""
)

func (f FileExtension) String() string {
	return string(f)
}

// CDNRoute is a route for interacting with images hosted on discord's CDN
type CDNRoute struct {
	*Route
	supportedFileExtensions []FileExtension
}

// NewCDNRoute generates a new discord cdn route struct
func NewCDNRoute(url string, supportedFileExtensions []FileExtension, queryParams ...string) *CDNRoute {
	return &CDNRoute{
		Route:                   newRoute(CDN, url, append(queryParams, "size", "v")),
		supportedFileExtensions: supportedFileExtensions,
	}
}

// Compile builds a full request URL based on provided arguments
func (r *CDNRoute) Compile(queryValues QueryValues, fileExtension FileExtension, size int, args ...interface{}) (*CompiledCDNRoute, error) {
	supported := false
	for _, supportedFileExtension := range r.supportedFileExtensions {
		if supportedFileExtension == fileExtension {
			supported = true
		}
	}
	if !supported {
		return nil, errors.New("provided file extension: " + fileExtension.String() + " is not supported by discord on this endpoint!")
	}
	if queryValues == nil {
		queryValues = QueryValues{}
	}
	queryValues["size"] = size
	compiledRoute, err := r.Route.Compile(queryValues, args...)
	if err != nil {
		return nil, err
	}

	if fileExtension.String() != "" {
		compiledRoute.route += "." + fileExtension.String()
	}
	return &CompiledCDNRoute{CompiledRoute: compiledRoute}, nil
}

// CompiledCDNRoute is CDNRoute compiled with all URL args
type CompiledCDNRoute struct {
	*CompiledRoute
}