const (
	HeaderLastModified            = "Last-Modified"
	HeaderContentType             = "Content-Type"
	HeaderContentEncoding         = "Content-Encoding"
	HeaderCacheControl            = "Cache-Control"
	HeaderContentLength           = "Content-Length"
	HeaderETag                    = "ETag"
	HeaderServer                  = "Server"
	HeaderIfModifiedSince         = "If-Modified-Since"
	HeaderExpires                 = "Expires"
	HeaderIfNoneMatch             = "If-None-Match"
	HeaderAccept                  = "Accept"
	HeaderUserAgent               = "User-Agent"
	HeaderAuthorization           = "Authorization"
	HeaderAltSvc                  = "Alt-Svc"
	HeaderStrictTransportSecurity = "Strict-Transport-Security"
	HeaderContentDisposition      = "Content-Disposition"
	HeaderReferer                 = "Referer"
	HeaderDoNotTrack              = "Dnt"
	HeaderAcceptLanguage          = "Accept-Language"
)

const (
	CacheControlNoCache = "private, no-cache, no-store, must-revalidate" // "no-cache, no-store, no-transform, must-revalidate, private, max-age=0"
	CacheControlDynamic = "public, no-cache, must-revalidate"            // TODO https://web.dev/http-cache/, https://web.dev/love-your-cache/
	// CacheControlDynamic    = "max-age=0, must-revalidate, public" // TODO https://web.dev/http-cache/, https://web.dev/love-your-cache/
	// CacheControlNoCache       = "no-cache, no-store, no-transform, must-revalidate" // "no-cache, no-store, no-transform, must-revalidate, private, max-age=0"
	CacheControl30Seconds = "public, max-age=30, must-revalidate"
	CacheControl1Minute   = "public, max-age=60, must-revalidate"
	CacheControl5Minutes  = "public, max-age=300, stale-while-revalidate=30"
	CacheControl10Minutes = "public, max-age=600, stale-while-revalidate=60"
	CacheControl15Minutes = "public, max-age=900, stale-while-revalidate=90"
	CacheControl30Minutes = "public, max-age=1800, stale-while-revalidate=180"
	CacheControl1Hour     = "public, max-age=3600, stale-while-revalidate=360"
	CacheControl1Day      = "public, max-age=86400, stale-while-revalidate=600"
	CacheControl1Week     = "public, max-age=604800, stale-while-revalidate=600"
	CacheControl1Month    = "public, max-age=2592000, stale-while-revalidate=600"
	CacheControlImmutable = "public, max-age=31536000, immutable"
)

const (
	MediaTypeText = "text/plain"
	MediaTypeXml  = "application/xml"
	MediaTypeJson = "application/json"

	MediaTypeHtmlUtf8 = "text/html; charset=utf-8"
	MediaTypeTextUtf8 = "text/plain; charset=utf-8"

	MediaTypeJsonFeed = "application/feed+json"
	MediaTypeRSS      = "application/rss+xml"
	MediaTypeAtom     = "application/atom+xml"

	MediaTypeAudio = "audio"
	MediaTypeVideo = "video"
	MediaTypePNG   = "image/png"
	MediaTypeJPEG  = "image/jpeg"
	MediaTypeSVG   = "image/svg+xml"

	// https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types
	// alternative value from the 'file' command line program: text/x-shellscript
	MediaTypeShellScript = "application/x-sh"
)

const (
	CacheControl30SecondsCdnOnly = "public, max-age=0, s-max-age=30, must-revalidate"
)

var ErrDir = errors.New("path is a folder")

var ErrInternalError = errors.New("Internal Server Error")

var ErrInvalidPath = errors.New("path is not valid")

type CacheRule struct {
	Regexp string

	CacheControl string
	// contains filtered or unexported fields
}

type WebappHandlerConfig struct {
	// default: index.html
	NotFoundFile string
	// default: 200
	NotFoundStatus int
	// default: public, no-cache, must-revalidate
	NotFoundCacheControl string
	// default: ".js", ".css", ".woff", ".woff2"
	Cache []CacheRule
}