package server

import (
	`embed`
	`encoding/json`
	`encoding/xml`
	`html/template`
	`os`
	`syscall`

	sysdUtil `github.com/coreos/go-systemd/util`
	`github.com/goccy/go-yaml`
)

const (
	convertTag      string = "uaField"
	prettyTag       string = "renderName"
	baseTitle       string = "r00t^2 Client Info Revealer"
	titleSep        string = " || "
	xmlHdrElem      string = "header"
	xmlHdrElemName  string = "name"
	xmlHdrVal       string = "value"
	nilUaFieldStr   string = "(N/A)"
	trueUaFieldStr  string = "Yes"
	falseUaFieldStr string = "No"
	dfltIndent      string = "  "
	httpRealHdr     string = "X-ClientInfo-RealIP"
)

var (
	//go:embed "tpl"
	tplDir embed.FS
	tpl    *template.Template = template.Must(
		template.New("").
			Funcs(
				template.FuncMap{
					"getTitle": getTitle,
				},
			).ParseFS(tplDir, "tpl/*.tpl"),
	)
)

// Signal traps
var (
	stopSigs []os.Signal = []os.Signal{
		syscall.SIGQUIT,
		os.Interrupt,
		syscall.SIGTERM,
	}
	reloadSigs []os.Signal = []os.Signal{
		syscall.SIGHUP,
		// We also add stopSigs so we trigger the Reload loop to close. TODO.
		syscall.SIGQUIT,
		os.Interrupt,
		syscall.SIGTERM,
	}
	isSystemd bool = sysdUtil.IsRunningSystemd()
)

// media/MIME types
const (
	mediaJSON string = "application/json"
	mediaXML  string = "application/xml"
	mediaYAML string = "application/yaml"
	mediaHTML string = "text/html"
	// TODO: plain/text? CSV? TOML?
)

var (
	// mediaNoIndent covers everything (except HTML).
	mediaNoIndent map[string]func(obj any) (b []byte, err error) = map[string]func(obj any) (b []byte, err error){
		mediaJSON: json.Marshal,
		mediaXML:  xml.Marshal,
		mediaYAML: yaml.Marshal,
		// HTML is handled explicitly.
	}
	// mediaIndent only contains MIME types that support configured indents.
	mediaIndent map[string]func(obj any, pfx string, indent string) (b []byte, err error) = map[string]func(obj any, pfx string, indent string) (b []byte, err error){
		mediaJSON: json.MarshalIndent,
		mediaXML:  xml.MarshalIndent,
	}
	// valid MIMEs.
	okAcceptMime []string = []string{
		mediaJSON,
		mediaXML,
		mediaYAML,
		mediaHTML,
	}
	// These are actually HTML.
	htmlOverride map[string]bool = map[string]bool{
		"Links": true,
	}
)