package syw

import (
	"embed"
	"net/url"
	"strings"
	"text/template"
)

var (
	//go:embed templates/*.gmi templates/*.gmi.txt
	geminiTemplateFS embed.FS
	geminiTemplate   = template.Must(template.ParseFS(
		geminiTemplateFS,
		"templates/*.gmi",
		"templates/*.gmi.txt",
	))
)

var (
	//go:embed templates/*.nex.txt
	nexTemplateFS embed.FS
	nexTemplate   = template.Must(template.ParseFS(
		nexTemplateFS,
		"templates/*.nex.txt",
	))
)

var (
	//go:embed templates/*.gph templates/*.gph.txt
	gopherTemplateFS embed.FS
	gopherTemplate   = template.Must(
		template.New("gopher").Funcs(template.FuncMap{
			"combine": gopherCombine,
			"join":    gopherJoin,
			"rawtext": gopherRawtext,
		}).ParseFS(
			gopherTemplateFS,
			"templates/*.gph",
			"templates/*.gph.txt",
		),
	)
)

func gopherCombine(base string, relative ...string) (string, error) {
	bu, err := url.Parse(base)
	if err != nil {
		return "", err
	}

	for _, rel := range relative {
		ru, err := url.Parse(rel)
		if err != nil {
			return "", err
		}
		bu = bu.ResolveReference(ru)
	}

	return bu.Path, nil
}

func gopherJoin(base string, relative ...string) (string, error) {
	bu, err := url.Parse(base)
	if err != nil {
		return "", err
	}

	return bu.JoinPath(relative...).Path, nil
}

func gopherRawtext(selector, host, port, text string) string {
	trailer := "\t" + selector + "\t" + host + "\t" + port + "\r\n"
	lines := strings.Split(text, "\n")
	for i := range lines {
		lines[i] = "i" + strings.TrimRight(strings.ReplaceAll(lines[i], "\t", "    "), "\r\n") + trailer
	}
	return strings.Join(lines, "")
}

func addTemplates(base *template.Template, additions *template.Template) (*template.Template, error) {
	base, err := base.Clone()
	if err != nil {
		return nil, err
	}
	if additions == nil {
		return base, nil
	}

	for _, addition := range additions.Templates() {
		if _, err := base.AddParseTree(addition.Name(), addition.Tree); err != nil {
			return nil, err
		}
	}

	return base, nil
}