package main

import (
	"bytes"
	"embed"
	"flag"
	"github.com/yuin/goldmark"
	"github.com/yuin/goldmark/parser"
	"go.abhg.dev/goldmark/frontmatter"
	"html/template"
	"log"
	"os"
)

//go:embed frame.tmpl
var frameTmpl embed.FS

func main() {
	flag.Parse()

	if flag.NArg() != 1 {
		log.Fatalln("usage: gendocs [markdown]")
	}

	md := goldmark.New(goldmark.WithExtensions(&frontmatter.Extender{}))

	mdData, err := os.ReadFile(flag.Arg(0))
	if err != nil {
		log.Fatal(err)
	}

	ctx := parser.NewContext()

	var buf bytes.Buffer
	if err := md.Convert(mdData, &buf, parser.WithContext(ctx)); err != nil {
		log.Fatal(err)
	}

	var frontMatter struct {
		Title string `yaml:"title"`
	}
	if fm := frontmatter.Get(ctx); fm != nil {
		if err := fm.Decode(&frontMatter); err != nil {
			log.Fatal(err)
		}
	}

	frameTmpls, err := template.ParseFS(frameTmpl, "*.tmpl")
	if err != nil {
		log.Fatal(err)
	}
	var res bytes.Buffer
	if err := frameTmpls.ExecuteTemplate(&res, "frame.tmpl", map[string]interface{}{
		"Title": frontMatter.Title,
		"Body":  template.HTML(buf.Bytes()),
	}); err != nil {
		log.Fatal(err)
	}

	os.Stdout.Write(res.Bytes())
}