package blog

import (
	"github.com/gomarkdown/markdown"
	"github.com/gomarkdown/markdown/html"
	"github.com/gomarkdown/markdown/parser"
	"html/template"
	"regexp"
	"time"
)

func makePost(markdownContent []byte) Post {
	headerRegex := regexp.MustCompile(`(?ms)^---\n.*?---`)
	header := headerRegex.Find(markdownContent)
	headerKeysRegex := regexp.MustCompile(`(?m)^(\w+): ([^\n]*)$`)
	headerKeys := headerKeysRegex.FindAllSubmatch(header, -1)
	postBody := headerRegex.ReplaceAll(markdownContent, []byte(""))

	post := Post{}

	for _, headerKey := range headerKeys {
		key, value := string(headerKey[1]), string(headerKey[2])
		switch key {
		case "title":
			post.Title = value
		case "date":
			date, err := time.Parse(time.DateOnly, value)
			if err != nil {
				panic(err)
			}
			post.Date = date
		case "updatedDate":
			date, err := time.Parse(time.DateOnly, value)
			if err != nil {
				panic(err)
			}
			post.UpdatedDate = date
		case "author":
			post.Author = value
		case "slug":
			post.Slug = value
		}
	}

	extensions := parser.CommonExtensions | parser.AutoHeadingIDs | parser.NoEmptyLineBeforeBlock
	p := parser.NewWithExtensions(extensions)
	doc := p.Parse(postBody)

	// create HTML renderer with extensions
	htmlFlags := html.CommonFlags | html.HrefTargetBlank
	opts := html.RendererOptions{Flags: htmlFlags}
	renderer := html.NewRenderer(opts)

	post.Body = template.HTML(markdown.Render(doc, renderer))

	return post
}