package app

import (
	"bytes"
	"embed"
	"fmt"
	"html/template"
	"net/http"
	"path"
	"regexp"

	"github.com/gomarkdown/markdown"
	"github.com/gomarkdown/markdown/html"
	"github.com/gomarkdown/markdown/parser"
)

//go:embed embeded/markdown/*.md
var markdownFS embed.FS

const markdownEmbedPath = "embeded/markdown"
const markdownTemplate = "markdown"

var stratBoardRegex = regexp.MustCompile(`\[stgy:a.*\]`)

func markdownInjectStrategyBoard(input []byte, created string) ([]byte, error) {
	for _, sb := range stratBoardRegex.FindAllSubmatch(input, -1) {
		record, err := processStrategyBoard(string(sb[0]), created)
		if err != nil {
			return input, err
		}
		boardURL := getStrategyBoardURL(record.ID)
		input = bytes.ReplaceAll(input, sb[0], fmt.Appendf(nil, "[![Strategy Board: %s](%s.png)](%s)", record.Name, boardURL, boardURL))
	}
	return input, nil
}

func markdownToHTML(input []byte) string {
	extensions := parser.CommonExtensions | parser.AutoHeadingIDs | parser.NoEmptyLineBeforeBlock
	p := parser.NewWithExtensions(extensions)
	doc := p.Parse(input)
	htmlFlags := html.CommonFlags | html.HrefTargetBlank
	opts := html.RendererOptions{Flags: htmlFlags}
	renderer := html.NewRenderer(opts)
	return string(markdown.Render(doc, renderer))
}

func markdownToHTMLStripTitle(input []byte) (string, string) {
	extensions := parser.CommonExtensions | parser.AutoHeadingIDs | parser.NoEmptyLineBeforeBlock
	p := parser.NewWithExtensions(extensions)
	doc := p.Parse(input)

	title := ""
	children := doc.AsContainer().GetChildren()
	if len(children) > 1 {
		leaf := children[0].AsContainer().GetChildren()[0].AsLeaf()
		if leaf != nil {
			title = string(leaf.Literal)
		}
	}
	if title == "" {
		title = "(Untitled)"
	}

	htmlFlags := html.CommonFlags | html.HrefTargetBlank
	opts := html.RendererOptions{Flags: htmlFlags}
	renderer := html.NewRenderer(opts)

	return title, string(markdown.Render(doc, renderer))
}

func httpHandleMarkdown(w http.ResponseWriter, r *http.Request, name string) {
	rawMd, err := markdownFS.ReadFile(path.Join(markdownEmbedPath, name+".md"))
	if err != nil {
		httpHandleError(w, err)
		return
	}
	title, content := markdownToHTMLStripTitle(rawMd)
	if name == "home" {
		title = "Home"
	}
	httpHandleTemplate(w, markdownTemplate, map[string]any{
		"title":   title,
		"name":    name,
		"content": template.HTML(content),
		"url":     fmt.Sprintf("//%s%s", r.Host, r.URL.String()),
	})

}