package main

import (
	"embed"
	"fmt"
	"html/template"
	"io/fs"
	"net/http"
	"os"
)

const PORT = 3003

type frontendInfo struct {
	Name, Mountpoint string
}

//go:embed "all:vuejs/dist"
var vueFiles embed.FS

//go:embed "all:reactNextJS/out"
var nextFiles embed.FS

//go:embed "all:svelte/dist"
var svelteFiles embed.FS

//go:embed "vanillaJS"
var vanillaFiles embed.FS

//go:embed "alpinejs"
var alpineFiles embed.FS

//go:embed "react"
var reactFiles embed.FS

func addFrontend(files embed.FS, mountpoint string, subfs string, name string) frontendInfo {
	subFiles, _ := fs.Sub(files, subfs)
	fileServer := http.FileServerFS(subFiles)
	http.Handle(mountpoint, http.StripPrefix(mountpoint, fileServer))
	return frontendInfo{name, mountpoint}
}

func outputIndexAndExit(indexTemplate template.Template, frontends []frontendInfo) {
	file, err := os.OpenFile("index.html", os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
	if err != nil {
		panic(err) // Handle error
	}
	defer file.Close()
	indexTemplate.Execute(file, frontends)
	os.Exit(0)
}

func main() {
	args := os.Args

	home_template, err := template.ParseFiles("index.tmpl")
	if err != nil {
		panic(fmt.Sprintf("Error parsing homepage template\n%s", err))
	}

	frontends := []frontendInfo{
		addFrontend(vanillaFiles, "/vanillaJS/", "vanillaJS", "JS Only"),
		addFrontend(alpineFiles, "/alpinejs/", "alpinejs", "Alpine.js"),
		addFrontend(reactFiles, "/react/", "react", "React"),
		addFrontend(nextFiles, "/reactNextJS/", "reactNextJS/out", "React (Next.js)"),
		addFrontend(vueFiles, "/vuejs/", "vuejs/dist", "Vue.js"),
		addFrontend(svelteFiles, "/svelte/", "svelte/dist", "Svelte"),
	}

	if len(args) == 2 && args[1] == "generate" {
		outputIndexAndExit(*home_template, frontends)
	}

	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		err = home_template.Execute(w, frontends)
	})

	err = http.ListenAndServe(fmt.Sprintf(":%d", PORT), nil)
	if err != nil {
		panic(fmt.Sprintf("Error starting server: %s", err))
	}
}