package main

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

const PORT = 3003

//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

//go:embed "all:reactNative/dist"
var reactNativeFiles embed.FS

type frontendInfo struct {
	Name, Mountpoint string
	Filesystem       fs.FS
}

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

func getSubFS(f fs.FS, dir string) fs.FS {
	files, err := fs.Sub(f, dir)
	if err != nil {
		panic(err)
	}
	return files
}

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
	}
	indexTemplate.Execute(file, frontends)
	file.Close()
	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))
	}

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

	for _, info := range frontends {
		fileServer := http.FileServerFS(info.Filesystem)
		http.Handle(info.Mountpoint, http.StripPrefix(info.Mountpoint, fileServer))
	}

	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))
	}
}