package main

import (
	"bytes"
	"embed"
	"encoding/csv"
	"flag"
	"fmt"
	"html/template"
	"log"
	"net/http"
	"os"
	"strings"
	"time"
)

type EmojiDetails struct {
	Label string
	Url   string
}

type Config struct {
	RequestsFile string
	Listen       string
}

//go:embed templates
var indexHTML embed.FS
var config Config

func handleForm(w http.ResponseWriter, r *http.Request) {
	tmpl := template.Must(template.ParseFS(indexHTML, "templates/index.html"))

	if r.Method != http.MethodPost {
		tmpl.Execute(w, nil)
		return
	}

	details := EmojiDetails{
		Label: r.FormValue("shortcode"),
		Url:   r.FormValue("url"),
	}

	now := time.Now().UTC().Format(time.RFC3339)
	var username string
	if r.Header.Get("X-Forwarded-Preferred-Username") == "" {
		username = "unknown"
	} else {
		username = r.Header.Get("X-Forwarded-Preferred-Username")
	}
	entry := strings.Join([]string{now, username, details.Label, details.Url}, ",")
	insertEntry(entry)

	tmpl.Execute(w, struct{ Success bool }{true})
}

func handleRequested(w http.ResponseWriter, r *http.Request) {
	tmpl := template.Must(template.ParseFS(indexHTML, "templates/requested.html"))
	file, _ := os.ReadFile(config.RequestsFile)
	requests, _ := csv.NewReader(bytes.NewReader(file)).ReadAll()

	tmpl.Execute(w, struct{ Requests [][]string }{requests})
}

func setupRoutes() {
	http.HandleFunc("/", handleForm)
	http.HandleFunc("/requested", handleRequested)
	err := http.ListenAndServe(config.Listen, nil)
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}
}

func insertEntry(entry string) {
	f, err := os.OpenFile(config.RequestsFile, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		log.Println(err)
	}
	defer f.Close()
	entryFormatted := fmt.Sprintf("%s\n", entry)
	if _, err := f.WriteString(entryFormatted); err != nil {
		log.Println(err)
	}
}

func main() {
	requestsFile := flag.String("requests", "./requests.txt", "Where the file containing all the requests is")
	listen := flag.String("listen", ":8080", "The listen address and port")
	flag.Parse()

	config.RequestsFile = *requestsFile
	config.Listen = *listen

	log.Println("Going to listen for incoming connections!")
	setupRoutes()
}