package main

import (
	"bytes"
	"fmt"
	"html/template"
	"net/http"
	"strconv"
)

type player struct {
	Name  string
	Score int
}

type playersPage struct {
	Min     string
	Players []player
}

// Nothing changes this slice, so the handlers can share it.
var allPlayers = []player{
	{Name: "Keiko", Score: 70},
	{Name: "Arif", Score: 45},
	{Name: "Ada", Score: 90},
}

var playersTemplate *template.Template

func handleHome(w http.ResponseWriter, r *http.Request) {
	minText := r.URL.Query().Get("min")

	lowest := 0
	if minText != "" {
		number, err := strconv.Atoi(minText)
		if err != nil {
			http.Error(w, "min must be a whole number.", http.StatusBadRequest)
			return
		}
		lowest = number
	}

	shown := []player{}
	for _, p := range allPlayers {
		if p.Score >= lowest {
			shown = append(shown, p)
		}
	}

	data := playersPage{Min: minText, Players: shown}

	var page bytes.Buffer
	err := playersTemplate.Execute(&page, data)
	if err != nil {
		fmt.Println("Template error:", err)
		http.Error(w, "The page could not be built.", http.StatusInternalServerError)
		return
	}

	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	page.WriteTo(w)
}

func main() {
	parsed, err := template.ParseFiles("templates/players.html")
	if err != nil {
		fmt.Println("Could not read the template:", err)
		fmt.Println("Run this program from its own folder, and check the template.")
		return
	}
	playersTemplate = parsed

	http.HandleFunc("GET /{$}", handleHome)

	fmt.Println("Server running at http://localhost:8080")
	fmt.Println("Press Ctrl+C to stop it.")

	err = http.ListenAndServe("localhost:8080", nil)
	if err != nil {
		fmt.Println("Server stopped:", err)
	}
}