package main

import (
	"github.com/oschwald/maxminddb-golang"
	log "github.com/sirupsen/logrus"
	"github.com/spf13/viper"
	"net"
	"net/http"
	"net/url"
	"strings"
)

var (
	db      *maxminddb.Reader
	servers ServerList

	dlMap map[string]string
)

// City represents a MaxmindDB city
type City struct {
	Location struct {
		Latitude  float64 `maxminddb:"latitude"`
		Longitude float64 `maxminddb:"longitude"`
	} `maxminddb:"location"`
}

func main() {
	viper.SetDefault("bind", ":8080")

	viper.SetConfigName("dlrouter")        // name of config file (without extension)
	viper.SetConfigType("yaml")            // REQUIRED if the config file does not have the extension in the name
	viper.AddConfigPath("/etc/dlrouter/")  // path to look for the config file in
	viper.AddConfigPath("$HOME/.dlrouter") // call multiple times to add many search paths
	viper.AddConfigPath(".")               // optionally look for config in the working directory
	err := viper.ReadInConfig()            // Find and read the config file

	if err != nil { // Handle errors reading the config file
		log.WithError(err).Fatalln("Unable to load config file")
	}

	db, err = maxminddb.Open(viper.GetString("geodb"))

	if err != nil {
		log.WithError(err).Fatalln("Unable to open database")
	}

	if mapFile := viper.GetString("dl_map"); mapFile != "" {
		log.WithField("file", mapFile).Info("Loading download map")

		dlMap, err = loadMap(mapFile)

		if err != nil {
			log.WithError(err).Fatalln("Unable to load download map")
		}
	}

	serverList := viper.GetStringSlice("servers")

	for _, server := range serverList {
		var prefix string

		if !strings.HasPrefix(server, "http") {
			prefix = "https://"
		}

		u, err := url.Parse(prefix + server)

		if err != nil {
			log.WithFields(log.Fields{
				"error":  err,
				"server": server,
			}).Warning("Server is invalid")
			continue
		}

		ips, err := net.LookupIP(u.Host)

		if err != nil {
			log.WithFields(log.Fields{
				"error":  err,
				"server": server,
			}).Warning("Could not resolve address")
			continue
		}

		var city City
		err = db.Lookup(ips[0], &city)

		if err != nil {
			log.WithFields(log.Fields{
				"error":  err,
				"server": server,
			}).Warning("Could not geolocate address")
			continue
		}

		servers = append(servers, &Server{
			Host:      u.Host,
			Path:      u.Path,
			Latitude:  city.Location.Latitude,
			Longitude: city.Location.Longitude,
		})

		log.WithFields(log.Fields{
			"server":    u.Host,
			"path":      u.Path,
			"latitude":  city.Location.Latitude,
			"longitude": city.Location.Longitude,
		}).Info("Added server")
	}

	log.Info("Servers added, checking statuses")
	// Force initial check before running
	servers.Check()

	// Start check loop
	go servers.checkLoop()

	log.Info("Starting")

	mux := http.NewServeMux()

	mux.HandleFunc("/status", statusHandler)
	mux.HandleFunc("/mirrors", mirrorsHandler)
	mux.HandleFunc("/reload", reloadHandler)
	mux.HandleFunc("/dl_map", dlMapHandler)
	mux.HandleFunc("/", RealIPMiddleware(redirectHandler))

	http.ListenAndServe(viper.GetString("bind"), mux)
}