package main

import (
	"encoding/json"
	"fmt"
	"net"
	"net/http"
	"net/url"
	"os"
	"path"
	"strings"
)

func statusHandler(w http.ResponseWriter, r *http.Request) {
	w.WriteHeader(http.StatusOK)
	w.Write([]byte("OK"))
}

func legacyMirrorsHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")

	mirrors := make(map[string][]string)

	for _, server := range servers {
		u := &url.URL{
			Scheme: r.URL.Scheme,
			Host:   server.Host,
			Path:   server.Path,
		}

		mirrors[server.Continent] = append(mirrors[server.Continent], u.String())
	}

	mirrors["default"] = append(mirrors["NA"], mirrors["EU"]...)

	json.NewEncoder(w).Encode(mirrors)
}

func mirrorsHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(servers)
}

func redirectHandler(w http.ResponseWriter, r *http.Request) {
	ipStr, _, err := net.SplitHostPort(r.RemoteAddr)

	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	ip := net.ParseIP(ipStr)

	if ip.IsLoopback() || ip.IsPrivate() {
		overrideIP := os.Getenv("OVERRIDE_IP")

		if overrideIP == "" {
			overrideIP = "1.1.1.1"
		}

		ip = net.ParseIP(overrideIP)
	}

	server, distance, err := servers.Closest(ip)

	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	scheme := r.URL.Scheme

	if scheme == "" {
		scheme = "https"
	}

	redirectPath := path.Join(server.Path, r.URL.Path)

	if dlMap != nil {
		p := r.URL.Path

		if p[0] != '/' {
			p = "/" + p
		}

		if newPath, exists := dlMap[p]; exists {
			downloadsMapped.Inc()
			redirectPath = path.Join(server.Path, newPath)
		}
	}

	if strings.HasSuffix(r.URL.Path, "/") && !strings.HasSuffix(redirectPath, "/") {
		redirectPath += "/"
	}

	u := &url.URL{
		Scheme: scheme,
		Host:   server.Host,
		Path:   redirectPath,
	}

	server.Redirects.Inc()
	redirectsServed.Inc()

	w.Header().Set("X-Geo-Distance", fmt.Sprintf("%f", distance))
	w.Header().Set("Location", u.String())
	w.WriteHeader(http.StatusFound)
}

func reloadHandler(w http.ResponseWriter, r *http.Request) {
	reloadConfig()

	w.WriteHeader(http.StatusOK)
	w.Write([]byte("OK"))
}

func dlMapHandler(w http.ResponseWriter, r *http.Request) {
	if dlMap == nil {
		w.WriteHeader(http.StatusNotFound)
		return
	}

	w.Header().Set("Content-Type", "application/json")

	json.NewEncoder(w).Encode(dlMap)
}

func geoIPHandler(w http.ResponseWriter, r *http.Request) {
	ipStr, _, err := net.SplitHostPort(r.RemoteAddr)

	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	ip := net.ParseIP(ipStr)

	var city City
	err = db.Lookup(ip, &city)

	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	json.NewEncoder(w).Encode(city)
}