package main

import (
	"fmt"
	"github.com/gin-gonic/gin"
	"html/template"
	"net"
	"net/http"
	"regexp"
)

func RunWebService(conn *RedisConnection) {
	r := gin.Default()
	r.SetHTMLTemplate(BuildTemplate())

	r.GET("/", func(g *gin.Context) {
		g.HTML(200, "index.html", gin.H{"domain": DdnsDomain})
	})

	r.GET("/available/:hostname", func(c *gin.Context) {
		hostname, valid := ValidHostname(c.Params.ByName("hostname"))

		c.JSON(200, gin.H{
			"available": valid && !conn.HostExist(hostname),
		})
	})

	r.GET("/new/:hostname", func(c *gin.Context) {
		hostname, valid := ValidHostname(c.Params.ByName("hostname"))

		if !valid {
			c.JSON(404, gin.H{"error": "This hostname is not valid"})
			return
		}

		if conn.HostExist(hostname) {
			c.JSON(403, gin.H{
				"error": "This hostname has already been registered.",
			})
			return
		}

		host := &Host{Hostname: hostname, Ip: "127.0.0.1"}
		host.GenerateAndSetToken()

		conn.SaveHost(host)

		c.JSON(200, gin.H{
			"hostname":    host.Hostname,
			"token":       host.Token,
			"update_link": fmt.Sprintf("/update/%s/%s", host.Hostname, host.Token),
		})
	})

	r.GET("/update/:hostname/:token", func(c *gin.Context) {
		hostname, valid := ValidHostname(c.Params.ByName("hostname"))
		token := c.Params.ByName("token")

		if !valid {
			c.JSON(404, gin.H{"error": "This hostname is not valid"})
			return
		}

		if !conn.HostExist(hostname) {
			c.JSON(404, gin.H{
				"error": "This hostname has not been registered or is expired.",
			})
			return
		}

		host := conn.GetHost(hostname)

		if host.Token != token {
			c.JSON(403, gin.H{
				"error": "You have supplied the wrong token to manipulate this host",
			})
			return
		}

		ip, err := GetRemoteAddr(c.Request)
		if err != nil {
			c.JSON(400, gin.H{
				"error": "Your sender IP address is not in the right format",
			})
			return
		}

		host.Ip = ip
		conn.SaveHost(host)

		c.JSON(200, gin.H{
			"current_ip": ip,
			"status":     "Successfuly updated",
		})
	})

	r.Run(DdnsWebListenSocket)
}

// Get the Remote Address of the client. At First we try to get the
// X-Forwarded-For Header which holds the IP if we are behind a proxy,
// otherwise the RemoteAddr is used
func GetRemoteAddr(req *http.Request) (string, error) {
	header_data, ok := req.Header["X-Forwarded-For"]

	if ok {
		return header_data[0], nil
	} else {
		ip, _, err := net.SplitHostPort(req.RemoteAddr)
		return ip, err
	}
}

// Get index template from bindata
func BuildTemplate() *template.Template {
	html, err := template.New("index.html").Parse(indexTemplate)
	HandleErr(err)

	return html
}

func ValidHostname(host string) (string, bool) {
	valid, _ := regexp.Match("^[a-z0-9]{1,32}$", []byte(host))

	return host, valid
}