package main

import (
    "bufio"
    "fmt"
    "github.com/jlaffaye/ftp"
    "io/ioutil"
    "log"
    "net/http"
    "os"
)

var (
    Server   = ""
    Login    = ""
    Password = ""
    BasePath = "/home/iu9_33_03/GoProjects/src/Laba1"
    client *ftp.ServerConn
    file *os.File
    err error
    cur1, _ = ioutil.ReadFile("web/Home.html")
    homeScreenForm = string(cur1)
    cur2, _ = ioutil.ReadFile("web/Menu.html")
    menuScreenFormStart = string(cur2)
    cur3, _ = ioutil.ReadFile("web/Options.html")
    options = string(cur3)
    cur4, _ = ioutil.ReadFile("web/End.html")
    menuScreenFormEnd = string(cur4)
    //185.20.227.83
)

func HomeScreenHandler(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintf(w, homeScreenForm)
}

func MenuScreenHandler(w http.ResponseWriter, r *http.Request) {
    if r.URL.Query().Get("server") != "" {
        Server = r.URL.Query().Get("server")
    }
    if r.URL.Query().Get("login") != "" {
        Login = r.URL.Query().Get("login")
    }
    if r.URL.Query().Get("pass") != "" {
        Password = r.URL.Query().Get("pass")
    }
    res := menuScreenFormStart
    res += "<center><p><h2>" + Server + "</h2></p>" + "<p><h3> Connected </h3></p>"
    res += options
    option := r.URL.Query().Get("options")

    switch option {
    case "delete":
        err = removeDirectory(r.URL.Query().Get("f1"))
        if err != nil {
            log.Fatal(err)
        }
    case "make":
        err = makeDirectory(r.URL.Query().Get("f1"))
        if err != nil {
            log.Fatal(err)
        }
    case "list":
        entries, err := listOfDirectories(r.URL.Query().Get("f1"))
        if err != nil {
            log.Fatal(err)
        }
        res += "<p><b>" + r.URL.Query().Get("f1") + ": </b></p>"
        for _, e := range entries {
            res += "<p>" + e.Name + "</p>"
        }
    case "upload":
        err = uploadFile(r.URL.Query().Get("f1"), r.URL.Query().Get("f2"))
        if err != nil {
            log.Fatal(err)
        }
    case "read":
        str, err := readFile(r.URL.Query().Get("f1"))
        if err != nil {
            log.Fatal(err)
        }
        res += "<p>" + str + "</p>"
    case "currentDir":
        str, err := currentDirectory()
        if err != nil {
            log.Fatal(err)
        }
        res += "<p>" + str + "</p>"
    case "change":
        err := changeDirectory(r.URL.Query().Get("f1"))
        if err != nil {
            log.Fatal(err)
        }
    }
    res += menuScreenFormEnd
    fmt.Fprint(w, res)
}

func uploadFile(from string, to string) error {
    client, err = ftp.Dial(Server)
    if err != nil {
        return err
    }

    err = client.Login(Login, Password)
    if err != nil {
        return err
    }

    file, err = os.Open(BasePath + from)
    if err != nil {
        return err
    }
    reader := bufio.NewReader(file)
    err = client.Stor(to, reader)
    if err != nil {
        return err
    }
    return nil
}

func removeDirectory(path string) error {
    client, err = ftp.Dial(Server)
    if err != nil {
        return err
    }

    err = client.Login(Login, Password)
    if err != nil {
        return err
    }

    err = client.Delete(path)
    if err != nil {
        return err
    }
    return nil
}

func makeDirectory(dir string) error {
    client, err = ftp.Dial(Server)
    if err != nil {
        return err
    }

    err = client.Login(Login, Password)
    if err != nil {
        return err
    }

    err = client.MakeDir(dir)
    if err != nil {
        return err
    }
    return nil
}

func listOfDirectories(path string) ([]*ftp.Entry, error) {
    client, err = ftp.Dial(Server)
    if err != nil {
        return nil, err
    }

    err = client.Login(Login, Password)
    if err != nil {
        return nil, err
    }

    entries, err := client.List(path)
    if err != nil {
        return nil, err
    }
    return entries, nil
}

func readFile(path string) (string, error) {
    client, err = ftp.Dial(Server)
    if err != nil {
        return "", err
    }

    err = client.Login(Login, Password)
    if err != nil {
        return "", err
    }

    file, err := client.Retr(path)
    if err != nil {
        return "", err
    }
    buffer, err := ioutil.ReadAll(file)
    if err != nil {
        return "", err
    }
    return string(buffer), nil
}

func currentDirectory() (string, error) {
    client, err = ftp.Dial(Server)
    if err != nil {
        return "", err
    }

    err = client.Login(Login, Password)
    if err != nil {
        return "", err
    }

    name, err := client.CurrentDir()
    if err != nil {
        return "", err
    }
    return name, nil
}

func changeDirectory(path string) error {
    client, err = ftp.Dial(Server)
    if err != nil {
        return err
    }

    err = client.Login(Login, Password)
    if err != nil {
        return err
    }

    err = client.ChangeDir(path)
    if err != nil {
        return err
    }
    return nil
}

func main() {
    http.HandleFunc("/", HomeScreenHandler)
    http.HandleFunc("/menu", MenuScreenHandler)
    err = http.ListenAndServe(":9210", nil)
    if err != nil {
        log.Fatal("ListenAndServe: ", err)
    }
}