#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <gtk/gtk.h>

#include <security/pam_appl.h>
#include <security/pam_misc.h>

/* 

*/

struct auth_message {
    enum {
        AUTH_MSGTYPE_INFO,
        AUTH_MSGTYPE_ERROR,
        AUTH_MSGTYPE_PROMPT_NOECHO,
        AUTH_MSGTYPE_PROMPT_ECHO,
    } type;
    const char *msg;
};

struct auth_response {
    char *response;
};

static int pam_conversation (int nmsgs, const struct pam_message **msg, struct pam_response **resp, void *appdata_ptr);

typedef struct {
    GtkWidget *msg;
    GtkWidget *username;
    GtkWidget *password;

} LoginWidget;



static void destroy (GtkWidget *window, gpointer data);

int do_authenticate(GtkButton *button, LoginWidget *w_login );

int main (int argc, char *argv[])
{
    GtkWidget *window;
    GtkWidget *hbox, *vbox, *cancel_btn, *ok_btn;
    
    LoginWidget *w_login = (LoginWidget *) g_malloc (sizeof (LoginWidget));
    
    gtk_init (&argc, &argv);

    window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    
    g_signal_connect (G_OBJECT (window), "destroy",
                        G_CALLBACK (destroy), NULL);
    
    w_login->msg = gtk_label_new ("");
    w_login->username = gtk_entry_new ();
    w_login->password = gtk_entry_new ();
    gtk_entry_set_visibility (GTK_ENTRY(w_login->password), FALSE);
    gtk_entry_set_invisible_char (GTK_ENTRY(w_login->password), '*');

    ok_btn = gtk_button_new_with_label ("OK!");
    cancel_btn = gtk_button_new_with_label ("Cancel!");

    g_signal_connect (G_OBJECT (ok_btn), "clicked",
                        G_CALLBACK (do_authenticate),
                        (gpointer)  w_login);

    vbox = gtk_vbox_new(FALSE, 5);
    gtk_box_pack_start_defaults (GTK_BOX (vbox), w_login->msg);    
    gtk_box_pack_start_defaults (GTK_BOX (vbox), w_login->username);    
    gtk_box_pack_start_defaults (GTK_BOX (vbox), w_login->password);    
    
    hbox = gtk_hbox_new(FALSE, 5);
    gtk_box_pack_start_defaults (GTK_BOX (hbox), ok_btn); 
    gtk_box_pack_start_defaults (GTK_BOX (hbox), cancel_btn); 

    gtk_box_pack_start_defaults (GTK_BOX (vbox), hbox);

    gtk_container_add(GTK_CONTAINER (window), vbox);
    gtk_widget_show_all(window);

    gtk_main();
    

}

static void 
destroy (GtkWidget *window, gpointer data)
{
    gtk_main_quit();
}


int do_authenticate(GtkButton *button, LoginWidget *w_login )
{
    const gchar *_username = gtk_entry_get_text(GTK_ENTRY (w_login->username));
    char *tty = strdup(":0.0");

    pam_handle_t *pamh = NULL;
    int retval;
    struct pam_conv conv;
   
    conv.conv = &pam_conversation; 
    conv.appdata_ptr = w_login;

    retval = pam_start("capu", _username, &conv, &pamh);

    retval = pam_set_item (pamh, PAM_TTY, tty);
    retval = pam_set_item (pamh, PAM_XDISPLAY, tty);


    pam_get_item (pamh, PAM_TTY, (const void **)&tty);
    g_message("TTY: %s",tty);
 
    pam_get_item (pamh, PAM_XDISPLAY, (const void **)&tty);
    g_message("XDISPLAY: %s",tty);

    if (retval == PAM_SUCCESS) {
        retval = pam_authenticate(pamh, 0);
        g_message("Auth");
    }

    if (retval == PAM_SUCCESS) {
        retval = pam_acct_mgmt(pamh, 0);
    }


    if (retval == PAM_SUCCESS) {
        g_message ("Authenticated");
    } else {
        g_message ("Not Authenticated");
    }

    if (pam_end(pamh, retval) != PAM_SUCCESS ) {
        pamh = NULL;
    }

    gtk_main_quit();
    return 0;
} 


static int
pam_conversation (int nmsgs,
                    const struct pam_message **msg,
                    struct pam_response **resp,
                    void *appdata_ptr)
{

    int i, ret = -1;
    struct auth_message *messages = 0;
    struct auth_response *authresp = 0;
    struct pam_response *pam_responses;

    LoginWidget *w_login = ( LoginWidget *) appdata_ptr;

    messages = calloc(nmsgs, sizeof (struct auth_message));
    pam_responses = calloc(nmsgs, sizeof (*pam_responses));

    const gchar *_password = gtk_entry_get_text(GTK_ENTRY (w_login->password));

    for (i=0; i<nmsgs; ++i) 
    {
        pam_responses[i].resp_retcode = 0;
        pam_responses[i].resp = NULL;

        messages[i].msg = msg[i]->msg;

        switch (msg[i]->msg_style) {
        case PAM_PROMPT_ECHO_OFF: messages[i].type = AUTH_MSGTYPE_PROMPT_NOECHO;
            pam_responses[i].resp = strdup(_password);
            g_message("ECHO_OFF");
            break;
        case PAM_PROMPT_ECHO_ON: messages[i].type = AUTH_MSGTYPE_PROMPT_ECHO;
            g_message("ECHO_ON");
            fputs(msg[i]->msg, stderr);
            break;
        case PAM_ERROR_MSG: messages[i].type = AUTH_MSGTYPE_ERROR;
            g_message("ERROR_MSG");
            break;
        case PAM_TEXT_INFO: messages[i].type = AUTH_MSGTYPE_INFO;
            g_message("TEXT_INFO");
            break;
        default: messages[i].type = AUTH_MSGTYPE_PROMPT_ECHO;
            break;

        }
    }
 
    *resp = pam_responses;
  
    ret = 0;
    
    return PAM_SUCCESS; 
}