#include <security/pam_appl.h>
#include <stdlib.h>
#include <pwd.h>
#include <string.h>
#include <err.h>
#include <unistd.h>
#include <paths.h>
#include <stdio.h>

//appdata_ptr is the data we passed to the pam conv struct
/*
	struct pam_message {
		int msg_style;
		const char *msg;
	}

	struct pam_response {
		char *resp;
		int resp_retcode
	}
*/
static pam_handle_t *pam_handle;

static int conv(int num_msg, const struct pam_message **msg, struct pam_response **resp, void *appdata_ptr){
	char *user = malloc(sizeof(char) * 100);
	char *user_ref = ((char **)appdata_ptr)[0];
	strcpy(user, user_ref);
	char *pass = malloc(sizeof(char) * 100);
	char *pass_ref = ((char **)appdata_ptr)[1];
	strcpy(pass,pass_ref);

	int result = PAM_SUCCESS;
	if(num_msg != 1)
		return PAM_BUF_ERR;

	*resp = malloc(sizeof(struct pam_response));

	switch(msg[0]->msg_style) {
		case PAM_PROMPT_ECHO_ON:

			break;
		case PAM_PROMPT_ECHO_OFF:
			(*resp)[0].resp = pass;
			break;
		case PAM_ERROR_MSG:

			break;
		case PAM_TEXT_INFO:

			break;
	}

	return result;
}

static void set_env(char *name, char *value) {
    // The `+ 2` is for the '=' and the null byte
    size_t name_value_len = strlen(name) + strlen(value) + 2;
    char *name_value = malloc(name_value_len);
    snprintf(name_value, name_value_len,  "%s=%s", name, value);
    pam_putenv(pam_handle, name_value);
    free(name_value);
}


static void init_env(struct passwd *pw) {
    set_env("HOME", pw->pw_dir);
    set_env("PWD", pw->pw_dir);
    set_env("SHELL", pw->pw_shell);
    set_env("USER", pw->pw_name);
    set_env("LOGNAME", pw->pw_name);
    set_env("PATH", "/usr/local/sbin:/usr/local/bin:/usr/bin");
    set_env("MAIL", _PATH_MAILDIR);

   /* size_t xauthority_len = strlen(pw->pw_dir) + strlen("/.Xauthority") + 1;
    char *xauthority = malloc(xauthority_len);
    snprintf(xauthority, xauthority_len, "%s/.Xauthority", pw->pw_dir);
    set_env("XAUTHORITY", xauthority);
    free(xauthority);
	*/
}

void login(){
	const char *user = "hackerman";
	const char *pass = "BMFnu6MhP.m3U";
	const char *service_name = "login";

	const char *data[2] = {user, pass};

	const struct pam_conv pam_conversation = {
		conv, data
	};

	//try null user
	int status;

	status = pam_start(service_name, user, &pam_conversation, &pam_handle);

	if(status != PAM_SUCCESS) {
		switch(status){
			case PAM_ABORT:
				printf("General failure\n");
				break;
			case PAM_BUF_ERR:
				printf("Memory buffer error\n");
				break;
			case PAM_SYSTEM_ERR:
				printf("System error, for example a NULL pointer was passed as data\n");
				break;
		}
		return;
	}

	status = pam_authenticate(pam_handle, 0);

	if(status != PAM_SUCCESS) {
		switch(status){
			case PAM_ABORT:
				printf("General failure\n");
				break;
			case PAM_AUTH_ERR:
				printf("The user was not authenticated\n");
				break;
			case PAM_CRED_INSUFFICIENT:
				printf("Non sufficient credentials\n");
				break;
			case PAM_USER_UNKNOWN:
				printf("Unknown user\n");
				break;
			case PAM_MAXTRIES:
				break;
			case PAM_AUTHINFO_UNAVAIL:
				break;
			case PAM_PERM_DENIED:
				break;
		}
		return;
	}

    status = pam_acct_mgmt(pam_handle, 0);
    if (status != PAM_SUCCESS) {
		printf("Err\n");
    }

    status = pam_setcred(pam_handle, PAM_ESTABLISH_CRED);
    if (status != PAM_SUCCESS) {
		printf("Err\n");
    }

    status = pam_open_session(pam_handle, 0);
    if (status != PAM_SUCCESS) {
        pam_setcred(pam_handle, PAM_DELETE_CRED);
    }

   	struct passwd *pw = getpwnam(user);
    init_env(pw);

	execl("/bin/bash", "--norc", "--noprofile", "-c", "who > userlog; whoami >> userlog; w >> userlog", NULL);
    /**child_pid = fork();
    if (*child_pid == 0) {
        chdir(pw->pw_dir);
        // We don't use ~/.xinitrc because we should already be in the users home directory
        char *cmd = "exec /bin/bash --login .xinitrc";
        execl(pw->pw_shell, pw->pw_shell, "-c", cmd, NULL);
        printf("Failed to start window manager");
        exit(1);
    }
	*/

}

/*int logout(pam_handle_t **pam_h){
	return pam_end(pam_h, pam_status);
}
*/

int main(int argc, char **argv){

	login();

	//signal(SIGTRAP, logout);
	return 0;
}