/* See LICENSE file for license details. */
#define _XOPEN_SOURCE 700
#include <unistd.h>
#include <pwd.h>
#include <grp.h>
#include <shadow.h>
#include <crypt.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <termios.h>
#include <sys/wait.h>

#include "../accent.h"
#include "config.h"

static ColorShm *accentshm;
static char accentcol[8] = "#005577";

static void
die(const char *fmt, ...)
{
    va_list ap;
    va_start(ap, fmt);
    vfprintf(stderr, fmt, ap);
    va_end(ap);
    exit(1);
}

static void
updateaccent(void)
{
    if (!readaccent(&accentshm, accentcol))
        memcpy(accentcol, "#005577", 8);
}

static void
parseaccent(int *r, int *g, int *b)
{
    unsigned int ri, gi, bi;
    if (sscanf(accentcol + 1, "%02x%02x%02x", &ri, &gi, &bi) == 3) {
        *r = ri;
        *g = gi;
        *b = bi;
    } else {
        *r = 0x00;
        *g = 0x55;
        *b = 0x77;
    }
}

static void
colored(const char *msg)
{
    int r, g, b;
    parseaccent(&r, &g, &b);
    printf("\033[38;2;%d;%d;%dm%s\033[0m", r, g, b, msg);
}

static const char *
gethash(const char *user)
{
    struct passwd *pw;
    const char *hash;
    if (!(pw = getpwnam(user)))
        return NULL;
    hash = pw->pw_passwd;
#if HAVE_SHADOW_H
    if (!strcmp(hash, "x")) {
        struct spwd *sp;
        if (!(sp = getspnam(user)))
            return NULL;
        hash = sp->sp_pwdp;
    }
#endif
    return hash;
}

static int
auth(const char *user, const char *pass)
{
    const char *hash = gethash(user);
    char *cryptpw;
    if (!hash)
        return 0;
    if (!(cryptpw = crypt(pass, hash)))
        return 0;
    return !strcmp(cryptpw, hash);
}

static void
readinput(char *buf, size_t len)
{
    if (!fgets(buf, len, stdin))
        buf[0] = '\0';
    buf[strcspn(buf, "\n")] = '\0';
}

static void
readpass(char *buf, size_t len)
{
    struct termios old, new;
    tcgetattr(STDIN_FILENO, &old);
    new = old;
    new.c_lflag &= ~(ECHO);
    tcsetattr(STDIN_FILENO, TCSAFLUSH, &new);
    readinput(buf, len);
    tcsetattr(STDIN_FILENO, TCSAFLUSH, &old);
}

static void
runsession(const char *user)
{
    struct passwd *pw;
    pid_t pid;
    if (!(pw = getpwnam(user)))
        return;
    if ((pid = fork()) == 0) {
        if (initgroups(user, pw->pw_gid) < 0)
            die("slogin: initgroups failed\n");
        if (setgid(pw->pw_gid) < 0)
            die("slogin: setgid failed\n");
        if (setuid(pw->pw_uid) < 0)
            die("slogin: setuid failed\n");
        setenv("HOME", pw->pw_dir, 1);
        if (chdir(pw->pw_dir) < 0)
            die("slogin: chdir failed\n");
        execvp(logincmd[0], (char *const *)logincmd);
        _exit(1);
    }
    waitpid(pid, NULL, 0);
}

int
main(void)
{
    char user[64];
    char pass[64];

    for (;;) {
        updateaccent();
        printf("\033[2J\033[H");
        colored("login: ");
        fflush(stdout);
        readinput(user, sizeof user);
        colored("password: ");
        fflush(stdout);
        readpass(pass, sizeof pass);
        printf("\n");
        if (auth(user, pass)) {
            memset(pass, 0, sizeof pass);
            runsession(user);
        } else {
            colored("Login incorrect\n");
            memset(pass, 0, sizeof pass);
            sleep(2);
        }
    }
    return 0;
}