/*
 * ui.c - hlogin(1) user interface functions
 *
 * Copyleft (C) 2022 ~keith <keith@keithhacks.cyou>
 *
 * This file is part of hlogin.
 *
 * hlogin is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation, version 3.
 *
 * hlogin is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with hlogin. If not, see <https://www.gnu.org/licenses/>.
 */
#include "config.h"
#include "ui.h"

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <errno.h>

#include <locale.h>
#include "gettext.h"

#include <unistd.h>
#include <limits.h>
#include <time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>

int term_rows, term_cols;

WINDOW *back_w;
PANEL  *back_p;

WINDOW *login_w;
PANEL  *login_p;

WINDOW *login_shadow_w;
PANEL  *login_shadow_p;

WINDOW *error_w;
PANEL  *error_p;

WINDOW *error_shadow_w;
PANEL  *error_shadow_p;

const int login_rows = 8;
const int login_cols = 48;

int error_rows, error_cols;
int error_curx;

char *input_buf;
size_t input_buflen;
int input_pos;
int input_scroll;

char *msg;
bool hide_input;

int btn_focus = 0;
int btn_count = 2;

char *hostname;
char *domain;

char *unknown_str = "(unknown)";

char *xgethostname()
{
	size_t len = HOST_NAME_MAX;
	char *buf = malloc(sizeof(char) * (len + 1));
	if (!buf)
		return unknown_str;

	while (gethostname(buf, len) != 0) {
		if (errno != EINVAL && errno != ENAMETOOLONG) {
			free(buf);
			return unknown_str;
		}
		len *= 2;
		buf = realloc(buf, sizeof(char) * (len + 1));
		if (!buf)
			return unknown_str;
	}

	buf[len] = '\0';
	return buf;
}

char *xgetdomainname(char *host)
{
	struct addrinfo hints, *info = NULL;
	memset(&hints, 0, sizeof(hints));
	hints.ai_flags = AI_CANONNAME;

	if ((getaddrinfo(host, NULL, &hints, &info) != 0) || !info || !info->ai_canonname)
		goto FAILURE;

	// skip the first part of the canonname (the hostname)
	char *domain = strchr(info->ai_canonname, '.');
	if (!domain || (strlen(domain) <= 1))
		goto FAILURE;
	domain++;

	// copy into a new buffer & return
	char *buf = malloc(sizeof(char) * (strlen(domain) + 1));
	strcpy(buf, domain);
	freeaddrinfo(info);
	return buf;

FAILURE:
	if (info)
		freeaddrinfo(info);
	return unknown_str;
}

void safe_free(void *ptr, size_t size)
{
	memset(ptr, (int)'\0', size);
	free(ptr);
}

void *safe_realloc(void *ptr, size_t size, size_t new_size)
{
	void *new_ptr = malloc(new_size);
	if (new_ptr == NULL)
		return NULL;
	memcpy(new_ptr, ptr, size);
	safe_free(ptr, size);
	return new_ptr;
}

/*
char *xgetnisdomainname()
{
	size_t len = HOST_NAME_MAX;
	char *buf = malloc(sizeof(char) * (len + 1));
	if (!buf)
		return unknown_str;

	while (getdomainname(buf, len) != 0) {
		if (errno != EINVAL && errno != ENAMETOOLONG) {
			free(buf);
			return unknown_str;
		}
		len *= 2;
		buf = realloc(buf, sizeof(char) * (len + 1));
		if (!buf)
			return unknown_str;
	}

	buf[len] = '\0';
	return buf;
}
*/

char erase_ch;

void ui_setup_dialog(char *prompt, bool password)
{
	memset(input_buf, (int)'\0', sizeof(char) * input_buflen);
	input_pos = 0;
	input_scroll = 0;
	btn_focus = 0;
	btn_count = 2;

	msg = prompt;
	hide_input = password;

	hide_panel(error_p);
	hide_panel(error_shadow_p);
	show_panel(login_shadow_p);
	top_panel(login_p);

	wclear(login_w);
	draw_outline(login_w, login_rows, login_cols, 0, 0, false);
	paint_login();
}

void ui_setup_message(char *text)
{
	btn_focus = 0;
	btn_count = 1;

	int tcols = login_cols - 4;
	int trows = 1;
	char **msg_lines = word_wrap(text, tcols, tcols / 2, &trows);

	if (trows == 1)
		tcols = strlen(msg_lines[0]);
	if (tcols < 16)
		tcols = 16;

	error_rows = trows + 4;
	error_cols = tcols + 4;

	hide_panel(login_shadow_p);

	wresize(error_w, error_rows, error_cols);
	wresize(error_shadow_w, error_rows, error_cols);

	replace_panel(error_shadow_p, error_shadow_w);
	show_panel(error_shadow_p);
	move_panel(error_shadow_p, ((term_rows - error_rows) / 2) + 1, ((term_cols - error_cols) / 2) + 1);

	replace_panel(error_p, error_w);
	show_panel(error_p);
	move_panel(error_p, (term_rows - error_rows) / 2, (term_cols - error_cols) / 2);

	wbkgd(error_shadow_w, ' ' | COLOR_PAIR(4));
	wclear(error_shadow_w);
	touchwin(error_shadow_w);

	wclear(error_w);
	draw_outline(error_w, error_rows, error_cols, 0, 0, false);

	// draw text
	wattron(error_w, COLOR_PAIR(2));
	for (int i = 0; i < trows; i++) {
		wmove(error_w, i + 1, 2);
		waddstr(error_w, msg_lines[i]);
		free(msg_lines[i]);
	}
	free(msg_lines);

	// draw button
	wmove(error_w, error_rows - 2, 2);
	wattron(error_w, A_REVERSE);
	wprintw(error_w, "< %s >", _("OK"));
	error_curx = error_w->_curx - 2;
	wattroff(error_w, A_REVERSE);
}

/** ui_init - initialize the UI subsystem
 */
void ui_init()
{
	initscr();
	noecho();
	cbreak();
	halfdelay(2);
	start_color();
	getmaxyx(stdscr, term_rows, term_cols);
	clear();

	erase_ch = erasechar();

	// set up input buffer
	input_pos = 0;
	input_buflen = 256;
	input_buf = malloc(input_buflen * sizeof(char));
	if (!input_buf)
		exit(EXIT_FAILURE);
	input_buf[0] = '\0';

	// get hostname & domain
	hostname = xgethostname();
	domain = xgetdomainname(hostname);

	// set up colours
	init_pair(1, COLOR_WHITE, COLOR_BLUE);
	init_pair(2, COLOR_BLACK, COLOR_WHITE);
	init_pair(3, COLOR_WHITE, COLOR_WHITE);
	init_pair(4, COLOR_BLACK, COLOR_BLACK);

	// set up background window
	back_w = newwin(term_rows, term_cols, 0, 0);
	back_p = new_panel(back_w);
	wattron(back_w, COLOR_PAIR(1));
	wbkgd(back_w, ' ' | COLOR_PAIR(1));
	wclear(back_w);
	paint_back();

	// set up login shadow window
	login_shadow_w = newwin(login_rows, login_cols, ((term_rows - login_rows) / 2) + 1, ((term_cols - login_cols) / 2) + 1);
	login_shadow_p = new_panel(login_shadow_w);
	wbkgd(login_shadow_w, ' ' | COLOR_PAIR(4));
	wclear(login_shadow_w);

	// set up login window
	login_w = newwin(login_rows, login_cols, (term_rows - login_rows) / 2, (term_cols - login_cols) / 2);
	login_p = new_panel(login_w);
	wattron(login_w, COLOR_PAIR(2));
	wbkgd(login_w, ' ' | COLOR_PAIR(2));
	wclear(login_w);
	draw_outline(login_w, login_rows, login_cols, 0, 0, false);
	paint_login();

	// set up error shadow window
	error_shadow_w = newwin(2, 2, 1, 1);
	error_shadow_p = new_panel(error_shadow_w);
	wbkgd(error_shadow_w, ' ' | COLOR_PAIR(4));
	wclear(error_shadow_w);
	hide_panel(error_shadow_p);

	// set up error window
	error_w = newwin(1, 1, 0, 0);
	error_p = new_panel(error_w);
	wbkgd(error_w, ' ' | COLOR_PAIR(2));
	wclear(error_w);
	hide_panel(error_p);

	// enable keypad mode
	keypad(login_w, true);
	keypad(error_w, true);
}

void ui_end()
{
	safe_free(input_buf, input_buflen);

	del_panel(back_p);
	del_panel(login_p);
	del_panel(login_shadow_p);
	del_panel(error_p);
	del_panel(error_shadow_p);

	delwin(back_w);
	delwin(login_w);
	delwin(login_shadow_w);
	delwin(error_w);
	delwin(error_shadow_w);

	endwin();
}

/** paint_back - redraw info displayed on background
 */
void paint_back()
{
	wmove(back_w, 0, 0);
	wclrtoeol(back_w);

	wattron(back_w, A_BOLD);
	wprintw(back_w, _("Welcome to %s.%s"), hostname, domain);
	wattroff(back_w, A_BOLD);

	char time_buf[256];
	time_t now = time(NULL);
	if (strftime(time_buf, 256, "%c", localtime(&now)) == 0)
		time_buf[0] = '\0';

	wmove(back_w, 0, term_cols - strlen(time_buf));
	wprintw(back_w, "%s", time_buf);
}

/** paint_login - redraw login dialog
 */
void paint_login()
{
	// Field outline
	draw_outline(login_w, 3, login_cols - 4, 2, 2, true);

	// Field label
	wmove(login_w, 1, 2);
	wattron(login_w, A_BOLD | COLOR_PAIR(2));
	waddstr(login_w, msg);
	wattroff(login_w, A_BOLD);

	// Field text
	wmove(login_w, 3, 3);
	whline(login_w, ' ', login_cols - 6);
	if (!hide_input)
		waddnstr(login_w, input_buf + input_scroll, login_cols - 6);
	else {
		int num_dots = strlen(input_buf) - input_scroll;
		if (num_dots > login_cols - 6)
			num_dots = login_cols - 6;
		whline(login_w, '*', num_dots);
	}

	// Buttons
	wmove(login_w, login_rows - 2, 2);
	if (btn_focus == 0)
		wattron(login_w, A_REVERSE);
	wprintw(login_w, "< %s >", _("OK"));
	wattroff(login_w, A_REVERSE);

	wmove(login_w, login_rows - 2, login_w->_curx + 2);
	if (btn_focus == 1)
		wattron(login_w, A_REVERSE);
	wprintw(login_w, "< %s >", _("Cancel"));
	wattroff(login_w, A_REVERSE);
}

int ui_update()
{
	paint_back();
	wmove(login_w, 3, 3 + input_pos - input_scroll);

	update_panels();
	doupdate();

	int ch = wgetch(login_w);
	if (ch == ERR)
		return -1;

	if (ch >= ' ' && ch < 0x7F)
		input_add_char(ch);
	else if (ch == 0x08 || ch == KEY_BACKSPACE || ch == erase_ch)
		input_backdel_char();
	else if (ch == 0x7F || ch == KEY_DC)
		input_del_char();
	else if (ch == KEY_LEFT && input_pos > 0) {
		input_pos--;
		if (input_pos < input_scroll)
			input_scroll--;
	} else if (ch == KEY_RIGHT && input_pos < strlen(input_buf)) {
		input_pos++;
		if (input_pos >= (input_scroll + login_cols - 6))
			input_scroll++;
	} else if (ch == '\t')
		btn_focus = (btn_focus + 1) % btn_count;
	else if (ch == 0x1B) // escape
		return -2;
	else if (ch == KEY_ENTER || ch == '\r' || ch == '\n')
		return btn_focus;

	paint_login();

	return -1;
}

int ui_error_update()
{
	paint_back();
	wmove(error_w, error_rows - 2, error_curx);

	update_panels();
	doupdate();

	int ch = wgetch(error_w);
	if (ch == ERR)
		return -1;

	if (ch == 0x1B)
		return -2;
	else if (ch == KEY_ENTER || ch == '\r' || ch == '\n')
		return btn_focus;

	return -1;
}

int ui_run()
{
	int result;
	while ((result = ui_update()) == -1);
	btn_focus = -1;
	paint_back();
	paint_login();
	update_panels();
	doupdate();
	return result;
}

int ui_message_run()
{
	int result;
	while ((result = ui_error_update()) == -1);
	btn_focus = -1;
	paint_back();
	wmove(error_w, error_rows - 2, 2);
	wattron(error_w, COLOR_PAIR(2));
	wprintw(error_w, "< %s >", _("OK"));
	wmove(error_w, error_rows - 2, error_curx);
	update_panels();
	doupdate();
	hide_panel(error_p);
	hide_panel(error_shadow_p);
	show_panel(login_shadow_p);
	top_panel(login_p);
	clear();
	return result;
}

char *ui_get_text()
{
	unsigned int len = strlen(input_buf) + 1;
	char *buf = malloc(len * sizeof(char));
	strcpy(buf, input_buf);
	memset(input_buf, (int)'\0', input_buflen * sizeof(char));
	return buf;
}

void input_add_char(char ch)
{
	// resize if necessary
	if ((strlen(input_buf) + 2) > input_buflen) {
		input_buf = safe_realloc(input_buf, input_buflen * sizeof(char), input_buflen * 2 * sizeof(char));
		input_buflen *= 2;
	}
	// insert new char & shift everything over
	for (int i = (input_pos++); i < input_buflen; i++) {
		char temp = input_buf[i];
		input_buf[i] = ch;
		ch = temp;
		if (input_buf[i] == '\0')
			break;
	}
	if (input_pos >= (input_scroll + login_cols - 6))
		input_scroll++;
}

void input_backdel_char()
{
	if (input_pos <= 0)
		return;
	input_pos--;
	input_del_char();
}

void input_del_char()
{
	if (input_buf[input_pos] == '\0')
		return;

	for (int i = input_pos; i < input_buflen - 1; i++) {
		input_buf[i] = input_buf[i + 1];
		if (input_buf[i] == '\0')
			break;
	}
	if ((input_scroll + login_cols - 6) > strlen(input_buf) && input_scroll > 0)
		input_scroll--;
}

const attr_t light = A_BOLD | COLOR_PAIR(3);
const attr_t shadow = COLOR_PAIR(2);

void draw_outline(WINDOW *win, int height, int width, int y, int x, bool inset)
{
	wattron(win, A_ALTCHARSET);

	wattron(win, inset ? shadow : light);
	mvwhline(win, y, x + 1, ACS_HLINE, width - 2);
	mvwvline(win, y + 1, x, ACS_VLINE, height - 2);

	mvwaddch(win, y, x, ACS_ULCORNER);
	mvwaddch(win, y + height - 1, x, ACS_LLCORNER);
	wattroff(win, inset ? shadow : light);

	wattron(win, inset ? light : shadow);
	mvwhline(win, y + height - 1, x + 1, ACS_HLINE, width - 2);
	mvwvline(win, y + 1, x + width - 1, ACS_VLINE, height - 2);

	mvwaddch(win, y, x + width - 1, ACS_URCORNER);
	mvwaddch(win, y + height - 1, x + width - 1, ACS_LRCORNER);
	wattroff(win, inset ? light : shadow);

	wattroff(win, A_ALTCHARSET);
}

/** output_word - used in word_wrap
 */
void output_word(char *word, size_t len,
		 char ***out, int *line_pos, int *lines, int width)
{
	int i = 0;
	while (i < len) {
		int space = width - (*line_pos);
		int remain = len - i;
		if (space > remain) { // can fit on line
			memcpy((*out)[(*lines) - 1] + (*line_pos), word + i, sizeof(char) * remain);
			i += remain;
			*line_pos += remain;
		} else {
			// copy part of word
			memcpy((*out)[(*lines) - 1] + (*line_pos), word + i, sizeof(char) * space);
			i += space;
			*line_pos += space;
			// add newline
			(*out)[(*lines) - 1][(*line_pos)] = '\0';
			*line_pos = 0;
			(*lines)++;
			*out = realloc(*out, sizeof(char *) * (*lines));
			(*out)[(*lines) - 1] = malloc(sizeof(char) * (width + 1));
		}
	}
}

char **word_wrap(char *text, int width, int max_word, int *lines)
{
	// output lines
	*lines = 1;
	char **out = malloc(sizeof(char *) * (*lines));
	out[0] = malloc(sizeof(char) * (width + 1));
	// word buffer
	char *word = malloc(sizeof(char) * max_word);
	int word_len = 0;

	int line_pos = 0;

	for (char ch; (ch = *text) != '\0'; text++) {
		switch (ch) {
			case '\n':
			case ' ':
				if (word[0] == '\0')
					word_len = 0;
				if (word_len > 0) {
					// do we have to wrap to a new line?
					if (line_pos + word_len > width) {
						out[(*lines) - 1][line_pos] = '\0';
						line_pos = 0;
						(*lines)++;
						out = realloc(out, sizeof(char *) * (*lines));
						out[(*lines) - 1] = malloc(sizeof(char) * (width + 1));
					}
					memcpy(out[(*lines) - 1] + line_pos, word, sizeof(char) * word_len);
					line_pos += word_len;
					word_len = 0;
				}
				// output \n
				if (ch == '\n' || line_pos >= width) {
					out[(*lines) - 1][line_pos] = '\0';
					line_pos = 0;
					(*lines)++;
					out = realloc(out, sizeof(char *) * (*lines));
					out[(*lines) - 1] = malloc(sizeof(char) * (width + 1));
				} else {
					out[(*lines) - 1][line_pos++] = ' ';
				}
				break;
			default:
				// word longer than word buffer
				if (word_len >= max_word) {
					if (word[0] != '\0') {
						// write what we have
						output_word(word, word_len,
							    &out, &line_pos, lines, width);
						word[0] = '\0';
					}
					// write char and maybe newline
					out[(*lines) - 1][line_pos++] = ch;
					if (line_pos >= width) {
						out[(*lines) - 1][line_pos] = '\0';
						line_pos = 0;
						(*lines)++;
						out = realloc(out, sizeof(char *) * (*lines));
						out[(*lines) - 1] = malloc(sizeof(char) * (width + 1));
					}
				} else
					word[word_len++] = ch;
		}
	}

	if (word_len > 0 && word[0] != '\0') {
		// do we have to wrap to a new line?
		if (line_pos + word_len > width) {
			out[(*lines) - 1][line_pos] = '\0';
			line_pos = 0;
			(*lines)++;
			out = realloc(out, sizeof(char *) * (*lines));
			out[(*lines) - 1] = malloc(sizeof(char) * (width + 1));
		}
		memcpy(out[(*lines) - 1] + line_pos, word, sizeof(char) * word_len);
		line_pos += word_len;
		word_len = 0;
	}

	free(word);

	if (line_pos == 0)
		// remove last line
		free(out[--(*lines)]);
	else
		// non-empty line, add null terminator
		out[(*lines) - 1][line_pos] = '\0';

	return out;
}