/*******************************************************************************

    Copyright(C) Jonas 'Sortie' Termansen 2015, 2016.

    This program 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, either version 3 of the License, or (at your option)
    any later version.

    This program 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
    this program. If not, see <http://www.gnu.org/licenses/>.

    interactive.c
    Interactive utility functions.

*******************************************************************************/

#include <sys/termmode.h>
#include <sys/types.h>

#include <ctype.h>
#include <err.h>
#include <limits.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <wchar.h>

#include "execute.h"
#include "interactive.h"

void shlvl(void)
{
	long shlvl = 0;
	if ( getenv("SHLVL") && (shlvl = atol(getenv("SHLVL"))) < 0 )
		shlvl = 0;
	if ( shlvl < LONG_MAX )
		shlvl++;
	char shlvl_string[sizeof(long) * 3];
	snprintf(shlvl_string, sizeof(shlvl_string), "%li", shlvl);
	setenv("SHLVL", shlvl_string, 1);
}

void text(const char* str)
{
	fflush(stdout);
	struct winsize ws;
	if ( tcgetwinsize(1, &ws) < 0 )
		err(2, "tcgetwinsize");
	struct wincurpos wcp;
	if ( tcgetwincurpos(1, &wcp) < 0 )
		err(2, "tcgetwinsize");
	size_t columns = ws.ws_col;
	size_t column = wcp.wcp_col;
	bool blank = false;
	while ( str[0] )
	{
		if ( str[0] == '\n' )
		{
			putchar('\n');
			blank = false;
			column = 0;
			str++;
			continue;
		}
		else if ( isblank((unsigned char) str[0]) )
		{
			blank = true;
			str++;
			continue;
		}
		size_t word_length = 0;
		size_t word_columns = 0;
		mbstate_t ps = { 0 };
		while ( str[word_length] &&
		        str[word_length] != '\n' &&
		        !isblank((unsigned char) str[word_length]) )
		{
			wchar_t wc;
			size_t amount = mbrtowc(&wc, str + word_length, SIZE_MAX, &ps);
			if ( amount == (size_t) -2 )
				 break;
			if ( amount == (size_t) -1 )
			{
				memset(&ps, 0, sizeof(ps));
				amount = 1;
			}
			if ( amount == (size_t) 0 )
				break;
			word_length += amount;
			int width = wcwidth(wc);
			if ( width < 0 )
				continue;
			word_columns += width;
		}
		if ( (column && blank ? 1 : 0) + word_columns <= columns - column )
		{
			if ( column && blank )
			{
				putchar(' ');
				column++;
			}
			blank = false;
			fwrite(str, 1, word_length, stdout);
			column += word_columns;
			if ( column == columns )
				column = 0;
		}
		else
		{
			if ( column != 0 && column != columns )
				putchar('\n');
			column = 0;
			blank = false;
			fwrite(str, 1, word_length, stdout);
			column += word_columns;
			column %= columns;
		}
		str += word_length;
	}
	fflush(stdout);
}

void textf(const char* format, ...)
{
	va_list ap;
	va_start(ap, format);
	char* str;
	int len = vasprintf(&str, format, ap);
	va_end(ap);
	if ( len < 0 )
	{
		vprintf(format, ap);
		return;
	}
	text(str);
	free(str);
}

void prompt(char* buffer,
            size_t buffer_size,
            const char* question,
            const char* answer)
{
	while ( true )
	{
		text(question);
		if ( answer )
			printf(" [%s] ", answer);
		else
			printf(" ");
		fflush(stdout);
		fgets(buffer, buffer_size, stdin);
		size_t buffer_length = strlen(buffer);
		if ( buffer_length && buffer[buffer_length-1] == '\n' )
			buffer[--buffer_length] = '\0';
		while ( buffer_length && buffer[buffer_length-1] == ' ' )
			buffer[--buffer_length] = '\0';
		if ( !strcmp(buffer, "") )
		{
			if ( !answer )
				continue;
			strlcpy(buffer, answer, buffer_size);
		}
		if ( !strcmp(buffer, "!") )
		{
			printf("Type 'exit' to return to install.\n");
			fflush(stdout);
			execute((const char*[]) { "sh", NULL }, "f");
			continue;
		}
		if ( !strcmp(buffer, "!man") )
		{
			execute((const char*[]) { "man", prompt_man_section,
			                          prompt_man_page, NULL }, "f");
			continue;
		}
		break;
	}
}

void password(char* buffer,
              size_t buffer_size,
              const char* question)
{
	unsigned int termmode;
	gettermmode(0, &termmode);
	settermmode(0, termmode & ~TERMMODE_ECHO);
	text(question);
	printf(" ");
	fflush(stdout);
	fflush(stdin);
	// TODO: This may leave a copy of the password in the stdio buffer.
	fgets(buffer, buffer_size, stdin);
	fflush(stdin);
	printf("\n");
	size_t buffer_length = strlen(buffer);
	if ( buffer_length && buffer[buffer_length-1] == '\n' )
		buffer[--buffer_length] = '\0';
	settermmode(0, termmode);
}

static bool has_program(const char* program)
{
	return execute((const char*[]) { "which", "--", program, NULL }, "q") == 0;
}

bool missing_program(const char* program)
{
	if ( has_program(program) )
		return false;
	warnx("%s: Program is absent", program);
	return true;
}