/*
 * Debian Installer main menu program.
 *
 * Copyright 2000  Joey Hess <joeyh@debian.org>
 * 
 * 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 2 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.
 */

#include "main-menu.h"
#include <cdebconf/debconfclient.h>
#include <stdlib.h>
#include <search.h>
#include <stdio.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <sys/types.h>
#include <unistd.h>

const int RAISE = 1;
const int LOWER = 0;

/* Save default priority, to be able to return to it when we have to lower it */
int default_priority = 1;

/* Save priority set by main-menu to detect priority changes from the user */
int local_priority = -1;

static struct debconfclient *debconf;

static int di_config_package(di_system_package *p,
			     int (*virtfunc)(di_system_package *),
			     int (*walkfunc)(di_system_package *));
/*
 * qsort comparison function (sort by menu item values, fall back to
 * lexical sort to resolve ties deterministically).
 */
int package_array_compare (const void *v1, const void *v2) {
	di_system_package *p1, *p2;

	p1 = *(di_system_package **)v1;
	p2 = *(di_system_package **)v2;

	int r = p1->installer_menu_item - p2->installer_menu_item;
	if (r) return r;
	return strcmp(p1->p.package, p2->p.package);
}

int isdefault(di_system_package *p) {
	int check;

	check = di_system_dpkg_package_control_file_exec(&p->p, "menutest", 0, NULL);
	if (check <= 0 || p->p.status == di_package_status_unpacked || p->p.status == di_package_status_half_configured)
		return true;
	return false;
}

bool isinstallable(di_system_package *p) {
	int check;

	check = di_system_dpkg_package_control_file_exec(&p->p, "isinstallable", 0, NULL);
	if (check <= 0)
		return true;
	return false;
}

int provides_installed_virtual_package(di_package *p) {
	di_slist_node *node1, *node2;

	for (node1 = p->depends.head; node1; node1 = node1->next) {
		di_package_dependency *d = node1->data;

		if (d->type == di_package_dependency_type_provides)
			for (node2 = d->ptr->depends.head; node2; node2 = node2->next) {
				d = node2->data;

				if (d->type == di_package_dependency_type_reverse_provides
				    && d->ptr->status == di_package_status_installed)
					return 1;
			}
	}

	return 0;
}

/* Expects a topologically ordered linked list of packages. */
static di_system_package *
get_default_menu_item(di_slist *list)
{
	di_system_package *p;
	di_slist_node *node;

	/* Traverse the list, return the first menu item that isn't installed */
	for (node = list->head; node != NULL; node = node->next) {
		p = node->data;
		if (!p->installer_menu_item ||
		    p->p.status == di_package_status_installed ||
		    !isinstallable(p))
			continue;
		/* If menutest says this item should be default, make it so */
		if (!isdefault(p))
			continue;
		/* Do not default to a package that provides a virtual
		   package that is provided by a package that is
		   already installed.  */
		if (!provides_installed_virtual_package(&p->p))
			return p;
	}
	/* Severely broken, there are no menu items in the sorted list */
	return NULL;
}

/* Return the text of the menu entry for PACKAGE, translated to
   LANGUAGE if possible.  */
static size_t menu_entry(struct debconfclient *debconf, char *language, di_system_package *package, char *buf, size_t size)
{
	char question[256];

	snprintf(question, sizeof(question), "debian-installer/%s/title", package->p.package);
	if (language) {
		/*  256 + strlen("Description-.UTF-8")  */
		char field[256+18];
		char *lang, *end, *und;

		strcpy(field, "Description-");
		lang = language;
		do {
			end = strchr(lang, ':');
			if (end == NULL)
				end = lang + strlen(lang);
		        strncpy(field+12, lang, end-lang);
		        strcpy(field+12+(end-lang), ".UTF-8");
			if (!debconf_metaget(debconf, question, field))
			{
				strncpy(buf, debconf->value, size);
				return strlen (buf);
			}
			// Was the language of the form xx_YY ? 
			und = strchr(lang, '_');
			if (und != NULL && (und - lang) < (end - lang)) {
		        	strncpy(field+12, lang, und-lang);
		        	strcpy(field+12+(und-lang), ".UTF-8");
				if (!debconf_metaget(debconf, question, field))
	                	{
	                        	strncpy(buf, debconf->value, size);
	                        	return strlen (buf);
	                	}
			}
			lang = end+1;
		} while (*end != '\0');
	}
	if (!debconf_metaget(debconf, question, "Description"))
	{
		strncpy(buf, debconf->value, size);
		return strlen (buf);
	}

	/* The following fallback case can go away once all packages
	   have transitioned to the new form.  */
	di_log(DI_LOG_LEVEL_INFO, "Falling back to the package description for %s", package->p.package);
	if (package->p.short_description)
		strncpy(buf, package->p.short_description, size);
	return strlen (buf);
}

/* Displays the main menu via debconf and returns the selected menu item. */
di_system_package *show_main_menu(di_packages *packages, di_packages_allocator *allocator) {
	char *language = NULL;
	di_system_package **package_array, *p;
	di_slist *list;
	di_slist_node *node;
	di_system_package *menudefault = NULL, *ret = NULL;
	int i = 0, num = 0;
	char buf[256], *menu, *s;
	int menu_size, menu_used, size;

	debconf_get(debconf,"debian-installer/language");
	if (language)
		free(language);
	if (debconf->value)
		language = strdup(debconf->value);

	for (node = packages->list.head; node; node = node->next) {
		p = node->data;
		if (((di_system_package *)p)->installer_menu_item)
			num++;
	}
	package_array = di_new (di_system_package *, num + 1);
	package_array[num] = NULL;
	for (node = packages->list.head; node; node = node->next) {
		p = node->data;
		if (p->installer_menu_item)
			package_array[i++] = node->data;
	}
	
	/* Sort by menu number. */
	qsort(package_array, num, sizeof (di_system_package *), package_array_compare);

	/* Order menu so depended-upon packages come first. */
	/* The menu number is really only used to break ties. */
	list = di_packages_resolve_dependencies_array (packages, (di_package **) package_array, allocator);

	/*
	 * Generate list of menu choices for debconf.
	 */
	menu = di_malloc(1024);
	menu[0] = '\0';
	menu_size = 1024;
	menu_used = 1;
	for (node = list->head; node != NULL; node = node->next) {
		p = node->data;
		if (!p->installer_menu_item ||
		    !isinstallable(p))
			continue;
		size = menu_entry(debconf, language, p, buf, sizeof (buf));
		if (menu_used + size + 2 > menu_size)
		{
			menu_size += 1024;
			menu = di_realloc(menu, menu_size);
		}
		strcat(menu, buf);
		menu_used += size + 2;
		if (node->next)
			strcat(menu, ", ");
	}
	menudefault = get_default_menu_item(list);
	di_slist_free(list);

	/* Make debconf show the menu and get the user's choice. */
	debconf_settitle(debconf, "debian-installer/main-menu-title");
	debconf_capb(debconf);
	debconf_fset(debconf,  MAIN_MENU, "seen", "false");
	debconf_subst(debconf, MAIN_MENU, "MENU", menu);
	if (menudefault) {
		menu_entry(debconf, language, menudefault, buf, sizeof (buf));
		debconf_set(debconf, MAIN_MENU, buf);
	}
	debconf_input(debconf, "medium", MAIN_MENU);
	debconf_go(debconf);
	debconf_get(debconf, MAIN_MENU);
	s = strdup(debconf->value);
	
	/* Figure out which menu item was selected. */
	for (i = 0; i < num; i++) {
		p = package_array[i];
		menu_entry(debconf, language, p, buf, sizeof (buf));
		if (strcmp(buf, s) == 0) {
			ret = p;
			break;
		}
	}
	
	if (! ret) {
		/* This could happen because of a debconf protocol problem
		 * (for example, leading whitespace in menu items can
		 * be stripped and confuse the comparisons), or other
		 * problem. */
		di_log(DI_LOG_LEVEL_INFO, "Internal error! Cannot find \"%s\" in menu.", s);
	}
	
	free(language);
	free(package_array);

	return ret;
}

static int check_special(di_system_package *p);

/*
 * Satisfy the dependencies of a virtual package. Its dependencies
 * that actually provide the package are presented in a debconf select
 * question for the user to pick and choose. Other dependencies are
 * just fed recursively through di_config_package.
 */
static int satisfy_virtual(di_system_package *p) {
	di_slist_node *node;
	di_system_package *dep, *defpkg = NULL;
	char *language = NULL;
	char buf[256], *menu, *s = NULL;
	size_t menu_size, menu_used, size;
	int is_menu_item = 0;

	debconf_get(debconf, "debian-installer/language");
	if (debconf->value)
		language = strdup(debconf->value);

	menu = di_malloc(1024);
	menu[0] = '\0';
	menu_size = 1024;
	menu_used = 1;
	/* Compile a list of providing package. The default choice will be the
	 * package with highest priority. If we have ties, menu items are
	 * preferred. If we still have ties, the default choice is arbitrary */
	for (node = p->p.depends.head; node; node = node->next) {
		di_package_dependency *d = node->data;
		dep = (di_system_package *)d->ptr;
		if (d->type == di_package_dependency_type_depends) {
			/* Non-providing dependency */
			di_log(DI_LOG_LEVEL_DEBUG, "non-providing dependency from %s to %s", p->p.package, dep->p.package);
			if (dep->p.status != di_package_status_installed &&
			    !di_config_package(dep, satisfy_virtual, check_special))
				return 0;
			continue;
		}
		if (d->type != di_package_dependency_type_reverse_provides)
			continue;
		if (dep->p.status == di_package_status_installed) {
			/* This means that a providing package is already
			 * configure. So we short-circuit. */
			menu_used = 0;
			break;
		}
		if (defpkg == NULL || dep->p.priority > defpkg->p.priority ||
				(dep->p.priority == defpkg->p.priority &&
				 dep->installer_menu_item < defpkg->installer_menu_item))
			defpkg = dep;
		/* This only makes sense if one of the dependencies
		 * is a menu item */
		if (dep->installer_menu_item)
			is_menu_item = 1;

		size = menu_entry(debconf, language, dep, buf, sizeof (buf));
		if (menu_used + size + 2 > menu_size)
		{
			menu_size += 1024;
			menu = di_realloc(menu, menu_size);
		}

		if (dep == defpkg) {
			/* We want the default to be the first item */
			char *temp;
			temp = di_malloc (menu_size);
			strcpy(temp, menu);
			strcpy(menu, buf);
			strcat(menu, ", ");
			strcat(menu, temp);
			di_free(temp);
		} else {
			strcat(menu, buf);
			strcat(menu, ", ");
		}
		menu_used += size + 2;
	}
	if (menu_used >= 2)
		menu[menu_used-2] = '\0';
	if (menu_used > 1) {
		if (is_menu_item) {
			char *priority = "medium";
			/* Only let the user choose if one of them is a menu item */
			debconf_fset(debconf, MISSING_PROVIDE, "seen", "false");
			if (defpkg != NULL) {
				menu_entry(debconf, language, defpkg, buf, sizeof(buf));
				debconf_set(debconf, MISSING_PROVIDE, buf);
			} else
				/* TODO: How to figure out a default? */
				priority = "critical";
			debconf_capb(debconf, "backup");
			debconf_subst(debconf, MISSING_PROVIDE, "CHOICES", menu);
			debconf_input(debconf, priority, MISSING_PROVIDE);
			if (debconf_go(debconf) != 0)
				return 0;
			debconf_capb(debconf);
			debconf_get(debconf, MISSING_PROVIDE);
			s = strdup(debconf->value);
		}
		/* Go through the dependencies again */
		for (node = p->p.depends.head; node; node = node->next) {
			di_package_dependency *d = node->data;
			dep = (di_system_package *)d->ptr;
			menu_entry(debconf, language, dep, buf, sizeof(buf));
			if (!is_menu_item || strcmp(s, buf) == 0) {
				/* Ick. If we have a menu item it has to match the
				 * debconf choice, otherwise we configure all of
				 * the providing packages */
				if (!di_config_package(dep, satisfy_virtual, check_special))
					return 0;
				if (is_menu_item)
					break;
			}
		}
	}
	free(menu);
	free(s);
	free(language);
	/* It doesn't make sense to configure virtual packages,
	 * since they are, well, virtual. */
	p->p.status = di_package_status_installed;
	return 1;
}

static void update_language (void) {
	debconf_get(debconf, "debian-installer/language");
	if (*debconf->value != 0)
		setenv("LANGUAGE", debconf->value, 1);
}

static int
check_special(di_system_package *p)
{
	di_slist_node *node;

	/*
	 * A language selection package must provide the virtual
	 * package 'language-selected'.
	 * The LANGUAGE environment variable must be updated
	 */
	for (node = p->p.depends.head; node; node = node->next) {
		di_package_dependency *d = node->data;
		if (d->type == di_package_dependency_type_provides && strcmp(d->ptr->package, "language-selected") == 0) {
			update_language();
			break;
		}
	}
	return 0;
}

static void set_package_title(di_system_package *p) {
	char *title;

	asprintf(&title, "debian-installer/%s/title", p->p.package);
	if (debconf_settitle(debconf, title))
		di_log(DI_LOG_LEVEL_WARNING, "Unable to set title for %s.", p->p.package);
	free(title);
}

int do_menu_item(di_system_package *p) {
	char *configcommand;
	const char *showold_template = "debconf/showold";
	char *showold = NULL;
	int ret = 0;

	di_log(DI_LOG_LEVEL_DEBUG, "Menu item '%s' selected", p->p.package);

	if (p->p.status == di_package_status_installed) {
		set_package_title(p);

		/* The menu item is already configured, so reconfigure it. */
		debconf_get(debconf, showold_template);
		if (debconf->value)
			showold = strdup(debconf->value);
		debconf_set(debconf, showold_template, "true");
		if (asprintf(&configcommand, "exec udpkg --configure --force-configure %s", p->p.package) == -1) {
			return 0;
		}
		ret = di_exec_shell_log(configcommand);
		ret = di_exec_mangle_status(ret);
		free(configcommand);
		if (showold) {
			debconf_set(debconf, showold_template, showold);
			free(showold);
		} else {
			debconf_reset(debconf, showold_template);
		}
		check_special(p);
		if (ret)
			di_log(DI_LOG_LEVEL_WARNING, "Reconfiguring '%s' failed with error code %d", p->p.package, ret);
		ret = !ret;
	}
	else if (p->p.status == di_package_status_unpacked || p->p.status == di_package_status_half_configured) {
		ret = di_config_package(p, satisfy_virtual, check_special);
	}

	return ret;
}

static char *debconf_priorities[] =
  {
    "low",
    "medium",
    "high",
    "critical"
  };

#define ARRAY_SIZE(a) (sizeof(a)/sizeof(a[0]))
static void modify_debconf_priority (int raise_or_lower) {
	int pri, i;
	const char *template = "debconf/priority";
	debconf_get(debconf, template);
	
	pri = 1;
	if ( debconf->value ) {
		for (i = 0; (size_t)i < ARRAY_SIZE(debconf_priorities); ++i) {
			if (0 == strcmp(debconf->value,
					debconf_priorities[i]) ) {
				pri = i;
				break;
			}
		}
	}
	if (raise_or_lower == LOWER)
		--pri;
	else if (raise_or_lower == RAISE)
		++pri;
	if (0 > pri)
		pri = 0;
	if (pri > default_priority)
		pri = default_priority;
	if (local_priority != pri) {
		di_log(DI_LOG_LEVEL_INFO, "Modifying debconf priority limit from '%s' to '%s'",
			debconf->value ? debconf->value : "(null)",
			debconf_priorities[pri] ? debconf_priorities[pri] : "(null)");
		local_priority = pri;
	    
		debconf_set(debconf, template, debconf_priorities[pri]);
	}
}
	
static void adjust_default_priority (void) {
	int pri, i;
	const char *template = "debconf/priority";
	debconf_get(debconf,  template);

	pri = 1;
	if ( debconf->value ) {
		for (i = 0; (size_t)i < ARRAY_SIZE(debconf_priorities); ++i) {
			if (0 == strcmp(debconf->value,
					debconf_priorities[i]) ) {
				pri = i;
				break;
			}
		}
	}
	
	if ( pri != local_priority ) {
		di_log(DI_LOG_LEVEL_INFO, "Priority changed externally, setting main-menu default to '%s' (%s)",
			debconf_priorities[pri] ? debconf_priorities[pri] : "(null)", debconf->value);
		local_priority = pri;
		default_priority = pri;
	}
}

int main (int argc __attribute__ ((unused)), char **argv) {
	di_system_package *p;
	di_packages *packages;
	di_packages_allocator *allocator;
	int ret;

	debconf = debconfclient_new();
	di_system_init(basename(argv[0]));
	
	/* Tell udpkg to shut up. */
	setenv("UDPKG_QUIET", "y", 1);

	allocator = di_system_packages_allocator_alloc ();
	packages = di_system_packages_status_read_file(DI_SYSTEM_DPKG_STATUSFILE, allocator);
	while ((p=show_main_menu(packages, allocator))) {
		ret = do_menu_item(p);
		adjust_default_priority();
		if (!ret) {
			if (ret == 10)
				di_log(DI_LOG_LEVEL_INFO, "Menu item '%s' succeeded but requested to be left unconfigured.", p->p.package); 
			else
				di_log(DI_LOG_LEVEL_WARNING, "Menu item '%s' failed.", p->p.package);
			/* Something went wrong.  Lower debconf
			   priority limit to try to give the user more
			   control over the situation. */
			modify_debconf_priority(LOWER);
		}
		else
			modify_debconf_priority(RAISE);
		
		di_packages_free (packages);
		di_packages_allocator_free (allocator);
		allocator = di_system_packages_allocator_alloc ();
		packages = di_system_packages_status_read_file(DI_SYSTEM_DPKG_STATUSFILE, allocator);

		/* tell cdebconf to save the database */
		kill(getppid(), SIGUSR1);
	}
	
	return(0);
}

/*
 * Configure all dependencies, special case for virtual packages.
 * This is done depth-first.
 */
static int di_config_package(di_system_package *p,
			     int (*virtfunc)(di_system_package *),
			     int (*walkfunc)(di_system_package *)) {
	char *configcommand;
	int ret;
	di_slist_node *node;
	di_system_package *dep;

	di_log(DI_LOG_LEVEL_DEBUG, "configure %s, status: %d\n", p->p.package, p->p.status);

	if (p->p.type == di_package_type_virtual_package) {
		di_log(DI_LOG_LEVEL_DEBUG, "virtual package %s\n", p->p.package);
		if (virtfunc)
			return virtfunc(p);
		else
			return 0;
	}
	else if (p->p.type == di_package_type_non_existent)
		return 1;

	for (node = p->p.depends.head; node; node = node->next) {
		di_package_dependency *d = node->data;
		dep = (di_system_package *)d->ptr;
		if (dep->p.status == di_package_status_installed)
			continue;
		if (d->type != di_package_dependency_type_depends)
			continue;
		/* Recursively configure this package */
		if (!di_config_package(dep, virtfunc, walkfunc))
			return 0;
	}

	set_package_title(p);
	if (asprintf(&configcommand, "exec udpkg --configure %s", p->p.package) == -1) {
		return 0;
	}
	ret = di_exec_shell_log(configcommand);
	ret = di_exec_mangle_status(ret);
	free(configcommand);
	if (ret == 0) {
		p->p.status = di_package_status_installed;
		if (walkfunc != NULL)
			walkfunc(p);
	} else {
		di_log(DI_LOG_LEVEL_WARNING, "Configuring '%s' failed with error code %d", p->p.package, ret);
		p->p.status = di_package_status_half_configured;
		return 0;
	}
	return !ret;
}