/* conffile.c - process the configuration file */
/*
 * This file is part of secnet.
 * See README for full list of copyright holders.
 *
 * secnet 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.
 * 
 * secnet 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
 * version 3 along with secnet; if not, see
 * https://www.gnu.org/licenses/gpl.html.
 */

/* #define DUMP_PARSE_TREE */

#include "secnet.h"
#include <assert.h>
#include <limits.h>
#include <stdio.h>
#include <string.h>
#include "conffile.h"
#include "conffile_internal.h"
#include "conffile.yy.h"
#include "util.h"
#include "ipaddr.h"

static struct cloc no_loc={"none",0};

struct atomlist {
    struct atomlist *next;
    atom_t a;
};

struct entry {
    struct entry *next;
    atom_t key;
    list_t *val;
};

struct searchlist {
    struct dict *d;
    struct searchlist *next;
};

struct dict {
    struct dict *parent;
    struct searchlist *search;
    struct entry *entries;
    int32_t size;
};

static struct atomlist *atoms=NULL;

static void process_alist(dict_t *context, struct p_node *c);
static list_t *process_invocation(dict_t *context, struct p_node *i);

static list_t *dict_ilookup_primitive(dict_t *dict, atom_t key)
{
    struct entry *i;
    for (i=dict->entries; i; i=i->next) {
	if (key==i->key) return i->val;
    }
    return NULL;
}

static list_t *dict_ilookup(dict_t *dict, atom_t key)
{
    dict_t *d;
    list_t *v;

    v=dict_ilookup_primitive(dict, key);
    if (v) return v;
    /* Check dictionaries in search path */
/* XXX */
    /* Check lexical parents */
    for (d=dict; d; d=d->parent) {
	v=dict_ilookup_primitive(d, key);
	if (v) return v;
    }
    return NULL;
}

static void dict_iadd(dict_t *dict, atom_t key, list_t *val)
{
    struct entry *e;
    if (dict_ilookup_primitive(dict, key)) {
	fatal("duplicate key \"%s\" in dictionary",key);
    }
    NEW(e);
    e->next=dict->entries;
    e->key=key;
    e->val=val;
    dict->entries=e;
    dict->size++;
}

/***** Functions beyond this point are private to the config system *****/

static dict_t *dict_new(dict_t *parent)
{
    dict_t *d;

    NEW(d);
    d->parent=parent;
    d->search=NULL;
    d->entries=NULL;
    d->size=0;
    return d;
}

static struct p_node *node_copy(struct p_node *n)
{
    struct p_node *r;
    NEW(r);
    *r=*n;
    return r;
}

static struct p_node *list_reverse(struct p_node *list)
{
    struct p_node *rl=NULL, *i, *n;

    for (i=list; i; i=i->r) {
	n=node_copy(i);
	n->r=rl;
	rl=n;
    }
    return rl;
}

/* Since we use left-recursion in the parser for efficiency, sequences
   end up "backwards" in the parse tree. Rather than have complicated
   code for, eg. processing assignments in the right order, we reverse
   these sequences here. */
static void ptree_mangle(struct p_node *t)
{
    if (!t) return;
    ptree_mangle(t->l);
    ptree_mangle(t->r);
    switch (t->type) {
    case T_DICT:
	ASSERT(!t->l || t->l->type==T_ALIST);
	ASSERT(!t->r || t->r->type==T_LISTITEM);
	t->l=list_reverse(t->l);
	t->r=list_reverse(t->r);
	break;
    case T_ASSIGNMENT:
	ASSERT(t->l->type==T_KEY);
	ASSERT(t->r->type==T_LISTITEM);
	t->r=list_reverse(t->r);
	break;
    case T_ABSPATH:
    case T_RELPATH:
	ASSERT(t->l==NULL);
	ASSERT(t->r->type==T_PATHELEM);
	t->r=list_reverse(t->r);
	break;
    case T_EXEC:
	ASSERT(t->l);
	ASSERT(t->r==NULL || t->r->type==T_LISTITEM);
	t->r=list_reverse(t->r);
	break;
    }
}

#ifdef DUMP_PARSE_TREE
/* Convert a node type to a string, for parse tree dump */
static const char *ntype(uint32_t type)
{
    switch(type) {
    case T_STRING:     return "T_STRING";
    case T_NUMBER:     return "T_NUMBER";
    case T_KEY:        return "T_KEY";
    case T_ASSIGNMENT: return "T_ASSIGNMENT";
    case T_LISTITEM:   return "T_LISTITEM";
    case T_EXEC:       return "T_EXEC";
    case T_PATHELEM:   return "T_PATHELEM";
    case T_ABSPATH:    return "T_ABSPATH";
    case T_RELPATH:    return "T_RELPATH";
    case T_DICT:       return "T_DICT";
    case T_ALIST:      return "T_ALIST";
    case T_ERROR:      return "T_ERROR";
    }
    return "**unknown**";
}

static void ptree_indent(int amount)
{
    int i;
    for (i=0; i<amount; i++) printf("  . ");
}

static void ptree_dump(struct p_node *n, int d)
{
    if (!n) {
	printf("NULL\n");
	return;
    }
    
    if (T_IS_PRIMITIVE(n->type)) {
	switch(n->type) {
	case T_STRING: printf("T_STRING: \"%s\" (%s line %d)\n",
			      n->data.string,n->loc.file,n->loc.line); break;
	case T_NUMBER: printf("T_NUMBER: %d (%s line %d)\n",
			      n->data.number, n->loc.file,n->loc.line);	break;
	case T_KEY:    printf("T_KEY:    %s (%s line %d)\n",
			      n->data.key, n->loc.file,n->loc.line); break;
	default:       printf("**unknown primitive type**\n"); break;
	}
    } else {
	assert(d<10000);
	printf("%s: (%s line %d)\n",ntype(n->type),n->loc.file,n->loc.line);
	ptree_indent(d);
	printf("  |-");	ptree_dump(n->l, d+1);
	ptree_indent(d);
	printf("  +-"); ptree_dump(n->r, d+1);
    }
}

#endif /* DUMP_PARSE_TREE */

static dict_t *dict_find_root(dict_t *d)
{
    dict_t *i;

    for (i=d; i->parent; i=i->parent);
    return i;
}

static list_t *dict_lookup_path(dict_t *context, struct p_node *p)
{
    dict_t *i;
    list_t *l;

    ASSERT(p->type==T_PATHELEM);
    ASSERT(p->l->type==T_KEY);
    l=dict_ilookup(context, p->l->data.key);
    if (!l) {
	cfgfatal(p->loc,"conffile","can't find key %s\n",
		 p->l->data.key);
    }

    while (p->r) {
	if (l->item->type != t_dict) {
	    cfgfatal(p->loc,"conffile","path element \"%s\" "
		     "is not a dictionary\n",p->l->data.key);
	}
	i=l->item->data.dict; /* First thing in list */

	p=p->r;
	l=dict_ilookup_primitive(i, p->l->data.key);
	if (!l) {
	    cfgfatal(p->loc,"conffile","can't find key %s\n",
		     p->l->data.key);
	}
    }
    return l;
}

static item_t *new_item(enum types type, struct cloc loc)
{
    item_t *i;

    NEW(i);
    i->type=type;
    i->loc=loc;
    return i;
}

static list_t *process_item(dict_t *context, struct p_node *i)
{
    item_t *item=NULL;

    switch (i->type) {
    case T_STRING:
	item=new_item(t_string, i->loc);
	item->data.string=i->data.string; /* XXX maybe strcpy */
	break;
    case T_NUMBER:
	item=new_item(t_number, i->loc);
	item->data.number=i->data.number;
	break;
    case T_ABSPATH:
	context=dict_find_root(context);
	/* falls through */
    case T_RELPATH:
	return dict_lookup_path(context, i->r);
	/* returns immediately */
	break;
    case T_DICT:
	item=new_item(t_dict, i->loc);
	item->data.dict=dict_new(context);
/* XXX	dict_add_searchpath(context,process_ilist(context, i->r)); */
	process_alist(item->data.dict, i->l);
	break;
    case T_EXEC:
	return process_invocation(context, i);
	/* returns immediately */
	break;
    default:
#ifdef DUMP_PARSE_TREE
	ptree_dump(i,0);
	fatal("process_item: invalid node type for a list item (%s)",
	      ntype(i->type));
#else
	fatal("process_item: list item has invalid node type %d - recompile "
	      "with DUMP_PARSE_TREE defined in conffile.c for more "
	      "detailed debug output",i->type);
#endif /* DUMP_PARSE_TREE */
	break;
    }
    return list_append(NULL,item);
}

static list_t *process_ilist(dict_t *context, struct p_node *l)
{
    struct p_node *i;
    list_t *r;

    ASSERT(!l || l->type==T_LISTITEM);

    r=list_new();

    for (i=l; i; i=i->r) {
	r=list_append_list(r,process_item(context,i->l));
    }
    return r;
}
	
static list_t *process_invocation(dict_t *context, struct p_node *i)
{
    list_t *cll;
    item_t *cl;
    list_t *args;

    ASSERT(i->type==T_EXEC);
    ASSERT(i->r==NULL || i->r->type==T_LISTITEM);
    cll=process_item(context,i->l);
    cl=cll->item;
    if (cl->type != t_closure) {
	cfgfatal(i->l->loc,"conffile","only closures can be invoked\n");
    }
    if (!cl->data.closure->apply) {
	cfgfatal(i->l->loc,"conffile","this closure cannot be invoked\n");
    }
    args=process_ilist(context, i->r);
    return cl->data.closure->apply(cl->data.closure, i->loc, context, args);
}

static void process_alist(dict_t *context, struct p_node *c)
{
    struct p_node *i;
    atom_t k;
    list_t *l;

    if (!c) return; /* NULL assignment lists are valid (empty dictionary) */

    ASSERT(c->type==T_ALIST);
    if (c->type!=T_ALIST) {
	fatal("invalid node type in assignment list");
    }

    for (i=c; i; i=i->r) {
	ASSERT(i->l && i->l->type==T_ASSIGNMENT);
	ASSERT(i->l->l->type==T_KEY);
	ASSERT(i->l->r->type==T_LISTITEM);
	k=i->l->l->data.key;
	l=process_ilist(context, i->l->r);
	dict_iadd(context, k, l);
    }
}

/* Take a list of items; turn any dictionaries in this list into lists */
static list_t *makelist(closure_t *self, struct cloc loc,
			dict_t *context, list_t *args)
{
    list_t *r=NULL, *i;
    struct entry *e;
    
    for (i=args; i; i=i->next) {
	if (i->item->type==t_dict) {
	    /* Convert */
	    for (e=i->item->data.dict->entries; e; e=e->next) {
		r=list_append_list(r, e->val);
	    }
	} else {
	    r=list_append_list(r, list_append(NULL,i->item));
	}
    }
    return r;
}

/* Take a list consisting of a closure and some other things. Apply the
   closure to the other things, and return the resulting list */
static list_t *map(closure_t *self, struct cloc loc, dict_t *context,
		   list_t *args)
{
    list_t *r=NULL, *al;
    item_t *ci;
    closure_t *cl;
    list_t se;
    
    ci=list_elem(args,0);
    if (ci && ci->type==t_closure) {
	cl=ci->data.closure;
	if (!cl->apply) {
	    cfgfatal(loc,"map","closure cannot be applied\n");
	}
	for (al=args->next; al; al=al->next) {
	    /* Construct a single-element list */
	    se.next=NULL;
	    se.item=al->item;
	    /* Invoke the closure, append its result to the output */
	    r=list_append_list(r,cl->apply(cl,loc,context,&se));
	}
    } else {
	cfgfatal(loc,"map","you must supply a closure as the "
		 "first argument\n");
    }
    return r;
}

/* Read a file and turn it into a string */
static list_t *readfile(closure_t *self, struct cloc loc,
			dict_t *context, list_t *args)
{
    FILE *f;
    string_t filename;
    long length;
    item_t *r;

    r=list_elem(args,0);
    if (!r) {
	cfgfatal(loc,"readfile","you must supply a filename\n");
    }
    if (r->type!=t_string) {
	cfgfatal(loc,"readfile","filename must be a string\n");
    }
    filename=r->data.string;
    f=fopen(filename,"rb");
    if (!f) {
	fatal_perror("readfile (%s:%d): cannot open file \"%s\"",
		     loc.file,loc.line, filename);
    }
    if (fseek(f, 0, SEEK_END)!=0) {
	fatal_perror("readfile (%s:%d): fseek(SEEK_END)",loc.file,loc.line);
    }
    length=ftell(f);
    if (length<0) {
	fatal_perror("readfile (%s:%d): ftell()",loc.file,loc.line);
    }
    if (fseek(f, 0, SEEK_SET)!=0) {
	fatal_perror("readfile (%s:%d): fseek(SEEK_SET)",loc.file,loc.line);
    }
    r=new_item(t_string,loc);
    r->data.string=safe_malloc(length+1,"readfile");
    if (fread(r->data.string,length,1,f)!=1) {
	(ferror(f) ? fatal_perror : fatal)
	    ("readfile (%s:%d): fread: could not read all of file",
	     loc.file,loc.line);
    }
    r->data.string[length]=0;
    if (fclose(f)!=0) {
	fatal_perror("readfile (%s:%d): fclose",loc.file,loc.line);
    }
    return list_append(NULL,r);
}
    
static dict_t *process_config(struct p_node *c)
{
    dict_t *root;
    dict_t *context;
    item_t *i;
    list_t *false_;
    list_t *true_;

    root=dict_new(NULL);
    context=root;

    /* Predefined keys for boolean values */
    /* "nowise" and "verily" have the advantage of being the same
       length, so they line up nicely...  thanks VKC and SGT (who also
       point out that "mayhap" is a good "maybe" value as well) */
    i=new_item(t_bool,no_loc);
    i->data.bool_=False;
    false_=list_append(NULL,i);
    i=new_item(t_bool,no_loc);
    i->data.bool_=True;
    true_=list_append(NULL,i);
    dict_add(root,"false",false_);
    dict_add(root,"False",false_);
    dict_add(root,"FALSE",false_);
    dict_add(root,"no",false_);
    dict_add(root,"No",false_);
    dict_add(root,"NO",false_);
    dict_add(root,"nowise",false_);
    dict_add(root,"Nowise",false_);
    dict_add(root,"NOWISE",false_);
    dict_add(root,"true",true_);
    dict_add(root,"True",true_);
    dict_add(root,"TRUE",true_);
    dict_add(root,"yes",true_);
    dict_add(root,"Yes",true_);
    dict_add(root,"YES",true_);
    dict_add(root,"verily",true_);
    dict_add(root,"Verily",true_);
    dict_add(root,"VERILY",true_);

    add_closure(root,"makelist",makelist);
    add_closure(root,"readfile",readfile);
    add_closure(root,"map",map);

    init_builtin_modules(root);

    process_alist(context, c);

    return root;
}

/***** Externally accessible functions */

atom_t intern(cstring_t s)
{
    struct atomlist *i;

    for (i=atoms; i; i=i->next) {
	if (strcmp(i->a, s)==0) break;
    }

    if (!i) {
	/* Did't find it; create a new one */
	NEW(i);
	i->a=safe_strdup(s,"intern: alloc string");
	i->next=atoms;
	atoms=i;
    }
    return i->a;
}

list_t *dict_lookup(dict_t *dict, cstring_t key)
{
    return dict_ilookup(dict, intern(key));
}

list_t *dict_lookup_primitive(dict_t *dict, cstring_t key)
{
    return dict_ilookup_primitive(dict, intern(key));
}

void dict_add(dict_t *dict, cstring_t key, list_t *val)
{
    dict_iadd(dict,intern(key),val);
}

cstring_t *dict_keys(dict_t *dict)
{
    atom_t *r, *j;
    struct entry *i;
    NEW_ARY(r,dict->size+1);
    for (i=dict->entries, j=r; i; i=i->next, j++) {
	*j=i->key;
    }
    *j=NULL;
    return r;
}


/* List-related functions */

list_t *list_new(void)
{
    return NULL;
}

int32_t list_length(const list_t *a)
{
    int32_t l=0;
    const list_t *i;
    for (i=a; i; i=i->next) { assert(l < INT_MAX); l++; }
    return l;
}

static list_t *list_copy(list_t *a)
{
    list_t *r, *i, *b, *l;

    if (!a) return NULL;
    l=NULL;
    r=NULL;
    for (i=a; i; i=i->next) {
	NEW(b);
	if (l) l->next=b; else r=b;
	l=b;
	b->item=i->item;
	b->next=NULL;
    }
    return r;
}

list_t *list_append_list(list_t *a, list_t *b)
{
    list_t *i;

    b=list_copy(b);
    if (!a) return b;
    for (i=a; i->next; i=i->next);
    i->next=b;
    return a;
}

list_t *list_append(list_t *list, item_t *item)
{
    list_t *l;

    NEW(l);
    l->item=item;
    l->next=NULL;

    return list_append_list(list,l);
}

item_t *list_elem(list_t *l, int32_t index)
{
    if (!l) return NULL;
    if (index==0) return l->item;
    return list_elem(l->next, index-1);
}

list_t *new_closure(closure_t *cl)
{
    item_t *i;

    i=new_item(t_closure,no_loc);
    i->data.closure=cl;
    return list_append(NULL,i);
}

void add_closure(dict_t *dict, cstring_t name, apply_fn apply)
{
    closure_t *c;
    NEW(c);
    c->description=name;
    c->type=CL_PURE;
    c->apply=apply;
    c->interface=NULL;

    dict_add(dict,name,new_closure(c));
}

void *find_cl_if(dict_t *dict, cstring_t name, uint32_t type,
		 bool_t required, cstring_t desc, struct cloc loc)
{
    item_t *i;
    closure_t *cl;

    i = dict_find_item(dict,name,required,desc,loc);
    if (!i) return NULL;
    if (i->type!=t_closure) {
	cfgfatal(loc,desc,"\"%s\" must be a closure\n",name);
    }
    cl=i->data.closure;
    if (cl->type!=type) {
	cfgfatal_cl_type(loc,desc,cl,type,name);
    }
    return cl->interface;
}

/* Convenience functions for modules reading configuration dictionaries */
item_t *dict_find_item(dict_t *dict, cstring_t key, bool_t required,
		       cstring_t desc, struct cloc loc)
{
    list_t *l;
    item_t *i;

    l=dict_lookup(dict,key);
    if (!l) {
	if (!required) return NULL;
	cfgfatal(loc,desc,"required parameter \"%s\" not found\n",key);
    }
    if(list_length(l) != 1)
	cfgfatal(loc,desc,"parameter \"%s\" has wrong number of values",key);
    i=list_elem(l,0);
    return i;
}

string_t dict_read_string(dict_t *dict, cstring_t key, bool_t required,
			  cstring_t desc, struct cloc loc)
{
    item_t *i;
    string_t r;

    i=dict_find_item(dict,key,required,desc,loc);
    if (!i) return NULL;
    if (i->type!=t_string) {
	cfgfatal(loc,desc,"\"%s\" must be a string\n",key);
    }
    if (strlen(i->data.string) > INT_MAX/10) {
	cfgfatal(loc,desc,"\"%s\" is unreasonably long\n",key);
    }
    r=i->data.string;
    return r;
}

const char **dict_read_string_array(dict_t *dict, cstring_t key,
				    bool_t required, cstring_t desc,
				    struct cloc loc, const char *const *def)
{
    list_t *l;
    const char **ra, **rap;

    l=dict_lookup(dict,key);
    if (!l) {
	if (!required) return (const char**)def;
	cfgfatal(loc,desc,"required string list \"%s\" not found\n",key);
    }

    int32_t ll=list_length(l);
    NEW_ARY(ra, ll+1);
    for (rap=ra; l; l=l->next,rap++) {
	item_t *it=l->item;
	if (it->type!=t_string)
	    cfgfatal(it->loc,desc,"\"%s\" entry must be a string\n",key);
	*rap=it->data.string;
    }
    *rap=0;
    return ra;
}

uint32_t dict_read_number(dict_t *dict, cstring_t key, bool_t required,
			  cstring_t desc, struct cloc loc, uint32_t def)
{
    item_t *i;
    uint32_t r;

    i=dict_find_item(dict,key,required,desc,loc);
    if (!i) return def;
    if (i->type!=t_number) {
	cfgfatal(loc,desc,"\"%s\" must be a number\n",key);
    }
    if (i->data.number >= 0x80000000) {
        cfgfatal(loc,desc,"\"%s\" must fit into a 32-bit signed integer\n",key);
    }
    r=i->data.number;
    return r;
}

bool_t dict_read_bool(dict_t *dict, cstring_t key, bool_t required,
		      cstring_t desc, struct cloc loc, bool_t def)
{
    item_t *i;
    bool_t r;

    i=dict_find_item(dict,key,required,desc,loc);
    if (!i) return def;
    if (i->type!=t_bool) {
	cfgfatal(loc,desc,"\"%s\" must be a boolean\n",key);
    }
    r=i->data.bool_;
    return r;
}

dict_t *dict_read_dict(dict_t *dict, cstring_t key, bool_t required,
		       cstring_t desc, struct cloc loc)
{
    item_t *i;
    dict_t *r;

    i=dict_find_item(dict,key,required,desc,loc);
    if (!i) return NULL;
    if (i->type!=t_dict) {
	cfgfatal(loc,desc,"\"%s\" must be a dictionary\n",key);
    }
    r=i->data.dict;
    return r;
}

uint32_t string_to_word(cstring_t s, struct cloc loc,
			struct flagstr *f, cstring_t desc)
{
    struct flagstr *j;
    for (j=f; j->name; j++)
	if (strcmp(s,j->name)==0)
	    return j->value;
    cfgfatal(loc,desc,"option \"%s\" not known\n",s);
    return 0;
}

uint32_t string_list_to_word(list_t *l, struct flagstr *f, cstring_t desc)
{
    list_t *i;
    uint32_t r=0;
    struct flagstr *j;

    for (i=l; i; i=i->next) {
	if (i->item->type!=t_string) {
	    cfgfatal(i->item->loc,desc,"all elements of list must be "
		     "strings\n");
	}
	for (j=f; j->name; j++)
	    r|=string_to_word(i->item->data.string,i->item->loc,f,desc);
    }
    return r;
}

dict_t *read_conffile(const char *name)
{
    FILE *conffile;
    struct p_node *config;

    if (strcmp(name,"-")==0) {
	conffile=stdin;
    } else {
	conffile=fopen(name,"r");
	if (!conffile)
	    fatal_perror("Cannot open configuration file \"%s\"",name);
    }
    config_lineno=1;
    config_file=name;
    config=parse_conffile(conffile);
    fclose(conffile);

#ifdef DUMP_PARSE_TREE
    printf("*** config file parse tree BEFORE MANGLE\n");
    ptree_dump(config,0);
#endif /* DUMP_PARSE_TREE */
    /* The root of the configuration is a T_ALIST, which needs reversing
       before we mangle because it isn't the child of a T_DICT. */
    config=list_reverse(config);
    ptree_mangle(config);
#ifdef DUMP_PARSE_TREE
    printf("\n\n*** config file parse tree AFTER MANGLE\n");
    ptree_dump(config,0);
#endif /* DUMP_PARSE_TREE */
    return process_config(config);
}