/***MODULE:regexp
 * rspamd module that implements different regexp rules
 */

#include <sys/types.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/param.h>

#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <syslog.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>

#include <evdns.h>

#include "../config.h"
#include "../main.h"
#include "../modules.h"
#include "../cfg_file.h"

struct regexp_module_item {
	struct expression *expr;
	int regexp_number;
	int op_number;
	char *symbol;
};

struct regexp_ctx {
	int (*header_filter)(struct worker_task *task);
	int (*mime_filter)(struct worker_task *task);
	int (*message_filter)(struct worker_task *task);
	int (*url_filter)(struct worker_task *task);
	GList *items;
	char *metric;

	memory_pool_t *regexp_pool;
};

static struct regexp_ctx *regexp_module_ctx = NULL;

static int regexp_common_filter (struct worker_task *task);

int
regexp_module_init (struct config_file *cfg, struct module_ctx **ctx)
{
	regexp_module_ctx = g_malloc (sizeof (struct regexp_ctx));

	regexp_module_ctx->header_filter = regexp_common_filter;
	regexp_module_ctx->mime_filter = NULL;
	regexp_module_ctx->message_filter = NULL;
	regexp_module_ctx->url_filter = NULL;
	regexp_module_ctx->regexp_pool = memory_pool_new (1024);
	regexp_module_ctx->items = NULL;
	
	return 0;
}

static void
read_regexp_expression (memory_pool_t *pool, struct regexp_module_item *chain, char *line)
{	
	struct expression *e, *cur;

	e = parse_expression (regexp_module_ctx->regexp_pool, line);
	chain->expr = e;
	cur = e;
	while (cur) {
		if (cur->type == EXPR_OPERAND) {
			cur->content.operand = parse_regexp (pool, cur->content.operand);
			chain->regexp_number ++;
		}
		else {
			chain->op_number ++;
		}
		cur = cur->next;
	}
}

int
regexp_module_config (struct config_file *cfg)
{
	LIST_HEAD (moduleoptq, module_opt) *cur_module_opt = NULL;
	struct module_opt *cur;
	struct regexp_module_item *cur_item;
	char *value;

	if ((value = get_module_opt (cfg, "regexp", "metric")) != NULL) {
		regexp_module_ctx->metric = memory_pool_strdup (regexp_module_ctx->regexp_pool, value);
		g_free (value);
	}
	else {
		regexp_module_ctx->metric = DEFAULT_METRIC;
	}

	cur_module_opt = g_hash_table_lookup (cfg->modules_opts, "regexp");
	if (cur_module_opt != NULL) {
		LIST_FOREACH (cur, cur_module_opt, next) {
			if (strcmp (cur->param, "metric") == 0) {
				continue;
			}
			cur_item = memory_pool_alloc0 (regexp_module_ctx->regexp_pool, sizeof (struct regexp_module_item));
			cur_item->symbol = cur->param;
			read_regexp_expression (regexp_module_ctx->regexp_pool, cur_item, cur->value);
			regexp_module_ctx->items = g_list_prepend (regexp_module_ctx->items, cur_item);
		}
	}
	
	return 0;
}

int
regexp_module_reconfig (struct config_file *cfg)
{
	memory_pool_delete (regexp_module_ctx->regexp_pool);
	regexp_module_ctx->regexp_pool = memory_pool_new (1024);

	return regexp_module_config (cfg);
}

static gsize
process_regexp (struct rspamd_regexp *re, struct worker_task *task)
{
	char *headerv;
	struct mime_part *part;
	struct uri *url;

	switch (re->type) {
		case REGEXP_NONE:
			return 0;
		case REGEXP_HEADER:
			if (re->header == NULL) {
				msg_info ("process_regexp: header regexp without header name");
				return 0;
			}
			msg_debug ("process_regexp: checking header regexp: %s = /%s/", re->header, re->regexp_text);
			headerv = (char *)g_mime_message_get_header (task->message, re->header);
			if (headerv == NULL) {
				return 0;
			}
			else {
				if (re->regexp == NULL) {
					msg_debug ("process_regexp: regexp contains only header and it is found %s", re->header);
					return 1;
				}
				if (g_regex_match (re->regexp, headerv, 0, NULL) == TRUE) {
					return 1;
				}
				else {
					return 0;
				}
			}
			break;
		case REGEXP_MIME:
			msg_debug ("process_regexp: checking mime regexp: /%s/", re->regexp_text);
			TAILQ_FOREACH (part, &task->parts, next) {
				if (g_regex_match_full (re->regexp, part->content->data, part->content->len, 0, 0, NULL, NULL) == TRUE) {
					return 1;
				}
			}
			return 0;
		case REGEXP_MESSAGE:
			msg_debug ("process_message: checking mime regexp: /%s/", re->regexp_text);
			if (g_regex_match_full (re->regexp, task->msg->buf->begin, task->msg->buf->len, 0, 0, NULL, NULL) == TRUE) {
				return 1;
			}
			return 0;
		case REGEXP_URL:
			msg_debug ("process_url: checking mime regexp: /%s/", re->regexp_text);
			TAILQ_FOREACH (url, &task->urls, next) {
				if (g_regex_match (re->regexp, struri (url), 0, NULL) == TRUE) {
					return 1;
				}
			}
			return 0;
	}

	/* Not reached */
	return 0;
}

static void
process_regexp_item (struct regexp_module_item *item, struct worker_task *task)
{
	GQueue *stack;
	gsize cur, op1, op2;
	struct expression *it = item->expr;
	
	stack = g_queue_new ();

	while (it) {
		if (it->type == EXPR_OPERAND) {
			/* Find corresponding symbol */
			cur = process_regexp ((struct rspamd_regexp *)it->content.operand, task);
			msg_debug ("process_regexp_item: regexp %s found", cur ? "is" : "is not");
			g_queue_push_head (stack, GSIZE_TO_POINTER (cur));
		}
		else {
			if (g_queue_is_empty (stack)) {
				/* Queue has no operands for operation, exiting */
				g_queue_free (stack);
				return;
			}
			switch (it->content.operation) {
				case '!':
					op1 = GPOINTER_TO_SIZE (g_queue_pop_head (stack));
					op1 = !op1;
					g_queue_push_head (stack, GSIZE_TO_POINTER (op1));
					break;
				case '&':
					op1 = GPOINTER_TO_SIZE (g_queue_pop_head (stack));
					op2 = GPOINTER_TO_SIZE (g_queue_pop_head (stack));
					g_queue_push_head (stack, GSIZE_TO_POINTER (op1 && op2));
				case '|':
					op1 = GPOINTER_TO_SIZE (g_queue_pop_head (stack));
					op2 = GPOINTER_TO_SIZE (g_queue_pop_head (stack));
					g_queue_push_head (stack, GSIZE_TO_POINTER (op1 || op2));
				default:
					it = it->next;
					continue;
			}
		}
		it = it->next;
	}
	if (!g_queue_is_empty (stack)) {
		op1 = GPOINTER_TO_SIZE (g_queue_pop_head (stack));
		if (op1) {
			/* Add symbol to results */
			insert_result (task, regexp_module_ctx->metric, item->symbol, op1);
		}
	}

	g_queue_free (stack);
}

static int
regexp_common_filter (struct worker_task *task)
{
	GList *cur_expr = g_list_first (regexp_module_ctx->items);

	while (cur_expr) {
		process_regexp_item ((struct regexp_module_item *)cur_expr->data, task);
		cur_expr = g_list_next (cur_expr);
	}
}