#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <err.h>
#include <unistd.h>

static char* conf_directory = NULL;
static char* work_directory = NULL;

typedef struct _graph
{
	const char* name;
	char* title;
	int width;
	int height;
	int interval;
	char* category;

	struct _graph *next;
}
graph;

static graph* allgraphs = NULL;

/* -----------------------------------------------------------------------------
 * CONFIG PARSING
 */

int cfg_value(const char* filename, const char* header, const char* name,
              char* value, void* data)
{
	static graph* gr = NULL;

	/*  called like this after ever file */
	if (!header)
	{
		/* add to the list */
		gr->next = allgraphs;
		allgraphs = gr;

		gr = NULL;
		return 0;
	}

	if (gr == NULL)
	{
		gr = calloc(1, sizeof(graph));
		if (!gr)
			err(1, "Out of memory");
		gr->name = filename;
		gr->category = "";
	}

	if (strcmp(header, "general") == 0)
	{
		if (strcmp(name, "title") == 0)
			gr->title = value;
		else if (strcmp(name, "category") == 0)
			gr->category = value;
	}
	else if (strcmp(header, "graph") == 0)
	{
		if (strcmp(name, "height") == 0)
			gr->height = atoi(value);
		else if (strcmp(name, "width") == 0)
			gr->width = atoi(value);
	}
	else if (strcmp(header, "poll") == 0)
	{
		if (strcmp(name, "interval") == 0)
			gr->interval = atoi(value);
	}
}

int cfg_error(const char* filename, const char* errmsg, void* data)
{
	/* todo skip the rest of this file on error */
    warnx("%s", errmsg);
    return 0;
}

void
freegraphs ()
{
	graph* l;
	graph* t;

	for (l = allgraphs; l != NULL; )
	{
		t = l->next;
		free(l);
		l = t;
	}
}

/* -----------------------------------------------------------------------------
 * METHODS
 */

static void
listgraphs ()
{
	graph* l;

	printf("Content-Type: text/xml\n\n");
	printf("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
	printf("<data>\n");

	for (l = allgraphs; l != NULL; l = l->next)
	{
		printf("    <graph name=\"%s\" category=\"%s\" title=\"%s\"", \
			  l->name, l->category, l->title);

		if (l->width)
			printf(" width=\"%d\"", l->width);

		if (l->height)
			printf(" height=\"%d\"", l->height);

		if (l->interval)
			printf(" interval=\"%d\"", l->interval);

		printf(" />\n");
	}
	printf("</data>\n");
}

#if 0
static void
displaygraphs ()
{
	char* name = NULL;
	int width;
	int height;
	char* q;
	char* query = NULL;

	q = getenv("QUERY_STRING");

	if (q)
	{
		query = q = strdup(q);
		while (q[0] && (q[0] == '?' || isspace(q[0])))
			q++;

		while (q && q[0])
		{
			nm = strsep(&q, "&");
			vl = strchr(nm, '=');
			if (!vl)
				continue;
			vl[0] = 0;
			vl++;

			if (strcmp(nm, "name") == 0)
				name = vl;
			else if (strcmp(nm, "width") == 0)
				width = atoi(vl);
			else if (strcmp(nm, "height") == )
				height = atoi(vl);
		}

	}
}
#endif

/* -----------------------------------------------------------------------------
 * MAIN
 */

static void
usererror (const char* msg)
{
	printf("Content-Type: text/plain\n\n");
	printf("%s\n", msg);

	/* Custom error so webserver doesn't think it's a server error */
	exit(0);
}

static int
pathstarts (const char* path, const char* method)
{
	int len = strlen(method);

	if (strncmp(path, method, len) != 0)
		return 0;

	if (path[len] == '/' || !path[len])
		return 1;

	return 0;
}

int
main (int argc, char* argv[])
{
	char* path;

	conf_directory = getenv("CONFDIR");
	work_directory = getenv("WORKDIR");

	if (!conf_directory || !work_directory)
		errx(2, "not setup properly. CONFDIR and WORKDIR env variables must be set");

	/*
	 * We always have this as our current directory.
	 * It helps when constructing graphs and the like
	 */
	if (chdir(work_directory) < 0)
		err(1, "Couldn't change to work directory: %s", work_directory);


	path = getenv("PATH_INFO");

	while (path && path[0] &&
		   (isspace(path[0]) || path[0] == '/'))
		path++;

	cfg_parse_dir(conf_directory, NULL);

	if (!path || !path[0] || pathstarts(path, "list"))
		listgraphs();
	else if (pathstarts(path, "graph"))
		printf("graph\n");
	else
		usererror("Invalid request");

	freegraphs();

	return 0;
}