#include <socks/object.h>

#define NAMESPACE_CAST(p) OBJECT_C_CAST(struct object_namespace, ns_base, &ns_type, p)

static struct object_type ns_type;
static struct object_namespace *global_ns;

struct object_namespace {
	/* root directory set object */
	struct object ns_base;
	struct object *ns_root;
};

static kern_status_t ns_query_name(struct object *obj, char out[OBJECT_NAME_MAX])
{
	out[0] = '/';
	out[1] = 0;
	return KERN_OK;
}

static kern_status_t ns_get_child_at(struct object *obj, size_t at, struct object **out)
{
	struct object_namespace *ns = NAMESPACE_CAST(obj);
	return object_get_child_at(ns->ns_root, at, out);
}

static kern_status_t ns_get_child_named(struct object *obj, const char *name, struct object **out)
{
	struct object_namespace *ns = NAMESPACE_CAST(obj);
	return object_get_child_named(ns->ns_root, name, out);
}

static struct object_type ns_type = {
	.ob_name = "namespace",
	.ob_size = sizeof(struct object_namespace),
	.ob_header_offset = offsetof(struct object_namespace, ns_base),
	.ob_ops = {
		.query_name = ns_query_name,
		.get_named = ns_get_child_named,
		.get_at = ns_get_child_at,
	},
};

void init_global_namespace(void)
{
	object_type_register(&ns_type);
	global_ns = object_namespace_create();
}

struct object_namespace *global_namespace(void)
{
	return global_ns;
}

struct object_namespace *object_namespace_create(void)
{
	struct object *ns_object = object_create(&ns_type);
	struct object_namespace *ns = NAMESPACE_CAST(ns_object);
	ns->ns_root = set_create("/");
	return ns;
}

static void cleanup_object_path(char *path, size_t len, size_t *parts)
{
	while (path[len - 1] == '/') {
		path[--len] = 0;
	}

	size_t final_len = len;
	*parts = 0;

	int slashes = 0;
	for (int i = 0; path[i]; i++) {
		if (path[i] == '/') {
			slashes++;
			continue;
		}

		if (slashes < 1) {
			continue;
		}

		char *from = path + i;
		char *to = path + i - slashes + 1;
		int count = len - i;
		memmove(to, from, count);
		final_len -= (slashes - 1);
		slashes = 0;
		(*parts)++;
	}

	path[final_len] = 0;
}

struct object *ns_header(struct object_namespace *ns)
{
	return &ns->ns_base;
}

kern_status_t object_namespace_get_object(struct object_namespace *ns, const char *path, struct object **out)
{
	if (*path != '/') {
		return KERN_INVALID_ARGUMENT;
	}

	while (*path == '/') {
		path++;
	}

	size_t path_len = strlen(path);
	if (path_len == 0) {
		*out = object_ref(ns->ns_root);
		return KERN_OK;
	}

	size_t parts = 0;
	char *rpath = kmalloc(path_len, 0);
	if (!rpath) {
		return KERN_NO_MEMORY;
	}

	memcpy(rpath, path, path_len);
	cleanup_object_path(rpath, path_len, &parts);

	char *sp;
	char *tok = strtok_r(rpath, "/", &sp);
	struct object *cur = ns->ns_root;

	unsigned long flags;
	while (tok) {
		object_lock_irqsave(cur, &flags);

		struct object *next;
		kern_status_t status = object_get_child_named(cur, tok, &next);
		if (status != KERN_OK) {
			object_unlock_irqrestore(cur, flags);
			kfree(rpath);
			return status;
		}

		object_unlock_irqrestore(cur, flags);
		cur = next;
		tok = strtok_r(NULL, "/", &sp);

		object_lock_irqsave(cur, &flags);
		if (!object_is_link(cur)) {
			object_unlock_irqrestore(cur, flags);
			continue;
		}

		struct object *dest_obj;
		dest_obj = link_read_ptr(cur);
		object_unlock_irqrestore(cur, flags);

		if (!dest_obj) {
			kfree(rpath);
			/* TODO better error code for broken links */
			return KERN_INVALID_ARGUMENT;
		}

		object_deref(cur);
		cur = dest_obj;
	}

	kfree(rpath);

	if (object_is_link(cur)) {
		struct object *link_dest = link_read_ptr(cur);
		object_deref(cur);
		cur = object_ref(link_dest);
	}

	*out = cur;
	return KERN_OK;
}

kern_status_t object_namespace_create_link(struct object_namespace *ns, const char *linkpath, struct object *dest)
{
	if (*linkpath != '/') {
		return KERN_INVALID_ARGUMENT;
	}

	while (*linkpath == '/') {
		linkpath++;
	}

	size_t path_len = strlen(linkpath);
	if (path_len == 0) {
		return KERN_INVALID_ARGUMENT;
	}

	size_t parts = 0;
	char *rpath = kmalloc(path_len, 0);
	if (!rpath) {
		return KERN_NO_MEMORY;
	}

	memcpy(rpath, linkpath, path_len);
	cleanup_object_path(rpath, path_len, &parts);

	char *p = rpath + strlen(rpath) - 1;
	while (*p != '/' && p >= rpath) {
		p--;
	}

	if (p == rpath) {
		kfree(rpath);
		return KERN_INVALID_ARGUMENT;
	}

	*p = '\0';
	const char *linkname = p + 1;

	char *sp;
	char *tok = strtok_r(rpath, "/", &sp);
	struct object *cur = object_ref(ns->ns_root);

	unsigned long flags;
	while (tok) {
		object_lock_irqsave(cur, &flags);

		struct object *next;
		kern_status_t status = object_get_child_named(cur, tok, &next);
		if (status == KERN_NO_ENTRY) {
			next = set_create(tok);
			if (!next) {
				object_unlock_irqrestore(cur, flags);
				object_deref(cur);
				kfree(rpath);
				return KERN_NO_MEMORY;
			}

			status = set_add_object(cur, next);

			object_unlock_irqrestore(cur, flags);
			object_deref(cur);
		} else {
			object_unlock_irqrestore(cur, flags);
		}

		if (status != KERN_OK) {
			kfree(rpath);
			return status;
		}

		cur = next;
		tok = strtok_r(NULL, "/", &sp);
	}

	struct object *link = link_create(linkname, dest);
	kfree(rpath);

	if (!link) {
		object_deref(cur);
		return KERN_NO_MEMORY;
	}

	object_lock_irqsave(cur, &flags);
	kern_status_t status = set_add_object(cur, link);
	object_unlock_irqrestore(cur, flags);

	object_deref(cur);
	object_deref(link);

	return status;
}

kern_status_t object_publish(struct object_namespace *ns, const char *path, struct object *obj)
{
	if (*path != '/') {
		return KERN_INVALID_ARGUMENT;
	}

	while (*path == '/') {
		path++;
	}

	size_t path_len = strlen(path);
	if (path_len == 0) {
		return set_add_object(ns->ns_root, obj);
	}

	size_t parts = 0;
	char *rpath = kmalloc(path_len, 0);
	if (!rpath) {
		return KERN_NO_MEMORY;
	}

	memcpy(rpath, path, path_len);
	cleanup_object_path(rpath, path_len, &parts);

	char *sp;
	char *tok = strtok_r(rpath, "/", &sp);
	struct object *cur = ns->ns_root;

	unsigned long flags;
	while (tok) {
		object_lock_irqsave(cur, &flags);

		struct object *next;
		kern_status_t status = object_get_child_named(cur, tok, &next);
		if (status == KERN_NO_ENTRY) {
			next = set_create(tok);
			if (!next) {
				object_unlock_irqrestore(cur, flags);
				kfree(rpath);
				return KERN_NO_MEMORY;
			}

			status = set_add_object(cur, next);
		}

		if (status != KERN_OK) {
			object_unlock_irqrestore(cur, flags);
			kfree(rpath);
			return status;
		}

		object_unlock_irqrestore(cur, flags);
		cur = next;
		tok = strtok_r(NULL, "/", &sp);
	}

	kfree(rpath);

	return set_add_object(cur, obj);
}

kern_status_t object_unpublish(struct object_namespace *ns, struct object *obj)
{
	return KERN_OK;
}