#ifndef CACHE_SUPERBLOCK_H
#define CACHE_SUPERBLOCK_H

#include "persistent-data/endian_utils.h"
#include "persistent-data/data-structures/btree.h"

//----------------------------------------------------------------

namespace caching {
	namespace superblock_detail {
		using namespace base;

		unsigned const SPACE_MAP_ROOT_SIZE = 128;
		unsigned const CACHE_POLICY_NAME_SIZE = 16;
		unsigned const CACHE_POLICY_VERSION_SIZE = 3;

		typedef unsigned char __u8;

		struct superblock_disk {
			le32 csum;
			le32 flags;
			le64 blocknr;

			__u8 uuid[16];
			le64 magic;
			le32 version;

			__u8 policy_name[CACHE_POLICY_NAME_SIZE];
			le32 policy_version[CACHE_POLICY_VERSION_SIZE];
			le32 policy_hint_size;

			__u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];

			le64 mapping_root;
			le64 hint_root;

			le64 discard_root;
			le64 discard_block_size;
			le64 discard_nr_blocks;

			le32 data_block_size; /* in 512-byte sectors */
			le32 metadata_block_size; /* in 512-byte sectors */
			le32 cache_blocks;

			le32 compat_flags;
			le32 compat_ro_flags;
			le32 incompat_flags;

			le32 read_hits;
			le32 read_misses;
			le32 write_hits;
			le32 write_misses;
		} __attribute__ ((packed));

		struct superblock {
			uint32_t csum;
			uint32_t flags;
			uint64_t blocknr;

			__u8 uuid[16];
			uint64_t magic;
			uint32_t version;

			__u8 policy_name[CACHE_POLICY_NAME_SIZE];
			uint32_t policy_version[CACHE_POLICY_VERSION_SIZE];
			uint32_t policy_hint_size;

			__u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];

			uint64_t mapping_root;
			uint64_t hint_root;

			uint64_t discard_root;
			uint64_t discard_block_size;
			uint64_t discard_nr_blocks;

			uint32_t data_block_size; /* in 512-byte sectors */
			uint32_t metadata_block_size; /* in 512-byte sectors */
			uint32_t cache_blocks;

			uint32_t compat_flags;
			uint32_t compat_ro_flags;
			uint32_t incompat_flags;

			uint32_t read_hits;
			uint32_t read_misses;
			uint32_t write_hits;
			uint32_t write_misses;
		};

		struct superblock_traits {
			typedef superblock_disk disk_type;
			typedef superblock value_type;

			static void unpack(superblock_disk const &disk, superblock &value);
			static void pack(superblock const &value, superblock_disk &disk);
		};

		block_address const SUPERBLOCK_LOCATION = 0;
		uint32_t const SUPERBLOCK_MAGIC = 06142003;

		//--------------------------------

		class damage_visitor;

		struct damage {
			virtual ~damage() {}
			virtual void visit(damage_visitor &v) const = 0;
		};

		struct superblock_corruption : public damage {
			superblock_corruption(std::string const &desc);
			void visit(damage_visitor &v) const;

			std::string desc_;
		};

		class damage_visitor {
		public:
			virtual ~damage_visitor() {}

			void visit(damage const &d);

			virtual void visit(superblock_corruption const &d) = 0;
		};
	}

	persistent_data::block_manager<>::validator::ptr superblock_validator();

	superblock_detail::superblock read_superblock(persistent_data::block_manager<>::ptr bm);
	superblock_detail::superblock read_superblock(persistent_data::block_manager<>::ptr bm,
						      persistent_data::block_address location);
	void check_superblock(persistent_data::block_manager<>::ptr bm,
			      superblock_detail::damage_visitor &visitor);
}

//----------------------------------------------------------------

#endif