#ifndef WORLD_HPP
#define WORLD_HPP

#include "luastack.hpp"
#include "planemap.hpp"
#include "idalloc.hpp"
#include "animqueue.hpp"
#include "sched.hpp"
#include "source.hpp"
#include "gui.hpp"
#include "luasnap.hpp"
#include <set>
#include <utility>
#include <memory>
#include <unordered_map>

class World;

class Tangible {
private:
    friend class World;

    // Serialize and deserialize
    //
    // The tangible's ID is not serialized.  When you serialize a tangible, you
    // should probably serialize the ID separately.
    //
    // The Lua portion of the tangible is not serialized here.  Instead, the lua
    // portion is serialized when you serialize the lua state as a whole.
    //
    // PlaneItem is not serialized.  The deserialize routine rebuilds the
    // PlaneItem from the AnimQueue.
    //
    // World pointer is not serialized.
    //
    void serialize(StreamBuffer *sb);
    void deserialize(StreamBuffer *sb);

public:
    // Always points back to the world model.
    World *world_;

    // Animation queue.
    //
    AnimQueue anim_queue_;

    // Plane Item.
    //
    // The PlaneItem also contains this tangible's ID.
    // To move this PlaneItem, update the anim_queue first, then call
    // update_plane_item, which copies the data from the anim_queue.
    //
    PlaneItem plane_item_;

    // Player ID pool
    //
    // This is present in every tangible, whether a player or not.
    // However, the fifo is only enabled in logged-in players.
    //
    IdPlayerPool id_player_pool_;

    // constructor.
    //
    Tangible(World *w, int64_t id);

    // Get the ID
    //
    int64_t id() { return plane_item_.id(); }
    void be_a_player();
    void update_plane_item();
};

class World {
public:
    // A lua intepreter with snapshot function.
    //
    LuaSnap lua_snap_;
    
    // The Global ID Pool.
    //
    IdGlobalPool id_global_pool_;

    // Source Database.
    //
    SourceDB source_db_;
    PlaneMap plane_map_;

    // Tangibles table.
    //
    std::unordered_map<int64_t, std::unique_ptr<Tangible>> tangibles_;

    // Thread schedule: must include every thread, except
    // for the one currently-executing thread.
    //
    Schedule thread_sched_;

    // Serialized snapshot of world model.
    StreamBuffer snapshot_;

    void run_scheduled_threads(int64_t clk);
public:
    // Constructor.
    //
    // The constructor also calls 'lua_open' to create a new
    // lua interpreter for this world model.  The lua interpreter
    // is stored in world::lua_state_.  A significant amount of
    // initial setup is done by this constructor.
    //
    World();

    // Destructor.
    //
    // Not currently functional.
    //
    ~World();

    // Initialize for single-player mode.
    //
    void init_standalone();

    // get_lua_state
    //
    // Get the lua interpreter associated with this world model.
    //
    lua_State *state() { return lua_snap_.state(); }

    // get_near
    //
    // Get a list of the tangibles that are near the player.
    //
    std::vector<int64_t> get_near(int64_t player_id, float radius);
    
    // Make a tangible.
    //
    // If the ID is zero, allocates an ID using the thread's ID allocator. If
    // pushdb is true, pushes the tangible's database onto the lua stack.
    // Otherwise, leaves the lua stack untouched.
    //
    Tangible *tangible_make(lua_State *L, int64_t id, bool pushdb);

    // Get a pointer to the specified tangible.
    //
    Tangible *tangible_get(int64_t id);

    // Get a pointer to the specified tangible.
    //
    // The value on the lua stack should be a valid lua tangible.  If not,
    // a lua error is generated.
    //
    Tangible *tangible_get(lua_State *L, int idx);
    
    // Delete a tangible with the specified ID.
    //
    // If the tangible doesn't exist, does nothing.
    //
    void tangible_del(int64_t id);

    // Probe the 'interface' function of the specified sprite.
    //
    void update_gui(int64_t actor_id, int64_t place_id, Gui *gui);

    // Invoke an action plan.
    //
    // Eventually we'll add another parameter for gui-state.
    //
    void invoke_plan(int64_t actor_id, int64_t place_id, const std::string &action, const GuiResult &gres);
    
    // fetch
    //
    // Given a lua state, fetch the world model associated with
    // that lua state.
    //
    static void store_global_pointer(lua_State *L, World *w);
    static World *fetch_global_pointer(lua_State *L);

    // Serialize and deserialize.
    //
    void serialize(StreamBuffer *sb);
    void deserialize(StreamBuffer *sb);

    // Snapshot and rollback - temporary.
    //
    void snapshot();
    void rollback();
};

#endif // WORLD_HPP