-- definitions of BUILD and game types for the Lunatic Interpreter
-- INTERNAL!

local ffi = require("ffi")

-- sector, wall, sprite
ffi.cdef[[
#pragma pack(push,1)
typedef struct
{
    const int16_t wallptr, wallnum;
    int32_t ceilingz, floorz;
    int16_t ceilingstat, floorstat;
    int16_t ceilingpicnum, ceilingheinum;
    int8_t ceilingshade;
    uint8_t ceilingpal, ceilingxpanning, ceilingypanning;
    int16_t floorpicnum, floorheinum;
    int8_t floorshade;
    uint8_t floorpal, floorxpanning, floorypanning;
    uint8_t visibility, filler;
    int16_t lotag, hitag, extra;
} sectortype;

typedef struct
{
    int32_t x, y;
    int16_t point2, nextwall, nextsector, cstat;
    int16_t picnum, overpicnum;
    int8_t shade;
    uint8_t pal, xrepeat, yrepeat, xpanning, ypanning;
    int16_t lotag, hitag, extra;
} walltype;

typedef struct
{
    int32_t x, y, z;
    int16_t cstat, picnum;
    int8_t shade;
    uint8_t pal, clipdist, filler;
    uint8_t xrepeat, yrepeat;
    int8_t xoffset, yoffset;
    int16_t sectnum, statnum;
    int16_t ang, owner, xvel, yvel, zvel;
    int16_t lotag, hitag, extra;
} spritetype;
#pragma pack(pop)
]]

ffi.cdef[[
sectortype *sector;
walltype *wall;
spritetype *sprite;

const int16_t numsectors, numwalls;
]]

--

sector = {}
local tmpmt = {
    __index = function(tab, key)
                  if (key >= 0 and key < ffi.C.numsectors) then return ffi.C.sector[key] end
                  error('out-of-bounds sector[] read access')
              end,

    __newindex = function(tab, key, val) error('cannot write to sector[] structs directly') end
}
setmetatable(sector, tmpmt)

wall = {}
local tmpmt = {
    __index = function(tab, key)
                  if (key >= 0 and key < ffi.C.numwalls) then return ffi.C.wall[key] end
                  error('out-of-bounds wall[] read access')
              end,

    __newindex = function(tab, key, val) error('cannot write to wall[] structs directly') end
}
setmetatable(wall, tmpmt)

sprite = {}
local tmpmt = {
    __index = function(tab, key)
                  -- MAXSPRITES == 16384
                  if (key >= 0 and key < 16384) then return ffi.C.sprite[key] end
                  error('out-of-bounds sprite[] read access')
              end,

    __newindex = function(tab, key, val) error('cannot write to sprite[] structs directly') end
}
setmetatable(sprite, tmpmt)

-- yes, this does export a couple of other stuff that users ought not see,
-- but without the ffi.cdef declarations, they will just sit there and
-- refuse to be accessed.
gv = ffi.C

-- nope, this would create two numeric variables with their initial values, but
-- certainly not references to numsectors and numwalls like we want:
--numsectors = ffi.C.numsectors
--numwalls = ffi.C.numwalls