#include "luastack.hpp"
#include "cellgrid.hpp"
#include "table.hpp"
#include <math.h>
#include <cfloat>

LuaDefine(cellgrid_initregistry, "a") {
    LuaVar grid;
    LuaStack LS(L, grid);

    LS.getfield(grid, LuaRegistry, "cellgrid_cells");
    if (LS.isnil(grid)) {
        LS.newtable(grid);
        LS.setfield(LuaRegistry, "cellgrid_cells", grid);
    }
    return LS.result();
}

LuaDefine(cellgrid_addplane, "c") {
    LuaArg grid, plane;
    LuaVar planegrid;
    LuaStack LS(L, grid, plane, planegrid);

    // Get the grid.
    if (LS.isnil(grid)) LS.getfield(grid, LuaRegistry, "cellgrid_cells");
    LS.checktable(grid);

    // Check for the plane.  If not present, add it.
    LS.checkstring(plane);
    LS.rawget(planegrid, grid, plane);
    if (LS.isnil(planegrid)) {
        LS.rawset(grid, plane, LuaNewTable);
    }
    return LS.result();
}

#define CELL_SCALE 10.0
#define CELL_INVALID 0

LuaDefine(cellgrid_scale, "c") {
    LuaRet scale;
    LuaStack LS(L, scale);
    LS.set(scale, CELL_SCALE);
    return LS.result();
}

lua_Number calc_cellid(lua_Number x, lua_Number y, lua_Number z) {
    lua_Number cellx = floor(x / CELL_SCALE);
    lua_Number celly = floor(y / CELL_SCALE);
    lua_Number cellz = floor(z / CELL_SCALE);
    if ((cellx > 32767)||(celly > 32767)||(cellz > 32767)) {
        return CELL_INVALID;
    }
    if ((cellx < -32767)||(celly < -32767)||(cellz < -32767)) {
        return CELL_INVALID;
    }
    int64_t icellx = int64_t(cellx) & 0xFFFF;
    int64_t icelly = int64_t(celly) & 0xFFFF;
    int64_t icellz = int64_t(cellz) & 0xFFFF;
    return lua_Number(0x0001000000000000 | (icellx << 32) | (icelly << 16) | (icellz << 0));
}

LuaDefine(cellgrid_cellid, "c") {
    LuaArg x, y, z;
    LuaRet cellid;
    LuaStack LS(L, x, y, z, cellid);
    lua_Number nx = LS.cknumber(x);
    lua_Number ny = LS.cknumber(y);
    lua_Number nz = LS.cknumber(z);
    LS.set(cellid, calc_cellid(nx, ny, nz));
    return LS.result();
}

LuaDefine(cellgrid_setpos, "c") {
    LuaArg grid, sprite, x, y, z, nplane;
    LuaVar smt, oplane, planegrid, cell;
    LuaStack LS(L, grid, sprite, x, y, z, nplane, smt, oplane, planegrid, cell);

    // Get the grid.
    if (LS.isnil(grid)) LS.getfield(grid, LuaRegistry, "cellgrid_cells");
    LS.checktable(grid);

    // Calculate the new plane and cell ID.
    lua_Number nx, ny, nz;
    nx = LS.cknumber(x);
    ny = LS.cknumber(y);
    nz = LS.cknumber(z);
    if (!LS.isnil(nplane)) LS.checkstring(nplane);
    lua_Number ncellid = calc_cellid(nx, ny, nz);

    // Check that the new plane is an existing plane.
    LS.rawget(planegrid, grid, nplane);
    if (!LS.istable(planegrid)) {
        luaL_error(L, "invalid plane");
    }

    // Get the sprite metatable.
    LS.checktable(sprite);
    LS.getmetatable(smt, sprite);
    LS.checktable(smt);

    // Get the sprite's old plane and cell ID.
    lua_Number ox, oy, oz;
    LS.getfield(LuaAcceptNil(ox), smt, "x");
    LS.getfield(LuaAcceptNil(oy), smt, "y");
    LS.getfield(LuaAcceptNil(oz), smt, "z");
    LS.getfield(oplane, smt, "plane");
    lua_Number ocellid = calc_cellid(ox, oy, oz);

    // The sprite 'moved' if it's in a new cell.
    bool moved = (!LS.equal(nplane, oplane)) || (ncellid != ocellid);

    // Change the sprite position.
    LS.rawset(smt, "x", x);
    LS.rawset(smt, "y", y);
    LS.rawset(smt, "z", z);
    LS.rawset(smt, "plane", nplane);

    // Remove sprite from the old cell.
    if (moved && LS.isstring(oplane) && (ocellid != CELL_INVALID)) {
        LS.rawget(planegrid, grid, oplane);
        if (LS.istable(planegrid)) {
            LS.rawget(cell, planegrid, ocellid);
            if (LS.istable(cell)) {
                LS.call(LuaDiscard, table_findremove, cell, sprite);
                if (LS.isemptytable(cell)) {
                    LS.rawset(planegrid, ocellid, LuaNil);
                }
            }
        }
    }

    // Insert sprite into the new cell
    if (moved && LS.isstring(nplane) && (ncellid != CELL_INVALID)) {
        LS.rawget(planegrid, grid, nplane);
        if (LS.istable(planegrid)) {
            LS.rawget(cell, planegrid, ncellid);
            if (!LS.istable(cell)) {
                LS.newtable(cell);
                LS.rawset(planegrid, ncellid, cell);
            }
            LS.call(table_append, cell, sprite);
        }
    }

    return LS.result();
}

int cellgrid_scanradius(lua_State *L);
int cellgrid_scanregion(lua_State *L);