#include "nuvieDefs.h"
#include "U6misc.h"
#include "Map.h"
#include "DirFinder.h"

/** STATIC FUNCTIONS **/

/* From a normalized direction xdir,ydir as base, get the normalized direction
 * towards one of the seven nearby tiles to the left or right of base.
 * For rotate: -n = left n tiles, n = right n tiles
 */
void DirFinder::get_adjacent_dir(sint8 &xdir, sint8 &ydir, sint8 rotate)
{
    struct
    {
        sint8 x, y;
    } neighbors[8] = { {-1,-1}, {+0,-1}, {+1,-1},
                       {+1,+0},/*ACTOR*/ {+1,+1},
                       {+0,+1}, {-1,+1}, {-1,+0} };

    for(uint32 start = 0; start < 8; start++)
        if(neighbors[start].x == xdir && neighbors[start].y == ydir)
        {
            sint32 dest = start + rotate;
            while(dest < 0 || dest > 7)
                dest += (dest < 0) ? 8 : -8;
            xdir = neighbors[dest].x; ydir = neighbors[dest].y;
            break;
        }
}

uint8 DirFinder::get_nuvie_dir(sint16 xrel, sint16 yrel)
{
    uint8 direction = NUVIE_DIR_N; // default

    if(xrel == 0 && yrel == 0) // nowhere
        return(direction);
    if(xrel == 0) // up or down
        direction = (yrel < 0) ? NUVIE_DIR_N : NUVIE_DIR_S;
    else if(yrel == 0) // left or right
        direction = (xrel < 0) ? NUVIE_DIR_W : NUVIE_DIR_E;
    else if(xrel < 0 && yrel < 0)
        direction = NUVIE_DIR_NW;
    else if(xrel > 0 && yrel < 0)
        direction = NUVIE_DIR_NE;
    else if(xrel < 0 && yrel > 0)
        direction = NUVIE_DIR_SW;
    else if(xrel > 0 && yrel > 0)
        direction = NUVIE_DIR_SE;
    return(direction);
}

uint8 DirFinder::get_nuvie_dir(uint16 sx, uint16 sy, uint16 tx, uint16 ty, uint8 z)
{
  return DirFinder::get_nuvie_dir(get_wrapped_rel_dir(tx, sx, z), get_wrapped_rel_dir(ty, sy, z));
}

// oxdir = original xdir, txdir = to xdir
sint8 DirFinder::get_turn_towards_dir(sint16 oxdir, sint16 oydir, sint8 txdir, sint8 tydir)
{
    oxdir = clamp(oxdir, -1, 1); oydir = clamp(oydir, -1, 1);
    txdir = clamp(txdir, -1, 1); tydir = clamp(tydir, -1, 1);
    struct
    {
        sint8 x, y;
    } dirs[8] = {{-1,-1},{+0,-1},{+1,-1},{+1,+0},{+1,+1},{+0,+1},{-1,+1},{-1,+0}};
    uint8 t = 0, o = 0;
    for(uint8 d = 0; d < 8; d++)
    {
        if(dirs[d].x == oxdir && dirs[d].y == oydir)
            o = d;
        if(dirs[d].x == txdir && dirs[d].y == tydir)
            t = d;
    }
    sint8 turn = t - o;
    if(turn > 4)
        turn = -(8 - turn);
    return(clamp(turn, -1, 1));
}

// xdir,ydir = normal direction from->to (simple method)
void DirFinder::get_normalized_dir(MapCoord from, MapCoord to, sint8 &xdir, sint8 &ydir)
{
    xdir = clamp(to.x - from.x, -1, 1);
    ydir = clamp(to.y - from.y, -1, 1);

/*    uint16 dx = from.xdistance(to), dy = from.ydistance(to);
    if(dx > 0 && dy > 0)
    {
        if(dx > dy) xdir = 0;
        else if(dx < dy) ydir = 0;
    }*/
}
