pokecrystal connection macro

; Connections go in order: north, south, west, east
connection: MACRO
;\1: direction
;\2: map name
;\3: map id
;\4: offset of the target map relative to the current map
;    (x offset for east/west, y offset for north/south)

; legacy support for old connection macro
if _NARG == 6
    connection \1, \2, \3, (\4) - (\5)
else

; Calculate tile offsets for source (current) and target maps
_r = (\4) + 3
if _r < 0
_s = -_r
_t = 0
else
_s = 0
_t = _r
endc

if "\1" == "north"
_foo1 = \3_WIDTH * (\3_HEIGHT + -3) + _s
_foo2 = _t
_foo3 = CURRENT_MAP_WIDTH + 3 - (\4)
if \3_WIDTH < _foo3
_foo3 = \3_WIDTH
endc
_foo4 = \3_HEIGHT * 2 - 1
_foo5 = (\4) * -2
_foo6 = (\3_WIDTH + 6) * \3_HEIGHT + 1

elif "\1" == "south"
_foo1 = _s
_foo2 = (CURRENT_MAP_WIDTH + 6) * (CURRENT_MAP_HEIGHT + 3) + _t
_foo3 = CURRENT_MAP_WIDTH + 3 - (\4)
if \3_WIDTH < _foo3
_foo3 = \3_WIDTH
endc
_foo4 = 0
_foo5 = (\4) * -2
_foo6 = \3_WIDTH + 7

elif "\1" == "west"
_foo1 = (\3_WIDTH * _s) + \3_WIDTH + -3
_foo2 = (CURRENT_MAP_WIDTH + 6) * _t
_foo3 = CURRENT_MAP_HEIGHT + 3 - (\4)
if \3_HEIGHT < _foo3
_foo3 = \3_HEIGHT
endc
_foo4 = (\4) * -2
_foo5 = \3_WIDTH * 2 - 1
_foo6 = (\3_WIDTH + 6) * 2 + -6

elif "\1" == "east"
_foo1 = (\3_WIDTH * _s)
_foo2 = (CURRENT_MAP_WIDTH + 6) * _t + CURRENT_MAP_WIDTH + 3
_foo3 = CURRENT_MAP_HEIGHT + 3 - (\4)
if \3_HEIGHT < _foo3
_foo3 = \3_HEIGHT
endc
_foo4 = (\4) * -2
_foo5 = 0
_foo6 = \3_WIDTH + 7

else
fail "Invalid direction for 'connection'."
endc

    map_id \3
    dw \2_Blocks + _foo1
    dw wOverworldMapBlocks + _foo2
    db _foo3 - _s
    db \3_WIDTH
    db _foo4
    db _foo5
    dw wOverworldMapBlocks + _foo6
endc
ENDM