import re
import math
import argparse
import itertools
from enum import Flag,Enum

class Connection(Flag):
    Empty = 0b0000
    North = 0b0001
    South = 0b0010
    East = 0b01000
    West = 0b10000

def connected_directions(first:Connection,second:Connection) -> bool:
    return bool(((first.value >> 1) & second.value) or
            ((first.value << 1) & second.value))

def opposite_direction(dir:Connection) -> Connection:
    if dir.value & 0b00011:
        return Connection(dir.value ^ 0b00011)
    if dir.value & 0b11000:
        return Connection(dir.value ^ 0b11000)
    return Connection(0)

class PipeElement:
    def __init__(self,symbol:chr) -> None:
        self.symbol = symbol
        self.connection = Connection.Empty
        if symbol in [*'|LJS']:
            self.connection |= Connection.North
        if symbol in [*'|7FS']:
            self.connection |= Connection.South
        if symbol in [*'-LFS']:
            self.connection |= Connection.East
        if symbol in [*'-J7S']:
            self.connection |= Connection.West
        if self.connection == Connection.Empty:
            self.symbol = '.'

    def __repr__(self) -> str:
        return f"Pipe({self.connection})"
    
    def __str__(self) -> str:
        return self.symbol

    def connected_to(self,pipe,direction:Connection) -> bool:
        if not (self.connection & direction):
            return False
        
        if self.connection & direction and pipe.connection & opposite_direction(direction):
            return True
        
        return False
        
class Navigator:
    def __init__(self,list:list,width) -> None:
        self.list = list
        self.width = width

    def at(self,position):
        return self.list[position]
    
    def neighbor(self,position,direction:Connection) -> tuple | None:
        match direction:
            case Connection.North:
                return self.prev_row(position)
            case Connection.South:
                return self.next_row(position)
            case Connection.East:
                return self.next(position)
            case Connection.West:
                return self.prev(position)
        raise Exception(f"Direction not found: {direction}")

    def prev_row(self,position) -> tuple | None:
        p = position - self.width
        if p < 0:
            return None
        return (p,self.list[p])

    def next_row(self,position) -> tuple | None:
        p = position + self.width
        if p >= len(self.list):
            return None
        return (p,self.list[p])
    
    def prev(self,position) -> tuple | None:
        p = position - 1
        if p < 0:
            return None
        return (p,self.list[p])

    def next(self,position) -> tuple | None:
        p = position + 1
        if p >= len(self.list):
            return None
        return (p,self.list[p])
    
    def all_neighbors(self,position) -> list:
        l = list()
        for f in [self.next, self.prev, self.next_row,self.prev_row]:
            t = f(position)
            if t != None:
                l.append(t)
        return l
    
    def find_connected(self,position,exclude=Connection.Empty) -> tuple | None:
        for dir in [Connection.East,Connection.West,Connection.North,Connection.South]:
            if dir == exclude:
                continue

            n = self.neighbor(position,dir)
            if n == None:
                continue

            if self.at(position).connected_to(n[1],dir):
                return (*n,dir)
        return None

class TileType(Enum):
    Inside = 1
    Outside = 0
    Pipe = 2
    PlaceHolder = 3

def pipe_to_tile_expand(pipe:PipeElement) -> list:
    s = str(pipe)
    expansions = {
        '.': '.PP'+ 'PPP' + 'PPP',
        '-': 'PPP'+ '---' + 'PPP',
        '|': 'P|P'+ 'P|P' + 'P|P',
        'F': 'PPP'+ 'PF-' + 'P|P',
        '7': 'PPP'+ '-7P' + 'P|P',
        'J': 'P|P'+ '-JP' + 'PPP',
        'L': 'P|P'+ 'PL-' + 'PPP',
        'S': 'P|P'+ '-S-' + 'P|P'
        }
    l = expansions[s]
    return [pipe_to_tile(x) for x in [*l]]
def pipe_to_tile(pipe:str) -> TileType:
    expansions = {
        '.': TileType.Inside,
        '-': TileType.Pipe,
        '|': TileType.Pipe,
        'F': TileType.Pipe,
        '7': TileType.Pipe,
        'J': TileType.Pipe,
        'L': TileType.Pipe,
        'S': TileType.Pipe,
        'P': TileType.PlaceHolder
        }
    return expansions[pipe]

def chunks(lst, n):
    """Yield successive n-sized chunks from lst."""
    for i in range(0, len(lst), n):
        yield lst[i:i + n]

def print_tiles(tile_list:list,width:int):
    for c in chunks(tile_list,width):
        print("".join([str(t.value) for t in c]))

def print_pipes(tile_list:list,width:int):
    for c in chunks(tile_list,width):
        print("".join([str(t) for t in c]))

def main(line_list:list,part:int):
    width = None

    pipe_list = list()
    tile_list = list()
    start_o = None
    for line in line_list:
        line = line + ' ' # stops east/west joining over new lines
        if width == None:
            width = len(line)
        for c in [*line]:
            o = PipeElement(c)
            pipe_list.append(o)
            tile_list.append(TileType.Inside)
            if c == 'S':
                start_o = o
    #print(pipe_list)
    start_pos = pipe_list.index(start_o)
    start_co = (start_pos // width, start_pos % width)
    print(f"starting index: {start_pos}: {start_co}")

    nav = Navigator(pipe_list,width)

    cur_pos = None
    last_dir = Connection.Empty
    steps = 0
    while cur_pos != start_pos:
        if cur_pos == None:
            cur_pos = start_pos
        
        pipe = nav.find_connected(cur_pos,exclude=opposite_direction(last_dir))
        if pipe == None:
            raise Exception(f"end of pipe at: {cur_pos}, {nav.at(cur_pos)}")
        cur_pos = pipe[0]
        last_dir = pipe[2]
        steps += 1
        #print(f"{cur_pos}->",end="")

        tile_list[cur_pos] = TileType.Pipe
    
    print(f"end: {cur_pos}, steps: {steps}")

    clean_pipe = list()
    for i in range(0,len(pipe_list)):
        if tile_list[i] == TileType.Pipe:
            clean_pipe.append(pipe_list[i])
        else:
            clean_pipe.append(PipeElement('.'))

    print_pipes(clean_pipe,width)
    print(f"part 1: {steps/2}")

    # part 2 outputs
    #print("start tile:")
    #print_tiles(tile_list,width)

    # add outsides to edge of map
    tile_list2 = list()
    #first row
    expanded_width = (width*3)+2
    for i in range(0,expanded_width):
        tile_list2.append(TileType.Outside)
    for row in chunks(clean_pipe, width):
        ## we need to expand this to 2x size tiles
        t_rows = [ list() for x in range(0,3)]
        [ x.append(TileType.Outside) for x in t_rows]
        for r in row:
            parts = pipe_to_tile_expand(r)
            [ t_rows[x].extend( parts[x*3:(x*3)+3] ) for x in range(0,3)]
        [ x.append(TileType.Outside) for x in t_rows]
        [ tile_list2.extend(x) for x in t_rows]
    for i in range(0,expanded_width):
        tile_list2.append(TileType.Outside)

    #print("with o tile:")
    #print_tiles(tile_list2,width+2)

    tilenav = Navigator(tile_list2,expanded_width)
    changes = True
    while changes == True:
        changes = False
        count_in = 0
        
        for i in range(0,len(tile_list2)):
            t = tilenav.at(i)
            if t == TileType.Inside or t == TileType.PlaceHolder:
                n = tilenav.all_neighbors(i)
                if any([x[1] == TileType.Outside for x in n]):
                    tilenav.list[i] = TileType.Outside
                    changes = True
                    continue
                if t == TileType.Inside:
                    count_in += 1

    print("with outside tile:")
    print_tiles(tile_list2,expanded_width)
    print(count_in)

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="template for aoc solver")
    parser.add_argument("-input",type=str)
    parser.add_argument("-part",type=int)
    args = parser.parse_args()
    filename = args.input
    if filename == None:
        parser.print_help()
        exit(1)
    part = args.part
    file = open(filename,'r')
    main([line.rstrip('\n') for line in file.readlines()],part)
    file.close()