#!/usr/bin/python3
import os
import sys
import pwd
import grp
import time
import argparse
from enum import Enum

# ANSI escape codes for colors
COLORS = {
    'RESET': '\033[0m',
    'BOLD': '\033[1m',
    'RED': '\033[91m',
    'GREEN': '\033[92m',
    'YELLOW': '\033[93m',
    'BLUE': '\033[94m',
    'MAGENTA': '\033[95m',
    'CYAN': '\033[96m',
    'WHITE': '\033[97m'
}

class Filetype(Enum):
    S_IFMT = 0o0170000
    S_IFSOCK = 0o140000
    S_IFLNK = 0o120000
    S_IFREG = 0o100000
    S_IFBLK = 0o060000
    S_IFDIR = 0o040000
    S_IFCHR = 0o020000
    S_IFIFO = 0o010000

def colorize(text, color):
    return f"{COLORS[color]}{text}{COLORS['RESET']}"


def color_file(text, mode):
    match Filetype(mode & Filetype.S_IFMT.value):
        case Filetype.S_IFREG:
            if mode & 0o100 or mode & 0o010 or mode & 0o001:
                return colorize(text, "GREEN") # file is executable, return green
            return colorize(text, "WHITE")
        case Filetype.S_IFDIR:
            return colorize(text, "BLUE")
        case Filetype.S_IFLNK:
            return colorize(text, "CYAN")
        case Filetype.S_IFSOCK:
            return colorize(text, "MAGENTA")
        case Filetype.S_IFBLK:
            return colorize(text, "YELLOW")
        case Filetype.S_IFCHR:
            return colorize(text, "YELLOW")
        case Filetype.S_IFIFO:
            return colorize(text, "MAGENTA")
        case _:
            return colorize(text, "RED")


def parse_permission(mode):
    permissions = "-"
    match Filetype(mode & Filetype.S_IFMT.value):
        case Filetype.S_IFSOCK:
            permissions = 's'
        case Filetype.S_IFLNK:
            permissions = 'l'
        case Filetype.S_IFREG:
            permissions = '-'
        case Filetype.S_IFBLK:
            permissions = 'b'
        case Filetype.S_IFDIR:
            permissions = 'd'
        case Filetype.S_IFCHR:
            permissions = 'c'
        case Filetype.S_IFIFO:
            permissions = 'f'
        case _:
            permissions = '?'

    permissions += ''.join([
        "r" if mode & 0o400 else "-",
        "w" if mode & 0o200 else "-",
        "x" if mode & 0o100 else "-",
        "r" if mode & 0o040 else "-",
        "w" if mode & 0o020 else "-",
        "x" if mode & 0o010 else "-",
        "r" if mode & 0o004 else "-",
        "w" if mode & 0o002 else "-",
        "x" if mode & 0o001 else "-"
    ])
    return permissions

def sizeof_fmt(num):
    for unit in ("", "K", "M", "G", "T", "P", "E", "Z"):
        if abs(num) < 1024.0:
            if unit == "": return f"{num}" #exception to not do .0 for bytes
            return f"{num:3.1f}{unit}"
        num /= 1024.0
    return f"{num:.1f}Y"


def list_files(directory='.', args={}):
    files = os.listdir(directory)
    
    print(f"files: {len(files)}")

    if args.time_sorted:
        files.sort(key=lambda name: os.lstat(name).st_mtime, reverse=(not args.reverse))
    else:
        files.sort()

    # filter out hid files if needed
    if not args.all:
        files = [file for file in files if not file.startswith('.')]

    if args.long:
        for file in files:
                #file_path = os.path.join(directory, file) # for rel paths
            file_path = os.path.abspath(file) # for full path
            stats = os.lstat(file_path)
            mode = stats.st_mode
            permissions = parse_permission(mode)
            if args.sparse and permissions[0] == 'l':
                permissions = 'l         '
            nlink = stats.st_nlink
            user = pwd.getpwuid(stats.st_uid).pw_name
            group = grp.getgrgid(stats.st_gid).gr_name
            
            size = stats.st_size
            if args.human:
                size=sizeof_fmt(size)
            if args.sparse and Filetype(mode & Filetype.S_IFMT.value) == Filetype.S_IFDIR:
                size=""
            
            if args.full_time:
                mtime = time.strftime("%b %d %Y %X %z", time.localtime(stats.st_mtime)) # -0400
                #mtime = time.strftime("%b %d %X %Z", time.localtime(stats.st_mtime)) # CST
            else:
                mtime = time.strftime("%b %d %H:%M", time.localtime(stats.st_mtime))

            colored_file = color_file(file_path, mode)

            if os.path.islink(file_path):
                color = "RED"
                if os.path.exists(os.readlink(file_path)):
                    color = "GREEN"
                print(f"{permissions} {nlink:2d} {user:<8s} {group:<8s} {size:>6}  {mtime} {colored_file} -> {colorize(os.readlink(file_path), color)}")
            else:
                print(f"{permissions} {nlink:2d} {user:<8s} {group:<8s} {size:>6}  {mtime} {colored_file}")

    else:
        for file in files:
            file_path = os.path.join(directory, file)
            if os.path.islink(file_path):
                print(colorize(file + " -> " + os.readlink(file_path), 'CYAN'))
            elif os.path.isdir(file_path):
                print(colorize(file, 'BLUE'))
            else:
                print(file)




if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="List files in a directory", add_help=False)
    parser.add_argument('directory', nargs='?', default='.', help="Directory path")
    parser.add_argument('-a', '--all', action='store_true', help="Show hidden files")
    parser.add_argument('-l', '--long', action='store_true', help="Use a long listing format")
    parser.add_argument('-F', '--full-time', action='store_true', help="Show full full time")
    parser.add_argument('-s', '--sparse', action='store_true', help="Blank irrelevant information")
    
    parser.add_argument('-t', '--time-sorted', action='store_true', help="Sort by time")
    parser.add_argument('-r', '--reverse', action='store_true', help="Reverse sort order")
    
    parser.add_argument('-h', '--human', action='store_true', help="Human Readable size")

    args = parser.parse_args()

    print(f"ls.py {' '.join(sys.argv[1:])}")
    list_files(args.directory, args)