lsx

#!/usr/bin/env python

import os, sys, stat, re, pathlib as pl, collections as cs

p_err = lambda *a,**kw: print('ERROR:', *a, **kw, file=sys.stderr, flush=True)


def sz_repr(size, _units=list(
		reversed(list((u, 2 ** (n * 10)) for n, u in enumerate('BKMGT'))) )):
	for u, u1 in _units:
		if size > u1: break
	if u1 > 1: size = f'{size/u1:.1f}'
	return f'{size}{u}'.rstrip('B')


def list_adjacent(paths, specs, files_only=False):
	p_dirs, stats, p_out = dict(), dict(), dict()
	op_out_sort = None

	for p in paths:
		try: st = stats[p] = p.stat()
		except OSError: p_err(f'path inaccessible [ {p} ]'); continue
		ps = set(p.parent.iterdir())
		if files_only:
			if not stat.S_ISREG(st.st_mode): continue # arg path discarded
			for pa in list(ps):
				try: st = stats[pa] = pa.stat()
				except OSError: ps.remove(pa)
				if not stat.S_ISREG(st.st_mode): ps.remove(pa)
		p_out[p], p_dirs[p] = {p}, tuple(ps)

	for opt in (opt.lower() for opt in specs):
		if n := re.findall(r'(\d+)', opt): n = max(map(int, n))
		else: n = 10
		ops = set(opt).difference('1234567890')
		if ops.difference('bants'):
			parser.error(f'Unrecognized letters in -a/--adjacent spec: {opt!r}')
		if ('a' in ops) ^ ('b' in ops) == 0: na = nb = n
		elif 'a' in ops: na, nb = n, 0
		elif 'b' in ops: na, nb = 0, n
		ops.difference_update('ab')
		if not ops: ops.add('n')
		elif not op_out_sort:
			op_out_sort = sorted(ops, key=lambda k: opt.find(k))[0]

		p_lists = cs.defaultdict(set) # {p: set(ps_sorted, ...), ...}
		for p, ps in p_dirs.items():
			if 'n' in ops:
				p_lists[p].add(tuple(sorted(ps, key=lambda pa: pa.name)))
			if ops.intersection('ts'):
				for pa in ps:
					if pa in stats: continue
					try: stats[pa] = pa.stat()
					except OSError: pass
				for k, sk in ('t', 'st_mtime'), ('s', 'st_size'):
					if k not in ops: continue
					p_lists[p].add(tuple(sorted( ps,
						key=lambda pa: getattr(stats[pa], sk) )))

		for p, pss in p_lists.items():
			for ps in pss:
				try: n = ps.index(p)
				except ValueError: p_err(f'path vanished [ {p} ]'); continue
				p_out[p].update(ps[max(0, n-nb):n])
				p_out[p].update(ps[n+1:n+na+1])

	ps_print, sort_func = dict(), dict(
		n=lambda p: p.name,
		t=lambda p: stats[p].st_mtime,
		s=lambda p: stats[p].st_size )[op_out_sort or 'n']
	for p, ps in p_out.items():
		p_out[p] = sorted(ps, key=sort_func)
	for ps in p_out.values():
		for p in ps:
			if p in ps_print: continue
			if not (st := stats.get(p)):
				try: st = stats[p] = p.stat()
				except OSError: continue
			ps_print[p] = None
	return list(ps_print.keys())


def mtime_parse(mtimes, err_func):
	import datetime as dt
	ts_now = dt.datetime.now()
	_td_days = dict(
		y=365.2422, yr=365.2422, year=365.2422,
		mo=30.5, month=30.5, w=7, week=7, d=1, day=1 )
	_td_s = dict( h=3600, hr=3600, hour=3600,
		m=60, min=60, minute=60, s=1, sec=1, second=1 )
	_td_usort = lambda d: sorted(
		d.items(), key=lambda kv: (kv[1], len(kv[0])), reverse=True )
	_td_re = re.compile('(?i)^[-+]?' + ''.join( fr'(?P<{k}>\d+{k}\s*)?'
		for k, v in [*_td_usort(_td_days), *_td_usort(_td_s)] ) + '$')
	def _ts_parse(ts_str, rel=False):
		ts = (ts_str := ts_str.strip()).lower() == 'now' and dt.timedelta(0)
		no_ts = lambda: ts in [None, False]
		if no_ts():
			try: ts = dt.timedelta(seconds=float(ts_str))
			except: pass
		if no_ts() and ( # short time offset like "3d 5h"
				(m := _td_re.search(ts_str)) and any(m.groups()) ):
			delta = list()
			for units in _td_days, _td_s:
				val = 0
				for k, v in units.items():
					if not m.group(k): continue
					val += v * int(''.join(filter(str.isdigit, m.group(k))) or 1)
				delta.append(val)
			ts = dt.timedelta(*delta)
		if no_ts() and (m := re.search( # common BE format
				r'^(?P<date>(?:\d{2}|(?P<Y>\d{4}))-\d{2}-\d{2})'
				r'(?:[ T](?P<time>\d{2}(?::\d{2}(?::\d{2})?)?)?)?$', ts_str )):
			tpl = 'y' if not m.group('Y') else 'Y'
			tpl, tss = f'%{tpl}-%m-%d', m.group('date')
			if m.group('time'):
				tpl_time = ['%H', '%M', '%S']
				tss += ' ' + ':'.join(tss_time := m.group('time').split(':'))
				tpl += ' ' + ':'.join(tpl_time[:len(tss_time)])
			try: ts = dt.datetime.strptime(tss, tpl)
			except ValueError: pass
		if no_ts() and (m := re.search( # just time without AM/PM - treat as 24h format
				r'^\d{1,2}:\d{2}(?::\d{2}(?P<us>\.\d+)?)?$', ts_str )):
			us, tpl = 0, ':'.join(['%H', '%M', '%S'][:len(ts_str.split(':'))])
			if m.group('us'):
				ts_str, us = ts_str.rsplit('.', 1)
				us = us[:6] + '0'*max(0, 6 - len(us))
			try: ts = dt.datetime.strptime(ts_str, tpl)
			except ValueError: pass
			else:
				ts = ts_now.replace( hour=ts.hour,
					minute=ts.minute, second=ts.second, microsecond=int(us) )
				if ts > ts_now: ts -= dt.timedelta(1)
		if no_ts(): # coreutils' "date" parses everything, but is more expensive to use
			import subprocess as sp
			while True:
				res = sp.run( ['date', '+%s', '-d', ts_str],
					stdout=sp.PIPE, stderr=sp.DEVNULL )
				if res.returncode:
					if ',' in ts_str: ts_str = ts_str.replace(',', ' '); continue
				else:
					ts = dt.datetime.fromtimestamp(int(res.stdout.strip()))
					if 0 < (ts - ts_now).total_seconds() <= 24*3600 and re.search(
							r'(?i)^[\d:]+\s*(am|pm)?\s*([-+][\d:]+|\w+|\w+[-+][\d:]+)?$', ts_str.strip() ):
						ts -= dt.timedelta(1)
				break
		if no_ts(): err_func(f'Failed to parse -t/--mtime spec: {ts_str}')
		if not rel and isinstance(ts, dt.timedelta): ts = ts_now - ts
		return ts

	if (ranges := any('/' in td for td in mtimes)) and not all('/' in td for td in mtimes):
		err_func( '-t/--mtime values must either be'
			' all deltas or time-ranges, cannot be a mix of both' )
	for n, ts_str in enumerate(mtimes):
		if ranges:
			a, s, b = ts_str.partition('/')
			mtimes[n] = sorted(_ts_parse(ts).timestamp() for ts in [a, b])
		else:
			if not isinstance(td := _ts_parse(ts_str, rel=True), dt.timedelta):
				err_func(f'Absolute -t/--mtime specs can only be used in A/B ranges: {ts_str}')
			mtimes[n] = td.total_seconds()
	return mtimes, not ranges

def mtime_list_vicinity(paths, mtimes):
	ps, td = list(), max(mtimes)
	for p in paths:
		try: ps.append((ts := p.stat().st_mtime, p))
		except OSError: p_err(f'path inaccessible [ {p} ]'); continue
		for p2 in p.parent.iterdir():
			try: ts2 = p2.stat().st_mtime
			except OSError: continue
			if abs(ts - ts2) <= td: ps.append((ts2, p2))
	return list(dict.fromkeys(p for ts, p in sorted(ps)))

def mtime_list_ranges(paths, mtimes):
	ps = list()
	for p in paths:
		try: ts = p.stat().st_mtime
		except OSError: continue
		for a, b in mtimes:
			if a <= ts <= b: ps.append((ts, p))
	return list(dict.fromkeys(p for ts, p in sorted(ps)))


def main(argv=None):
	import argparse, textwrap
	dd = lambda text: re.sub( r' \t+', ' ',
		textwrap.dedent(text).strip('\n') + '\n' ).replace('\t', '  ')
	parser = argparse.ArgumentParser(
		formatter_class=argparse.RawTextHelpFormatter,
		usage='%(prog)s [opts] [[--] file/dir...]',
		description='Custom functionality extensions of the common "ls" tool.')

	parser.add_argument('paths', nargs='*', help=dd('''
		File/dir path arguments for various options below.
		If no other options are provided, tool will simply list all existing
			path(s), printing errors on stderr for those that can't be accessed.
		Unlike "ls" tool, directory contents aren't listed
			recursively, unless -r/--recursive option is used.'''))

	parser.add_argument('-f', '--files', action='store_true',
		help='Print only files, not dirs or any other stuff.')
	parser.add_argument('-0', '--null', action='store_true',
		help='Print null-terminated list, instead of default newline-terminated.')
	parser.add_argument('-r', '--recursive', action='store_true',
		help='Recurse into specified directories, if other options support that.')
	parser.add_argument('-s', '--size', action='store_true', help=dd('''
		Print file size space-separated on the left, human-readable
			with IEC 1024-base units (KiB, MiB, etc), with a decimal digit.
		Always prints "0" for anything other than regular files (dirs, symlinks, etc).
		Intended to be less ambiguous and more precise compared to other tools.
		Works with "sort -h" to order output by that size column.'''))

	parser.add_argument('-a', '--adjacent', metavar='opts', action='append', help=dd('''
		List specified file/dir path, and also N files/dirs adjacent to it.
			"Adjacent" as in located within same directory, and sorted right before/after it.
		Requires a parameter, consisting of optional numbers/letters:
			number (digits) - count of items (default=10) to display before/after path(s),
				counting before/after separately (if enabled), and not counting path itself.
			b/B - before - only list entries sorted before specified one(s).
			a/A - after - same as "before" above, can be combined for before + after (default).
			n/N - name - order items by filenames alphabetically (default).
			t/T - time - order items by mtime.
			s/S - size - order items by apparent filesize (from stat.st_size).
		Default is to return 10 before/after items with alphabetical ordering.
		Option usage examples: -aS, -a 50as, -a 5bt, -a a3
		Some file/dir arguments must be specified for this option.
		Option can be used multiple times to select more items by additional criteria,
			in which case they will be returned sorted by the first
			parameter that's explicitly specified (or default alpha-sorted otherwise).'''))

	parser.add_argument('-t', '--mtime',
		metavar='delta-or-range', action='append', help=dd('''
			List files/dirs that have modification time within specified range or vicinity.
			Either time delta or time range(s) can be specified with this option:
				delta examples: 1h30m, 1d, 2w 3d 4h, 4:10:20, 55s, 55, ...
				range examples: 5d/8d, 1d/now, 2024-10-20 4:10:20 / 2mo, 1:00/6:00, ...
			If delta (relative time) is specified, adjacent files/dirs within mtime-vicinity
				from file/dir command-line arguments are listed (and at least one is required).
			If time range is specified (two absolute or relative timestamps in any order),
				then files/dirs that have mtime within that range are listed, either in the
				current dir, or among/within specified file/dir arguments (see -r/--recursive option).
			General usage examples: -t 1h, -t 5d/10d, -t 2024-10-20/2024-10-25, -t 1am/3:30
			Multiple time ranges can be specified.
			Results are ordered by mtime, pipe through "sort" for alphabetic ordering.
			Works somewhat similar to "find" tool with its -mtime option,
				but mostly intended to easily list files created/modified around the same time.'''))

	opts = parser.parse_args(sys.argv[1:] if argv is None else argv)

	pp_first, pp_nullsep = True, opts.null
	def _pp(p):
		nonlocal pp_first
		p, (cc, cn) = str(p), ('\n', 'newline') if not pp_nullsep else ('\0', 'null-char')
		if cc in p: p_err(f'Skipping entry with {cn} in it: {p!r}')
		if opts.size:
			sz = s.st_size if stat.S_ISREG((s := os.stat(p)).st_mode) else 0
			p = f'{sz and sz_repr(sz)} {p}'
		if not pp_nullsep: p = f'{p}\n'
		elif not pp_first: p = f'\0{p}'
		else: pp_first = False
		sys.stdout.write(p)

	no_opts, paths = True, list(pl.Path(p) for p in opts.paths)

	if opts.adjacent:
		for p in list_adjacent(paths, opts.adjacent, opts.files): _pp(p)
		no_opts = False

	if opts.mtime:
		no_opts, (tds, td_vicinity) = False, mtime_parse(opts.mtime, parser.error)
		if td_vicinity:
			if not paths: parser.error(
				'At least one path argument required for -t/--mtime time-delta' )
			for p in mtime_list_vicinity(paths, tds): _pp(p)
		else:
			ps = list()
			if opts.recursive and not paths: paths = [pl.Path('.')]
			for p in paths:
				if not p.exists(): p_err(f'path inaccessible [ {p} ]'); continue
				if opts.recursive and p.is_dir(): ps.extend(p.iterdir())
				elif not opts.files or p.is_file(): ps.append(p)
			for p in mtime_list_ranges(ps, tds): _pp(p)

	if no_opts: # no options - print filtered input paths back
		if opts.recursive and not paths: paths = [pl.Path('.')]
		for p in paths:
			if not p.exists(): p_err(f'path inaccessible [ {p} ]'); continue
			if opts.recursive and p.is_dir():
				for p2 in p.iterdir(): _pp(p2)
			elif not opts.files or p.is_file(): _pp(p)

if __name__ == '__main__':
	try: sys.exit(main())
	except BrokenPipeError: # stdout pipe closed
		os.dup2(os.open(os.devnull, os.O_WRONLY), sys.stdout.fileno())
		sys.exit(1)