import os
import builtins

import xonsh.tools as xt
import xonsh.platform as xp

from xonsh.completers.tools import get_filter_function

SKIP_TOKENS = {"sudo", "time", "timeit", "which", "showcmd", "man"}
END_PROC_TOKENS = {"|", "||", "&&", "and", "or"}


def complete_command(cmd, line, start, end, ctx):
    """
    Returns a list of valid commands starting with the first argument
    """
    space = " "
    out = {
        s + space
        for s in builtins.__xonsh__.commands_cache
        if get_filter_function()(s, cmd)
    }
    if xp.ON_WINDOWS:
        out |= {i for i in xt.executables_in(".") if i.startswith(cmd)}
    base = os.path.basename(cmd)
    if os.path.isdir(base):
        out |= {
            os.path.join(base, i) for i in xt.executables_in(base) if i.startswith(cmd)
        }
    return out


def complete_skipper(cmd, line, start, end, ctx):
    """
    Skip over several tokens (e.g., sudo) and complete based on the rest of the
    line.
    """
    parts = line.split(" ")
    skip_part_num = 0
    for i, s in enumerate(parts):
        if s in END_PROC_TOKENS:
            skip_part_num = i + 1
    while len(parts) > skip_part_num:
        if parts[skip_part_num] not in SKIP_TOKENS:
            break
        skip_part_num += 1

    if skip_part_num == 0:
        return set()

    # If there's no space following an END_PROC_TOKEN, insert one
    if parts[-1] in END_PROC_TOKENS:
        return(set(" "), 0)

    if len(parts) == skip_part_num + 1:
        comp_func = complete_command
    else:
        comp = builtins.__xonsh__.shell.shell.completer
        comp_func = comp.complete

    skip_len = len(" ".join(line[:skip_part_num])) + 1
    return comp_func(
        cmd, " ".join(parts[skip_part_num:]), start - skip_len, end - skip_len, ctx
    )
