# minifileset.py - a simple language to select files

#

# Copyright 2017 Facebook, Inc.

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

from .i18n import _

from . import (

    error,

    fileset,

)

def _compile(tree):

    if not tree:

        raise error.ParseError(_("missing argument"))

    op = tree[0]

    if op == 'symbol':

        name = fileset.getstring(tree, _('invalid file pattern'))

        if name.startswith('**'): # file extension test, ex. "**.tar.gz"

            ext = name[2:]

            for c in ext:

                if c in '*{}[]?/\\':

                    raise error.ParseError(_('reserved character: %s') % c)

            return lambda n, s: n.endswith(ext)

        raise error.ParseError(_('invalid symbol: %s') % name)

    elif op == 'string':

        # TODO: teach fileset about 'path:', so that this can be a symbol and

        # not require quoting.

        name = fileset.getstring(tree, _('invalid path literal'))

        if name.startswith('path:'): # directory or full path test

            p = name[5:] # prefix

            pl = len(p)

            f = lambda n, s: n.startswith(p) and (len(n) == pl or n[pl] == '/')

            return f

        raise error.ParseError(_("invalid string"),

                               hint=_('paths must be prefixed with "path:"'))

    elif op == 'or':

        func1 = _compile(tree[1])

        func2 = _compile(tree[2])

        return lambda n, s: func1(n, s) or func2(n, s)

    elif op == 'and':

        func1 = _compile(tree[1])

        func2 = _compile(tree[2])

        return lambda n, s: func1(n, s) and func2(n, s)

    elif op == 'not':

        return lambda n, s: not _compile(tree[1])(n, s)

    elif op == 'group':

        return _compile(tree[1])

    elif op == 'func':

        symbols = {

            'all': lambda n, s: True,

            'none': lambda n, s: False,

            'size': lambda n, s: fileset.sizematcher(tree[2])(s),

        }

        name = fileset.getsymbol(tree[1])

        if name in symbols:

            return symbols[name]

        raise error.UnknownIdentifier(name, symbols.keys())

    elif op == 'minus':     # equivalent to 'x and not y'

        func1 = _compile(tree[1])

        func2 = _compile(tree[2])

        return lambda n, s: func1(n, s) and not func2(n, s)

    elif op == 'negate':

        raise error.ParseError(_("can't use negate operator in this context"))

    elif op == 'list':

        raise error.ParseError(_("can't use a list in this context"),

                               hint=_('see hg help "filesets.x or y"'))

    raise error.ProgrammingError('illegal tree: %r' % (tree,))

def compile(text):

    """generate a function (path, size) -> bool from filter specification.

    "text" could contain the operators defined by the fileset language for

    common logic operations, and parenthesis for grouping.  The supported path

    tests are '**.extname' for file extension test, and '"path:dir/subdir"'

    for prefix test.  The ``size()`` predicate is borrowed from filesets to test

    file size.  The predicates ``all()`` and ``none()`` are also supported.

    '(**.php & size(">10MB")) | **.zip | ("path:bin" & !"path:bin/README")' for

    example, will catch all php files whose size is greater than 10 MB, all

    files whose name ends with ".zip", and all files under "bin" in the repo

    root except for "bin/README".

    """

    tree = fileset.parse(text)

    return _compile(tree)