from __future__ import unicode_literals

from prompt_toolkit.completion import CompleteEvent, Completer, Completion
from prompt_toolkit.contrib.regular_languages import compile
from prompt_toolkit.contrib.regular_languages.compiler import Match, Variables
from prompt_toolkit.contrib.regular_languages.completion import \
    GrammarCompleter
from prompt_toolkit.document import Document


def test_simple_match():
    g = compile('hello|world')

    m = g.match('hello')
    assert isinstance(m, Match)

    m = g.match('world')
    assert isinstance(m, Match)

    m = g.match('somethingelse')
    assert m is None


def test_variable_varname():
    """
    Test `Variable` with varname.
    """
    g = compile('((?P<varname>hello|world)|test)')

    m = g.match('hello')
    variables = m.variables()
    assert isinstance(variables, Variables)
    assert variables.get('varname') == 'hello'
    assert variables['varname'] == 'hello'

    m = g.match('world')
    variables = m.variables()
    assert isinstance(variables, Variables)
    assert variables.get('varname') == 'world'
    assert variables['varname'] == 'world'

    m = g.match('test')
    variables = m.variables()
    assert isinstance(variables, Variables)
    assert variables.get('varname') is None
    assert variables['varname'] is None


def test_prefix():
    """
    Test `match_prefix`.
    """
    g = compile(r'(hello\ world|something\ else)')

    m = g.match_prefix('hello world')
    assert isinstance(m, Match)

    m = g.match_prefix('he')
    assert isinstance(m, Match)

    m = g.match_prefix('')
    assert isinstance(m, Match)

    m = g.match_prefix('som')
    assert isinstance(m, Match)

    m = g.match_prefix('hello wor')
    assert isinstance(m, Match)

    m = g.match_prefix('no-match')
    assert m.trailing_input().start == 0
    assert m.trailing_input().stop == len('no-match')

    m = g.match_prefix('hellotest')
    assert m.trailing_input().start == len('hello')
    assert m.trailing_input().stop == len('hellotest')


def test_completer():
    class completer1(Completer):

        def get_completions(self, document, complete_event):
            yield Completion(
                'before-%s-after' % document.text, -len(document.text))
            yield Completion(
                'before-%s-after-B' % document.text, -len(document.text))

    class completer2(Completer):

        def get_completions(self, document, complete_event):
            yield Completion(
                'before2-%s-after2' % document.text, -len(document.text))
            yield Completion(
                'before2-%s-after2-B' % document.text, -len(document.text))

    # Create grammar.  "var1" + "whitespace" + "var2"
    g = compile(r'(?P<var1>[a-z]*) \s+ (?P<var2>[a-z]*)')

    # Test 'get_completions()'
    completer = GrammarCompleter(
        g, {'var1': completer1(), 'var2': completer2()})
    completions = list(completer.get_completions(
        Document('abc def', len('abc def')),
        CompleteEvent()))

    assert len(completions) == 2
    assert completions[0].text == 'before2-def-after2'
    assert completions[0].start_position == -3
    assert completions[1].text == 'before2-def-after2-B'
    assert completions[1].start_position == -3