import pytest
from   headerparser import scan_next_stanza, scan_next_stanza_string

def test_simple():
    lines = [
        'Foo: red\n',
        'Bar: green\n',
        'Baz: blue\n',
        '\n',
        'This is a body.\n',
    ]
    liter = iter(lines)
    assert list(scan_next_stanza(liter)) \
        == [('Foo', 'red'), ('Bar', 'green'), ('Baz', 'blue')]
    assert list(liter) == ['This is a body.\n']

def test_simple_string():
    lines = (
        'Foo: red\n'
        'Bar: green\n'
        'Baz: blue\n'
        '\n'
        'This is a body.\n'
    )
    assert scan_next_stanza_string(lines) == (
        [('Foo', 'red'), ('Bar', 'green'), ('Baz', 'blue')],
        'This is a body.\n',
    )

@pytest.mark.parametrize('skip_leading_newlines', [True, False])
def test_extra_interstitial_blanks(skip_leading_newlines):
    lines = [
        'Foo: red\n',
        'Bar: green\n',
        'Baz: blue\n',
        '\n',
        '\n',
        'This is a body.\n',
    ]
    liter = iter(lines)
    assert list(scan_next_stanza(
        liter,
        skip_leading_newlines=skip_leading_newlines,
    )) == [('Foo', 'red'), ('Bar', 'green'), ('Baz', 'blue')]
    assert list(liter) == ['\n', 'This is a body.\n']

@pytest.mark.parametrize('skip_leading_newlines', [True, False])
def test_extra_interstitial_blanks_string(skip_leading_newlines):
    lines = (
        'Foo: red\n'
        'Bar: green\n'
        'Baz: blue\n'
        '\n'
        '\n'
        'This is a body.\n'
    )
    assert scan_next_stanza_string(
        lines,
        skip_leading_newlines=skip_leading_newlines,
    ) == (
        [('Foo', 'red'), ('Bar', 'green'), ('Baz', 'blue')],
        '\nThis is a body.\n',
    )

def test_leading_blanks_skip():
    lines = [
        '\n',
        '\n',
        'Foo: red\n',
        'Bar: green\n',
        'Baz: blue\n',
        '\n',
        'This is a body.\n',
    ]
    liter = iter(lines)
    assert list(scan_next_stanza(liter, skip_leading_newlines=True)) \
        == [('Foo', 'red'), ('Bar', 'green'), ('Baz', 'blue')]
    assert list(liter) == ['This is a body.\n']

def test_leading_blanks_skip_string():
    lines = (
        '\n'
        '\n'
        'Foo: red\n'
        'Bar: green\n'
        'Baz: blue\n'
        '\n'
        'This is a body.\n'
    )
    assert scan_next_stanza_string(lines, skip_leading_newlines=True) == (
        [('Foo', 'red'), ('Bar', 'green'), ('Baz', 'blue')],
        'This is a body.\n',
    )

def test_leading_blanks_no_skip():
    lines = [
        '\n',
        '\n',
        'Foo: red\n',
        'Bar: green\n',
        'Baz: blue\n',
        '\n',
        'This is a body.\n',
    ]
    liter = iter(lines)
    assert list(scan_next_stanza(liter, skip_leading_newlines=False)) == []
    assert list(liter) == [
        '\n',
        'Foo: red\n',
        'Bar: green\n',
        'Baz: blue\n',
        '\n',
        'This is a body.\n',
    ]

def test_leading_blanks_no_skip_string():
    lines = (
        '\n'
        '\n'
        'Foo: red\n'
        'Bar: green\n'
        'Baz: blue\n'
        '\n'
        'This is a body.\n'
    )
    assert scan_next_stanza_string(lines, skip_leading_newlines=False) == (
        [],
        '\n'
        'Foo: red\n'
        'Bar: green\n'
        'Baz: blue\n'
        '\n'
        'This is a body.\n',
    )

def test_stanza_only():
    lines = [
        'Foo: red\n',
        'Bar: green\n',
        'Baz: blue\n',
    ]
    liter = iter(lines)
    assert list(scan_next_stanza(liter)) \
        == [('Foo', 'red'), ('Bar', 'green'), ('Baz', 'blue')]
    assert list(liter) == []

def test_stanza_only_string():
    lines = (
        'Foo: red\n'
        'Bar: green\n'
        'Baz: blue\n'
    )
    assert scan_next_stanza_string(lines) == (
        [('Foo', 'red'), ('Bar', 'green'), ('Baz', 'blue')],
        '',
    )

def test_empty():
    lines = []
    liter = iter(lines)
    assert list(scan_next_stanza(liter)) == []
    assert list(liter) == []

def test_empty_string():
    assert scan_next_stanza_string('') == ([], '')

def test_all_blanks_skip():
    lines = ['\n', '\n']
    liter = iter(lines)
    assert list(scan_next_stanza(liter, skip_leading_newlines=True)) == []
    assert list(liter) == []

def test_all_blanks_no_skip():
    lines = ['\n', '\n']
    liter = iter(lines)
    assert list(scan_next_stanza(liter, skip_leading_newlines=False)) == []
    assert list(liter) == ['\n']

def test_all_blanks_skip_string():
    assert scan_next_stanza_string('\n\n', skip_leading_newlines=True) \
        == ([], '')

def test_all_blanks_no_skip_string():
    assert scan_next_stanza_string('\n\n', skip_leading_newlines=False) \
        == ([], '\n')