from __future__ import absolute_import, print_function
import struct
import unittest

import silenttestrunner

from mercurial import (
    bdiff,
    mpatch,
)

class BdiffTests(unittest.TestCase):

    def assert_bdiff_applies(self, a, b):
        d = bdiff.bdiff(a, b)
        c = a
        if d:
            c = mpatch.patches(a, [d])
        self.assertEqual(
            c, b, ("bad diff+patch result from\n  %r to\n  "
                   "%r: \nbdiff: %r\npatched: %r" % (a, b, d, c[:200])))

    def assert_bdiff(self, a, b):
        self.assert_bdiff_applies(a, b)
        self.assert_bdiff_applies(b, a)

    def test_bdiff_basic(self):
        cases = [
            ("a\nc\n\n\n\n", "a\nb\n\n\n"),
            ("a\nb\nc\n", "a\nc\n"),
            ("", ""),
            ("a\nb\nc", "a\nb\nc"),
            ("a\nb\nc\nd\n", "a\nd\n"),
            ("a\nb\nc\nd\n", "a\nc\ne\n"),
            ("a\nb\nc\n", "a\nc\n"),
            ("a\n", "c\na\nb\n"),
            ("a\n", ""),
            ("a\n", "b\nc\n"),
            ("a\n", "c\na\n"),
            ("", "adjfkjdjksdhfksj"),
            ("", "ab"),
            ("", "abc"),
            ("a", "a"),
            ("ab", "ab"),
            ("abc", "abc"),
            ("a\n", "a\n"),
            ("a\nb", "a\nb"),
        ]
        for a, b in cases:
            self.assert_bdiff(a, b)

#issue1295
def showdiff(a, b):
    print('showdiff(\n  %r,\n  %r):' % (a, b))
    bin = bdiff.bdiff(a, b)
    pos = 0
    q = 0
    while pos < len(bin):
        p1, p2, l = struct.unpack(">lll", bin[pos:pos + 12])
        pos += 12
        if p1:
            print('', repr(a[q:p1]))
        print('', p1, p2, repr(a[p1:p2]), '->', repr(bin[pos:pos + l]))
        pos += l
        q = p2
    if q < len(a):
        print('', repr(a[q:]))

showdiff("x\n\nx\n\nx\n\nx\n\nz\n", "x\n\nx\n\ny\n\nx\n\nx\n\nz\n")
showdiff("x\n\nx\n\nx\n\nx\n\nz\n", "x\n\nx\n\ny\n\nx\n\ny\n\nx\n\nz\n")
# we should pick up abbbc. rather than bc.de as the longest match
showdiff("a\nb\nb\nb\nc\n.\nd\ne\n.\nf\n",
         "a\nb\nb\na\nb\nb\nb\nc\n.\nb\nc\n.\nd\ne\nf\n")

print("done")

def testfixws(a, b, allws):
    c = bdiff.fixws(a, allws)
    if c != b:
        print("*** fixws", repr(a), repr(b), allws)
        print("got:")
        print(repr(c))

testfixws(" \ta\r b\t\n", "ab\n", 1)
testfixws(" \ta\r b\t\n", " a b\n", 0)
testfixws("", "", 1)
testfixws("", "", 0)

print("done")

print("Nice diff for a trivial change:")
showdiff(
    ''.join('<%s\n-\n' % i for i in range(5)),
    ''.join('>%s\n-\n' % i for i in range(5)))

print("Diff 1 to 3 lines - preference for appending:")
showdiff('a\n', 'a\n' * 3)
print("Diff 1 to 5 lines - preference for appending:")
showdiff('a\n', 'a\n' * 5)
print("Diff 3 to 1 lines - preference for removing trailing lines:")
showdiff('a\n' * 3, 'a\n')
print("Diff 5 to 1 lines - preference for removing trailing lines:")
showdiff('a\n' * 5, 'a\n')

if __name__ == '__main__':
    silenttestrunner.main(__name__)