import itertools
import unittest
import os
import subprocess
import binascii
import random
import tempfile

from cobs import cobs

INTERESTING = bytes([1, 2, 3, 0, 1, 2, 3, 0, 0, 1, 2, 3, 0, 0, 0, 1, 2, 3] + list(range(256)))
class MicrocobsScatterGatherTest(unittest.TestCase):
    def do_test(self, data_sglist):
        data_sglist = list(data_sglist)
        ref = cobs.encode(b''.join(data_sglist))
        input = b'\n'.join(binascii.hexlify(x) for x in data_sglist)

        debug_file = tempfile.NamedTemporaryFile(prefix='microcobs_test_', delete=False)
        debug_file.write(input)

        try:
            test = subprocess.check_output(os.getenv('MICROCOBS_SG_TEST_BINARY', 'build/microcobs_test_sg'),
                    input=input, stderr=subprocess.DEVNULL)
            test = binascii.unhexlify(test.strip())

            self.assertEqual(test[-1], 0, 'Missing terminating null byte')
            self.assertEqual(ref, test[:-1], f'Mismatched output for input {debug_file.name}')

            debug_file.close()
            os.remove(debug_file.name)
        except Exception as e:
            raise SystemError(f'Test error for input {debug_file.name}') from e


    def test_empty_chunks(self):
        for i in range(256):
            self.do_test([b''] * i)


    def test_interspersed_empty_chunks(self):
        testdata = INTERESTING
        for i in range(len(testdata) + 1):
            self.do_test([testdata[:i], b'', testdata[i:]])

    def test_interspersed_double_empty_chunks(self):
        testdata = INTERESTING
        for i in range(len(testdata) + 1):
            self.do_test([testdata[:i], b'', b'', testdata[i:]])

    def test_one_byte_chunks(self):
        testdata = INTERESTING
        self.do_test(itertools.chain.from_iterable(zip([bytes([x]) for x in testdata], [b''] * len(testdata))))

    def test_one_byte(self):
        for i in range(256):
            self.do_test([bytes([i])])

    def test_lengths(self):
        for i in range(260):
            self.do_test([bytes([0xff] * i)])

    def test_null_then_lengths(self):
        for i in range(256):
            self.do_test([bytes([0] + [0xff] * i)])

    def test_lengths_then_null(self):
        for i in range(256):
            self.do_test([bytes([0xff] * i + [0])])

    def test_two_byte(self):
        for i in range(4):
            for j in range(4):
                self.do_test([bytes([i, j])])
                self.do_test([bytes([i]), bytes([j])])

    def test_long(self):
        for i in range(5):
            self.do_test([b'A' * (100 + 256*i)])
            self.do_test([b'A' * 100] * 256*i)

    def test_random(self):
        for i in range(1000):
            testdata = os.urandom(random.randint(0, 600))

            chunks = [testdata]
            for i in range(random.randint(0, len(testdata) // 5)):
                idx = random.randint(0, len(chunks)-1)
                chunk = chunks[idx]
                bidx = random.randint(0, len(chunk))
                chunks = chunks[:idx] + [chunk[:bidx], chunk[bidx:]] + chunks[idx+1:]

            self.do_test(chunks)

class MicrocobsTest(unittest.TestCase):
    def do_test(self, data):
        ref = cobs.encode(data)
        input = binascii.hexlify(data)

        debug_file = tempfile.NamedTemporaryFile(prefix='microcobs_test_', delete=False)
        debug_file.write(input)

        try:
            test = subprocess.check_output(os.getenv('MICROCOBS_TEST_BINARY', 'build/microcobs_test'),
                    input=input, stderr=subprocess.DEVNULL)
            test = binascii.unhexlify(test.strip())

            self.assertEqual(test[-1], 0, 'Missing terminating null byte')
            self.assertEqual(ref, test[:-1], f'Mismatched output for input {debug_file.name}')

            debug_file.close()
            os.remove(debug_file.name)
        except Exception as e:
            raise SystemError(f'Test error for input {debug_file.name}') from e


    def test_one_byte(self):
        for i in range(256):
            self.do_test(bytes([i]))

    def test_lengths(self):
        for i in range(260):
            self.do_test(bytes([0xff] * i))

    def test_null_then_lengths(self):
        for i in range(256):
            self.do_test(bytes([0] + [0xff] * i))

    def test_lengths_then_null(self):
        for i in range(256):
            self.do_test(bytes([0xff] * i + [0]))

    def test_two_byte(self):
        for i in range(4):
            for j in range(4):
                self.do_test(bytes([i, j]))

    def test_long(self):
        for i in range(5):
            self.do_test(b'A' * (100 + 256*i))

    def test_random(self):
        for i in range(10000):
            self.do_test(os.urandom(random.randint(0, 600)))

class MicrocobsDecodeTest(unittest.TestCase):
    def do_test(self, data):
        enc = cobs.encode(data)
        input = binascii.hexlify(enc)

        debug_file = tempfile.NamedTemporaryFile(prefix='microcobs_test_', delete=False)
        debug_file.write(input)

        try:
            test = subprocess.check_output(os.getenv('MICROCOBS_DECODE_TEST_BINARY', 'build/microcobs_decode_test'),
                    input=input, stderr=subprocess.DEVNULL)
            test = binascii.unhexlify(test.strip())

            self.assertEqual(data, test, f'Mismatched output for input {debug_file.name}')

            debug_file.close()
            os.remove(debug_file.name)
        except Exception as e:
            raise SystemError(f'Test error for input {debug_file.name}') from e


    def test_one_byte(self):
        for i in range(256):
            self.do_test(bytes([i]))

    def test_lengths(self):
        for i in range(260):
            self.do_test(bytes([0xff] * i))

    def test_null_then_lengths(self):
        for i in range(256):
            self.do_test(bytes([0] + [0xff] * i))

    def test_lengths_then_null(self):
        for i in range(256):
            self.do_test(bytes([0xff] * i + [0]))

    def test_two_byte(self):
        for i in range(4):
            for j in range(4):
                self.do_test(bytes([i, j]))

    def test_long(self):
        for i in range(5):
            self.do_test(b'A' * (100 + 256*i))

    def test_random(self):
        for i in range(10000):
            self.do_test(os.urandom(random.randint(0, 600)))