"""
Tests for `bx.misc.seekbzip2`.
"""

import bz2
import os
import random
from codecs import encode

from bx.misc import seekbzip2

F = None
T = None

# F="/Users/james/work/seek-bzip2/test_random.dat.bz2"
# T="/Users/james/cache/hg18/align/multiz28way/chr10.maf.bz2"

# F=/depot/data1/cache/human/hg18/align/multiz28way/chr1.maf.bz2


if F and os.path.exists(F):

    def test_linear_reading():
        raw_data = bz2.BZ2File(F).read()
        f = seekbzip2.SeekableBzip2File(F, F + "t")
        chunk = 1221
        pos = 0
        for i in range((len(raw_data) // chunk) + 1):
            a = raw_data[pos : pos + chunk]
            b = f.read(chunk)
            assert a == b
            pos += chunk
            assert f.tell() == min(pos, len(raw_data))
        f.close()

    def test_random_seeking():
        raw_data = bz2.BZ2File(F).read()
        f = seekbzip2.SeekableBzip2File(F, F + "t")
        for i in range(10):
            seek_to = random.randrange(len(raw_data) - 100)
            chunk = random.randrange(10, 20)

            f.seek(seek_to)
            a = f.read(chunk)
            b = raw_data[seek_to : seek_to + chunk]

            assert a == b, "'%s' != '%s' on %dth attempt" % (encode(a, "hex"), encode(b, "hex"), i)

            assert f.tell() == min(seek_to + chunk, len(raw_data))
        f.close()


if T and os.path.exists(T):

    def test_text_reading():
        raw_file = bz2.BZ2File(T)
        f = seekbzip2.SeekableBzip2File(T, T + "t")
        pos = 0
        for i, (line, raw_line) in enumerate(zip(f, raw_file)):
            assert line == raw_line, "%d: %r != %r" % (i, line.rstrip(b"\n"), raw_line)
            pos += len(line)
            ftell = f.tell()
            assert ftell == pos, "%d != %d" % (ftell, pos)
        f.close()

    def test_text_reading_2():
        raw_data = bz2.BZ2File(T).read()
        f = seekbzip2.SeekableBzip2File(T, T + "t")
        raw_lines = raw_data.split(b"\n")
        pos = 0
        i = 0
        while True:
            line = f.readline()
            if line == b"":
                break
            assert line.rstrip(b"\r\n") == raw_lines[i], "{!r} != {!r}".format(line.rstrip(b"\r\n"), raw_lines[i])
            pos += len(line)
            ftell = f.tell()
            assert ftell == pos, "%d != %d" % (ftell, pos)
            i += 1
        f.close()