import difflib
import hashlib
import multiprocessing
import os
import platform
import re
import shlex
import shutil
import subprocess
import time
from http import server
from urllib import request


"""
Part 1:
Here is the configuration part of test cases.
"""

class Config:
    # The configuration parameters for bash test
    # When you run the test cases through `python3 runner.py`, the function configure_suite() in system_tests.py will override these parameters.
    exiv2_dir   = os.path.normpath(os.path.join(os.path.abspath(__file__), '../../../'))
    exiv2_ext   = ''    # or '.exe'
    bin_dir     = os.path.join(exiv2_dir, 'build/bin')
    data_dir    = os.path.join(exiv2_dir, 'test/data')
    tmp_dir     = os.path.join(exiv2_dir, 'test/tmp')
    system_name = platform.system() or 'Unknown'
    exiv2_http  = 'http://127.0.0.1'
    exiv2_port  = 12760

    @classmethod
    def init(cls):
        """ Init test environments and variables that may be modified """
        os.makedirs(cls.tmp_dir, exist_ok=True)
        os.chdir(cls.tmp_dir)
        log.buffer      = []
        cls.bin_files   = [i.split('.')[0] for i in os.listdir(cls.bin_dir)]
        cls.encoding    = 'utf-8'


"""
Part 2:
Here are some common functions that are poorly coupled with test cases.
"""

def cp(src, dest):
    """ It is used to copy one file, cannot handle directories """
    shutil.copy(src, dest)


def mv(src, dest):
    """ It is used to move one file, cannot handle directories """
    shutil.move(src, dest)


def rm(*files):
    """ It is used to remove files, cannot handle directories """
    for i in files:
        try:
            os.remove(i)
        except FileNotFoundError:
            continue


def cat(*files, encoding=None, return_bytes=False):
    if return_bytes:
        result = b''
        for i in files:
            with open(i, 'rb') as f:
                result += f.read()
    else:
        result = ''
        for i in files:
            with open(i, 'r', encoding=encoding or Config.encoding) as f:
                result += f.read()
    return result


def grep(pattern, *files, encoding=None):
    result  = ''
    pattern = '.*{}.*'.format(pattern)
    for i in files:
        content = cat(i, encoding=encoding or Config.encoding)
        result += '\n'.join(re.findall(pattern, content))
    return result


def save(content: (bytes, str, tuple, list), filename, encoding=None):
    if isinstance(content, bytes):
        with open(filename, 'wb') as f:
            f.write(content)
        return
    if isinstance(content, (tuple, list)):
        content = '\n'.join(content)
    if isinstance(content, str):
        with open(filename, 'w', encoding=encoding or Config.encoding) as f:
            f.write(content)
    else:
        raise ValueError('Expect content of type (bytes, str, tuple, list), but get {}'.format(type(content).__name__))


def diff(file1, file2, encoding=None):
    """
    Simulates the output of GNU diff.
    You can use `diff(f1, f2)` to simulate `diff -w f1 f2`
    """
    encoding     = encoding or Config.encoding
    texts        = []
    for f in [file1, file2]:
        with open(f, encoding=encoding) as f:
            text = f.read()
        text     = text.replace('\r\n', '\n') # Ignore line breaks for Windows
        texts   += [text.split('\n')]
    text1, text2 = texts

    output       = []
    new_part     = True
    num          = 0
    for line in difflib.unified_diff(text1, text2, fromfile=file1, tofile=file2, lineterm=''):
        num     += 1
        if num   < 3:
            # line         = line.replace('--- ', '<<< ')
            # line         = line.replace('+++ ', '>>> ')
            # output      += [line]
            continue

        flag             = line[0]
        if flag         == '-':   # line unique to sequence 1
            new_flag     = '< '
        elif flag       == '+':   # line unique to sequence 2
            new_flag     = '> '
            if new_part:
                new_part = False
                output  += ['---']
        elif flag       == ' ':   # line common to both sequences
            # new_flag   = '  '
            continue
        elif flag       == '?':   # line not present in either input sequence
            new_flag     = '? '
        elif flag       == '@':
            output      += [re.sub(r'@@ -([^ ]+) \+([^ ]+) @@', r'\1c\2', line)]
            new_part     = True
            continue
        else:
            new_flag     = flag
        output          += [new_flag + line[1:]]

    return '\n'.join(output)


def diff_bytes(file1, file2, return_str=False):
    """
    Compare the bytes of two files.
    Simulates the output of GNU diff.
    """
    texts        = []
    for f in [file1, file2]:
        with open(f, 'rb') as f:
            text = f.read()
        text     = text.replace(b'\r\n', b'\n') # Ignore line breaks for Windows
        texts   += [text.split(b'\n')]
    text1, text2 = texts

    output       = []
    new_part     = True
    num          = 0
    for line in difflib.diff_bytes(difflib.unified_diff, text1, text2,
                                   fromfile=file1.encode(), tofile=file2.encode(), lineterm=b''):
        num     += 1
        if num   < 3:
            line         = line.decode()
            line         = line.replace('--- ', '<<< ')
            line         = line.replace('+++ ', '>>> ')
            output      += [line.encode()]
            continue

        flag             = line[0:1]
        if flag         == b'-':   # line unique to sequence 1
            new_flag     = b'< '
        elif flag       == b'+':   # line unique to sequence 2
            new_flag     = b'> '
            if new_part:
                new_part = False
                output  += [b'---']
        elif flag       == b' ':   # line common to both sequences
            # new_flag   = b'  '
            continue
        elif flag       == b'?':   # line not present in either input sequence
            new_flag     = b'? '
        elif flag       == b'@':
            output      += [re.sub(rb'@@ -([^ ]+) \+([^ ]+) @@', rb'\1c\2', line)]
            new_part     = True
            continue
        else:
            new_flag     = flag
        output          += [new_flag + line[1:]]

    if return_str:
        return '\n'.join([repr(line)[2:-1] for line in output])
    else:
        return b'\n'.join(output)


def md5sum(filename):
    """ Calculate the MD5 value of the file """
    with open(filename, "rb") as f:
        return hashlib.md5(f.read()).hexdigest()


class Log:

    def __init__(self):
        self.buffer = []

    def to_str(self):
        return '\n'.join(self.buffer)

    def add(self, msg):
        self.buffer.append(str(msg))

    def info(self, msg, index=None):
        self.add('[INFO] {}'.format(msg))

    def warn(self, msg):
        self.add('[WARN] {}'.format(msg))

    def error(self, msg):
        self.add('[ERROR] {}'.format(msg))


log = Log()


class Output:
    """
    Simulate the stdout buffer.
    You can use `out+=x` to simulate `print(x)`

    Sample:
    >>> out = Output()
    >>> out
    >>> str(out)
    >>> out += 'Hello'
    >>> out += 1
    >>> out += ['Hi' , 2]
    >>> out += None         # no effect
    >>> str(out)
    """
    def __init__(self):
        self.lines = []
        self.newline = '\n'

    def __str__(self):
        return self.newline.join(self.lines)

    # Comment it so that log does not automatically convert to str type
    # def __repr__(self):
    #     return str(self)

    def __add__(self, other):
        if other or other == '':
            self.lines.append(str(other))
        return self

    def __radd__(self, other):
        if other or other == '':
            self.lines.append(str(other))
        return self


class HttpServer:
    def __init__(self, bind='127.0.0.1', port=80, work_dir='.'):
        self.bind = bind
        self.port = int(port)
        self.work_dir = work_dir

    def _start(self):
        """ Equivalent to executing `python3 -m http.server` """
        os.chdir(self.work_dir)
        server.test(HandlerClass=server.SimpleHTTPRequestHandler, bind=self.bind, port=self.port)
        log.error('The HTTP server exits without calling stop()')
        print(log.to_str())

    def start(self):
        log.info('Starting HTTP server ...')
        self.proc = multiprocessing.Process(target=self._start, name=str(self))
        self.proc.start()
        time.sleep(1)
        try:
            with request.urlopen('http://127.0.0.1:{}'.format(self.port), timeout=3) as f:
                if f.status != 200:
                    raise RuntimeError()
        except:
            raise RuntimeError('Failed to run the HTTP server')
        log.info('The HTTP server started')

    def stop(self):
        self.proc.terminate()


"""
Part 3:
Here are some functions that are highly coupled to test cases.
"""

def copyTestFile(src, dest=''):
    """ Copy one test file from data_dir to tmp_dir """
    if not dest:
        dest = src
    shutil.copy(os.path.join(Config.data_dir, src),
                os.path.join(Config.tmp_dir, dest))


def diffCheck(file1, file2, in_bytes=False, encoding=None):
    """ Compare two files to see if they are different """
    if in_bytes:
        d = diff_bytes(file1, file2, return_str=True)
        if d:
            log.info('diff_bytes:\n' + d)
    else:
        d = diff(file1, file2, encoding=encoding or Config.encoding)
        if d:
            log.info('diff:\n' + d)
    return d == ''


def simply_diff(file1, file2, encoding=None):
    """ Find the first different line of the two text files """
    encoding         = encoding or Config.encoding
    list1            = cat(file1, encoding=encoding).split('\n')
    list2            = cat(file2, encoding=encoding).split('\n')
    if list1        == list2:
        return
    report           = []
    report          += ['{}: {} lines'.format(file1, len(list1))]
    report          += ['{}: {} lines'.format(file2, len(list2))]
    max_lines        = max(len(list1), len(list2))
    for i in [list1, list2]:
        i           += [''] * (max_lines - len(i))    # Make them have the same number of lines
    for i in range(max_lines):
        if list1[i] != list2[i]:
            report  += ['The first mismatch is in line {}:'.format(i + 1)]
            report  += ['- {}'.format(list1[i])]
            report  += ['+ {}'.format(list2[i])]
            break
    return '\n'.join(report)


def execute(cmd: str,
            vars_dict=dict(),
            stdin: (str, bytes) = None,
            encoding=None,
            expected_returncodes=[0],
            return_raw=False,
            return_bytes=False,
            redirect_stderr_to_stdout=True):
    """
    Execute a command in the shell and return its stdout and stderr.
    - If the binary of Exiv2 is executed, the absolute path is automatically added.
    - When return_raw is true, returns the raw output. Otherwise, the path separator, whitespace character in output will be filtered.
    - When return_bytes is true, returns the output bytes. Otherwise, the output is decoded to a str and returned.

    Sample:
    >>> execute('echo Hello')
    >>> execute('exiv2 --help')
    """
    # Check args
    cmd             = cmd.format(**vars_dict)
    args            = cmd.split(' ', maxsplit=1)
    if args[0] in Config.bin_files:
        args[0]     = os.path.join(Config.bin_dir, args[0]) + Config.exiv2_ext
    args            = ' '.join(args)
    if Config.system_name == 'Windows':
        args        = args.replace('\'', '\"')
    else:
        args        = shlex.split(args, posix=os.name == 'posix')

    # Check stdin
    encoding        = encoding or Config.encoding
    if stdin:
        if not isinstance(stdin, bytes):
            stdin   = str(stdin).encode(encoding)

    # Check stdout
    if redirect_stderr_to_stdout:
        stderr_to   = subprocess.STDOUT
    else:
        stderr_to   = subprocess.PIPE

    # Execute the command
    try:
        with subprocess.Popen(args, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=stderr_to, cwd=Config.tmp_dir) as proc:
            try:
                output  = proc.communicate(stdin, timeout=10)  # Assign (stdout, stderr) to output
            except subprocess.TimeoutExpired:
                proc.kill()
                output  = proc.communicate()
    except:
        raise RuntimeError('Failed to execute: {}'.format(args))
    output          = [i or b'' for i in output]
    output          = [i.rstrip(b'\r\n').rstrip(b'\n') for i in output] # Remove the last line break of the output

    # Check the output
    if not return_raw:
        output      = [i.replace(b'\r\n', b'\n') for i in output]   # Fix dos line-endings
        output      = [i.replace(b'\\', rb'/') for i in output]     # Fix dos path separators
    if not return_bytes:
        output      = [i.decode(encoding) for i in output]
    if expected_returncodes and proc.returncode not in expected_returncodes:
        log.error('Failed to execute: {}'.format(args))
        log.error('The expected return code is {}, but get {}'.format(str(expected_returncodes), proc.returncode))
        log.info('OUTPUT:\n{}'.format(output[0] + output[1]))
        raise RuntimeError('\n' + log.to_str())

    if redirect_stderr_to_stdout:
        return output[0] + output[1] or None
    else:
        return [i or None for i in output]


def reportTest(testname, output: str, encoding=None):
    """ If the output of the test case is correct, this function returns None. Otherwise print its error. """
    output               = str(output) + '\n'
    encoding             = encoding or Config.encoding
    reference_file       = os.path.join(Config.data_dir, '{}.out'.format(testname))
    reference_output     = cat(reference_file, encoding=encoding)
    if reference_output == output:
        return
    log.error('The output of the testcase mismatch the reference')
    output_file = os.path.join(Config.tmp_dir, '{}.out'.format(testname))
    save(output, output_file, encoding=encoding)
    log.info('The output has been saved to file {}'.format(output_file))
    log.info('simply_diff:\n' + str(simply_diff(reference_file, output_file, encoding=encoding)))
    raise RuntimeError('\n' + log.to_str())


def ioTest(filename):
    src     = os.path.join(Config.data_dir, filename)
    out1    = os.path.join(Config.tmp_dir, '{}.1'.format(filename))
    out2    = os.path.join(Config.tmp_dir, '{}.2'.format(filename))
    execute('iotest {src} {out1} {out2}', vars())
    assert md5sum(src) == md5sum(out1), 'The output file is different'
    assert md5sum(src) == md5sum(out2), 'The output file is different'


def eraseTest(filename):
    test_file   = filename + '.etst'
    good_file   = os.path.join(Config.data_dir, filename + '.egd')
    copyTestFile(filename, test_file)
    execute('metacopy {test_file} {test_file}', vars())
    return diffCheck(good_file, test_file, in_bytes=True)


def copyTest(num, src, good):
    test_file   = '{}.c{}tst'.format(good, num)
    src_file    = os.path.join(Config.data_dir, src)
    good_file   = os.path.join(Config.data_dir, '{}.c{}gd'.format(good, num))
    copyTestFile(good, test_file)
    execute('metacopy -a {src_file} {test_file}', vars())
    return diffCheck(good_file, test_file, in_bytes=True)


def iptcTest(num, src, good):
    test_file   = '{}.i{}tst'.format(good, num)
    src_file    = os.path.join(Config.data_dir, src)
    good_file   = os.path.join(Config.data_dir, '{}.i{}gd'.format(good, num))
    copyTestFile(good, test_file)
    execute('metacopy -ip {src_file} {test_file}', vars())
    return diffCheck(good_file, test_file, in_bytes=True)


def printTest(filename):
    test_file   = filename + '.iptst'
    src_file    = os.path.join(Config.data_dir, filename)
    good_file   = os.path.join(Config.data_dir, filename + '.ipgd')
    copyTestFile(filename, test_file)
    output      = execute('iptcprint {src_file}', vars(), expected_returncodes=None, return_bytes=True)
    output      = output.replace(Config.data_dir.replace(os.path.sep, '/').encode(), b'../data') # Ignore the difference of data_dir
    save(output + b'\n', test_file)
    return diffCheck(good_file, test_file, in_bytes=True)


def removeTest(filename):
    tmp         = 'temp'
    test_file   = filename + '.irtst'
    src_file    = os.path.join(Config.data_dir, filename)
    good_file   = os.path.join(Config.data_dir, filename + '.irgd')
    copyTestFile(filename, tmp)
    stdin       = """
r Iptc.Application2.Byline
r Iptc.Application2.Caption
r Iptc.Application2.Keywords
r Iptc.Application2.Keywords
r Iptc.Application2.Keywords
r Iptc.Application2.CountryName
""".lstrip('\n').encode()
    execute('iptctest {tmp}', vars(), stdin=stdin)
    save(execute('iptcprint {tmp}', vars(), expected_returncodes=None, return_bytes=True) + b'\n',
         test_file)
    return diffCheck(good_file, test_file, in_bytes=True)


def addModTest(filename):
    tmp         = 'temp'
    test_file   = filename + '.iatst'
    src_file    = os.path.join(Config.data_dir, filename)
    good_file   = os.path.join(Config.data_dir, filename + '.iagd')
    copyTestFile(filename, tmp)
    stdin       = """
a Iptc.Application2.Headline		  The headline I am
a Iptc.Application2.Keywords		  Yet another keyword
m Iptc.Application2.DateCreated		  2004-8-3
a Iptc.Application2.Urgency			  3
m Iptc.Application2.SuppCategory	  "bla bla ba"
a Iptc.Envelope.ModelVersion		  2
a Iptc.Envelope.TimeSent			  14:41:0-05:00
a Iptc.Application2.RasterizedCaption 230 42 34 2 90 84 23 146
""".lstrip('\n').encode()
    execute('iptctest {tmp}', vars(), stdin=stdin)
    save(execute('iptcprint {tmp}', vars(), expected_returncodes=None, return_bytes=True) + b'\n',
         test_file)
    return diffCheck(good_file, test_file, in_bytes=True)


def extendedTest(filename):
    tmp         = 'temp'
    test_file   = filename + '.ixtst'
    src_file    = os.path.join(Config.data_dir, filename)
    good_file   = os.path.join(Config.data_dir, filename + '.ixgd')
    copyTestFile(filename, tmp)
    stdin       = cat(os.path.join(Config.data_dir, 'ext.dat'), return_bytes=False)
    execute('iptctest {tmp}', vars(), stdin=stdin)
    save(execute('iptcprint {tmp}', vars(), return_bytes=True) + b'\n',
         test_file)
    return diffCheck(good_file, test_file, in_bytes=True)