# Copyright (C) 2009 Canonical Ltd
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

"""Shell-like test scripts.

See developers/testing.html for more explanations.
"""

import doctest
import errno
import glob
import os
import shlex
from cStringIO import StringIO

from bzrlib import (
    osutils,
    tests,
    )


def split(s):
    """Split a command line respecting quotes."""
    scanner = shlex.shlex(s)
    scanner.quotes = '\'"`'
    scanner.whitespace_split = True
    for t in list(scanner):
        yield t


def _script_to_commands(text, file_name=None):
    """Turn a script into a list of commands with their associated IOs.

    Each command appears on a line by itself starting with '$ '. It can be
    associated with an input that will feed it and an expected output.

    Comments starts with '#' until the end of line.
    Empty lines are ignored.

    Input and output are full lines terminated by a '\n'.

    Input lines start with '<'.
    Output lines start with nothing.
    Error lines start with '2>'.
    """

    commands = []

    def add_command(cmd, input, output, error):
        if cmd is not None:
            if input is not None:
                input = ''.join(input)
            if output is not None:
                output = ''.join(output)
            if error is not None:
                error = ''.join(error)
            commands.append((cmd, input, output, error))

    cmd_cur = None
    cmd_line = 1
    lineno = 0
    input, output, error = None, None, None
    for line in text.split('\n'):
        lineno += 1
        # Keep a copy for error reporting
        orig = line
        comment =  line.find('#')
        if comment >= 0:
            # Delete comments
            line = line[0:comment]
            line = line.rstrip()
        if line == '':
            # Ignore empty lines
            continue
        if line.startswith('$'):
            # Time to output the current command
            add_command(cmd_cur, input, output, error)
            # And start a new one
            cmd_cur = list(split(line[1:]))
            cmd_line = lineno
            input, output, error = None, None, None
        elif line.startswith('<'):
            if input is None:
                if cmd_cur is None:
                    raise SyntaxError('No command for that input',
                                      (file_name, lineno, 1, orig))
                input = []
            input.append(line[1:] + '\n')
        elif line.startswith('2>'):
            if error is None:
                if cmd_cur is None:
                    raise SyntaxError('No command for that error',
                                      (file_name, lineno, 1, orig))
                error = []
            error.append(line[2:] + '\n')
        else:
            if output is None:
                if cmd_cur is None:
                    raise SyntaxError('No command for that output',
                                      (file_name, lineno, 1, orig))
                output = []
            output.append(line + '\n')
    # Add the last seen command
    add_command(cmd_cur, input, output, error)
    return commands


def _scan_redirection_options(args):
    """Recognize and process input and output redirections.

    :param args: The command line arguments

    :return: A tuple containing: 
        - The file name redirected from or None
        - The file name redirected to or None
        - The mode to open the output file or None
        - The reamining arguments
    """
    def redirected_file_name(direction, name, args):
        if name == '':
            try:
                name = args.pop(0)
            except IndexError:
                # We leave the error handling to higher levels, an empty name
                # can't be legal.
                name = ''
        return name

    remaining = []
    in_name = None
    out_name, out_mode = None, None
    while args:
        arg = args.pop(0)
        if arg.startswith('<'):
            in_name = redirected_file_name('<', arg[1:], args)
        elif arg.startswith('>>'):
            out_name = redirected_file_name('>>', arg[2:], args)
            out_mode = 'ab+'
        elif arg.startswith('>',):
            out_name = redirected_file_name('>', arg[1:], args)
            out_mode = 'wb+'
        else:
            remaining.append(arg)
    return in_name, out_name, out_mode, remaining


class ScriptRunner(object):

    def __init__(self, test_case):
        self.test_case = test_case
        self.output_checker = doctest.OutputChecker()
        self.check_options = doctest.ELLIPSIS

    def run_script(self, text):
        for cmd, input, output, error in _script_to_commands(text):
            self.run_command(cmd, input, output, error)

    def _check_output(self, expected, actual):
        if expected is None:
            # Specifying None means: any output is accepted
            return
        if actual is None:
            self.test_case.fail('Unexpected: %s' % actual)
        matching = self.output_checker.check_output(
            expected, actual, self.check_options)
        if not matching:
            # Note that we can't use output_checker.output_difference() here
            # because... the API is broken ('expected' must be a doctest
            # specific object of which a 'want' attribute will be our
            # 'expected' parameter. So we just fallback to our good old
            # assertEqualDiff since we know there *are* differences and the
            # output should be decently readable.
            self.test_case.assertEqualDiff(expected, actual)

    def _pre_process_args(self, args):
        new_args = []
        for arg in args:
            # Strip the simple and double quotes since we don't care about
            # them.  We leave the backquotes in place though since they have a
            # different semantic.
            if arg[0] in  ('"', "'") and arg[0] == arg[-1]:
                yield arg[1:-1]
            else:
                if glob.has_magic(arg):
                    matches = glob.glob(arg)
                    if matches:
                        # We care more about order stability than performance
                        # here
                        matches.sort()
                        for m in matches:
                            yield m
                else:
                    yield arg

    def run_command(self, cmd, input, output, error):
        mname = 'do_' + cmd[0]
        method = getattr(self, mname, None)
        if method is None:
            raise SyntaxError('Command not found "%s"' % (cmd[0],),
                              None, 1, ' '.join(cmd))
        if input is None:
            str_input = ''
        else:
            str_input = ''.join(input)
        args = list(self._pre_process_args(cmd[1:]))
        retcode, actual_output, actual_error = method(str_input, args)

        self._check_output(output, actual_output)
        self._check_output(error, actual_error)
        if retcode and not error and actual_error:
            self.test_case.fail('In \n\t%s\nUnexpected error: %s'
                                % (' '.join(cmd), actual_error))
        return retcode, actual_output, actual_error

    def _read_input(self, input, in_name):
        if in_name is not None:
            infile = open(in_name, 'rb')
            try:
                # Command redirection takes precedence over provided input
                input = infile.read()
            finally:
                infile.close()
        return input

    def _write_output(self, output, out_name, out_mode):
        if out_name is not None:
            outfile = open(out_name, out_mode)
            try:
                outfile.write(output)
            finally:
                outfile.close()
            output = None
        return output

    def do_bzr(self, input, args):
        retcode, out, err = self.test_case._run_bzr_core(
            args, retcode=None, encoding=None, stdin=input, working_dir=None)
        return retcode, out, err

    def do_cat(self, input, args):
        (in_name, out_name, out_mode, args) = _scan_redirection_options(args)
        if args and in_name is not None:
            raise SyntaxError('Specify a file OR use redirection')

        inputs = []
        if input:
            inputs.append(input)
        input_names = args
        if in_name:
            args.append(in_name)
        for in_name in input_names:
            try:
                inputs.append(self._read_input(None, in_name))
            except IOError, e:
                if e.errno == errno.ENOENT:
                    return (1, None,
                            '%s: No such file or directory\n' % (in_name,))
        # Basically cat copy input to output
        output = ''.join(inputs)
        # Handle output redirections
        try:
            output = self._write_output(output, out_name, out_mode)
        except IOError, e:
            if e.errno == errno.ENOENT:
                return 1, None, '%s: No such file or directory\n' % (out_name,)
        return 0, output, None

    def do_echo(self, input, args):
        (in_name, out_name, out_mode, args) = _scan_redirection_options(args)
        if input and args:
                raise SyntaxError('Specify parameters OR use redirection')
        if args:
            input = ' '.join(args)
        try:
            input = self._read_input(input, in_name)
        except IOError, e:
            if e.errno == errno.ENOENT:
                return 1, None, '%s: No such file or directory\n' % (in_name,)
        # Always append a \n'
        input += '\n'
        # Process output
        output = input
        # Handle output redirections
        try:
            output = self._write_output(output, out_name, out_mode)
        except IOError, e:
            if e.errno == errno.ENOENT:
                return 1, None, '%s: No such file or directory\n' % (out_name,)
        return 0, output, None

    def _ensure_in_jail(self, path):
        jail_root = self.test_case.get_jail_root()
        if not osutils.is_inside(jail_root, osutils.normalizepath(path)):
            raise ValueError('%s is not inside %s' % (path, jail_root))

    def do_cd(self, input, args):
        if len(args) > 1:
            raise SyntaxError('Usage: cd [dir]')
        if len(args) == 1:
            d = args[0]
            self._ensure_in_jail(d)
        else:
            d = self.test_case.get_jail_root()
        os.chdir(d)
        return 0, None, None

    def do_mkdir(self, input, args):
        if not args or len(args) != 1:
            raise SyntaxError('Usage: mkdir dir')
        d = args[0]
        self._ensure_in_jail(d)
        os.mkdir(d)
        return 0, None, None

    def do_rm(self, input, args):
        err = None

        def error(msg, path):
            return  "rm: cannot remove '%s': %s\n" % (path, msg)

        force, recursive = False, False
        opts = None
        if args and args[0][0] == '-':
            opts = args.pop(0)[1:]
            if 'f' in opts:
                force = True
                opts = opts.replace('f', '', 1)
            if 'r' in opts:
                recursive = True
                opts = opts.replace('r', '', 1)
        if not args or opts:
            raise SyntaxError('Usage: rm [-fr] path+')
        for p in args:
            self._ensure_in_jail(p)
            # FIXME: Should we put that in osutils ?
            try:
                os.remove(p)
            except OSError, e:
                # Various OSes raises different exceptions (linux: EISDIR,
                #   win32: EACCES, OSX: EPERM) when invoked on a directory
                if e.errno in (errno.EISDIR, errno.EPERM, errno.EACCES):
                    if recursive:
                        osutils.rmtree(p)
                    else:
                        err = error('Is a directory', p)
                        break
                elif e.errno == errno.ENOENT:
                    if not force:
                        err =  error('No such file or directory', p)
                        break
                else:
                    raise
        if err:
            retcode = 1
        else:
            retcode = 0
        return retcode, None, err


class TestCaseWithMemoryTransportAndScript(tests.TestCaseWithMemoryTransport):

    def setUp(self):
        super(TestCaseWithMemoryTransportAndScript, self).setUp()
        self.script_runner = ScriptRunner(self)
        # Break the circular dependency
        def break_dependency():
            self.script_runner = None
        self.addCleanup(break_dependency)

    def get_jail_root(self):
        raise NotImplementedError(self.get_jail_root)

    def run_script(self, script):
        return self.script_runner.run_script(script)

    def run_command(self, cmd, input, output, error):
        return self.script_runner.run_command(cmd, input, output, error)


class TestCaseWithTransportAndScript(tests.TestCaseWithTransport):

    def setUp(self):
        super(TestCaseWithTransportAndScript, self).setUp()
        self.script_runner = ScriptRunner(self)
        # Break the circular dependency
        def break_dependency():
            self.script_runner = None
        self.addCleanup(break_dependency)

    def get_jail_root(self):
        return self.test_dir

    def run_script(self, script):
        return self.script_runner.run_script(script)

    def run_command(self, cmd, input, output, error):
        return self.script_runner.run_command(cmd, input, output, error)