r"""nodoctest [[remove the nodoctest, so doctests will run]]
Interface Template

[[Describe the math software you are interfacing with here.]]

[[Replace this by something relevant to your system.]]
    Type \code{gp.[tab]} for a list of all the functions available
    from your Gp install.  Type \code{gp.[tab]?} for Gp's
    help about a given function.  Type \code{gp(...)} to create
    a new Gp object, and \code{gp.eval(...)} to run a string
    using Gp (and get the result back as a string).


EXAMPLES:

[[Go through a standard tutorial for your software package
and do it via your SAGE interface.]]
    
AUTHORS:
    -- William Stein (template)
"""

##########################################################################
#
#       Copyright (C) 2006 William Stein <wstein@gmail.com>
#
#  Distributed under the terms of the GNU General Public License (GPL)
#
#                  http://www.gnu.org/licenses/
#
##########################################################################

from __future__ import with_statement
from expect import Expect, ExpectElement, ExpectFunction, FunctionElement, gc_disabled
from sage.misc.misc import verbose

class MitScheme(Expect):
    """
    [[Some basic help about your system.  This is what
      will be displayed when somebody write mitscheme?.]]
    """
    def __init__(self,
                 maxread=100000, script_subdirectory=None,
                 logfile=None,
                 server=None,
                 server_tmpdir=None):
        Expect.__init__(self,

                        # The capitalized version of this is used for printing.
                        name = 'MIT/GNU Scheme',

                        # This is regexp of the input prompt.  If you can change
                        # it to be very obfuscated that would be better.   Even
                        # better is to use sequence numbers. 
                        prompt = '\d? \]=> ',

                        # This is the command that starts up your program
                        command = "/usr/local/scmutils/mit-scheme/bin/scheme --library /usr/local/scmutils/mit-scheme/lib/ --heap 12000 --band edwin-mechanics.com",
                        #command = "mit-scheme",

                        maxread = maxread,

                        server=server,
                        server_tmpdir=server_tmpdir,

                        script_subdirectory = script_subdirectory,

                        # If this is true, then whenever the user presses Control-C to
                        # interrupt a calculation, the whole interface is restarted. 
                        restart_on_ctrlc = True,

                        # If true, print out a message when starting
                        # up the command when you first send a command
                        # to this interface.
                        verbose_start = True,

                        logfile=logfile,

                        # If an input is longer than this number of characters, then
                        # try to switch to outputing to a file. 
                        eval_using_file_cutoff=1024)
        
        self.__seq = 0
        self.eval('(set! standard-error-hook (lambda (x) (begin (warn x) (cmdl-interrupt/abort-top-level))))')

    def chdir(self, dir):
        raise NotImplemented

    def eval(self, code, strip=True, synchronize=False, **kwds):
        """
        For Scheme, don't listen for prompt except for the last line
        Also, for MIT/GNU Scheme strip the ;Value:  part of results

        INPUT:
            code -- text to evaluate
            strip -- bool; whether to strip output prompts, etc.
                     (ignored in the base class).
            **kwds -- All other arguments are passed onto the _eval_line method.
                     An often useful example is reformat=False. 
        """
        if synchronize:
            try:
                self._synchronize()
            except AttributeError:
                pass

        if strip:
            try:
                code = self._strip_prompt(code)
            except AttributeError:
                pass

        if not isinstance(code, basestring):
            raise TypeError, 'input code must be a string.'

        #Remove extra whitespace
        code = code.strip()

        try:
            with gc_disabled():
                return self._strip_prompt(self._eval_line(code.replace('\n',' ').replace('\r',' '), **kwds))
        except KeyboardInterrupt:
            # DO NOT CATCH KeyboardInterrupt, as it is being caught
            # by _eval_line
            # In particular, do NOT call self._keyboard_interrupt()
            raise
        except TypeError, s:
            raise TypeError, 'error evaluating "%s":\n%s'%(code,s)

    def _strip_prompt(self, code):
        return code.strip().replace(';Value: ','')

    def _repr_(self):
        return 'MIT/GNU Scheme Interpreter'

    def __reduce__(self):
        return reduce_load_mitscheme, tuple([])
    
    def __getattr__(self, attrname):
        if attrname[:1] == "_":
            raise AttributeError
        return MitSchemeFunction(self, attrname)

    def _quit_string(self):
        return '(quite)'
    
    def _read_in_file_command(self, filename):
        raise NotImplementedError        

    def trait_names(self):
        ## [[implement giving a list of all functions and identifiers in the system]]
        raise NotImplementedError        
        
    def read(self, filename):
        # [[implement loading of the contents of filename into the system]]
        raise NotImplementedError        


    def kill(self, var):
        # [[send code that kills the variable with given name in the system.]]
        pass
        
    def console(self):
        # run the console command (defined below).
        mitscheme_console()

    def version(self):
        # run the version command (defined below)
        pass
    
    def _object_class(self):
        return MitSchemeElement

    def _left_list_delim(self):
        raise NotImplementedError

    def _right_list_delim(self):
        raise NotImplementedError

    def _assign_symbol(self):
        raise NotImplementedError

    def _true_symbol(self):
        # return the string rep of truth, i.e., what the system outputs
        # when you type 1==1.
        return '#t'

    def _false_symbol(self):
        # return the string rep of truth, i.e., what the system outputs
        # when you type 1==2.
        return '#f'
        
    def _equality_symbol(self):
        # return the symbol for checking equality, e.g., == or eq. 
        raise NotImplementedError

    def help(self, command):
        # return help on a given command. 
        raise NotImplementedError

    def set(self, var, value):
        """
        Set the variable var to the given value.
        """
        cmd = '(define %s %s)'%(var, value) 
        self.eval(cmd)

    def get(self, var):
        """
        Get the value of the variable var.
        """
        cmd = '%s'%var
        return self.eval(var)

    def function_call(self, function, args=[], kwds={}):
        """
        EXAMPLES:
            sage: maxima.quad_qags(x, x, 0, 1, epsrel=1e-4)
            [0.5,5.5511151231257...E-15,21,0]
            sage: maxima.function_call('quad_qags', [x, x, 0, 1], {'epsrel':'1e-4'})
            [0.5,5.5511151231257...E-15,21,0]
        """
        if function == '':
            raise ValueError, "function name must be nonempty"
        if function[:2] == "__":
            raise AttributeError
        if not isinstance(args, list):
            args = [args]
        for i in range(len(args)):
            if not isinstance(args[i], ExpectElement):
                args[i] = self.new(args[i])
        for key, value in kwds.iteritems():
            kwds[key] = self.new(value)

        return self.new("(%s %s)"%(function, " ".join([s.name() for s in args]+
                                                     ['%s'%(key,value.name()) for key, value in kwds.items()])))


class MitSchemeElement(ExpectElement):
    """
    Describe elements of your system here. 
    """
    def trait_names(self):
        # This is if your system doesn't really have types.  If you have types
        # this function should only return the relevant methods that take self
        # as their first argument. 
        return self.parent().trait_names()

    def __cmp__(self, other):
        P = self.parent()
        if P.eval("(eq? %s %s)"%(self.name(), other.name())) == P._true_symbol():
            return 0
        elif P.eval("(< %s %s)"%(self.name(), other.name())) == P._true_symbol():
            return -1
        elif P.eval("(> %s %s)"%(self.name(), other.name())) == P._true_symbol():
            return 1

        # everything is supposed to be comparable in Python, so we define
        # the comparison thus when no comparable in interfaced system.
        if (hash(self) < hash(other)):
            return -1
        else:
            return 1

    def hasattr(self, attrname):
        """
        Scheme things don't have attributes (unless SOS...)
        """
        raise NotImplementedError

    def attribute(self, attrname):
        """
        Scheme things don't have attributes (unless SOS...)
        """
        raise NotImplementedError

    def __getitem__(self, n):
        """
        Scheme things don't have attributes (unless SOS...)
        """
        raise NotImplementedError

    def bool(self):
        P = self.parent()
        t = P._true_symbol()
        cmd = '%s'%self._name
        return P.eval(cmd) == t

    def __nonzero__(self):
        """
        EXAMPLES:
            sage: bool(mitscheme('#t'))
            True
            sage: bool(mitscheme('#f'))
            False
        """
        P = self.parent()
        t = P._true_symbol()
        cmd = '(zero? %s)'%self._name
        return P.eval(cmd) == t

    def _operation(self, operation, right):
        P = self._check_valid()
        try:
            return P.new('(%s %s %s)'%(operation, self._name, right._name))
        except Exception, msg:
            raise TypeError, msg

    def __pow__(self, n):
        """
        EXAMPLES:
            sage: a = maxima('2')
            sage: a^(3/4)
            2^(3/4)
        """
        P = self._check_valid()
        if not hasattr(n, 'parent') or P is not n.parent():
            n = P(n)
        return self._operation("expt", n)


class MitSchemeFunctionElement(FunctionElement):
    def _sage_doc_(self):
        M = self._obj.parent()
        return M.help(self._name)
        
    
class MitSchemeFunction(ExpectFunction):
    def _sage_doc_(self):
        M = self._parent
        return M.help(self._name)


def is_MitSchemeElement(x):
    return isinstance(x, MitSchemeElement)

# An instance
mitscheme = MitScheme()

def reduce_load_MitScheme():
    return mitscheme

import os
def mitscheme_console():
    # This will only spawn local processes
    os.system('mitscheme')


def mitscheme_version():
    """
    UGH hard to implement
    """
    raise NotImplemented