import inspect
import copy
import itertools
import logging
from cle import SymbolType
from archinfo.arch_soot import SootAddressDescriptor

l = logging.getLogger(name=__name__)
symbolic_count = itertools.count()


class SimProcedure:
    """
    A SimProcedure is a wonderful object which describes a procedure to run on a state.

    You may subclass SimProcedure and override ``run()``, replacing it with mutating ``self.state`` however you like,
    and then either returning a value or jumping away somehow.

    A detailed discussion of programming SimProcedures may be found at https://docs.angr.io/extending-angr/simprocedures

    :param arch:            The architecture to use for this procedure

    The following parameters are optional:

    :param symbolic_return: Whether the procedure's return value should be stubbed into a
                            single symbolic variable constratined to the real return value
    :param returns:         Whether the procedure should return to its caller afterwards
    :param is_syscall:      Whether this procedure is a syscall
    :param num_args:        The number of arguments this procedure should extract
    :param display_name:    The name to use when displaying this procedure
    :param library_name:    The name of the library from which the function we're emulating comes
    :param cc:              The SimCC to use for this procedure
    :param sim_kwargs:      Additional keyword arguments to be passed to run()
    :param is_function:     Whether this procedure emulates a function

    The following class variables should be set if necessary when implementing a new SimProcedure:

    :cvar NO_RET:           Set this to true if control flow will never return from this function
    :cvar ADDS_EXITS:       Set this to true if you do any control flow other than returning
    :cvar IS_FUNCTION:      Does this procedure simulate a function? True by default
    :cvar ARGS_MISMATCH:    Does this procedure have a different list of arguments than what is provided in the
                            function specification? This may happen when we manually extract arguments in the run()
                            method of a SimProcedure. False by default.
    :cvar local_vars:       If you use ``self.call()``, set this to a list of all the local variable
                            names in your class. They will be restored on return.

    The following instance variables are available when working with simprocedures from the inside or the outside:

    :ivar project:          The associated angr project
    :ivar arch:             The associated architecture
    :ivar addr:             The linear address at which the procedure is executing
    :ivar cc:               The calling convention in use for engaging with the ABI
    :ivar canonical:        The canonical version of this SimProcedure. Procedures are deepcopied for many reasons,
                            including to be able to store state related to a specific run and to be able to hook
                            continuations.
    :ivar kwargs:           Any extra keyword arguments used to construct the procedure; will be passed to ``run``
    :ivar display_name:     See the eponymous parameter
    :ivar library_name:     See the eponymous parameter
    :ivar abi:
    :ivar symbolic_return:  See the eponymous parameter
    :ivar syscall_number:   If this procedure is a syscall, the number will be populated here.
    :ivar returns:          See eponymous parameter and NO_RET cvar
    :ivar is_syscall:       See eponymous parameter
    :ivar is_function:      See eponymous parameter and cvar
    :ivar is_stub:          See eponymous parameter
    :ivar is_continuation:  Whether this procedure is the original or a continuation resulting from ``self.call()``
    :ivar continuations:    A mapping from name to each known continuation
    :ivar run_func:         The name of the function implementing the procedure. "run" by default, but different in
                            continuations.
    :ivar num_args:         The number of arguments to the procedure. If not provided in the parameter, extracted from
                            the definition of ``self.run``

    The following instance variables are only used in a copy of the procedure that is actually executing on a state:

    :ivar state:            The SimState we should be mutating to perform the procedure
    :ivar successors:       The SimSuccessors associated with the current step
    :ivar arguments:        The function arguments, deserialized from the state
    :ivar use_state_arguments:
                            Whether we're using arguments extracted from the state or manually provided
    :ivar ret_to:           The current return address
    :ivar ret_expr:         The computed return value
    :ivar call_ret_expr:    The return value from having used ``self.call()``
    :ivar inhibit_autoret:  Whether we should avoid automatically adding an exit for returning once the run function
                            ends

    """
    def __init__(
        self, project=None, cc=None, symbolic_return=None,
        returns=None, is_syscall=False, is_stub=False,
        num_args=None, display_name=None, library_name=None,
        is_function=None, **kwargs
    ):
        # WE'LL FIGURE IT OUT
        self.project = project
        self.arch = project.arch if project is not None else None
        self.addr = None
        self.cc = cc
        self.canonical = self

        self.kwargs = kwargs
        self.display_name = type(self).__name__ if display_name is None else display_name
        self.library_name = library_name
        self.syscall_number = None
        self.abi = None
        self.symbolic_return = symbolic_return

        # set some properties about the type of procedure this is
        self.returns = returns if returns is not None else not self.NO_RET
        self.is_syscall = is_syscall
        self.is_function = is_function if is_function is not None else self.IS_FUNCTION
        self.is_stub = is_stub
        self.is_continuation = False
        self.continuations = {}
        self.run_func = 'run'

        # Get the concrete number of arguments that should be passed to this procedure
        if num_args is None:
            run_spec = inspect.getfullargspec(self.run)
            self.num_args = len(run_spec.args) - (len(run_spec.defaults) if run_spec.defaults is not None else 0) - 1
        else:
            self.num_args = num_args

        # runtime values
        self.state = None
        self.successors = None
        self.arguments = None
        self.use_state_arguments = True
        self.ret_to = None
        self.ret_expr = None
        self.call_ret_expr = None
        self.inhibit_autoret = None

    def __repr__(self):
        return "<SimProcedure %s%s%s%s%s>" % self._describe_me()

    def _describe_me(self):
        """
        return a 5-tuple of strings sufficient for formatting with ``%s%s%s%s%s`` to verbosely describe the procedure
        """
        return (
            self.display_name,
            ' (cont: %s)' % self.run_func if self.is_continuation else '',
            ' (syscall)' if self.is_syscall else '',
            ' (inline)' if not self.use_state_arguments else '',
            ' (stub)' if self.is_stub else '',
        )

    def execute(self, state, successors=None, arguments=None, ret_to=None):
        """
        Call this method with a SimState and a SimSuccessors to execute the procedure.

        Alternately, successors may be none if this is an inline call. In that case, you should
        provide arguments to the function.
        """
        # fill out all the fun stuff we don't want to frontload
        if self.addr is None and not state.regs.ip.symbolic:
            self.addr = state.addr
        if self.arch is None:
            self.arch = state.arch
        if self.project is None:
            self.project = state.project
        if self.cc is None:
            if self.arch.name in DEFAULT_CC:
                self.cc = DEFAULT_CC[self.arch.name](self.arch)
            else:
                raise SimProcedureError('There is no default calling convention for architecture %s.'
                                        ' You must specify a calling convention.' % self.arch.name)

        inst = copy.copy(self)
        inst.state = state
        inst.successors = successors
        inst.ret_to = ret_to
        inst.inhibit_autoret = False

        # check to see if this is a syscall and if we should override its return value
        if inst.is_syscall:
            state.history.recent_syscall_count = 1

        state._inspect(
            'simprocedure',
            BP_BEFORE,
            simprocedure_name=inst.display_name,
            simprocedure_addr=self.addr,
            simprocedure=inst,
            simprocedure_result=NO_OVERRIDE
        )

        r = state._inspect_getattr('simprocedure_result', NO_OVERRIDE)
        if r is NO_OVERRIDE:
            # get the arguments

            # If the simprocedure is related to a Java function call the appropriate setup_args methos
            # TODO: should we move this?
            if self.is_java:
                sim_args = self._setup_args(inst, state, arguments) #pylint:disable=assignment-from-no-return
                self.use_state_arguments = False

            # handle if this is a continuation from a return
            elif inst.is_continuation:
                if state.callstack.top.procedure_data is None:
                    raise SimProcedureError("Tried to return to a SimProcedure in an inapplicable stack frame!")

                saved_sp, sim_args, saved_local_vars, saved_lr, ideal_addr = state.callstack.top.procedure_data
                if ideal_addr != inst.addr:
                    raise SimShadowStackError("I can't emulate this consequence of stack smashing")
                state.regs.sp = saved_sp
                if saved_lr is not None:
                    state.regs.lr = saved_lr
                inst.arguments = sim_args
                inst.use_state_arguments = True
                inst.call_ret_expr = state.registers.load(state.arch.ret_offset, state.arch.bytes, endness=state.arch.register_endness)
                for name, val in saved_local_vars:
                    setattr(inst, name, val)
            else:
                if arguments is None:
                    inst.use_state_arguments = True
                    sim_args = [ inst.arg(_) for _ in range(inst.num_args) ]
                    inst.arguments = sim_args
                else:
                    inst.use_state_arguments = False
                    sim_args = arguments[:inst.num_args]
                    inst.arguments = arguments

            # run it
            l.debug("Executing %s%s%s%s%s with %s, %s", *(inst._describe_me() + (sim_args, inst.kwargs)))
            r = getattr(inst, inst.run_func)(*sim_args, **inst.kwargs)

        state._inspect(
            'simprocedure',
            BP_AFTER,
            simprocedure_result=r
        )
        r = state._inspect_getattr('simprocedure_result', r)

        if inst.returns and inst.is_function and not inst.inhibit_autoret:
            inst.ret(r)

        return inst

    def make_continuation(self, name):
        # make a copy of the canon copy, customize it for the specific continuation, then hook it
        if name not in self.canonical.continuations:
            cont = copy.copy(self.canonical)
            target_name = '%s.%s' % (self.display_name, name)
            should_be_none = self.project.loader.extern_object.get_symbol(target_name)
            if should_be_none is None:
                cont.addr = self.project.loader.extern_object.make_extern(target_name, sym_type=SymbolType.TYPE_OTHER).rebased_addr
            else:
                l.error("Trying to make continuation %s but it already exists. This is bad.", target_name)
                cont.addr = self.project.loader.extern_object.allocate()
            cont.is_continuation = True
            cont.run_func = name
            self.canonical.continuations[name] = cont
            self.project.hook(cont.addr, cont)
        return self.canonical.continuations[name].addr

    #
    # Implement these in a subclass of SimProcedure!
    #

    NO_RET = False
    ADDS_EXITS = False
    IS_FUNCTION = True
    ARGS_MISMATCH = False
    ALT_NAMES = None  # alternative names
    local_vars = ()

    def run(self, *args, **kwargs): # pylint: disable=unused-argument
        """
        Implement the actual procedure here!
        """
        raise SimProcedureError("%s does not implement a run() method" % self.__class__.__name__)

    def static_exits(self, blocks):  # pylint: disable=unused-argument
        """
        Get new exits by performing static analysis and heuristics. This is a fast and best-effort approach to get new
        exits for scenarios where states are not available (e.g. when building a fast CFG).

        :param list blocks: Blocks that are executed before reaching this SimProcedure.
        :return: A list of dicts. Each dict should contain the following entries: 'address', 'jumpkind', and 'namehint'.
        :rtype: list
        """

        if self.ADDS_EXITS:
            raise SimProcedureError("static_exits() is not implemented for %s" % self)

        # This SimProcedure does not add any new exit
        return []

    #
    # misc properties
    #

    @property
    def should_add_successors(self):
        return self.successors is not None

    #
    # Working with calling conventions
    #

    def _setup_args(self, inst, state, args): #pylint:disable=unused-argument,no-self-use
        raise SimProcedureError("the java-specific _setup_args() method was invoked on a non-Java SimProcedure.")
    def _compute_ret_addr(self, expr): #pylint:disable=unused-argument,no-self-use
        raise SimProcedureError("the java-specific _compute_ret_addr() method was invoked on a non-Java SimProcedure.")

    def set_args(self, args):
        arg_session = self.cc.arg_session
        for arg in args:
            if self.cc.is_fp_value(args):
                arg_session.next_arg(True).set_value(self.state, arg)
            else:
                arg_session.next_arg(False).set_value(self.state, arg)

    def arg(self, i):
        """
        Returns the ith argument. Raise a SimProcedureArgumentError if we don't have such an argument available.

        :param int i: The index of the argument to get
        :return: The argument
        :rtype: object
        """
        if self.use_state_arguments:
            r = self.cc.arg(self.state, i)
        else:
            if i >= len(self.arguments):
                raise SimProcedureArgumentError("Argument %d does not exist." % i)
            r = self.arguments[i]           # pylint: disable=unsubscriptable-object

        l.debug("returning argument")
        return r

    #
    # Control Flow
    #

    def inline_call(self, procedure, *arguments, **kwargs):
        """
        Call another SimProcedure in-line to retrieve its return value.
        Returns an instance of the procedure with the ret_expr property set.

        :param procedure:       The class of the procedure to execute
        :param arguments:       Any additional positional args will be used as arguments to the
                                procedure call
        :param sim_kwargs:      Any additional keyword args will be passed as sim_kwargs to the
                                procedure construtor
        """
        e_args = [ self.state.solver.BVV(a, self.state.arch.bits) if isinstance(a, int) else a for a in arguments ]
        p = procedure(project=self.project, **kwargs)
        return p.execute(self.state, None, arguments=e_args)

    def ret(self, expr=None):
        """
        Add an exit representing a return from this function.
        If this is not an inline call, grab a return address from the state and jump to it.
        If this is not an inline call, set a return expression with the calling convention.
        """
        self.inhibit_autoret = True

        if expr is not None:
            if o.SIMPLIFY_RETS in self.state.options:
                l.debug("... simplifying")
                l.debug("... before: %s", expr)
                expr = self.state.solver.simplify(expr)
                l.debug("... after: %s", expr)

            if self.symbolic_return:
                size = len(expr)
                new_expr = self.state.solver.Unconstrained(
                        "symbolic_return_" + self.display_name,
                        size,
                        key=('symbolic_return', self.display_name)) #pylint:disable=maybe-no-member
                self.state.add_constraints(new_expr == expr)
                expr = new_expr

            self.ret_expr = expr

        ret_addr = None
        # TODO: I had to put this check here because I don't understand why self.use_state_arguments gets reset to true
        # when calling the function ret. at the calling point the attribute is set to False
        if isinstance(self.addr, SootAddressDescriptor):
            ret_addr = self._compute_ret_addr(expr) #pylint:disable=assignment-from-no-return
        elif self.use_state_arguments:
            ret_addr = self.cc.teardown_callsite(
                    self.state,
                    expr,
                    arg_types=[False]*self.num_args if self.cc.args is None else None)

        if not self.should_add_successors:
            l.debug("Returning without setting exits due to 'internal' call.")
            return

        if self.ret_to is not None:
            ret_addr = self.ret_to

        if ret_addr is None:
            raise SimProcedureError("No source for return address in ret() call!")

        self._prepare_ret_state()

        self._exit_action(self.state, ret_addr)
        self.successors.add_successor(self.state, ret_addr, self.state.solver.true, 'Ijk_Ret')


    def call(self, addr, args, continue_at, cc=None):
        """
        Add an exit representing calling another function via pointer.

        :param addr:        The address of the function to call
        :param args:        The list of arguments to call the function with
        :param continue_at: Later, when the called function returns, execution of the current
                            procedure will continue in the named method.
        :param cc:          Optional: use this calling convention for calling the new function.
                            Default is to use the current convention.
        """
        self.inhibit_autoret = True

        if cc is None:
            cc = self.cc

        call_state = self.state.copy()
        ret_addr = self.make_continuation(continue_at)
        saved_local_vars = list(zip(self.local_vars, map(lambda name: getattr(self, name), self.local_vars)))
        simcallstack_entry = (self.state.regs.sp if hasattr(self.state.regs, "sp") else None,
                              self.arguments,
                              saved_local_vars,
                              self.state.regs.lr if self.state.arch.lr_offset is not None else None,
                              ret_addr)
        cc.setup_callsite(call_state, ret_addr, args)
        call_state.callstack.top.procedure_data = simcallstack_entry

        # TODO: Move this to setup_callsite?
        if isinstance(call_state.addr, SootAddressDescriptor):
            pass
        elif call_state.libc.ppc64_abiv == 'ppc64_1':
            call_state.regs.r2 = self.state.mem[addr + 8:].long.resolved
            addr = call_state.mem[addr:].long.resolved
        elif call_state.arch.name in ('MIPS32', 'MIPS64'):
            call_state.regs.t9 = addr

        self._exit_action(call_state, addr)
        self.successors.add_successor(call_state, addr, call_state.solver.true, 'Ijk_Call')

        if o.DO_RET_EMULATION in self.state.options:
            # we need to set up the call because the continuation will try to tear it down
            ret_state = self.state.copy()
            cc.setup_callsite(ret_state, ret_addr, args)
            ret_state.callstack.top.procedure_data = simcallstack_entry
            guard = ret_state.solver.true if o.TRUE_RET_EMULATION_GUARD in ret_state.options else ret_state.solver.false
            self.successors.add_successor(ret_state, ret_addr, guard, 'Ijk_FakeRet')

    def jump(self, addr):
        """
        Add an exit representing jumping to an address.
        """
        self.inhibit_autoret = True
        self._exit_action(self.state, addr)
        self.successors.add_successor(self.state, addr, self.state.solver.true, 'Ijk_Boring')

    def exit(self, exit_code):
        """
        Add an exit representing terminating the program.
        """
        self.inhibit_autoret = True
        self.state.options.discard(o.AST_DEPS)
        self.state.options.discard(o.AUTO_REFS)

        if isinstance(exit_code, int):
            exit_code = self.state.solver.BVV(exit_code, self.state.arch.bits)
        self.state.history.add_event('terminate', exit_code=exit_code)
        self.successors.add_successor(self.state, self.state.regs.ip, self.state.solver.true, 'Ijk_Exit')

    @staticmethod
    def _exit_action(state, addr):
        if o.TRACK_JMP_ACTIONS in state.options:
            state.history.add_action(SimActionExit(state, addr))

    #
    # misc
    #

    def ty_ptr(self, ty):
        return SimTypePointer(self.arch, ty)

    @property
    def is_java(self):
        return False

    def _prepare_ret_state(self):
        pass

    @property
    def argument_types(self):  # pylint: disable=no-self-use
        return None

    @argument_types.setter
    def argument_types(self, v):  # pylint: disable=unused-argument,no-self-use
        l.critical("SimProcedure.argument_types is deprecated. specify the function signature in the cc")

    @property
    def return_type(self):  # pylint: disable=no-self-use
        return None

    @return_type.setter
    def return_type(self, v):  # pylint: disable=unused-argument,no-self-use
        l.critical("SimProcedure.return_type is deprecated. specify the function signature in the cc")


from . import sim_options as o
from angr.errors import SimProcedureError, SimProcedureArgumentError, SimShadowStackError
from angr.sim_type import SimTypePointer
from angr.state_plugins.sim_action import SimActionExit
from angr.calling_conventions import DEFAULT_CC
from .state_plugins import BP_AFTER, BP_BEFORE, NO_OVERRIDE
