#
# Copyright (c) 2009- Spyder Kernels Contributors
#
# Licensed under the terms of the MIT License
# (see spyder_kernels/__init__.py for details)

"""Spyder debugger."""

import bdb
import pdb
import sys
import logging
import traceback
from collections import namedtuple

from IPython.core.getipython import get_ipython
from IPython.core.debugger import Pdb as ipyPdb

from spyder_kernels.comms.frontendcomm import CommError, frontend_request
from spyder_kernels.customize.utils import path_is_library
from spyder_kernels.py3compat import TimeoutError, PY2, _print, isidentifier

if not PY2:
    from IPython.core.inputtransformer2 import TransformerManager
    basestring = (str,)
else:
    from IPython.core.inputsplitter import IPythonInputSplitter as TransformerManager


logger = logging.getLogger(__name__)


class SpyderPdb(ipyPdb, object):  # Inherits `object` to call super() in PY2
    """
    Extends Pdb to add features:

     - Process IPython magics.
     - Accepts multiline input.
     - Better interrupt signal handling.
     - Option to skip libraries while stepping.
     - Add completion to non-command code.
    """

    send_initial_notification = True
    starting = True

    def __init__(self, completekey='tab', stdin=None, stdout=None,
                 skip=None, nosigint=False):
        """Init Pdb."""
        self.curframe_locals = None
        # Only set to true when calling debugfile
        self.continue_if_has_breakpoints = False
        self.pdb_ignore_lib = False
        self.pdb_execute_events = False
        super(SpyderPdb, self).__init__()
        self._pdb_breaking = False

    # --- Methods overriden for code execution
    def default(self, line):
        """
        Default way of running pdb statment.

        The only difference with Pdb.default is that if line contains multiple
        statments, the code will be compiled with 'exec'. It will not print the
        result but will run without failing.
        """
        execute_events = self.pdb_execute_events
        if line[:1] == '!':
            line = line[1:]
        locals = self.curframe_locals
        globals = self.curframe.f_globals
        try:
            line = TransformerManager().transform_cell(line)
            try:
                code = compile(line + '\n', '<stdin>', 'single')
            except SyntaxError:
                # support multiline statments
                code = compile(line + '\n', '<stdin>', 'exec')
            save_stdout = sys.stdout
            save_stdin = sys.stdin
            save_displayhook = sys.displayhook
            try:
                sys.stdin = self.stdin
                sys.stdout = self.stdout
                sys.displayhook = self.displayhook
                if execute_events:
                     get_ipython().events.trigger('pre_execute')
                exec(code, globals, locals)
                if execute_events:
                     get_ipython().events.trigger('post_execute')
            finally:
                sys.stdout = save_stdout
                sys.stdin = save_stdin
                sys.displayhook = save_displayhook
        except BaseException:
            if PY2:
                t, v = sys.exc_info()[:2]
                if type(t) == type(''):
                    exc_type_name = t
                else: exc_type_name = t.__name__
                print >>self.stdout, '***', exc_type_name + ':', v
            else:
                exc_info = sys.exc_info()[:2]
                self.error(
                    traceback.format_exception_only(*exc_info)[-1].strip())

    # --- Methods overriden for signal handling
    def sigint_handler(self, signum, frame):
        """
        Handle a sigint signal. Break on the frame above this one.

        This method is not present in python2 so this won't be called there.
        """
        if self.allow_kbdint:
            raise KeyboardInterrupt
        self.message("\nProgram interrupted. (Use 'cont' to resume).")
        # avoid stopping in set_trace
        sys.settrace(None)
        self._pdb_breaking = True
        self.set_step()
        self.set_trace(sys._getframe())

    def interaction(self, frame, traceback):
        """
        Called when a user interaction is required.

        If this is from sigint, break on the upper frame.
        If the frame is in spydercustomize.py, quit.
        Notifies spyder and print current code.

        """
        if self._pdb_breaking:
            self._pdb_breaking = False
            if frame and frame.f_back:
                return self.interaction(frame.f_back, traceback)
        if (frame is not None
                and "spydercustomize.py" in frame.f_code.co_filename
                and "exec_code" == frame.f_code.co_name):
            self.onecmd('exit')
        else:
            self.setup(frame, traceback)
            if self.send_initial_notification:
                self.notify_spyder(frame)
            if get_ipython().kernel._pdb_print_code:
                self.print_stack_entry(self.stack[self.curindex])
            self._cmdloop()
            self.forget()

    # --- Methods overriden for skipping libraries
    def stop_here(self, frame):
        """Check if pdb should stop here."""
        if not super(SpyderPdb, self).stop_here(frame):
            return False
        filename = frame.f_code.co_filename
        if filename.startswith('<'):
            # This is not a file
            return True
        if self.pdb_ignore_lib and path_is_library(filename):
            return False
        return True

    # --- Method defined by us to respond to ipython complete protocol
    def do_complete(self, code, cursor_pos):
        """
        Respond to a complete request.
        """
        if cursor_pos is None:
            cursor_pos = len(code)

        # Get text to complete
        text = code[:cursor_pos].split(' ')[-1]
        # Choose Pdb function to complete, based on cmd.py
        origline = code
        line = origline.lstrip()
        if not line:
            # Nothing to complete
            return
        stripped = len(origline) - len(line)
        begidx = cursor_pos - len(text) - stripped
        endidx = cursor_pos - stripped

        compfunc = None
        ipython_do_complete = True
        if begidx > 0:
            # This could be after a Pdb command
            cmd, args, _ = self.parseline(line)
            if cmd != '':
                try:
                    # Function to complete Pdb command arguments
                    compfunc = getattr(self, 'complete_' + cmd)
                    # Don't call ipython do_complete for commands
                    ipython_do_complete = False
                except AttributeError:
                    pass
        elif line[0] != '!':
            # This could be a Pdb command
            compfunc = self.completenames

        def is_name_or_composed(text):
            if not text or text[0] == '.':
                return False
            # We want to keep value.subvalue
            return isidentifier(text.replace('.', ''))

        while text and not is_name_or_composed(text):
            text = text[1:]
            begidx += 1

        matches = []
        if compfunc:
            matches = compfunc(text, line, begidx, endidx)

        cursor_start = cursor_pos - len(text)

        if ipython_do_complete:
            kernel = get_ipython().kernel
            # Make complete call with current frame
            if self.curframe:
                if self.curframe_locals:
                    Frame = namedtuple("Frame", ["f_locals", "f_globals"])
                    frame = Frame(self.curframe_locals,
                                  self.curframe.f_globals)
                else:
                    frame = self.curframe
                kernel.shell.set_completer_frame(frame)
            result = kernel._do_complete(code, cursor_pos)
            # Reset frame
            kernel.shell.set_completer_frame()
            # If there is no Pdb results to merge, return the result
            if not compfunc:
                return result

            ipy_matches = result['matches']
            # Make sure both match lists start at the same place
            if cursor_start < result['cursor_start']:
                # Fill IPython matches
                missing_txt = code[cursor_start:result['cursor_start']]
                ipy_matches = [missing_txt + m for m in ipy_matches]
            elif result['cursor_start'] < cursor_start:
                # Fill Pdb matches
                missing_txt = code[result['cursor_start']:cursor_start]
                matches = [missing_txt + m for m in matches]
                cursor_start = result['cursor_start']

            # Add Pdb-specific matches
            matches += [match for match in ipy_matches if match not in matches]

        return {'matches': matches,
                'cursor_end': cursor_pos,
                'cursor_start': cursor_start,
                'metadata': {},
                'status': 'ok'}

    # --- Methods overriden by us for Spyder integration
    def preloop(self):
        """Ask Spyder for breakpoints before the first prompt is created."""
        try:
            frontend_request(blocking=True).set_debug_state(True)
            pdb_settings = frontend_request().get_pdb_settings()
            self.pdb_ignore_lib = pdb_settings['pdb_ignore_lib']
            self.pdb_execute_events = pdb_settings['pdb_execute_events']
            if self.starting:
                self.set_spyder_breakpoints(pdb_settings['breakpoints'])
        except (CommError, TimeoutError):
            logger.debug("Could not get breakpoints from the frontend.")

    def postloop(self):
        """Notifies spyder that the loop has ended."""
        try:
            frontend_request(blocking=True).set_debug_state(False)
        except (CommError, TimeoutError):
            logger.debug("Could not send debugging state to the frontend.")
        super(SpyderPdb, self).postloop()

    def set_continue(self):
        """
        Stop only at breakpoints or when finished.

        Reimplemented to avoid stepping out of debugging if there are no
        breakpoints. We could add more later.
        """
        # Don't stop except at breakpoints or when finished
        self._set_stopinfo(self.botframe, None, -1)

    def reset(self):
        """
        Register Pdb session after reset.
        """
        super(SpyderPdb, self).reset()
        kernel = get_ipython().kernel
        kernel._register_pdb_session(self)

    def user_return(self, frame, return_value):
        """This function is called when a return trap is set here."""
        # This is useful when debugging in an active interpreter (otherwise,
        # the debugger will stop before reaching the target file)
        if self._wait_for_mainpyfile:
            if (self.mainpyfile != self.canonic(frame.f_code.co_filename)
                    or frame.f_lineno <= 0):
                return
            self._wait_for_mainpyfile = 0
        super(SpyderPdb, self).user_return(frame, return_value)

    def _cmdloop(self):
        """Modifies the error text."""
        while True:
            try:
                # keyboard interrupts allow for an easy way to cancel
                # the current command, so allow them during interactive input
                self.allow_kbdint = True
                self.cmdloop()
                self.allow_kbdint = False
                break
            except KeyboardInterrupt:
                _print("--KeyboardInterrupt--\n"
                       "For copying text while debugging, use Ctrl+Shift+C",
                       file=self.stdout)

    def postcmd(self, stop, line):
        """
        Notify spyder on any pdb command.

        Is that good or too lazy? i.e. is more specific behaviour desired?
        """
        if '!get_ipython().kernel' not in line:
            self.notify_spyder(self.curframe)
        return super(SpyderPdb, self).postcmd(stop, line)

    if PY2:
        def break_here(self, frame):
            """
            Breakpoints don't work for files with non-ascii chars in Python 2

            Fixes Issue 1484
            """
            from bdb import effective
            filename = self.canonic(frame.f_code.co_filename)
            try:
                filename = unicode(filename, "utf-8")
            except TypeError:
                pass
            if filename not in self.breaks:
                return False
            lineno = frame.f_lineno
            if lineno not in self.breaks[filename]:
                # The line itself has no breakpoint, but maybe the line is the
                # first line of a function with breakpoint set by function name
                lineno = frame.f_code.co_firstlineno
                if lineno not in self.breaks[filename]:
                    return False

            # flag says ok to delete temp. bp
            (bp, flag) = effective(filename, lineno, frame)
            if bp:
                self.currentbp = bp.number
                if (flag and bp.temporary):
                    self.do_clear(str(bp.number))
                return True
            else:
                return False

    # --- Methods defined by us for Spyder integration
    def set_spyder_breakpoints(self, breakpoints):
        """Set Spyder breakpoints."""
        self.clear_all_breaks()
        # -----Really deleting all breakpoints:
        for bp in bdb.Breakpoint.bpbynumber:
            if bp:
                bp.deleteMe()
        bdb.Breakpoint.next = 1
        bdb.Breakpoint.bplist = {}
        bdb.Breakpoint.bpbynumber = [None]
        # -----
        i = 0
        for fname, data in list(breakpoints.items()):
            for linenumber, condition in data:
                i += 1
                self.set_break(self.canonic(fname), linenumber,
                               cond=condition)

        # Jump to first breakpoint.
        # Fixes issue 2034
        if self.starting:
            # Only run this after a Pdb session is created
            self.starting = False

            # Get all breakpoints for the file we're going to debug
            frame = self.curframe
            if not frame:
                # We are not debugging, return. Solves #10290
                return
            lineno = frame.f_lineno
            breaks = self.get_file_breaks(frame.f_code.co_filename)

            # Do 'continue' if the first breakpoint is *not* placed
            # where the debugger is going to land.
            # Fixes issue 4681
            if (self.continue_if_has_breakpoints and
                    breaks and
                    lineno < breaks[0]):
                try:
                    get_ipython().kernel.pdb_continue()
                except (CommError, TimeoutError):
                    logger.debug(
                        "Could not send a Pdb continue call to the frontend.")

    def notify_spyder(self, frame=None):
        """Send kernel state to the frontend."""
        if frame is None:
            frame = self.curframe

        if frame is None:
            return

        kernel = get_ipython().kernel

        # Get filename and line number of the current frame
        fname = self.canonic(frame.f_code.co_filename)
        if PY2:
            try:
                fname = unicode(fname, "utf-8")
            except TypeError:
                pass
        lineno = frame.f_lineno

        # Set step of the current frame (if any)
        step = {}
        if isinstance(fname, basestring) and isinstance(lineno, int):
            step = dict(fname=fname, lineno=lineno)

        # Publish Pdb state so we can update the Variable Explorer
        # and the Editor on the Spyder side
        kernel._pdb_step = step
        try:
            kernel.publish_pdb_state()
        except (CommError, TimeoutError):
            logger.debug("Could not send Pdb state to the frontend.")
