# logexceptions.py - Write files containing info about Mercurial exceptions
#
# Copyright 2017 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import inspect
import os
import sys
import traceback
import uuid

from edenscm.mercurial import dispatch, extensions


def handleexception(orig, ui):
    res = orig(ui)

    if not ui.environ.get(b"HGEXCEPTIONSDIR"):
        return res

    dest = os.path.join(
        ui.environ[b"HGEXCEPTIONSDIR"], str(uuid.uuid4()).encode("ascii")
    )

    exc_type, exc_value, exc_tb = sys.exc_info()

    stack = []
    tb = exc_tb
    while tb:
        stack.append(tb)
        tb = tb.tb_next
    stack.reverse()

    hgframe = "unknown"
    hgline = "unknown"

    # Find the first Mercurial frame in the stack.
    for tb in stack:
        mod = inspect.getmodule(tb)
        if not mod.__name__.startswith(("hg", "mercurial")):
            continue

        frame = tb.tb_frame

        try:
            with open(inspect.getsourcefile(tb), "r") as fh:
                hgline = fh.readlines()[frame.f_lineno - 1].strip()
        except (IndexError, OSError):
            pass

        hgframe = "%s:%d" % (frame.f_code.co_filename, frame.f_lineno)
        break

    primary = traceback.extract_tb(exc_tb)[-1]
    primaryframe = "%s:%d" % (primary.filename, primary.lineno)

    with open(dest, "wb") as fh:
        parts = [str(exc_value), primaryframe, hgframe, hgline]
        fh.write(b"\0".join(p.encode("utf-8", "replace") for p in parts))


def extsetup(ui):
    extensions.wrapfunction(dispatch, "handlecommandexception", handleexception)