# SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
# SPDX-FileCopyrightText: 2021-2022 Harald Sitter <sitter@kde.org>

import os
import sys

sys.path.append(f'{os.path.dirname(os.path.dirname(os.path.abspath(__file__)))}/')

# Initialize sentry reports for exceptions in this script
# NOTE: this happens before other imports so we get reports when we have systems with missing deps
try:
    import sentry_sdk
    sentry_sdk.init(
        dsn="https://d6d53bb0121041dd97f59e29051a1781@crash-reports.kde.org/13",
        traces_sample_rate=1.0,
        release="drkonqi@" + os.getenv('DRKONQI_VERSION'),
        dist=os.getenv('DRKONQI_DISTRIBUTION'),
        ignore_errors=[KeyboardInterrupt],
        # Shutdown performance doesn't matter all that much, give us ample time to send a possible report instead.
        shutdown_timeout=30,
    )
except ImportError:
    print("python sentry-sdk not installed :(")

os.environ['LC_ALL'] = 'C.UTF-8'

import gdb
from gdb.FrameDecorator import FrameDecorator

from datetime import datetime, timezone
import uuid
import json
import subprocess
import signal
import re
import binascii
import platform
import multiprocessing
from pathlib import Path
import psutil
import traceback

crashed_thread = None
core_images = []

class UnexpectedMappingException(Exception):
    pass

class NoBuildIdException(Exception):
    pass

class DeletedMappingException(Exception):
    pass

def mangle_path(path):
    if not path:
        return path
    return re.sub(str(Path.home()), "$HOME", path, count=1)

class SentryVariablesStatistics:
    # All seen frames
    frames_count: int = 1 # we divide by this, it had better be >0
    # Amount of frames that had local variables
    frames_with_vars: int = 0

    # Only ever consider frames in the crashing thread!
    # The other threads are 99% of the time not interesting.

    def increment_frames():
        if gdb.selected_thread() and gdb.selected_thread() == crashed_thread:
            SentryVariablesStatistics.frames_count = SentryVariablesStatistics.frames_count + 1

    def increment_vars():
        if gdb.selected_thread() and gdb.selected_thread() == crashed_thread:
            SentryVariablesStatistics.frames_with_vars = SentryVariablesStatistics.frames_with_vars + 1

    def vars_rate():
        return round(SentryVariablesStatistics.frames_with_vars / SentryVariablesStatistics.frames_count, 2)

# Only grabing the most local block, technically we could also gather up encompassing scopes but it may be a bit much.
class SentryVariables:
    def __init__(self, frame):
        self.frame = frame
        SentryVariablesStatistics.increment_frames()

    def block(self):
        try:
            return self.frame.block()
        except:
            return None

    def to_dict(self):
        ret = self._to_dict_internal()
        if len(ret) > 0:
            SentryVariablesStatistics.increment_vars()
        return ret

    def _to_dict_internal(self):
        ret = {}
        block = self.block()
        if not block:
            return ret

        for symbol in block:
            try:
                ret[str(symbol)] = str(symbol.value(self.frame))
            except:
                pass # either not a variable or not stringable

        return ret

class SentryFrame:
    def __init__(self, gdb_frame):
        self.frame = gdb_frame
        self.sal = gdb_frame.find_sal()

    def type(self):
        return self.frame.type()

    def filename(self):
        return self.sal.symtab.fullname() if (self.sal and self.sal.symtab) else None

    def lineNumber(self):
        if self.sal.line < 0:
            return None
        # NOTE "The line number of the call, starting at 1." - I'm almost sure gdb starts at 0, so add 1
        return self.sal.line + 1

    def function(self):
        return self.frame.name() or self.frame.function() or None

    def package(self):
        name = gdb.solib_name(self.frame.pc())
        if not name:
            return name
        # NOTE: realpath because neon's gdb is confused over UsrMerge symlinking of /lib to /usr/lib messing up
        # path consistency (mapping data and by extension SentryImage instances use the real path already though
        return os.path.realpath(name)

    def address(self):
        return ('0x%x' % self.frame.pc())

    def to_dict(self, with_vars):
        data = {
            'filename': mangle_path(self.filename()),
            'function': self.function(),
            'package': mangle_path(self.package()),
            'instruction_addr': self.address(),
            'lineno': self.lineNumber(),
        }
        if with_vars:
            data['vars'] = SentryVariables(self.frame).to_dict()
        return data

class SentryRegisters:
    def __init__(self, gdb_frame):
        self.frame = gdb_frame

    def to_dict(self):
        js = {}
        try: # registers() is only available in somewhat new gdbs. (e.g. not ubuntu 20.04)
            for register in self.frame.architecture().registers():
                if register.startswith('ymm'): # ymm actually contains stuff sentry cannot handle. alas :(
                    continue
                value = self.frame.read_register(register).format_string(format='x')
                if value: # may be empty if the value cannot be expressed as hex (happens for extra gdb register magic - 'ymm0' etc)
                    js[register.name] = value
                else:
                    js[register.name] = "0x0"
        except AttributeError:
            return None
        return js

class LockReason:
    def __init__(self, frame: SentryFrame, type, class_name):
        self.type = type
        self.class_name = class_name
        self.thread_id = gdb.selected_thread().ptid[1]

    def to_dict(self):
        return {
            'type': self.type,
            'class_name': self.class_name,
            'thread_id': self.thread_id,
            'package_name': 'java.lang',
        }

    def make(frame):
        # export enum LockType {
        #   LOCKED = 1,
        #   WAITING = 2,
        #   SLEEPING = 4,
        #   BLOCKED = 8,
        # }
        func = frame.function()
        match func:
            case 'QtLinuxFutex::_q_futex':
                return LockReason(frame, 8, 'QtLinuxFutex')
            case ('___pthread_cond_wait', 'pthread_cond_wait'):
                return LockReason(frame, 2, 'pthread_cond_wait')
            case 'QWaitCondition::wait':
                return LockReason(frame, 2, 'QWaitCondition')
        return None

class SentryTrace:
    loaded_solibs = []

    def __init__(self, thread, is_crashed):
        thread.switch()
        self.thread = thread
        self.is_crashed = is_crashed
        self.lock_reasons = {}
        self.was_main_thread = False
        self.crashed = self.is_crashed # different from is_crashed (=input) this indicates if we stumbled over the kcrash handler

    def load_solib(thread, cramped): # NOTE: we pull thread into scope for its diagnostic value
        # Lazy load solibs. This is super complicated because the gdb CLI and API don't actually give us all the control.
        # Also loading new symbols resets the trace so we need to select-frames fairly aggressively.

        i = -1

        while True:
            # Check if the next frame even exists
            if i >= 0:
                gdb.execute(f'select-frame {i}')
                if not gdb.selected_frame().older():
                    break

            # Increment in the beginning so we can `continue` early without having to worry that the index will be off
            i = i + 1

            # Select the actual frame for loading
            gdb.execute(f'select-frame {i}')
            frame = gdb.selected_frame()

            pc = frame.pc()

            # Determine the solib path
            solib = gdb.current_progspace().solib_name(pc)
            if solib in SentryTrace.loaded_solibs:
                continue
            image = None
            for core_image in core_images:
                if int(core_image.address, 16) <= pc < (int(core_image.address, 16) + core_image.length):
                    image = core_image
                    break
            if not solib and not image:
                raise UnexpectedMappingException(f"No solib and no image found for frame #{i} on thread {thread}! You could try with debug symbols downloading enabled.")
            if not image:
                raise UnexpectedMappingException(f"No image found for frame #{i} on thread {thread}!")
            solib = solib or image.file

            if solib in SentryTrace.loaded_solibs:
                continue

            # Actually execute the load
            gdb.execute(f'sharedlibrary {solib}')
            # Make sure we loaded the correct solib (guards against live system updates having removed the correct file)
            objfile = gdb.lookup_objfile(image.build_id, by_build_id=True)
            if objfile.build_id != image.build_id:
                raise UnexpectedMappingException(f"Unexpected mapping for {image.file} ({image.build_id})")
            if cramped:
                # Explicit off in cramped mode even when the user enabled it.
                gdb.execute('set debuginfod enabled off')
            else:
                # (Re)load the symbols
                gdb.execute(f'add-symbol-file {solib}')

            if 'sentry_sdk' in globals():
                sentry_sdk.add_breadcrumb(
                    category='debug',
                    level='debug',
                    message=f'Loaded solib {solib}',
                )
            SentryTrace.loaded_solibs.append(solib)

        gdb.execute('select-frame 0')

    def to_dict(self):
        cramped_memory = os.getenv('DRKONQI_MEMORY') == 'cramped' and self.is_crashed
        little_memory = os.getenv('DRKONQI_MEMORY') == 'little' and self.is_crashed
        some_memory = os.getenv('DRKONQI_MEMORY') == 'some'
        spacious_memory = os.getenv('DRKONQI_MEMORY') == 'spacious'
        # In spacious mode we load all solibs by default and don't need to do anything extra. All other modes load on-demand.
        if cramped_memory or little_memory or some_memory:
            SentryTrace.load_solib(self.thread, cramped_memory)

        frames = [ SentryFrame(frame) for frame in gdb.FrameIterator.FrameIterator(gdb.newest_frame()) ]

        self.lock_reasons = {}
        self.was_main_thread = False

        kcrash_index = -1
        trap_index = -1
        for index, frame in enumerate(frames):
            if frame.function():
                lock_reason = LockReason.make(frame)
                if lock_reason:
                    r = lock_reason.to_dict()
                    address = f'0x{str(len(self.lock_reasons.keys()))}'
                    r['address'] = address
                    self.lock_reasons[address] = r
                if frame.function().startswith('KCrash::defaultCrashHandler'):
                    kcrash_index = index
                    self.crashed = True
                if frame.function().startswith('QCoreApplication::exec'):
                    self.was_main_thread = True
            if frame.type() == gdb.SIGTRAMP_FRAME:
                trap_index = index
        clip_index = max(kcrash_index, trap_index)

        # Throw away kcrash or sigtrap frame, and above. They are useless noise - but only when on the crashing thread.
        if self.is_crashed and clip_index > -1:
            frames = frames[(clip_index + 1):]

        # Sentry format wants oldest frame first.
        frames.reverse()
        data = { 'frames': [ frame.to_dict(with_vars=(some_memory or spacious_memory)) for frame in frames ] }
        if some_memory or spacious_memory:
            data['registers'] = SentryRegisters(gdb.newest_frame()).to_dict()
        return data

class SentryThread:
    def __init__(self, gdb_thread, is_crashed):
        self.thread = gdb_thread
        self.is_crashed = is_crashed

    def to_dict(self):
        # https://develop.sentry.dev/sdk/event-payloads/threads/
        # As per Sentry policy, the thread that crashed with an exception should not have a stack trace,
        #  but instead, the thread_id attribute should be set on the exception and Sentry will connect the two.
        trace = SentryTrace(self.thread, self.is_crashed)
        # NB: trace.to_dict creates members as side effect, run it asap
        payload = {
            'stacktrace': trace.to_dict(),
            'id': self.thread.ptid[1],
            'name': self.thread.name,
            'current': self.is_crashed,
            'crashed': trace.crashed, # side effect
            'main': trace.was_main_thread, # side effect
            'held_locks': trace.lock_reasons, # side effect
        }
        # States appear not documented. They are
        #   RUNNABLE = 'Runnable',
        #   TIMED_WAITING = 'Timed waiting',
        #   BLOCKED = 'Blocked',
        #   WAITING = 'Waiting',
        #   NEW = 'New',
        #   TERMINATED = 'Terminated',
        state = None
        if self.thread.is_exited():
            state = 'Terminated'
        if not state:
            for addr, reason in trace.lock_reasons.items():
                match reason['type']:
                    case 1:
                        state = None # locked doesn't exist as thread state
                    case 2:
                        state = 'Waiting'
                    case 4:
                        state = 'Runnable'
                    case 8:
                        state = 'Blocked'
                break
        payload['state'] = state
        return payload

class SentryImage:
    # This can throw if objfiles fail to resolve!
    def __init__(self, image):
        self.image = image

    def debug_id(self):
        # Identifier of the dynamic library or executable.
        # It is the value of the build_id custom section and must be formatted
        # as UUID truncated to the leading 16 bytes.
        build_id = self.build_id()
        if not build_id:
            raise NoBuildIdException(f'Unexpectedly stumbled over an objfile ({self.file}) without build_id. Not creating payload.')
        truncate_bytes = 16
        build_id = build_id + ("00" * truncate_bytes)
        return str(uuid.UUID(bytes_le=binascii.unhexlify(build_id)[:truncate_bytes]))

    def build_id(self):
        return self.image.build_id

    def to_dict(self):
        # https://develop.sentry.dev/sdk/event-payloads/debugmeta

        return {
            'type': 'elf',
            'image_addr': self.image.address,
            'image_size': self.image.length,
            'debug_id': self.debug_id(),
            # 'debug_file': None, # technically could get this from objfiles somehow but probably not useful cause it can't be used for anything
            'code_id': self.build_id(),
            'code_file': self.image.file,
            # 'image_vmaddr': None, # not available we'd have to read the ELF I think
            'arch': platform.machine(),
        }

def get_stdout(proc, env=None):
    proc = subprocess.run(proc, stdout=subprocess.PIPE, env=env)
    if proc.returncode != 0:
        return ''
    return proc.stdout.decode("utf-8").strip()

class SentryImages:
    def to_list(self):
        ret = []
        for core_image in core_images:
            image = SentryImage(image=core_image)
            ret.append(image.to_dict())
        return ret

class SentryEvent:
    def cpu_model(self):
        with open("/proc/cpuinfo") as f:
            for line in f.readlines():
                line = line.strip()
                if not line: # skip empty lines
                    continue
                key, value = line.split(':', 1)
                key = key.strip()
                if key == 'model name' or key == 'model': # on arm64 this is just 'model'
                    return value.strip()
        return None

    def make(self, program, crash_thread):
        crash_signal = int(os.getenv('DRKONQI_SIGNAL'))
        vm = psutil.virtual_memory()
        boot_time = datetime.fromtimestamp(psutil.boot_time()).astimezone(timezone.utc).strftime('%Y-%m-%dT%H:%M:%S')

        # crutch to get the build id. if we did this outside gdb I expect it'd be neater
        progfile = gdb.current_progspace().filename
        build_id = gdb.lookup_objfile(progfile).build_id

        # NOTE: this is run before the other threads because as a side effect it may load symbols that help other threads produce useful output.
        stacktrace = SentryTrace(crash_thread, True).to_dict()

        base_data = json.loads(get_stdout(['drkonqi-sentry-data']))
        sentry_event = { # https://develop.sentry.dev/sdk/event-payloads/
            "debug_meta": { # https://develop.sentry.dev/sdk/event-payloads/debugmeta/
                "images": SentryImages().to_list()
            },
            'threads':  [ # https://develop.sentry.dev/sdk/event-payloads/threads/
                 SentryThread(thread, is_crashed=(thread == crash_thread)).to_dict() for thread in gdb.selected_inferior().threads()
            ],
            'event_id': uuid.uuid4().hex,
            # Gets overwritten by ReportInterface with a more accurate value
            'timestamp': datetime.now(timezone.utc).isoformat(),
            'message': 'Signal {} in {}'.format(crash_signal, program),
            'platform': 'native',
            'sdk': {
                'name': 'kde.drkonqi.gdb',
                'version': os.getenv('DRKONQI_VERSION'),
             },
            'level': 'fatal',
            # FIXME this is kind of wrong, program ought to be mapped to the project name via our DSNs mapping table (see reportinterface.cpp)
            'release': "{}@unknown".format(program),
            'dist': build_id,
            # TODO environment entry (could be staging for beta releases?)
            'contexts': { # https://develop.sentry.dev/sdk/event-payloads/contexts/
                'device': {
                    'name': base_data['Hostname'],
                    'model': self.cpu_model(),
                    'family': base_data['Chassis'],
                    'simulator': base_data['Virtualization'],
                    'arch': platform.machine(),
                    'memory_size': vm.total,
                    'free_memory': vm.available,
                    'boot_time': boot_time,
                    'timezone': base_data['Timezone'],
                    'processor_count': multiprocessing.cpu_count()
                },
                # 'os' gets injected on the cpp side so it is always available
            },
            'exception': { # https://develop.sentry.dev/sdk/event-payloads/exception/
                'values': [
                    {
                        'value': signal.strsignal(crash_signal),
                        'thread_id': crash_thread.ptid[1],
                        'mechanism': {
                            'type': 'drkonqi',
                            'handled': False,
                            "synthetic": True, # Docs: This flag should be set for all "segfaults"
                            'meta': {
                                'signal': {
                                    'number': crash_signal,
                                    'name': signal.strsignal(crash_signal)
                                },
                            },
                        },
                        'stacktrace': stacktrace,
                    }
                ]
            },
        }

        # WARNING: must be after the trace is constructed so SentryVariables are counted
        sentry_event['tags'] = {
            'binary': program, # for fallthrough we still need a convenient way to identify things
            'stack_vars': 'yes' if (SentryVariablesStatistics.vars_rate() > 0.25) else 'no',
            'stack_vars_rate': str(SentryVariablesStatistics.vars_rate()), # must be str for sentry to consume it properly
        }

        if os.getenv('DRKONQI_APP_VERSION'):
            sentry_event['release'] = '{}@{}'.format(program, os.getenv('DRKONQI_APP_VERSION'))

        return sentry_event

def print_kcrash_error_message():
    symbol = gdb.lookup_static_symbol("s_kcrashErrorMessage")
    if not symbol or not symbol.is_valid():
        return

    try:
        value = symbol.value()
    except: # docs say value can throw!
        return
    print("KCRASH_INFO_MESSAGE: Content of s_kcrashErrorMessage: " + value.format_string())
    print() # separator newline

def print_sentry_payload(thread):
    program = os.path.basename(gdb.current_progspace().filename)
    payload = SentryEvent().make(program, thread)

    tmpdir = os.getenv('DRKONQI_TMP_DIR')
    if tmpdir:
        with open(tmpdir + '/sentry_payload.json', mode='w') as tmpfile:
            tmpfile.write(json.dumps(payload))
            tmpfile.flush()

class CoreImage:
    def __init__(self, eu_unstrip_line):
        self.valid = False
        self.file = None # may not end up set otherwise, causing exceptions

        address_pack, build_id_pack, file, debug, self.name = eu_unstrip_line.split(' ', 4)
        if self.name.endswith(' (deleted)'):
            raise DeletedMappingException(f'Unexpectedly stumbled over a deleted mapping: {eu_unstrip_line}')
        self.have_elf = file != '-'
        self.have_dwarf = debug != '-'
        if build_id_pack == '-':
            raise NoBuildIdException(f'No build id found in core image: {eu_unstrip_line}')
        self.build_id, self.build_id_address = build_id_pack.split('@', 1)
        self.address, self.length = address_pack.split('+', 1)
        self.length = int(self.length, 16)
        if self.have_elf:
            # For builtin images the file will be '.'. This notably happens for the executable itself, but also for linux-vdso.
            # For the former we expect the name to be a path and for the latter we don't care since we can't resolve it anyway.
            if file == '.':
                if self.name.startswith('/'):
                    self.file = self.name
                else:
                    return # invalid image (e.g. linux-vdso)
            else:
                self.file = file

        self.valid = self.file is not None

def resolve_modules():
    corefile = os.getenv("DRKONQI_COREFILE")
    if not corefile:
        raise RuntimeError("No corefile found. Cannot resolve modules.")

    global core_images

    env = os.environ.copy()
    env.pop('DEBUGINFOD_URLS', None) # we don't want debug info downloads, we'll do them from gdb if necessary
    # Beware that build ids from eu-unstrip are a bit unreliable in that we get back the current build id in case the
    # core doesn't contain one. That makes the ids a bit unreliable but still better than nothing I suppose.
    # Ultimately we'll want to use gdb here.
    # https://sourceware.org/bugzilla/show_bug.cgi?id=32844
    output = get_stdout(['eu-unstrip', "--list-only", f"--core={corefile}"], env=env)
    for line in output.splitlines():
        image = CoreImage(line)
        if image.valid:
            core_images.append(image)

def print_preamble_internal():
    resolve_modules()

    thread = gdb.selected_thread()
    if thread == None:
        # Can happen when e.g. the core is missing or not readable etc. We basically aren't debugging anything
        return
    if 'sentry_sdk' in globals():
        sentry_sdk.add_breadcrumb(
            category='debug',
            level='debug',
            message=f'Selected thread {thread}',
        )
    global crashed_thread
    crashed_thread = thread
    # run this first as it expects the current frame to be the crashing one and further tracing changes the frames around
    print_kcrash_error_message()
    try:
        print_sentry_payload(thread)
    except NoBuildIdException as e:
        # TODO should this get re-raised
        traceback.print_exc()
        print(e)
        pass

def print_preamble():
    try:
        print_preamble_internal()
    except Exception as e:
        if 'sentry_sdk' in globals():
            sentry_sdk.capture_exception(e)
        traceback.print_exc()
        print(e)
        gdb.execute('quit 1')
