#!/usr/bin/python3

# Copyright (C) 2019 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

#
# This is an ADB proxy for Winscope.
#
# Requirements: python3.5 and ADB installed and in system PATH.
#
# Usage:
#     run: python3 winscope_proxy.py
#

import json
import logging
import os
import re
import secrets
import signal
import subprocess
import sys
import threading
import time
from abc import abstractmethod
from enum import Enum
from http import HTTPStatus
from http.server import HTTPServer, BaseHTTPRequestHandler
from tempfile import NamedTemporaryFile
import base64

# CONFIG #

LOG_LEVEL = logging.DEBUG

PORT = 5544

# Keep in sync with WINSCOPE_PROXY_VERSION in Winscope DataAdb.vue
VERSION = '0.5'

WINSCOPE_VERSION_HEADER = "Winscope-Proxy-Version"
WINSCOPE_TOKEN_HEADER = "Winscope-Token"

# Location to save the proxy security token
WINSCOPE_TOKEN_LOCATION = os.path.expanduser('~/.config/winscope/.token')

# Max interval between the client keep-alive requests in seconds
KEEP_ALIVE_INTERVAL_S = 5

logging.basicConfig(stream=sys.stderr, level=LOG_LEVEL,
                    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s')
log = logging.getLogger("ADBProxy")


class TraceTarget:
    """Defines a single parameter to trace.

    Attributes:
        file: the path on the device the trace results are saved to.
        trace_start: command to start the trace from adb shell, must not block.
        trace_stop: command to stop the trace, should block until the trace is stopped.
    """

    def __init__(self, file: str, trace_start: str, trace_stop: str) -> None:
        self.file = file
        self.trace_start = trace_start
        self.trace_stop = trace_stop


TRACE_TARGETS = {
    "window_trace": TraceTarget(
        "/data/misc/wmtrace/wm_trace.pb",
        'su root cmd window tracing start\necho "WM trace started."',
        'su root cmd window tracing stop >/dev/null 2>&1'
    ),
    "layers_trace": TraceTarget(
        "/data/misc/wmtrace/layers_trace.pb",
        'su root service call SurfaceFlinger 1025 i32 1\necho "SF trace started."',
        'su root service call SurfaceFlinger 1025 i32 0 >/dev/null 2>&1'
    ),
    "screen_recording": TraceTarget(
        "/data/local/tmp/screen.winscope.mp4",
        'screenrecord --bit-rate 8M /data/local/tmp/screen.winscope.mp4 >/dev/null 2>&1 &\necho "ScreenRecorder started."',
        'pkill -l SIGINT screenrecord >/dev/null 2>&1'
    ),
    "transaction": TraceTarget(
        "/data/misc/wmtrace/transaction_trace.pb",
        'su root service call SurfaceFlinger 1020 i32 1\necho "SF transactions recording started."',
        'su root service call SurfaceFlinger 1020 i32 0 >/dev/null 2>&1'
    ),
    "proto_log": TraceTarget(
        "/data/misc/wmtrace/wm_log.pb",
        'su root cmd window logging start\necho "WM logging started."',
        'su root cmd window logging stop >/dev/null 2>&1'
    ),
}


class DumpTarget:
    """Defines a single parameter to trace.

    Attributes:
        file: the path on the device the dump results are saved to.
        dump_command: command to dump state to file.
    """

    def __init__(self, file: str, dump_command: str) -> None:
        self.file = file
        self.dump_command = dump_command


DUMP_TARGETS = {
    "window_dump": DumpTarget(
        "/data/local/tmp/wm_dump.pb",
        'su root dumpsys window --proto > /data/local/tmp/wm_dump.pb'
    ),
    "layers_dump": DumpTarget(
        "/data/local/tmp/sf_dump.pb",
        'su root dumpsys SurfaceFlinger --proto > /data/local/tmp/sf_dump.pb'
    )
}


# END OF CONFIG #


def get_token() -> str:
    """Returns saved proxy security token or creates new one"""
    try:
        with open(WINSCOPE_TOKEN_LOCATION, 'r') as token_file:
            token = token_file.readline()
            log.debug("Loaded token {} from {}".format(token, WINSCOPE_TOKEN_LOCATION))
            return token
    except IOError:
        token = secrets.token_hex(32)
        os.makedirs(os.path.dirname(WINSCOPE_TOKEN_LOCATION), exist_ok=True)
        try:
            with open(WINSCOPE_TOKEN_LOCATION, 'w') as token_file:
                log.debug("Created and saved token {} to {}".format(token, WINSCOPE_TOKEN_LOCATION))
                token_file.write(token)
            os.chmod(WINSCOPE_TOKEN_LOCATION, 0o600)
        except IOError:
            log.error("Unable to save persistent token {} to {}".format(token, WINSCOPE_TOKEN_LOCATION))
        return token


secret_token = get_token()


class RequestType(Enum):
    GET = 1
    POST = 2
    HEAD = 3


def add_standard_headers(server):
    server.send_header('Cache-Control', 'no-cache, no-store, must-revalidate')
    server.send_header('Access-Control-Allow-Origin', '*')
    server.send_header('Access-Control-Allow-Methods', 'POST, GET, OPTIONS')
    server.send_header('Access-Control-Allow-Headers', WINSCOPE_TOKEN_HEADER + ', Content-Type, Content-Length')
    server.send_header('Access-Control-Expose-Headers', 'Winscope-Proxy-Version')
    server.send_header(WINSCOPE_VERSION_HEADER, VERSION)
    server.end_headers()


class RequestEndpoint:
    """Request endpoint to use with the RequestRouter."""

    @abstractmethod
    def process(self, server, path):
        pass


class AdbError(Exception):
    """Unsuccessful ADB operation"""
    pass


class BadRequest(Exception):
    """Invalid client request"""
    pass


class RequestRouter:
    """Handles HTTP request authenticationn and routing"""

    def __init__(self, handler):
        self.request = handler
        self.endpoints = {}

    def register_endpoint(self, method: RequestType, name: str, endpoint: RequestEndpoint):
        self.endpoints[(method, name)] = endpoint

    def __bad_request(self, error: str):
        log.warning("Bad request: " + error)
        self.request.respond(HTTPStatus.BAD_REQUEST, b"Bad request!\nThis is Winscope ADB proxy.\n\n"
                             + error.encode("utf-8"), 'text/txt')

    def __internal_error(self, error: str):
        log.error("Internal error: " + error)
        self.request.respond(HTTPStatus.INTERNAL_SERVER_ERROR, error.encode("utf-8"), 'text/txt')

    def __bad_token(self):
        log.info("Bad token")
        self.request.respond(HTTPStatus.FORBIDDEN, b"Bad Winscope authorisation token!\nThis is Winscope ADB proxy.\n",
                             'text/txt')

    def process(self, method: RequestType):
        token = self.request.headers[WINSCOPE_TOKEN_HEADER]
        if not token or token != secret_token:
            return self.__bad_token()
        path = self.request.path.strip('/').split('/')
        if path and len(path) > 0:
            endpoint_name = path[0]
            try:
                return self.endpoints[(method, endpoint_name)].process(self.request, path[1:])
            except KeyError:
                return self.__bad_request("Unknown endpoint /{}/".format(endpoint_name))
            except AdbError as ex:
                return self.__internal_error(str(ex))
            except BadRequest as ex:
                return self.__bad_request(str(ex))
            except Exception as ex:
                return self.__internal_error(repr(ex))
        self.__bad_request("No endpoint specified")


def call_adb(params: str, device: str = None, stdin: bytes = None):
    command = ['adb'] + (['-s', device] if device else []) + params.split(' ')
    try:
        log.debug("Call: " + ' '.join(command))
        return subprocess.check_output(command, stderr=subprocess.STDOUT, input=stdin).decode('utf-8')
    except OSError as ex:
        log.debug('Error executing adb command: {}\n{}'.format(' '.join(command), repr(ex)))
        raise AdbError('Error executing adb command: {}\n{}'.format(' '.join(command), repr(ex)))
    except subprocess.CalledProcessError as ex:
        log.debug('Error executing adb command: {}\n{}'.format(' '.join(command), ex.output.decode("utf-8")))
        raise AdbError('Error executing adb command: adb {}\n{}'.format(params, ex.output.decode("utf-8")))


def call_adb_outfile(params: str, outfile, device: str = None, stdin: bytes = None):
    try:
        process = subprocess.Popen(['adb'] + (['-s', device] if device else []) + params.split(' '), stdout=outfile,
                                   stderr=subprocess.PIPE)
        _, err = process.communicate(stdin)
        outfile.seek(0)
        if process.returncode != 0:
            log.debug('Error executing adb command: adb {}\n'.format(params) + err.decode(
                'utf-8') + '\n' + outfile.read().decode('utf-8'))
            raise AdbError('Error executing adb command: adb {}\n'.format(params) + err.decode(
                'utf-8') + '\n' + outfile.read().decode('utf-8'))
    except OSError as ex:
        log.debug('Error executing adb command: adb {}\n{}'.format(params, repr(ex)))
        raise AdbError('Error executing adb command: adb {}\n{}'.format(params, repr(ex)))


class ListDevicesEndpoint(RequestEndpoint):
    ADB_INFO_RE = re.compile("^([A-Za-z0-9.:\\-]+)\\s+(\\w+)(.*model:(\\w+))?")

    def process(self, server, path):
        lines = list(filter(None, call_adb('devices -l').split('\n')))
        devices = {m.group(1): {
            'authorised': str(m.group(2)) != 'unauthorized',
            'model': m.group(4).replace('_', ' ') if m.group(4) else ''
        } for m in [ListDevicesEndpoint.ADB_INFO_RE.match(d) for d in lines[1:]] if m}
        j = json.dumps(devices)
        log.debug("Detected devices: " + j)
        server.respond(HTTPStatus.OK, j.encode("utf-8"), "text/json")


class DeviceRequestEndpoint(RequestEndpoint):
    def process(self, server, path):
        if len(path) > 0 and re.fullmatch("[A-Za-z0-9.:\\-]+", path[0]):
            self.process_with_device(server, path[1:], path[0])
        else:
            raise BadRequest("Device id not specified")

    @abstractmethod
    def process_with_device(self, server, path, device_id):
        pass


class FetchFileEndpoint(DeviceRequestEndpoint):
    def process_with_device(self, server, path, device_id):
        if len(path) != 1:
            raise BadRequest("File not specified")
        if path[0] in TRACE_TARGETS:
            file_path = TRACE_TARGETS[path[0]].file
        elif path[0] in DUMP_TARGETS:
            file_path = DUMP_TARGETS[path[0]].file
        else:
            raise BadRequest("Unknown file specified")

        with NamedTemporaryFile() as tmp:
            log.debug("Fetching file {} from device to {}".format(file_path, tmp.name))
            call_adb_outfile('exec-out su root cat ' + file_path, tmp, device_id)
            log.debug("Deleting file {} from device".format(file_path))
            call_adb('shell su root rm ' + file_path, device_id)
            server.send_response(HTTPStatus.OK)
            server.send_header('X-Content-Type-Options', 'nosniff')
            server.send_header('Content-type', 'application/octet-stream')
            add_standard_headers(server)
            log.debug("Uploading file {}".format(tmp.name))
            while True:
                buf = tmp.read(1024)
                if buf:
                    server.wfile.write(buf)
                else:
                    break


def check_root(device_id):
    log.debug("Checking root access on {}".format(device_id))
    return int(call_adb('shell su root id -u', device_id)) == 0


TRACE_THREADS = {}


class TraceThread(threading.Thread):
    def __init__(self, device_id, command):
        self._keep_alive_timer = None
        self.trace_command = command
        self._device_id = device_id
        self.out = None,
        self.err = None,
        self._success = False
        try:
            shell = ['adb', '-s', self._device_id, 'shell']
            log.debug("Starting trace shell {}".format(' '.join(shell)))
            self.process = subprocess.Popen(shell, stdout=subprocess.PIPE,
                                            stderr=subprocess.PIPE, stdin=subprocess.PIPE, start_new_session=True)
        except OSError as ex:
            raise AdbError('Error executing adb command: adb shell\n{}'.format(repr(ex)))

        super().__init__()

    def timeout(self):
        if self.is_alive():
            log.warning("Keep-alive timeout for trace on {}".format(self._device_id))
            self.end_trace()
            if self._device_id in TRACE_THREADS:
                TRACE_THREADS.pop(self._device_id)

    def reset_timer(self):
        log.debug("Resetting keep-alive clock for trace on {}".format(self._device_id))
        if self._keep_alive_timer:
            self._keep_alive_timer.cancel()
        self._keep_alive_timer = threading.Timer(KEEP_ALIVE_INTERVAL_S, self.timeout)
        self._keep_alive_timer.start()

    def end_trace(self):
        if self._keep_alive_timer:
            self._keep_alive_timer.cancel()
        log.debug("Sending SIGINT to the trace process on {}".format(self._device_id))
        self.process.send_signal(signal.SIGINT)
        try:
            log.debug("Waiting for trace shell to exit for {}".format(self._device_id))
            self.process.wait(timeout=5)
        except TimeoutError:
            log.debug("TIMEOUT - sending SIGKILL to the trace process on {}".format(self._device_id))
            self.process.kill()
        self.join()

    def run(self):
        log.debug("Trace started on {}".format(self._device_id))
        self.reset_timer()
        self.out, self.err = self.process.communicate(self.trace_command)
        log.debug("Trace ended on {}, waiting for cleanup".format(self._device_id))
        time.sleep(0.2)
        for i in range(10):
            if call_adb("shell su root cat /data/local/tmp/winscope_status", device=self._device_id) == 'TRACE_OK\n':
                call_adb("shell su root rm /data/local/tmp/winscope_status", device=self._device_id)
                log.debug("Trace finished successfully on {}".format(self._device_id))
                self._success = True
                break
            log.debug("Still waiting for cleanup on {}".format(self._device_id))
            time.sleep(0.1)

    def success(self):
        return self._success


class StartTrace(DeviceRequestEndpoint):
    TRACE_COMMAND = """
set -e

echo "Starting trace..."
echo "TRACE_START" > /data/local/tmp/winscope_status

# Do not print anything to stdout/stderr in the handler
function stop_trace() {{
  trap - EXIT HUP INT

{}

  echo "TRACE_OK" > /data/local/tmp/winscope_status
}}

trap stop_trace EXIT HUP INT
echo "Signal handler registered."

{}

# ADB shell does not handle hung up well and does not call HUP handler when a child is active in foreground,
# as a workaround we sleep for short intervals in a loop so the handler is called after a sleep interval.
while true; do sleep 0.1; done
"""

    def process_with_device(self, server, path, device_id):
        try:
            length = int(server.headers["Content-Length"])
        except KeyError as err:
            raise BadRequest("Missing Content-Length header\n" + str(err))
        except ValueError as err:
            raise BadRequest("Content length unreadable\n" + str(err))
        try:
            requested_types = json.loads(server.rfile.read(length).decode("utf-8"))
            requested_traces = [TRACE_TARGETS[t] for t in requested_types]
        except KeyError as err:
            raise BadRequest("Unsupported trace target\n" + str(err))
        if device_id in TRACE_THREADS:
            log.warning("Trace already in progress for {}", device_id)
            server.respond(HTTPStatus.OK, b'', "text/plain")
        if not check_root(device_id):
            raise AdbError(
                "Unable to acquire root privileges on the device - check the output of 'adb -s {} shell su root id'".format(
                    device_id))
        command = StartTrace.TRACE_COMMAND.format(
            '\n'.join([t.trace_stop for t in requested_traces]),
            '\n'.join([t.trace_start for t in requested_traces]))
        log.debug("Trace requested for {} with targets {}".format(device_id, ','.join(requested_types)))
        TRACE_THREADS[device_id] = TraceThread(device_id, command.encode('utf-8'))
        TRACE_THREADS[device_id].start()
        server.respond(HTTPStatus.OK, b'', "text/plain")


class EndTrace(DeviceRequestEndpoint):
    def process_with_device(self, server, path, device_id):
        if device_id not in TRACE_THREADS:
            raise BadRequest("No trace in progress for {}".format(device_id))
        if TRACE_THREADS[device_id].is_alive():
            TRACE_THREADS[device_id].end_trace()

        success = TRACE_THREADS[device_id].success()
        out = TRACE_THREADS[device_id].out + b"\n" + TRACE_THREADS[device_id].err
        command = TRACE_THREADS[device_id].trace_command
        TRACE_THREADS.pop(device_id)
        if success:
            server.respond(HTTPStatus.OK, out, "text/plain")
        else:
            raise AdbError(
                "Error tracing the device\n### Output ###\n" + out.decode(
                    "utf-8") + "\n### Command: adb -s {} shell ###\n### Input ###\n".format(device_id) + command.decode(
                    "utf-8"))


class StatusEndpoint(DeviceRequestEndpoint):
    def process_with_device(self, server, path, device_id):
        if device_id not in TRACE_THREADS:
            raise BadRequest("No trace in progress for {}".format(device_id))
        TRACE_THREADS[device_id].reset_timer()
        server.respond(HTTPStatus.OK, str(TRACE_THREADS[device_id].is_alive()).encode("utf-8"), "text/plain")


class DumpEndpoint(DeviceRequestEndpoint):
    def process_with_device(self, server, path, device_id):
        try:
            length = int(server.headers["Content-Length"])
        except KeyError as err:
            raise BadRequest("Missing Content-Length header\n" + str(err))
        except ValueError as err:
            raise BadRequest("Content length unreadable\n" + str(err))
        try:
            requested_types = json.loads(server.rfile.read(length).decode("utf-8"))
            requested_traces = [DUMP_TARGETS[t] for t in requested_types]
        except KeyError as err:
            raise BadRequest("Unsupported trace target\n" + str(err))
        if device_id in TRACE_THREADS:
            BadRequest("Trace in progress for {}".format(device_id))
        if not check_root(device_id):
            raise AdbError(
                "Unable to acquire root privileges on the device - check the output of 'adb -s {} shell su root id'"
                .format(device_id))
        command = '\n'.join(t.dump_command for t in requested_traces)
        shell = ['adb', '-s', device_id, 'shell']
        log.debug("Starting dump shell {}".format(' '.join(shell)))
        process = subprocess.Popen(shell, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                                   stdin=subprocess.PIPE, start_new_session=True)
        log.debug("Starting dump on device {}".format(device_id))
        out, err = process.communicate(command.encode('utf-8'))
        if process.returncode != 0:
            raise AdbError("Error executing command:\n" + command + "\n\n### OUTPUT ###" + out.decode('utf-8') + "\n"
                           + err.decode('utf-8'))
        log.debug("Dump finished on device {}".format(device_id))
        server.respond(HTTPStatus.OK, b'', "text/plain")


class ADBWinscopeProxy(BaseHTTPRequestHandler):
    def __init__(self, request, client_address, server):
        self.router = RequestRouter(self)
        self.router.register_endpoint(RequestType.GET, "devices", ListDevicesEndpoint())
        self.router.register_endpoint(RequestType.GET, "status", StatusEndpoint())
        self.router.register_endpoint(RequestType.GET, "fetch", FetchFileEndpoint())
        self.router.register_endpoint(RequestType.POST, "start", StartTrace())
        self.router.register_endpoint(RequestType.POST, "end", EndTrace())
        self.router.register_endpoint(RequestType.POST, "dump", DumpEndpoint())
        super().__init__(request, client_address, server)

    def respond(self, code: int, data: bytes, mime: str) -> None:
        self.send_response(code)
        self.send_header('Content-type', mime)
        add_standard_headers(self)
        self.wfile.write(data)

    def do_GET(self):
        self.router.process(RequestType.GET)

    def do_POST(self):
        self.router.process(RequestType.POST)

    def do_OPTIONS(self):
        self.send_response(HTTPStatus.OK)
        self.send_header('Allow', 'GET,POST')
        add_standard_headers(self)
        self.end_headers()
        self.wfile.write(b'GET,POST')

    def log_request(self, code='-', size='-'):
        log.info('{} {} {}'.format(self.requestline, str(code), str(size)))


if __name__ == '__main__':
    print("Winscope ADB Connect proxy version: " + VERSION)
    print('Winscope token: ' + secret_token)
    httpd = HTTPServer(('localhost', PORT), ADBWinscopeProxy)
    try:
        httpd.serve_forever()
    except KeyboardInterrupt:
        log.info("Shutting down")
