#!/usr/bin/env python
#
# Electrum - lightweight Bitcoin client
# Copyright (C) 2015 Thomas Voegtlin
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
import asyncio
import ast
import os
import time
import traceback
import sys
import threading
from typing import Dict, Optional, Tuple

from aiohttp import web
from jsonrpcserver import async_dispatch as dispatch
from jsonrpcserver.methods import Methods

import jsonrpclib

from .jsonrpc import PasswordProtectedJSONRPCServer
from .version import ELECTRUM_VERSION
from .network import Network
from .util import (json_decode, DaemonThread, to_string,
                   create_and_start_event_loop, profiler, standardize_path)
from .wallet import Wallet, Abstract_Wallet
from .storage import WalletStorage
from .commands import known_commands, Commands
from .simple_config import SimpleConfig
from .exchange_rate import FxThread
from .plugin import run_hook
from .logging import get_logger, Logger


_logger = get_logger(__name__)

class DaemonNotRunning(Exception):
    pass

def get_lockfile(config: SimpleConfig):
    return os.path.join(config.path, 'daemon')


def remove_lockfile(lockfile):
    os.unlink(lockfile)


def get_file_descriptor(config: SimpleConfig):
    '''Tries to create the lockfile, using O_EXCL to
    prevent races.  If it succeeds it returns the FD.
    Otherwise try and connect to the server specified in the lockfile.
    If this succeeds, the server is returned.  Otherwise remove the
    lockfile and try again.'''
    lockfile = get_lockfile(config)
    while True:
        try:
            return os.open(lockfile, os.O_CREAT | os.O_EXCL | os.O_WRONLY, 0o644)
        except OSError:
            pass
        try:
            request(config, 'ping')
            return None
        except DaemonNotRunning:
            # Couldn't connect; remove lockfile and try again.
            remove_lockfile(lockfile)


def request(config: SimpleConfig, endpoint, *args, **kwargs):
    lockfile = get_lockfile(config)
    while True:
        create_time = None
        try:
            with open(lockfile) as f:
                (host, port), create_time = ast.literal_eval(f.read())
            rpc_user, rpc_password = get_rpc_credentials(config)
            if rpc_password == '':
                # authentication disabled
                server_url = 'http://%s:%d' % (host, port)
            else:
                server_url = 'http://%s:%s@%s:%d' % (
                    rpc_user, rpc_password, host, port)
        except Exception:
            raise DaemonNotRunning()
        server = jsonrpclib.Server(server_url)
        try:
            # run request
            f = getattr(server, endpoint)
            return f(*args, **kwargs)
        except ConnectionRefusedError:
            _logger.info(f"failed to connect to JSON-RPC server")
            if not create_time or create_time < time.time() - 1.0:
                raise DaemonNotRunning()
        # Sleep a bit and try again; it might have just been started
        time.sleep(1.0)


def get_rpc_credentials(config: SimpleConfig) -> Tuple[str, str]:
    rpc_user = config.get('rpcuser', None)
    rpc_password = config.get('rpcpassword', None)
    if rpc_user is None or rpc_password is None:
        rpc_user = 'user'
        import ecdsa, base64
        bits = 128
        nbytes = bits // 8 + (bits % 8 > 0)
        pw_int = ecdsa.util.randrange(pow(2, bits))
        pw_b64 = base64.b64encode(
            pw_int.to_bytes(nbytes, 'big'), b'-_')
        rpc_password = to_string(pw_b64, 'ascii')
        config.set_key('rpcuser', rpc_user)
        config.set_key('rpcpassword', rpc_password, save=True)
    elif rpc_password == '':
        _logger.warning('RPC authentication is disabled.')
    return rpc_user, rpc_password


class WatchTowerServer(Logger):

    def __init__(self, network):
        Logger.__init__(self)
        self.config = network.config
        self.network = network
        self.lnwatcher = network.local_watchtower
        self.app = web.Application()
        self.app.router.add_post("/", self.handle)
        self.methods = Methods()
        self.methods.add(self.get_ctn)
        self.methods.add(self.add_sweep_tx)

    async def handle(self, request):
        request = await request.text()
        self.logger.info(f'{request}')
        response = await dispatch(request, methods=self.methods)
        if response.wanted:
            return web.json_response(response.deserialized(), status=response.http_status)
        else:
            return web.Response()

    async def run(self):
        host = self.config.get('watchtower_host')
        port = self.config.get('watchtower_port', 12345)
        self.runner = web.AppRunner(self.app)
        await self.runner.setup()
        site = web.TCPSite(self.runner, host, port)
        await site.start()

    async def get_ctn(self, *args):
        return await self.lnwatcher.sweepstore.get_ctn(*args)

    async def add_sweep_tx(self, *args):
        return await self.lnwatcher.sweepstore.add_sweep_tx(*args)


class Daemon(DaemonThread):

    @profiler
    def __init__(self, config: SimpleConfig, fd=None, *, listen_jsonrpc=True):
        DaemonThread.__init__(self)
        self.config = config
        if fd is None and listen_jsonrpc:
            fd = get_file_descriptor(config)
            if fd is None:
                raise Exception('failed to lock daemon; already running?')
        self.asyncio_loop, self._stop_loop, self._loop_thread = create_and_start_event_loop()
        if config.get('offline'):
            self.network = None
        else:
            self.network = Network(config)
            self.network._loop_thread = self._loop_thread
        self.fx = FxThread(config, self.network)
        self.gui = None
        # path -> wallet;   make sure path is standardized.
        self.wallets = {}  # type: Dict[str, Abstract_Wallet]
        # Setup JSONRPC server
        self.server = None
        if listen_jsonrpc:
            self.init_server(config, fd)
        # server-side watchtower
        self.watchtower = WatchTowerServer(self.network) if self.config.get('watchtower_host') else None
        jobs = [self.fx.run]
        if self.watchtower:
            jobs.append(self.watchtower.run)
        if self.network:
            self.network.start(jobs)
        self.start()

    def init_server(self, config: SimpleConfig, fd):
        host = config.get('rpchost', '127.0.0.1')
        port = config.get('rpcport', 0)
        rpc_user, rpc_password = get_rpc_credentials(config)
        try:
            server = PasswordProtectedJSONRPCServer(
                (host, port), logRequests=False,
                rpc_user=rpc_user, rpc_password=rpc_password)
        except Exception as e:
            self.logger.error(f'cannot initialize RPC server on host {host}: {repr(e)}')
            self.server = None
            os.close(fd)
            return
        os.write(fd, bytes(repr((server.socket.getsockname(), time.time())), 'utf8'))
        os.close(fd)
        self.server = server
        server.timeout = 0.1
        server.register_function(self.ping, 'ping')
        server.register_function(self.run_gui, 'gui')
        server.register_function(self.run_daemon, 'daemon')
        self.cmd_runner = Commands(self.config, None, self.network)
        for cmdname in known_commands:
            server.register_function(getattr(self.cmd_runner, cmdname), cmdname)
        server.register_function(self.run_cmdline, 'run_cmdline')

    def ping(self):
        return True

    def run_daemon(self, config_options):
        asyncio.set_event_loop(self.asyncio_loop)
        config = SimpleConfig(config_options)
        sub = config.get('subcommand')
        assert sub in [None, 'start', 'stop', 'status', 'load_wallet', 'close_wallet']
        if sub in [None, 'start']:
            response = "Daemon already running"
        elif sub == 'load_wallet':
            path = config.get_wallet_path()
            wallet = self.load_wallet(path, config.get('password'))
            if wallet is not None:
                self.cmd_runner.wallet = wallet
                run_hook('load_wallet', wallet, None)
            response = wallet is not None
        elif sub == 'close_wallet':
            path = config.get_wallet_path()
            path = standardize_path(path)
            if path in self.wallets:
                self.stop_wallet(path)
                response = True
            else:
                response = False
        elif sub == 'status':
            if self.network:
                net_params = self.network.get_parameters()
                current_wallet = self.cmd_runner.wallet
                current_wallet_path = current_wallet.storage.path \
                                      if current_wallet else None
                response = {
                    'path': self.network.config.path,
                    'server': net_params.host,
                    'blockchain_height': self.network.get_local_height(),
                    'server_height': self.network.get_server_height(),
                    'spv_nodes': len(self.network.get_interfaces()),
                    'connected': self.network.is_connected(),
                    'auto_connect': net_params.auto_connect,
                    'version': ELECTRUM_VERSION,
                    'wallets': {k: w.is_up_to_date()
                                for k, w in self.wallets.items()},
                    'current_wallet': current_wallet_path,
                    'fee_per_kb': self.config.fee_per_kb(),
                }
            else:
                response = "Daemon offline"
        elif sub == 'stop':
            self.stop()
            response = "Daemon stopped"
        return response

    def run_gui(self, config_options):
        config = SimpleConfig(config_options)
        if self.gui:
            if hasattr(self.gui, 'new_window'):
                config.open_last_wallet()
                path = config.get_wallet_path()
                self.gui.new_window(path, config.get('url'))
                response = "ok"
            else:
                response = "error: current GUI does not support multiple windows"
        else:
            response = "Error: Electrum is running in daemon mode. Please stop the daemon first."
        return response

    def load_wallet(self, path, password) -> Optional[Abstract_Wallet]:
        path = standardize_path(path)
        # wizard will be launched if we return
        if path in self.wallets:
            wallet = self.wallets[path]
            return wallet
        storage = WalletStorage(path, manual_upgrades=True)
        if not storage.file_exists():
            return
        if storage.is_encrypted():
            if not password:
                return
            storage.decrypt(password)
        if storage.requires_split():
            return
        if storage.requires_upgrade():
            return
        if storage.get_action():
            return
        wallet = Wallet(storage)
        wallet.start_network(self.network)
        self.wallets[path] = wallet
        return wallet

    def add_wallet(self, wallet: Abstract_Wallet):
        path = wallet.storage.path
        path = standardize_path(path)
        self.wallets[path] = wallet

    def get_wallet(self, path):
        path = standardize_path(path)
        return self.wallets.get(path)

    def delete_wallet(self, path):
        self.stop_wallet(path)
        if os.path.exists(path):
            os.unlink(path)
            return True
        return False

    def stop_wallet(self, path):
        path = standardize_path(path)
        wallet = self.wallets.pop(path, None)
        if not wallet: return
        wallet.stop_threads()

    def run_cmdline(self, config_options):
        asyncio.set_event_loop(self.asyncio_loop)
        password = config_options.get('password')
        new_password = config_options.get('new_password')
        config = SimpleConfig(config_options)
        # FIXME this is ugly...
        config.fee_estimates = self.network.config.fee_estimates.copy()
        config.mempool_fees  = self.network.config.mempool_fees.copy()
        cmdname = config.get('cmd')
        cmd = known_commands[cmdname]
        if cmd.requires_wallet:
            path = config.get_wallet_path()
            path = standardize_path(path)
            wallet = self.wallets.get(path)
            if wallet is None:
                return {'error': 'Wallet "%s" is not loaded. Use "electrum daemon load_wallet"'%os.path.basename(path) }
        else:
            wallet = None
        # arguments passed to function
        args = map(lambda x: config.get(x), cmd.params)
        # decode json arguments
        args = [json_decode(i) for i in args]
        # options
        kwargs = {}
        for x in cmd.options:
            kwargs[x] = (config_options.get(x) if x in ['password', 'new_password'] else config.get(x))
        cmd_runner = Commands(config, wallet, self.network)
        func = getattr(cmd_runner, cmd.name)
        try:
            result = func(*args, **kwargs)
        except TypeError as e:
            raise Exception("Wrapping TypeError to prevent JSONRPC-Pelix from hiding traceback") from e
        return result

    def run(self):
        while self.is_running():
            self.server.handle_request() if self.server else time.sleep(0.1)
        # stop network/wallets
        for k, wallet in self.wallets.items():
            wallet.stop_threads()
        if self.network:
            self.logger.info("shutting down network")
            self.network.stop()
        # stop event loop
        self.asyncio_loop.call_soon_threadsafe(self._stop_loop.set_result, 1)
        self._loop_thread.join(timeout=1)
        self.on_stop()

    def stop(self):
        if self.gui:
            self.gui.stop()
        self.logger.info("stopping, removing lockfile")
        remove_lockfile(get_lockfile(self.config))
        DaemonThread.stop(self)

    def init_gui(self, config, plugins):
        threading.current_thread().setName('GUI')
        gui_name = config.get('gui', 'qt')
        if gui_name in ['lite', 'classic']:
            gui_name = 'qt'
        gui = __import__('electrum.gui.' + gui_name, fromlist=['electrum'])
        self.gui = gui.ElectrumGui(config, self, plugins)
        try:
            self.gui.main()
        except BaseException as e:
            self.logger.exception('')
            # app will exit now