"""
A RESTful API for Ceph
"""

import os
import json
import time
import errno
import inspect
import tempfile
import threading
import traceback

import common

from uuid import uuid4
from pecan import jsonify, make_app
from OpenSSL import crypto
from pecan.rest import RestController
from werkzeug.serving import make_server, make_ssl_devcert

from hooks import ErrorHook
from mgr_module import MgrModule, CommandResult

# Global instance to share
instance = None



class CommandsRequest(object):
    """
    This class handles parallel as well as sequential execution of
    commands. The class accept a list of iterables that should be
    executed sequentially. Each iterable can contain several commands
    that can be executed in parallel.

    Example:
    [[c1,c2],[c3,c4]]
     - run c1 and c2 in parallel
     - wait for them to finish
     - run c3 and c4 in parallel
     - wait for them to finish
    """


    def __init__(self, commands_arrays):
        self.id = str(id(self))

        # Filter out empty sub-requests
        commands_arrays = filter(
            lambda x: len(x) != 0,
            commands_arrays,
        )

        self.running = []
        self.waiting = commands_arrays[1:]
        self.finished = []
        self.failed = []

        self.lock = threading.RLock()
        if not len(commands_arrays):
            # Nothing to run
            return

        # Process first iteration of commands_arrays in parallel
        results = self.run(commands_arrays[0])

        self.running.extend(results)


    def run(self, commands):
        """
        A static method that will execute the given list of commands in
        parallel and will return the list of command results.
        """

        # Gather the results (in parallel)
        results = []
        for index in range(len(commands)):
            tag = '%s:%d' % (str(self.id), index)

            # Store the result
            result = CommandResult(tag)
            result.command = common.humanify_command(commands[index])
            results.append(result)

            # Run the command
            instance.send_command(result, 'mon', '', json.dumps(commands[index]), tag)

        return results


    def next(self):
        with self.lock:
            if not self.waiting:
                # Nothing to run
                return

            # Run a next iteration of commands
            commands = self.waiting[0]
            self.waiting = self.waiting[1:]

            self.running.extend(self.run(commands))


    def finish(self, tag):
        with self.lock:
            for index in range(len(self.running)):
                if self.running[index].tag == tag:
                    if self.running[index].r == 0:
                        self.finished.append(self.running.pop(index))
                    else:
                        self.failed.append(self.running.pop(index))
                    return True

            # No such tag found
            return False


    def is_running(self, tag):
        for result in self.running:
            if result.tag == tag:
                return True
        return False


    def is_ready(self):
        with self.lock:
            return not self.running and self.waiting


    def is_waiting(self):
        return bool(self.waiting)


    def is_finished(self):
        with self.lock:
            return not self.running and not self.waiting


    def has_failed(self):
        return bool(self.failed)


    def get_state(self):
        with self.lock:
            if not self.is_finished():
                return "pending"

            if self.has_failed():
                return "failed"

            return "success"


    def __json__(self):
        return {
            'id': self.id,
            'running': map(
                lambda x: {
                    'command': x.command,
                    'outs': x.outs,
                    'outb': x.outb,
                },
                self.running
            ),
            'finished': map(
                lambda x: {
                    'command': x.command,
                    'outs': x.outs,
                    'outb': x.outb,
                },
                self.finished
            ),
            'waiting': map(
                lambda x: {
                    'command': x.command,
                    'outs': x.outs,
                    'outb': x.outb,
                },
                self.waiting
            ),
            'failed': map(
                lambda x: {
                    'command': x.command,
                    'outs': x.outs,
                    'outb': x.outb,
                },
                self.failed
            ),
            'is_waiting': self.is_waiting(),
            'is_finished': self.is_finished(),
            'has_failed': self.has_failed(),
            'state': self.get_state(),
        }



class Module(MgrModule):
    COMMANDS = [
        {
            "cmd": "restful create-key name=key_name,type=CephString",
            "desc": "Create an API key with this name",
            "perm": "rw"
        },
        {
            "cmd": "restful delete-key name=key_name,type=CephString",
            "desc": "Delete an API key with this name",
            "perm": "rw"
        },
        {
            "cmd": "restful list-keys",
            "desc": "List all API keys",
            "perm": "rw"
        },
        {
            "cmd": "restful create-self-signed-cert",
            "desc": "Create localized self signed certificate",
            "perm": "rw"
        },
        {
            "cmd": "restful restart",
            "desc": "Restart API server",
            "perm": "rw"
        },
    ]

    def __init__(self, *args, **kwargs):
        super(Module, self).__init__(*args, **kwargs)
        global instance
        instance = self

        self.requests = []
        self.requests_lock = threading.RLock()

        self.keys = {}
        self.disable_auth = False

        self.server = None

        self.stop_server = False
        self.serve_event = threading.Event()


    def serve(self):
        while not self.stop_server:
            try:
                self._serve()
                self.server.socket.close()
            except:
                self.log.error(str(traceback.format_exc()))

            # Wait and clear the threading event
            self.serve_event.wait()
            self.serve_event.clear()

    def refresh_keys(self):
        self.keys = {}
        rawkeys = self.get_config_prefix('keys/') or {}
        for k, v in rawkeys.iteritems():
            self.keys[k[5:]] = v  # strip of keys/ prefix

    def _serve(self):
        # Load stored authentication keys
        self.refresh_keys()

        jsonify._instance = jsonify.GenericJSON(
            sort_keys=True,
            indent=4,
            separators=(',', ': '),
        )

        server_addr = self.get_localized_config('server_addr', '::')
        if server_addr is None:
            raise RuntimeError('no server_addr configured; try "ceph config-key set mgr/restful/server_addr <ip>"')
        server_port = int(self.get_localized_config('server_port', '8003'))
        self.log.info('server_addr: %s server_port: %d',
                      server_addr, server_port)

        cert = self.get_localized_config("crt")
        if cert is not None:
            cert_tmp = tempfile.NamedTemporaryFile()
            cert_tmp.write(cert)
            cert_tmp.flush()
            cert_fname = cert_tmp.name
        else:
            cert_fname = self.get_localized_config('crt_file')

        pkey = self.get_localized_config("key")
        if pkey is not None:
            pkey_tmp = tempfile.NamedTemporaryFile()
            pkey_tmp.write(pkey)
            pkey_tmp.flush()
            pkey_fname = pkey_tmp.name
        else:
            pkey_fname = self.get_localized_config('key_file')

        if not cert_fname or not pkey_fname:
            raise RuntimeError('no certificate configured')
        if not os.path.isfile(cert_fname):
            raise RuntimeError('certificate %s does not exist' % cert_fname)
        if not os.path.isfile(pkey_fname):
            raise RuntimeError('private key %s does not exist' % pkey_fname)

        # Create the HTTPS werkzeug server serving pecan app
        self.server = make_server(
            host=server_addr,
            port=server_port,
            app=make_app(
                root='restful.api.Root',
                hooks = [ErrorHook()],  # use a callable if pecan >= 0.3.2
            ),
            ssl_context=(cert_fname, pkey_fname),
        )

        self.server.serve_forever()


    def shutdown(self):
        try:
            self.stop_server = True
            if self.server:
                self.server.shutdown()
            self.serve_event.set()
        except:
            self.log.error(str(traceback.format_exc()))
            raise


    def restart(self):
        try:
            if self.server:
                self.server.shutdown()
            self.serve_event.set()
        except:
            self.log.error(str(traceback.format_exc()))


    def notify(self, notify_type, tag):
        try:
            self._notify(notify_type, tag)
        except:
            self.log.error(str(traceback.format_exc()))


    def _notify(self, notify_type, tag):
        if notify_type == "command":
            # we can safely skip all the sequential commands
            if tag == 'seq':
                return

            request = filter(
                lambda x: x.is_running(tag),
                self.requests)

            if len(request) != 1:
                self.log.warn("Unknown request '%s'" % str(tag))
                return

            request = request[0]
            request.finish(tag)
            if request.is_ready():
                request.next()
        else:
            self.log.debug("Unhandled notification type '%s'" % notify_type)


    def create_self_signed_cert(self):
        # create a key pair
        pkey = crypto.PKey()
        pkey.generate_key(crypto.TYPE_RSA, 2048)

        # create a self-signed cert
        cert = crypto.X509()
        cert.get_subject().O = "IT"
        cert.get_subject().CN = "ceph-restful"
        cert.set_serial_number(int(uuid4()))
        cert.gmtime_adj_notBefore(0)
        cert.gmtime_adj_notAfter(10*365*24*60*60)
        cert.set_issuer(cert.get_subject())
        cert.set_pubkey(pkey)
        cert.sign(pkey, 'sha512')

        return (
            crypto.dump_certificate(crypto.FILETYPE_PEM, cert),
            crypto.dump_privatekey(crypto.FILETYPE_PEM, pkey)
        )


    def handle_command(self, command):
        self.log.warn("Handling command: '%s'" % str(command))
        if command['prefix'] == "restful create-key":
            if command['key_name'] in self.keys:
                return 0, self.keys[command['key_name']], ""

            else:
                key = str(uuid4())
                self.keys[command['key_name']] = key
                self.set_config('keys/' + command['key_name'], key)

            return (
                0,
                self.keys[command['key_name']],
                "",
            )

        elif command['prefix'] == "restful delete-key":
            if command['key_name'] in self.keys:
                del self.keys[command['key_name']]
                self.set_config('keys/' + command['key_name'], None)

            return (
                0,
                "",
                "",
            )

        elif command['prefix'] == "restful list-keys":
            self.refresh_keys()
            return (
                0,
                json.dumps(self.keys, indent=2),
                "",
            )

        elif command['prefix'] == "restful create-self-signed-cert":
            cert, pkey = self.create_self_signed_cert()

            self.set_config(self.get_mgr_id() + '/crt', cert)
            self.set_config(self.get_mgr_id() + '/key', pkey)

            self.restart()
            return (
                0,
                "Restarting RESTful API server...",
                ""
            )

        elif command['prefix'] == 'restful restart':
            self.restart();
            return (
                0,
                "Restarting RESTful API server...",
                ""
            )

        else:
            return (
                -errno.EINVAL,
                "",
                "Command not found '{0}'".format(command['prefix'])
            )


    def get_doc_api(self, root, prefix=''):
        doc = {}
        for _obj in dir(root):
            obj = getattr(root, _obj)

            if isinstance(obj, RestController):
                doc.update(self.get_doc_api(obj, prefix + '/' + _obj))

        if getattr(root, '_lookup', None) and isinstance(root._lookup('0')[0], RestController):
            doc.update(self.get_doc_api(root._lookup('0')[0], prefix + '/<arg>'))

        prefix = prefix or '/'

        doc[prefix] = {}
        for method in 'get', 'post', 'patch', 'delete':
            if getattr(root, method, None):
                doc[prefix][method.upper()] = inspect.getdoc(getattr(root, method)).split('\n')

        if len(doc[prefix]) == 0:
            del doc[prefix]

        return doc


    def get_mons(self):
        mon_map_mons = self.get('mon_map')['mons']
        mon_status = json.loads(self.get('mon_status')['json'])

        # Add more information
        for mon in mon_map_mons:
            mon['in_quorum'] = mon['rank'] in mon_status['quorum']
            mon['server'] = self.get_metadata("mon", mon['name'])['hostname']
            mon['leader'] = mon['rank'] == mon_status['quorum'][0]

        return mon_map_mons


    def get_osd_pools(self):
        osds = dict(map(lambda x: (x['osd'], []), self.get('osd_map')['osds']))
        pools = dict(map(lambda x: (x['pool'], x), self.get('osd_map')['pools']))
        crush_rules = self.get('osd_map_crush')['rules']

        osds_by_pool = {}
        for pool_id, pool in pools.items():
            pool_osds = None
            for rule in [r for r in crush_rules if r['rule_id'] == pool['crush_rule']]:
                if rule['min_size'] <= pool['size'] <= rule['max_size']:
                    pool_osds = common.crush_rule_osds(self.get('osd_map_tree')['nodes'], rule)

            osds_by_pool[pool_id] = pool_osds

        for pool_id in pools.keys():
            for in_pool_id in osds_by_pool[pool_id]:
                osds[in_pool_id].append(pool_id)

        return osds


    def get_osds(self, pool_id=None, ids=None):
        # Get data
        osd_map = self.get('osd_map')
        osd_metadata = self.get('osd_metadata')

        # Update the data with the additional info from the osd map
        osds = osd_map['osds']

        # Filter by osd ids
        if ids is not None:
            osds = filter(
                lambda x: str(x['osd']) in ids,
                osds
            )

        # Get list of pools per osd node
        pools_map = self.get_osd_pools()

        # map osd IDs to reweight
        reweight_map = dict([
            (x.get('id'), x.get('reweight', None))
            for x in self.get('osd_map_tree')['nodes']
        ])

        # Build OSD data objects
        for osd in osds:
            osd['pools'] = pools_map[osd['osd']]
            osd['server'] = osd_metadata.get(str(osd['osd']), {}).get('hostname', None)

            osd['reweight'] = reweight_map.get(osd['osd'], 0.0)

            if osd['up']:
                osd['valid_commands'] = common.OSD_IMPLEMENTED_COMMANDS
            else:
                osd['valid_commands'] = []

        # Filter by pool
        if pool_id:
            pool_id = int(pool_id)
            osds = filter(
                lambda x: pool_id in x['pools'],
                osds
            )

        return osds


    def get_osd_by_id(self, osd_id):
        osd = filter(
            lambda x: x['osd'] == osd_id,
            self.get('osd_map')['osds']
        )

        if len(osd) != 1:
            return None

        return osd[0]


    def get_pool_by_id(self, pool_id):
        pool = filter(
            lambda x: x['pool'] == pool_id,
            self.get('osd_map')['pools'],
        )

        if len(pool) != 1:
            return None

        return pool[0]


    def submit_request(self, _request, **kwargs):
        request = CommandsRequest(_request)
        with self.requests_lock:
            self.requests.append(request)
        if kwargs.get('wait', 0):
            while not request.is_finished():
                time.sleep(0.001)
        return request


    def run_command(self, command):
        # tag with 'seq' so that we can ingore these in notify function
        result = CommandResult('seq')

        self.send_command(result, 'mon', '', json.dumps(command), 'seq')
        return result.wait()
