import json
import logging
import os
from pathlib import Path
import psutil
import time
import signal
from collections import namedtuple
from dataclasses import dataclass
from typing import Optional, List

from firexapp.events.model import ADDITIONAL_CHILDREN_KEY
from firexapp.submit.uid import Uid

logger = logging.getLogger(__name__)

DEFAULT_FLAME_TIMEOUT = 60 * 60 * 24 * 2

# This structure contains an index by UUID for both ancestors and descendants. This is memory inefficient,
# but makes queries that would involve multiple graph traversals very fast.
# TODO: If further performance enhancements are sought, this structure could be maintained during event receiving
#  so that it isn't re-calculated per task query.
FlameTaskGraph = namedtuple('FlameTaskGraph', ['tasks_by_uuid', 'ancestors_by_uuid', 'descendants_by_uuid'])


@dataclass(frozen=True)
class FlameServerConfig:
    webapp_port: int
    serve_logs_dir: bool
    recording_file: Optional[str]
    extra_task_dump_paths: List[str]
    authed_user_request_path: List[str]


def get_flame_redirect_file_path(root_logs_dir):
    return os.path.join(root_logs_dir, 'flame.html')


def get_flame_debug_dir(root_logs_dir):
    return os.path.join(root_logs_dir, Uid.debug_dirname, 'flame')


def get_flame_pid_file_path(root_logs_dir):
    return os.path.join(get_flame_debug_dir(root_logs_dir), 'flame.pid')


def get_flame_pid(root_logs_dir):
    return int(Path(get_flame_pid_file_path(root_logs_dir)).read_text().strip())


def wait_until(predicate, timeout, sleep_for, *args, **kwargs):
    max_time = time.time() + timeout
    while time.time() < max_time:
        pred_result = predicate(*args, **kwargs)
        if pred_result:
            return pred_result
        time.sleep(sleep_for)
    return predicate(*args, **kwargs)


def wait_until_pid_not_exist(pid, timeout=7, sleep_for=1):
    return wait_until(lambda p: not psutil.pid_exists(p), timeout, sleep_for, pid)


def web_request_ok(url):
    import requests
    try:
        return requests.get(url).ok
    except requests.exceptions.ConnectionError:
        return False


def wait_until_web_request_ok(url, timeout=10, sleep_for=1):
    return wait_until(web_request_ok, timeout, sleep_for, url)


def wait_until_path_exist(path, timeout=7, sleep_for=1):
    return wait_until(os.path.exists, timeout, sleep_for, path)


def json_file_fn(json_file_path, fn):
    if not os.path.isfile(json_file_path):
        return False
    try:
        file_data = json.loads(Path(json_file_path).read_text())
    except (json.decoder.JSONDecodeError, OSError):
        return False
    else:
        return fn(file_data)


def get_rec_file(log_dir):
    return os.path.join(get_flame_debug_dir(log_dir), 'flame.rec')


def find_rec_file(log_dir):
    # Formerly was used for backwards compatability, now an alias for get_rec_file
    return get_rec_file(log_dir)


def get_flame_url(port, hostname=None):
    if hostname is None:
        from socket import gethostname
        hostname = gethostname()
    return 'http://%s:%d' % (hostname, int(port))


class PathNotFoundException(Exception):
    pass


def find(keys, input_dict, raise_error=False):
    result = input_dict
    for key in keys:
        try:
            result = result[key]
        except Exception:
            if raise_error:
                raise PathNotFoundException()
            return None
    return result


def filter_paths(input_dict, paths_to_values):
    results = {}
    for in_key, in_vals in input_dict.items():
        results[in_key] = []
        for in_val in in_vals:
            matches_all = all(to_equal == find(p, in_val) for p, to_equal in paths_to_values.items())
            if matches_all:
                results[in_key].append(in_val)
    return results


def kill_flame(log_dir, sig=signal.SIGKILL, timeout=10):
    flame_pid = get_flame_pid(log_dir)
    kill_and_wait(flame_pid, sig, timeout)
    return flame_pid


def kill_and_wait(pid, sig=signal.SIGKILL, timeout=10):
    if psutil.pid_exists(pid):
        os.kill(pid, sig)
        wait_until_pid_not_exist(pid, timeout=timeout)
    return not psutil.pid_exists(pid)


def create_rel_symlink(existing_path, symlink, target_is_directory=False):
    rel_new_file = os.path.relpath(existing_path, start=os.path.dirname(symlink))
    os.symlink(rel_new_file, symlink, target_is_directory=target_is_directory)


class BrokerConsumerConfig:

    def __init__(self, max_retry_attempts, receiver_ready_file, terminate_on_complete):
        self.max_retry_attempts = max_retry_attempts
        self.receiver_ready_file = receiver_ready_file
        self.terminate_on_complete = terminate_on_complete


def is_json_file(file_path):
    try:
        json.loads(Path(file_path).read_text())
    except json.decoder.JSONDecodeError:
        return False
    else:
        return True


def _both_instance(o1, o2, _type):
    return isinstance(o1, _type) and isinstance(o2, _type)


def deep_merge(dict1: dict, dict2: dict) -> dict:
    result = dict(dict1)
    for d2_key in dict2:
        if d2_key in dict1:
            v1 = dict1[d2_key]
            v2 = dict2[d2_key]
            if _both_instance(v1, v2, dict):
                result[d2_key] = deep_merge(v1, v2)
            elif _both_instance(v1, v2, list):
                result[d2_key] = v1 + v2
            elif _both_instance(v1, v2, set):
                result[d2_key] = v1.union(v2)
            elif v1 == v2:
                # already the same value in both dicts, take from either.
                result[d2_key] = v1
            else:
                # Both d1 and d2 have entries for d2_key, both entries are not dicts or lists or sets,
                # and the values are not the same. This is a conflict.
                # Overwrite d1's value to simulate dict.update() behaviour.
                result[d2_key] = v2
        else:
            # New key for d1, just add it.
            result[d2_key] = dict2[d2_key]
    return result


def _validate_task_queries(task_representation):
    if not isinstance(task_representation, list):
        return False

    missing_criterias = [r for r in task_representation
                         if 'matchCriteria' not in r
                            or not isinstance(r['matchCriteria'], dict)]
    if missing_criterias:
        return False

    # TODO: validate matchCriteria themselves

    return True


def _normalize_criteria_key(k):
    return k[1:] if k.startswith('?') else k


def task_matches_criteria(task: dict, criteria: dict):
    if criteria['type'] == 'all':
        return True

    if criteria['type'] == 'always-select-fields':
        # always-select-fields doesn't cause matches (tasks to be included), but paths here are always included
        # in results.
        return False

    if criteria['type'] == 'equals':
        criteria_val = criteria['value']
        # TODO: if more adjusting qualifiers are added, this needs to be reworked.
        required_keys = {k for k in criteria_val.keys() if not k.startswith('?')}
        optional_keys = {_normalize_criteria_key(k) for k in criteria_val.keys() if k.startswith('?')}

        present_required_keys = required_keys.intersection(task.keys())
        if len(required_keys) != len(present_required_keys):
            return False

        present_optional_keys = optional_keys.intersection(task.keys())
        normalized_criteria = {_normalize_criteria_key(k): v for k, v in criteria_val.items()}
        for k in present_required_keys.union(present_optional_keys):
            if task[k] != normalized_criteria[k]:
                return False

        return True

    return False


def _create_dict_with_path_val(path_list, val):
    r = {}
    lastest_dict = r
    for i, e in enumerate(path_list):
        is_last = i == len(path_list) - 1
        if is_last:
            lastest_dict[e] = val
        else:
            lastest_dict[e] = {}
            lastest_dict = lastest_dict[e]
    return r


def _get_paths_from_task(paths, task):
    r = {}
    for path in paths:
        try:
            path_list = path.split('.')
            val = find(path_list, task, raise_error=True)
        except PathNotFoundException:
            # Don't update the results dict if the current task doesn't have the path.
            pass
        else:
            r = deep_merge(r, _create_dict_with_path_val(path_list, val))
    return r


def _get_descendants_for_criteria(select_paths, descendant_criteria, ancestor_uuid, task_graph: FlameTaskGraph):
    ancestor_descendants = task_graph.descendants_by_uuid.get(ancestor_uuid, set())
    matched_descendants_by_uuid = {}
    for criteria in descendant_criteria:
        for descendant in ancestor_descendants:
            if task_matches_criteria(descendant, criteria):
                # Need no_descendants=True to prevent infinite loops.
                # The fields that are selected for each descendant are determined by all queries, except
                # descendant descendants are never included.
                matched_descendants_by_uuid[descendant['uuid']] = select_from_task(
                    select_paths,
                    [],  # Never include descendants in descendant queries to avoid infinite loop.
                    descendant,
                    task_graph)

    return matched_descendants_by_uuid


def select_from_task(select_paths, select_descendants, task, task_graph: FlameTaskGraph):
    selected_dict = {}
    paths_update_dict = _get_paths_from_task(select_paths, task)
    selected_dict.update(paths_update_dict)

    selected_descendants_by_uuid = _get_descendants_for_criteria(select_paths, select_descendants, task['uuid'],
                                                                 task_graph)
    if selected_descendants_by_uuid:
        selected_dict.update({'descendants': selected_descendants_by_uuid})

    return selected_dict


def flatten(l):
    return [item for sublist in l for item in sublist]


def get_always_select_fields(task_queries):
    return flatten([q.get('selectPaths', []) for q in task_queries
                    if q['matchCriteria']['type'] == 'always-select-fields'])


def select_ancestor_of_task_descendant_match(uuid, query, select_paths, task_graph: FlameTaskGraph):
    # Should the current task be included in the result because it matches some descendant criteria?
    task = task_graph.tasks_by_uuid[uuid]
    matching_criteria = [criteria for criteria in query.get('selectDescendants', [])
                         if task_matches_criteria(task, criteria)]
    if matching_criteria:
        # The current task matches some descendant criteria. Confirm that some ancestor matches the top-level
        # criteria.
        ancestor = next((a for a in task_graph.ancestors_by_uuid[uuid]
                         if task_matches_criteria(a, query['matchCriteria'])), None)
        if ancestor:
            # The current task and its ancestor should be included in the result.
            return ancestor['uuid'], select_from_task(select_paths, matching_criteria, ancestor, task_graph)
    return None, {}


def _get_children_by_uuid(tasks_by_uuid):
    children_by_uuid = {}
    for u, t in tasks_by_uuid.items():
        if u not in children_by_uuid:
            # Ensure every UUID has an entry in the result, even UUIDs with no children.
            children_by_uuid[u] = []

        # TODO: consider handling tasks with no 'parent_id' differently from tasks with None 'parent_id',
        #   since the latter case is the root task and the former seems inexplicable.
        parent_id = t.get('parent_id')
        if parent_id is not None:
            if parent_id not in children_by_uuid:
                children_by_uuid[parent_id] = []
            children_by_uuid[parent_id].append(t)

    return children_by_uuid


def _create_task_graph(tasks_by_uuid) -> FlameTaskGraph:
    children_by_uuid = _get_children_by_uuid(tasks_by_uuid)
    descendant_uuids_by_uuid = {}
    ancestor_uuids_by_uuid = {}
    root_task = next((t for t in tasks_by_uuid.values() if t['parent_id'] is None), None)
    if root_task:
        tasks_to_check = [root_task]
        while tasks_to_check:
            cur_task = tasks_to_check.pop()

            if cur_task['uuid'] not in ancestor_uuids_by_uuid:
                ancestor_uuids_by_uuid[cur_task['uuid']] = set()
            cur_task_ancestor_uuids = ancestor_uuids_by_uuid[cur_task['uuid']]

            # The task tree is being walked top-down, so it's safe to expect ancestors to be populated.
            if (cur_task.get('parent_id') is not None
                and cur_task['parent_id'] in ancestor_uuids_by_uuid):
                # This task's ancestors are its parent's ancestors plus its parent.
                ancestor_uuids = ancestor_uuids_by_uuid[cur_task['parent_id']].union([cur_task['parent_id']])
                cur_task_ancestor_uuids.update(ancestor_uuids)

            descendant_uuids_by_uuid[cur_task['uuid']] = set()
            for ancestor_uuid in cur_task_ancestor_uuids:
                descendant_uuids_by_uuid[ancestor_uuid].add(cur_task['uuid'])

            # traverse the graph via real children only, not additional_children.
            tasks_to_check.extend(children_by_uuid[cur_task['uuid']])

    #
    # now that descendant_uuids_by_uuid is populated, add ancestors/descedants
    # from additional children.
    #
    additional_children_uuids_by_uuid = {
        u: t[ADDITIONAL_CHILDREN_KEY] for u, t in tasks_by_uuid.items()
        if ADDITIONAL_CHILDREN_KEY in t
    }
    for cur_uuid, additional_children_uuids in additional_children_uuids_by_uuid.items():
        cur_task_ancestor_uuids = ancestor_uuids_by_uuid[cur_uuid]

        for additional_child_uuid in additional_children_uuids:
            if additional_child_uuid in ancestor_uuids_by_uuid:
                # additional_child_uuid should be in ancestor_uuids_by_uuid as long as graph is connected
                # via non-additional parent/child relationships.
                # Could assert, but it's always possible we miss events that complete the graph.
                ancestor_uuids_by_uuid[additional_child_uuid].update(cur_task_ancestor_uuids)

            add_desc_uuids = cur_task_ancestor_uuids.union({cur_uuid})
            for add_desc_uuid in add_desc_uuids:
                # Add this additional child UUID and all of its descedants to
                # this ancestor
                if add_desc_uuid in descendant_uuids_by_uuid:
                    # add_desc_uuid should be in descendant_uuids_by_uuid as long as graph is connected
                    # via non-additional parent/child relationships.
                    # Could assert, but it's always possible we miss events that complete the graph.
                    descendant_uuids_by_uuid[add_desc_uuid].add(additional_child_uuid)
                    descendant_uuids_by_uuid[add_desc_uuid].update(
                        descendant_uuids_by_uuid.get(additional_child_uuid, set())
                    )

    ancestors_by_uuid = {u: [tasks_by_uuid[au] for au in ancestor_uuids if au in tasks_by_uuid]
                         for u, ancestor_uuids in ancestor_uuids_by_uuid.items()}
    descendants_by_uuid = {u: [tasks_by_uuid[du] for du in descendant_uuids if du in tasks_by_uuid]
                           for u, descendant_uuids in descendant_uuids_by_uuid.items()}
    return FlameTaskGraph(tasks_by_uuid, ancestors_by_uuid, descendants_by_uuid)


def select_data_for_matches(task_uuid, task_queries, task_graph: FlameTaskGraph, match_descendant_criteria):
    result_tasks_by_uuid = {}
    always_select_fields = get_always_select_fields(task_queries)
    for query in task_queries:
        task = task_graph.tasks_by_uuid[task_uuid]
        matches_criteria = task_matches_criteria(task, query['matchCriteria'])
        select_paths = always_select_fields + query.get('selectPaths', [])
        updates_by_uuid = {}
        if matches_criteria:
            updates_by_uuid[task_uuid] = select_from_task(select_paths, query.get('selectDescendants', []), task,
                                                          task_graph)

        if match_descendant_criteria:
            uuid, task_update = select_ancestor_of_task_descendant_match(task_uuid, query, select_paths, task_graph)
            if uuid:
                updates_by_uuid[uuid] = task_update

        if updates_by_uuid:
            result_tasks_by_uuid = deep_merge(result_tasks_by_uuid, updates_by_uuid)

    return result_tasks_by_uuid


def _query_flame_tasks(task_uuids_to_query, task_queries, all_tasks_by_uuid, match_descendant_criteria):
    if not _validate_task_queries(task_queries):
        return {}

    task_graph = _create_task_graph(all_tasks_by_uuid)
    result_tasks_by_uuid = {}
    for uuid in task_uuids_to_query:
        selected_tasks_by_uuid = select_data_for_matches(uuid, task_queries, task_graph, match_descendant_criteria)
        result_tasks_by_uuid = deep_merge(result_tasks_by_uuid, selected_tasks_by_uuid)

    return result_tasks_by_uuid


def query_full_tasks(all_tasks_by_uuid, task_queries):
    # When querying a full set of tasks, descendants will be included when their ancestors are matched.
    return _query_flame_tasks(all_tasks_by_uuid.keys(), task_queries, all_tasks_by_uuid,
                              match_descendant_criteria=False)


def query_partial_tasks(task_uuids_to_query, task_queries, all_tasks_by_uuid):
    # When querying a partial set of tasks, count descendants as matches to be included in the result.
    return _query_flame_tasks(task_uuids_to_query, task_queries, all_tasks_by_uuid,
                              match_descendant_criteria=True)


def get_dict_json_md5(query_config):
    import hashlib
    return hashlib.md5(json.dumps(query_config, sort_keys=True).encode('utf-8')).hexdigest()
