import time
import json
from collections import defaultdict


class EventJournal:

    def __init__(self):
        # immutable append-only log
        self.events = []

        # indexed views for fast debug queries
        self.by_action = defaultdict(list)
        self.by_node = defaultdict(list)

    # -----------------------------
    # WRITE EVENT
    # -----------------------------
    def record(self, event_type, payload):

        event = {
            "ts": time.time(),
            "type": event_type,
            "data": payload
        }

        self.events.append(event)

        if "action" in payload:
            self.by_action[payload["action"]].append(event)

        if "node" in payload:
            self.by_node[payload["node"]].append(event)

    # -----------------------------
    # QUERY ACTION TRACE
    # -----------------------------
    def trace_action(self, action_name):
        return self.by_action.get(action_name, [])

    # -----------------------------
    # QUERY NODE TRACE
    # -----------------------------
    def trace_node(self, node_name):
        return self.by_node.get(node_name, [])

    # -----------------------------
    # FULL REPLAY STREAM
    # -----------------------------
    def replay(self):
        for event in sorted(self.events, key=lambda e: e["ts"]):
            yield event